Comparative study of SOS2 and a novel PMP3-1 gene expression in two sunflower (Helianthus annuus L.) lines differing in salt tolerance.

PubMed

Saadia, Mubshara; Jamil, Amer; Ashraf, Muhammad; Akram, Nudrat Aisha

2013-06-01

Gene expression pattern of two important regulatory proteins, salt overly sensitive 2 (SOS2) and plasma membrane protein 3-1 (PMP3-1), involved in ion homeostasis, was analyzed in two salinity-contrasting sunflower (Helianthus annuus L.) lines, Hysun-38 (salt tolerant) and S-278 (moderately salt tolerant). The pattern was studied at selected time intervals (24 h) under 150 mM NaCl treatment. Using reverse transcription PCR, SOS2 gene fragment was obtained from young leaf and root tissues of opposing lines while that for PMP3-1 was obtained only from young root tissues. Both tolerant and moderately tolerant lines showed a gradual increase in SOS2 expression in sunflower root tissues. Leaf tissues showed the gradually increasing pattern of SOS2 expression in tolerant plants as compared to that for moderately tolerant ones that showed a relatively lower level of expression for this gene. We found the highest level of PMP 3-1 expression in the roots of tolerant sunflower line at 6 and 12 h postsalinity treatment. The moderately tolerant line showed higher expression of PMP3-1 at 12 and 24 h after salt treatment. Overall, the expression of genes for both the regulator proteins varied significantly in the two sunflower lines differing in salinity tolerance.

Leaf and root C-to-N ratios are poor predictors of soil microbial biomass C and respiration across 32 tree species.

PubMed

Ferlian, Olga; Wirth, Christian; Eisenhauer, Nico

2017-11-01

Soil microorganisms are the main primary decomposers of plant material and drive biogeochemical processes like carbon and nitrogen cycles. Hence, knowledge of their nutritional demands and limitations for activity and growth is of particular importance. However, potential effects of the stoichiometry of soil and plant species on soil microbial activity and carbon use efficiency are poorly understood. Soil properties and plant traits are assumed to drive microbial carbon and community structure. We investigated the associations between C and N concentrations of leaf, root, and soil as well as their ratios and soil microbial biomass C and activity (microbial basal respiration and specific respiratory quotient) across 32 young native angiosperm tree species at two locations in Central Germany. Correlations between C:N ratios of leaves, roots, and soil were positive but overall weak. Only regressions between root and leaf C:N ratios as well as between root and soil C:N ratios were significant at one site. Soil microbial properties differed significantly between the two sites and were significantly correlated with soil C:N ratio across sites. Soil C concentrations rather than N concentrations drove significant effects of soil C:N ratio on soil microbial properties. No significant correlations between soil microbial properties and leaf as well as root C:N ratios were found. We found weak correlations of C:N ratios between plant aboveground and belowground tissues. Furthermore, microorganisms were not affected by the stoichiometry of plant tissues in the investigated young trees. The results suggest that soil stoichiometry represents a consistent determinant of soil microbial biomass and respiration. Our study indicates that stoichiometric relationships among tree organs can be weak and poor predictors of soil microbial properties in young tree stands. Further research in controlled experimental settings with a wide range of tree species is needed to study the role of plant chemical traits like the composition and stoichiometry of root exudates in determining interactions between above- and belowground compartments.

The consequences of alternating diet on performance and food preferences of a specialist leaf beetle.

PubMed

Tremmel, Martin; Müller, Caroline

2013-08-01

The food quality of a given host plant tissue will influence the performance and may also affect the preference behavior of herbivorous animals. As nutrient contents and defense metabolite concentrations can vary significantly between different parts of a plant and change over time, herbivores are potentially confronted with diet differing in quality even when feeding on a single plant individual. Here we investigated to what extent feeding exclusively either on young or old, mature leaves of Brassica rapa or on a mixed diet of young and old leaves offered in alternating order affects the larval performance, food consumption, and the host preference behavior of adult mustard leaf beetles, Phaedon cochleariae. Analyzing different leaf quality traits, we found lower water contents, no changes in C:N ratio but more than threefold higher glucosinolate concentrations in young compared to old leaves. Individuals reared on mixed diet performed as well as animals reared on young leaves. Thus, compared to animals feeding exclusively on highly nutritious young leaves, diet-mixing individuals may balance the lower nutrient intake by a dilution of adverse secondary metabolites. Alternatively, they may integrate over the variation in their food, using a previously assimilated resource for growth at times of scarcity. Animals reared on old leaves grew less and had a prolonged larval developmental time, although they showed increased consumption indicating compensatory feeding. Additionally, we found that experience with a certain diet affected the preference behavior. Whereas individuals reared exclusively on young leaves preferred young over old leaves for feeding and oviposition, we did not find any preferences by animals reared exclusively on old leaves or by females reared on alternating diet. Thus, in contrast to positive feedbacks for animals reared on young leaves, an integrative growth of diet-mixing individuals potentially leads to a lack of feedback during development. Taken together, our results suggest that different diet regimes can lead to comparable performance of mustard leaf beetles but experienced feedbacks may differ and thus convey distinct diet preferences. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous qualitative assessment and quantitative analysis of flavonoids in various tissues of lotus (Nelumbo nucifera) using high performance liquid chromatography coupled with triple quad mass spectrometry.

PubMed

Chen, Sha; Fang, Linchuan; Xi, Huifen; Guan, Le; Fang, Jinbao; Liu, Yanling; Wu, Benhong; Li, Shaohua

2012-04-29

Flavonoid composition and concentration were investigated in 12 different tissues of 'Ti-1' lotus (Nelumbo nucifera) by high performance liquid chromatography equipped with photodiode array detection tandem electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS(n)). A total of 20 flavonoids belonging to six groups (myricetin, quercetin, kaempferol, isohamnetin, diosmetin derivatives) were separated and identified. Myricetin 3-O-galactoside, myricetin 3-O-glucuronide, isorhamnetin 3-O-glucuronide and free aglycone diometin (3',5,7-trihydroxy-4'-methoxyflavone) were first reported in lotus. Flavonoid composition varied largely with tissue type, and diverse compounds (5-15) were found in leaf and flower stalks, flower pistils, seed coats and embryos. Flower tissues including flower petals, stamens, pistils, and, especially, reproductive tissue fruit coats had more flavonoid compounds (15-17) than leaves (12), while no flavonoids were detectable in seed kernels. The flavonoid content of seed embryos was high, 730.95 mg 100g(-1) DW (dry weight). As regards the other tissues, mature leaf pulp (771.79 mg 100 g(-1) FW (fresh weight)) and young leaves (650.67 mg 100 g(-1) FW) had higher total flavonoid amount than flower stamens (359.45 mg 100 g(-1) FW) and flower petals (342.97 mg 100g(-1) FW), while leaf stalks, flower stalks and seed coats had much less total flavonoid (less than 40 mg 100 g(-1) FW). Copyright © 2012 Elsevier B.V. All rights reserved.

Community-weighted mean of leaf traits and divergence of wood traits predict aboveground biomass in secondary subtropical forests.

PubMed

Ali, Arshad; Yan, En-Rong; Chang, Scott X; Cheng, Jun-Yang; Liu, Xiang-Yu

2017-01-01

Subtropical forests are globally important in providing ecological goods and services, but it is not clear whether functional diversity and composition can predict aboveground biomass in such forests. We hypothesized that high aboveground biomass is associated with high functional divergence (FDvar, i.e., niche complementarity) and community-weighted mean (CWM, i.e., mass ratio; communities dominated by a single plant strategy) of trait values. Structural equation modeling was employed to determine the direct and indirect effects of stand age and the residual effects of CWM and FDvar on aboveground biomass across 31 plots in secondary forests in subtropical China. The CWM model accounted for 78, 20, 6 and 2% of the variation in aboveground biomass, nitrogen concentration in young leaf, plant height and specific leaf area of young leaf, respectively. The FDvar model explained 74, 13, 7 and 0% of the variation in aboveground biomass, plant height, twig wood density and nitrogen concentration in young leaf, respectively. The variation in aboveground biomass, CWM of leaf nitrogen concentration and specific leaf area, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf explained by the joint model was 86, 20, 13, 7, 2 and 0%, respectively. Stand age had a strong positive direct effect but low indirect positive effects on aboveground biomass. Aboveground biomass was negatively related to CWM of nitrogen concentration in young leaf, but positively related to CWM of specific leaf area of young leaf and plant height, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf. Leaf and wood economics spectra are decoupled in regulating the functionality of forests, communities with diverse species but high nitrogen conservative and light acquisitive strategies result in high aboveground biomass, and hence, supporting both the mass ratio and niche complementarity hypotheses in secondary subtropical forests. Copyright © 2016 Elsevier B.V. All rights reserved.

The fate of glyphosate in water hyacinth and its physiological and biochemical influences on growth of algae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, Baolong.

Absorption, translocation, distribution, exudation, and guttation of {sup 14}C-glyphosate in water hyacinth (Eichhornia crassipes) were studied. Glyphosphate entered the plant by foliage and solution treatment. Plants were harvested and separated into the following parts: treated leaf blade, treated leaf petiole, young leaf blade, young leaf petiole, old leak blade, old leaf petiole, and root. Each part was extracted with methanol. Treated leaves, which exist only in foliage treatment, were washed with water and chloroform to remove the glyphosate residues. All {sup 14}C counting was made by liquid scintillation spectrometry. Autoradiography was used to locate {sup 14}C-glyphosate after foliage treatment. Resultsmore » indicated that glyphosate can be absorbed from the leaf surface and translocated rapidly through phloem tissues into the whole plant body. The roots of water hyacinth absorbed glyphosate without vertical transport. Guttation of glyphosate occurred in treated leaf tips. Exudation of glyphosate from roots of water hyacinth occurred within 8 hr after foliage treatment. Chlorella vulgaris, Chlamydomonas reihardii, Anabaena cylindrica, and Chroococcus turgidus were used to explore the physiological and biochemical effects of glyphosate on algae. Spectrophotometric assays were performed for algal growth, chlorophyll, carotenoids, phycobiliprotein, carbohydrate, and protein. TLC procedures and an image analyzer were used to detect the metabolites of glyphosate inside algal cells. The common visible symptom of glyphosate toxicity in all algal cells were bleaching effect and reduction of contents of carbohydrate, protein, and pigments. The results highly suggested that glyphosate injured the algal cells by destruction of photosynthetic pigments and resulted in lowering the contents of carbohydrate and protein in algal cells.« less

Response of Solanum tuberosum to Myzus persicae infestation at different stages of foliage maturity.

PubMed

Alvarez, Adriana E; Alberti D'Amato, Anahí M; Tjallingii, W Fred; Dicke, Marcel; Vosman, Ben

2014-12-01

Young leaves of the potato Solanum tuberosum L. cultivar Kardal contain resistance factors to the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) and normal probing behavior is impeded. However, M. persicae can survive and reproduce on mature and senescent leaves of the cv. Kardal plant without problems. We compared the settling of M. persicae on young and old leaves and analyzed the impact of aphids settling on the plant in terms of gene expression. Settling, as measured by aphid numbers staying on young or old leaves, showed that after 21 h significantly fewer aphids were found on the young leaves. At earlier time points there were no difference between young and old leaves, suggesting that the young leaf resistance factors are not located at the surface level but deeper in the tissue. Gene expression was measured in plants at 96 h postinfestation, which is at a late stage in the interaction and in compatible interactions this is long enough for host plant acceptance to occur. In old leaves of cv. Kardal (compatible interaction), M. persicae infestation elicited a higher number of differentially regulated genes than in young leaves. The plant response to aphid infestation included a larger number of genes induced than repressed, and the proportion of induced versus repressed genes was larger in young than in old leaves. Several genes changing expression seem to be involved in changing the metabolic state of the leaf from source to sink. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Effects of defoliation in the developing leaf zone on young Populus Xeuramericana plants. II. Distribution of UC-photosynthate after defoliation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bassman, J.H.; Dickmann, D.I.

Patterns of UC-photosynthate distribution in growth chamber-grown Populus xeuramericana cv. Negrito de Granada were determined 24 h, 3 weeks, and 5 weeks after defoliation in the developing leaf zone. Translocation patterns were determined by exposing leaves below, within, or above the defoliated zone to UCO2 and determining UC distribution within the plant after 48 h. Translocation patterns were altered within 24 h after defoliation. When leaves below or remaining tissue of leaves within the zone of defoliation were exposed to UCO2, a greater percentage of UC-photosynthate was transported to the expanding shoot and lateral branches and less to the rootsmore » in defoliated plants compared to controls. Little difference between defoliated and control plants and UC distribution occurred when new leaves produced subsequent to defoliation were exposed to UCO2. By 5 weeks after defoliation there was little difference in patterns of UC distribution between defoliated and control plants. These results substantiate biomass partitioning data which showed that a single defoliation of young poplar plants did not affect diameter or height growth, whereas leaf growth was stimulated and root growth reduced.« less

Consumption and utilization of experimentally altered corn by southern armyworm: Iron, nitrogen, and cyclic hydroxamates.

PubMed

Manuwoto, S; Scriber, J M

1985-11-01

The effects of differential leaf water, leaf nitrogen and cyclic hydroxamate (DIMBOA) concentrations in corn seedlings were analyzed for a polyphagous insect, the southern armyworm (Spodoptera eridania Cram.). Six different combinations of nutrients and allelochemicals [DIMBOA = 2,4-dihydroxy-7-methoxy(2H)-benzoxazin-3(4H)-one] were generated using two corn genotypes (WF9 and CI3IA) and three fertility regimes (complete nutrient, Fe-deficient, and N-deficient solutions) in the University Biotron. Poorest larval growth was observed in the low-nitrogen treatments (1.2% and 1.7% leaf N) and was the result of both low consumption rates and high metabolic costs (low efficiency of conversion of digested food, ECD). Fastest growth rates were observed forthe larvae fed leaves from the high-nitrogen treatments (4.6% and 4.4% leaf N). It is noteworthy that these treatments also contained the highest concentration of cyclic hydroxamates, which are generally believed to be the primary defensive chemicals mediating resistance against the European corn borer,Ostrinia nubilalis (Hubner). If these hydroxamates do have any deleterious or costly effects (perhaps accounting for a large portion of metabolic expenditures), the high digestibility of the leaf tissue and the increased consumption rates more than compensate, resulting in rapid growth (growth rate = consumption rate × approximate digestibility × efficiency of conversion of the digested food). These studies illustrate that variation in key nutrients and allelochemicals within a single plant species (Zea mays L.) may have significantly different effects upon various potential leaf-chewing caterpillars, such as these armyworms versus corn borers (which cannot handle the cyclic hydroxamates, even if provided with young nutritious leaf tissues).

Structure, inheritance, and expression of hybrid poplar (Populus trichocarpa x Populus deltoides) phenylalanine ammonia-lyase genes.

PubMed Central

Subramaniam, R; Reinold, S; Molitor, E K; Douglas, C J

1993-01-01

A heterologous probe encoding phenylalanine ammonia-lyase (PAL) was used to identify PAL clones in cDNA libraries made with RNA from young leaf tissue of two Populus deltoides x P. trichocarpa F1 hybrid clones. Sequence analysis of a 2.4-kb cDNA confirmed its identity as a full-length PAl clone. The predicted amino acid sequence is conserved in comparison with that of PAL genes from several other plants. Southern blot analysis of popular genomic DNA from parental and hybrid individuals, restriction site polymorphism in PAL cDNA clones, and sequence heterogeneity in the 3' ends of several cDNA clones suggested that PAL is encoded by at least two genes that can be distinguished by HindIII restriction site polymorphisms. Clones containing each type of PAL gene were isolated from a poplar genomic library. Analysis of the segregation of PAL-specific HindIII restriction fragment-length polymorphisms demonstrated the existence of two independently segregating PAL loci, one of which was mapped to a linkage group of the poplar genetic map. Developmentally regulated PAL expression in poplar was analyzed using RNA blots. Highest expression was observed in young stems, apical buds, and young leaves. Expression was lower in older stems and undetectable in mature leaves. Cellular localization of PAL expression by in situ hybridization showed very high levels of expression in subepidermal cells of leaves early during leaf development. In stems and petioles, expression was associated with subepidermal cells and vascular tissues. PMID:8108506

Leaf Responses to Mild Drought Stress in Natural Variants of Arabidopsis1[OPEN

PubMed Central

Clauw, Pieter; Coppens, Frederik; De Beuf, Kristof; Dhondt, Stijn; Van Daele, Twiggy; Maleux, Katrien; Storme, Veronique; Clement, Lieven; Gonzalez, Nathalie; Inzé, Dirk

2015-01-01

Although the response of plants exposed to severe drought stress has been studied extensively, little is known about how plants adapt their growth under mild drought stress conditions. Here, we analyzed the leaf and rosette growth response of six Arabidopsis (Arabidopsis thaliana) accessions originating from different geographic regions when exposed to mild drought stress. The automated phenotyping platform WIWAM was used to impose stress early during leaf development, when the third leaf emerges from the shoot apical meristem. Analysis of growth-related phenotypes showed differences in leaf development between the accessions. In all six accessions, mild drought stress reduced both leaf pavement cell area and number without affecting the stomatal index. Genome-wide transcriptome analysis (using RNA sequencing) of early developing leaf tissue identified 354 genes differentially expressed under mild drought stress in the six accessions. Our results indicate the existence of a robust response over different genetic backgrounds to mild drought stress in developing leaves. The processes involved in the overall mild drought stress response comprised abscisic acid signaling, proline metabolism, and cell wall adjustments. In addition to these known severe drought-related responses, 87 genes were found to be specific for the response of young developing leaves to mild drought stress. PMID:25604532

Quality Matters: Influences of Citrus Flush Physicochemical Characteristics on Population Dynamics of the Asian Citrus Psyllid (Hemiptera: Liviidae)

PubMed Central

Simpson, Catherine R.; Alabi, Olufemi J.; Nelson, Shad D.; Telagamsetty, Srilakshmi; Jifon, John L.

2016-01-01

Studies were conducted to relate the influence of the physical characteristics, leaf nutrient content and phloem sap amino acid concentration of citrus flush shoots on the densities of various Diaphorina citri life stages. Adult D. citri preferentially selected young shoots for feeding and numbers of D. citri immatures were positively correlated with flush shoot softness. Young flush shoots had higher concentrations of macro and micro nutrients relative to mature ones and this was associated with higher densities of all D. citri life stages. All D. citri life stages were positively correlated with higher nitrogen-carbon (N:C), nitrogen:sulfur (N:S) and nitrogen:calcium (N:Ca) ratios in leaf tissue, while densities of adults were negatively related to calcium, manganese and boron levels. Concentrations of total and essential amino acids were highest in phloem sap of young expanding flush shoots in both grapefruit and lemon, but dramatically declined as flush shoots matured. The sulfur-containing amino acids cystine, methionine and taurine occurred only in younger flush shoots. In contrast, cystathionine was only present in phloem sap of mature shoots. These results clearly indicate that young citrus flush shoots are a nutritionally richer diet relative to mature shoots, thus explaining their preference by D. citri for feeding and reproduction. Conversely, tissue hardness and the lower nutritional quality of mature flush shoots may limit oviposition and immature development. The data suggest that both physical characteristics and nutritional composition of flush shoots and their phloem sap are important factors regulating host colonization and behavior of D. citri, and this interaction can impact the dynamics and spread of HLB in citrus groves. PMID:28030637

Tissue-specific patterns of lignification are disturbed in the brown midrib2 mutant of maize (Zea mays L.).

PubMed

Vermerris, W; Boon, J J

2001-02-01

Despite recent progress, several aspects of lignin biosynthesis, including variation in lignin composition between species and between tissues within a given species, are still poorly understood. The analysis of mutants affected in cell wall biosynthesis may help increase the understanding of these processes. We have analyzed the maize brown midrib2 (bm2) mutant, one of the four bm mutants of maize, using pyrolysis-mass spectrometry (Py-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). Vascular tissues from the leaf blade and leaf sheath from different parts of the plant were investigated and compared to the corresponding samples from a wild-type plant of the same genetic background (inbred line A619). Multivariate analysis revealed that the bm2 mutant had reduced amounts of di- and trimeric lignin derivatives, notably species with m/z 272 and m/z 330, and that the ratio of guaiacyl residues to polysaccharides was reduced in the bm2 mutant. In addition, differences in cell wall composition between different parts of the plant (blade versus sheath, young versus old tissue) were much less pronounced in the bm2 mutant. These changes suggest that the functional Bm2 gene is important for the establishment of tissue-specific cell wall composition.

Antidepressant-like effects of young green barley leaf (Hordeum vulgare L.) in the mouse forced swimming test.

PubMed

Yamaura, Katsunori; Nakayama, Noriyuki; Shimada, Maki; Bi, Yuanyuan; Fukata, Hideki; Ueno, Koichi

2012-01-01

Young green barley leaf is one of the richest sources of antioxidants and has been widely consumed for health management in Japan. In this study, we examined whether oral administration of young green barley leaf has an antidepressant effect on the forced swimming test in mice. Mice were individually forced to swim in an open cylindrical container, one hour after oral administration of young green barley leaf (400 or 1000 mg / kg) or imipramine (100 mg / kg). Expression of mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor, and glucocorticoid receptor in the brain was analyzed using real-time quantitative polymerase chain reaction (PCR). There was a significant antidepressant-like effect in the forced swimming test; both 400 and 1000 mg / kg young green barley leaves, as well as the positive control imipramine (100 mg / kg), reduced the immobility duration compared to the vehicle group. The expression of mRNA for NGF detected in the hippocampus immediately after the last swimming test was higher than that in the non-swimming group (Nil). Oral administration of imipramine suppressed this increase to the level of the Nil group. Young green barley leaf (400 and 1000 mg / kg) also showed a moderate decrease in the expression of mRNA for NGF, in a dose-dependent manner. Oral administration of young green barley leaf is able to produce an antidepressant-like effect in the forced swimming test. Consequently it is possible that the antidepressant-like effects of the young green barley leaf are, at least in part, mediated by an inhibition of the increase in the hippocampus levels of NGF.

Acid-soluble nucleotides of pinto bean leaves at different stages of development.

PubMed

Weinstein, L H; McCune, D C; Mancini, J F; van Leuken, P

1969-11-01

Acid-soluble nucleotides of unifoliate leaves of Pinto bean plants (Phaseolus vulgaris L.) were determined at young, mature, and senescent stages of development. At least 25 components could be distinguished on the basis of inorganic phosphorus determinations and 37 or more fractions on the basis of (32)P labeling, with adenosine di- and triphosphates accounting for 60% of the total moles of nucleotide. The total nucleotide P and inorganic P, on a fresh weight basis, decreased about 44% between each stage of leaf development, but decrements in the levels of individual nucleotides varied from this over-all pattern.Minor changes in the relative abundance of the individual nucleotides accompanied aging although the percentage of purine-containing nucleotides decreased with age. Total (32)P activity per leaf in the nucleotide pool increased about 3-fold between the young and mature leaves and decreased slightly as leaves became senescent. In general, the specific activities of the nucleotides increased with increased age and adenosine-, guanosine-, uridine-, and cytidine triphosphates and adenosine diphosphate accounted for approximately 90% of the total activity. The changes in the relative sizes and energy status of the nucleotide pools were not so obvious as the changes in other metabolites that have been reported to accompany aging in leaf tissue.

Combining Metabolic Profiling and Gene Expression Analysis to Reveal the Biosynthesis Site and Transport of Ginkgolides in Ginkgo biloba L.

PubMed Central

Lu, Xu; Yang, Hua; Liu, Xinguang; Shen, Qian; Wang, Ning; Qi, Lian-wen; Li, Ping

2017-01-01

The most unique components of Ginkgo biloba extracts are terpene trilactones (TTLs) including ginkgolides and bilobalide. Study of TTLs biosynthesis has been stagnant in recent years. Metabolic profiling of 40 compounds, including TTLs, flavonoids, and phenolic acids, were globally analyzed in leaf, fibrous root, main root, old stem and young stem extracts of G. biloba. Most of the flavonoids were mainly distributed in the leaf and old stem. Most of phenolic acids were generally distributed among various tissues. The total content of TTLs decreased in the order of the leaf, fibrous root, main root, old stem and young stem. The TTLs were further analyzed in different parts of the main root and old stem. The content of TTLs decreases in the order of the main root periderm, the main root cortex and phloem and the main root xylem. In old stems, the content of TTLs in the cortex and phloem was much higher than both the old stem periderm and xylem. The expression patterns of five key genes in the ginkgolide biosynthetic pathway were measured by real-time quantitative polymerase chain reaction (RT-Q-PCR). Combining metabolic profiling and RT-Q-PCR, the results showed that the fibrous root and main root periderm tissues were the important biosynthesis sites of ginkgolides. Based on the above results, a model of the ginkgolide biosynthesis site and transport pathway in G. biloba was proposed. In this putative model, ginkgolides are synthesized in the fibrous root and main root periderm, and these compounds are then transported through the old stem cortex and phloem to the leaves. PMID:28603534

Inhibitor of striate conditionally suppresses cell proliferation in variegated maize

PubMed Central

Park, Sung Han; Park, Su Hyun; Chin, Hang Gyeong; Cho, Moo Je; Martienssen, Robert A.; Han, Chang-deok

2000-01-01

Since the work done by R.A. Emerson in the 1930s, Inhibitor of striate (Isr) has been recognized as a dose-dependent genetic modifier of variegation in chlorotic leaf striping mutants of maize such as striate2 (sr2). We have shown that Isr specifically inhibits proliferation and differentiation of plastid defective cells in sr2 mutants. Leaf narrowing is due to loss of intermediate veins and ground tissue located at leaf margins, and the few remaining plastid defective cells are of irregular size and aberrant organization. The Isr gene has been cloned by targeted transposon tagging. Isr mRNA is expressed throughout young leaves, but Isr chimeras indicate that the expression of Isr at leaf margins is sufficient to suppress both the lateral expansion of sr2 leaves and the extent of striping. Isr protein appears to encode a chloroplast protein with sequence similarity to a family of bacterial phosphatases involved in carbon catabolite repression or in carbon metabolism. We propose that the action of Isr in nuclear and plastid communication could be triggered by carbon stress. PMID:10783171

Organ-Level Analysis of Idioblast Patterning in Egeria densa Planch. Leaves

PubMed Central

Hara, Takuya; Kobayashi, Emi; Ohtsubo, Kohei; Kumada, Shogo; Kanazawa, Mikako; Abe, Tomoko; Itoh, Ryuuichi D.; Fujiwara, Makoto T.

2015-01-01

Leaf tissues of plants usually contain several types of idioblasts, defined as specialized cells whose shape and contents differ from the surrounding homogeneous cells. The spatial patterning of idioblasts, particularly of trichomes and guard cells, across the leaf epidermis has received considerable attention as it offers a useful biological model for studying the intercellular regulation of cell fate and patterning. Excretory idioblasts in the leaves of the aquatic monocotyledonous plant Egeria densa produced light blue autofluorescence when irradiated with ultraviolet light. The use of epifluorescence microscopy to detect this autofluorescence provided a simple and convenient method for detecting excretory idioblasts and allowed tracking of those cells across the leaf surfaces, enabling quantitative measurement of the clustering and spacing patterns of idioblasts at the whole leaf level. Occurrence of idioblasts was coordinated along the proximal–distal, medial–lateral, and adaxial–abaxial axes, producing a recognizable consensus spatial pattern of idioblast formation among fully expanded leaves. Idioblast clusters, which comprised up to nine cells aligned along the proximal–distal axis, showed no positional bias or regularity in idioblast-forming areas when compared with singlet idioblasts. Up to 75% of idioblasts existed as clusters on every leaf side examined. The idioblast-forming areas varied between leaves, implying phenotypic plasticity. Furthermore, in young expanding leaves, autofluorescence was occasionally detected in a single giant vesicle or else in one or more small vesicles, which eventually grew to occupy a large portion of the idioblast volume as a central vacuole. Differentiation of vacuoles by accumulating the fluorescence substance might be an integral part of idioblast differentiation. Red autofluorescence from chloroplasts was not detected in idioblasts of young expanding leaves, suggesting idioblast differentiation involves an arrest in chloroplast development at a very early stage, rather than transdifferentiation of chloroplast-containing epidermal cells. PMID:25742311

Simplified methods for screening cowpea cultivars for manganese leaf-tissue tolerance. [Vigna unguiculata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wissemeier, A.H.; Horst, W.J.

In cowpea (Vigna unguiculata (L.) Walp.) dark brown speckles on old leaves are typical symptoms of Mn toxicity and indicate Mn sensitivity of leaf tissue. Induction and subsequent quantification of brown Mn speckles in leaf tissues were used to screen cowpea cultivars for Mn leaf-tissue tolerance using three different techniques: (i) leaf cuttings cultured for 22 days in solution culture with 20 {mu}M MnSO{sub 4}, (ii) leaf rings mounted on leaves of intact plants and filled with 500 {mu}M MnSO{sub 4} for 5 days, and (iii) leaf disks floated for 3 days on 500 {mu}M MnSO{sub 4}. Density of brownmore » speckles differed considerably among the six cultivars tested, and was not related to the Mn concentrations of the leaf tissues. There were close relationships between genotypic Mn-toxicity symptom expression and depression of dry matter production of the cultivars at high Mn supply in a long-term sand culture experiment. The floating leaf-disk method is particularly suited for screening large numbers of cowpea cultivars for Mn leaf-tissue tolerance because it requires only 3 days. The ranking of the cultivars for Mn tolerance was highly correlated to Mn tolerance of intact plants.« less

Shear waves in vegetal tissues at ultrasonic frequencies

NASA Astrophysics Data System (ADS)

Fariñas, M. D.; Sancho-Knapik, D.; Peguero-Pina, J. J.; Gil-Pelegrín, E.; Gómez Álvarez-Arenas, T. E.

2013-03-01

Shear waves are investigated in leaves of two plant species using air-coupled ultrasound. Magnitude and phase spectra of the transmission coefficient around the first two orders of the thickness resonances (normal and oblique incidence) have been measured. A bilayer acoustic model for plant leaves (comprising the palisade parenchyma and the spongy mesophyll) is proposed to extract, from measured spectra, properties of these tissues like: velocity and attenuation of longitudinal and shear waves and hence Young modulus, rigidity modulus, and Poisson's ratio. Elastic moduli values are typical of cellular solids and both, shear and longitudinal waves exhibit classical viscoelastic losses. Influence of leaf water content is also analyzed.

Impairment of leaf photosynthesis after insect herbivory or mechanical injury on common milkweed, Asclepias syriaca.

PubMed

Delaney, K J; Haile, F J; Peterson, R K D; Higley, L G

2008-10-01

Insect herbivory has variable consequences on plant physiology, growth, and reproduction. In some plants, herbivory reduces photosynthetic rate (Pn) activity on remaining tissue of injured leaves. We sought to better understand the influence of leaf injury on Pn of common milkweed, Asclepias syriaca (Asclepiadaceae), leaves. Initially, we tested whether Pn reductions occurred after insect herbivory or mechanical injury. We also (1) examined the duration of photosynthetic recovery, (2) compared mechanical injury with insect herbivory, (3) studied the relationship between leaf Pn with leaf injury intensity, and (4) considered uninjured leaf compensatory Pn responses neighboring an injured leaf. Leaf Pn was significantly reduced on mechanically injured or insect-fed leaves in all reported experiments except one, so some factor(s) (cardiac glycoside induction, reproductive investment, and water stress) likely interacts with leaf injury to influence whether Pn impairment occurs. Milkweed tussock moth larval herbivory, Euchaetes egle L. (Arctiidae), impaired leaf Pn more severely than mechanical injury in one experiment. Duration of Pn impairment lasted > 5 d to indicate high leaf Pn sensitivity to injury, but Pn recovery occurred within 13 d in one experiment. The degree of Pn reduction was more severe from E. egle herbivory than similar levels of mechanical tissue removal. Negative linear relationships characterized leaf Pn with percentage tissue loss from single E. egle-fed leaves and mechanically injured leaves and suggested that the signal to trigger leaf Pn impairment on remaining tissue of an injured leaf was amplified by additional tissue loss. Finally, neighboring uninjured leaves to an E. egle-fed leaf had a small (approximately 10%) degree of compensatory Pn to partly offset tissue loss and injured leaf Pn impairment.

Soil compaction effects on water status of ponderosa pine assessed through 13C/12C composition.

PubMed

Gomez, G Armando; Singer, Michael J; Powers, Robert F; Horwath, William R

2002-05-01

Soil compaction is a side effect of forest reestablishment practices resulting from use of heavy equipment and site preparation. Soil compaction often alters soil properties resulting in changes in plant-available water. The use of pressure chamber methods to assess plant water stress has two drawbacks: (1) the measurements are not integrative; and (2) the method is difficult to apply extensively to establish seasonal soil water status. We evaluated leaf carbon isotopic composition (delta13C) as a means of assessing effects of soil compaction on water status and growth of young ponderosa pine (Pinus ponderosa var. ponderosa Dougl. ex Laws) stands across a range of soil textures. Leaf delta13C in cellulose and whole foliar tissue were highly correlated. Leaf delta13C in both whole tissue and cellulose (holocellulose) was up to 1.0 per thousand lower in trees growing in non-compacted (NC) loam or clay soils than in compacted (SC) loam or clay soils. Soil compaction had the opposite effect on leaf delta13C in trees growing on sandy loam soil, indicating that compaction increased water availability in this soil type. Tree growth response to compaction also varied with soil texture, with no effect, a negative effect and a positive effect as a result of compaction of loam, clay and sandy loam soils, respectively. There was a significant correlation between 13C signature and tree growth along the range of soil textures. Leaf delta13C trends were correlated with midday stem water potentials. We conclude that leaf delta13C can be used to measure retrospective water status and to assess the impact of site preparation on tree growth. The advantage of the leaf delta13C approach is that it provides an integrative assessment of past water status in different aged leaves.

Storage effects on genomic DNA in rolled and mature coca leaves.

PubMed

Johnson, Emanuel L; Kim, Soo-Hyung; Emche, Stephen D

2003-08-01

Rolled and mature leaf tissue was harvested from Erythroxylum coca var. coca Lam. (coca) to determine a method for storage that would maintain DNA with high quality and content up to 50 days. Harvesting coca leaf tissue under Andean field conditions often requires storage from 3 to 10 days before extraction where tissue integrity is lost. All samples of rolled and mature coca leaf tissue were harvested and separately stored fresh in RNAlater for 50 days at 4 degrees, -20 degrees, and 23 degrees C, while similar samples were air-dried for 72 h at 23 degrees C or oven-dried for 72 h at 40 degrees C after storage, before extraction. Triplicate samples of each tissue type were extracted for DNA at 10-day intervals and showed that DNA integrity and content were preserved in leaf tissue stored at 4 degrees and -20 degrees C for 50 days. Rolled and mature leaf tissue stored at 4 degrees, -20 degrees, and 23 degrees C showed insignificant degradation of DNA after 10 days, and by day 50, only leaf tissue stored at 4 degrees and -20 degrees C had not significantly degraded. All air- and oven-dried leaf tissue extracts showed degradation upon drying (day 0) and continuous degradation up to day 50, despite storage conditions. Amplified fragment length polymorphism analysis of DNA from rolled and mature leaf tissue of coca stored at 4 degrees and -20 degrees C for 0, 10, and 50 days showed that DNA integrity and content were preserved. We recommend that freshly harvested rolled or mature coca leaf tissue be stored at 4 degrees, -20 degrees, and 23 degrees C for 10 days after harvest, and if a longer storage is required, then store at 4 degrees or -20 degrees C.

Cloning, Expression, and Characterization of Sorbitol Transporters from Developing Sour Cherry Fruit and Leaf Sink Tissues1

PubMed Central

Gao, Zhifang; Maurousset, Laurence; Lemoine, Remi; Yoo, Sang-Dong; van Nocker, Steven; Loescher, Wayne

2003-01-01

The acyclic polyol sorbitol is a primary photosynthetic product and the principal photosynthetic transport substance in many economically important members of the family Rosaceace (e.g. almond [Prunus dulcis (P. Mill.) D.A. Webber], apple [Malus pumila P. Mill.], cherry [Prunus spp.], peach [Prunus persica L. Batsch], and pear [Pyrus communis]). To understand key steps in long-distance transport and particularly partitioning and accumulation of sorbitol in sink tissues, we have cloned two sorbitol transporter genes (PcSOT1 and PcSOT2) from sour cherry (Prunus cerasus) fruit tissues that accumulate large quantities of sorbitol. Sorbitol uptake activities and other characteristics were measured by heterologous expression of PcSOT1 and PcSOT2 in yeast (Saccharomyces cerevisiae). Both genes encode proton-dependent, sorbitol-specific transporters with similar affinities (Km sorbitol of 0.81 mm for PcSOT1 and 0.64 mm for PcSOT2). Analyses of gene expression of these transporters, however, suggest different roles during leaf and fruit development. PcSOT1 is expressed throughout fruit development, but especially when growth and sorbitol accumulation rates are highest. In leaves, PcSOT1 expression is highest in young, expanding tissues, but substantially less in mature leaves. In contrast, PcSOT2 is mainly expressed only early in fruit development and not in leaves. Compositional analyses suggest that transport mediated by PcSOT1 and PcSOT2 plays a major role in sorbitol and dry matter accumulation in sour cherry fruits. Presence of these transporters and the high fruit sorbitol concentrations suggest that there is an apoplastic step during phloem unloading and accumulation in these sink tissues. Expression of PcSOT1 in young leaves before completion of the transition from sink to source is further evidence for a role in determining sink activity. PMID:12692316

Photosynthetic capacity peaks at intermediate size in temperate deciduous trees.

PubMed

Thomas, Sean C

2010-05-01

Studies of age-related changes in leaf functional biology have generally been based on dichotomous comparisons of young and mature individuals (e.g., saplings and mature canopy trees), with little data available to describe changes through the entire ontogeny of trees, particularly of broadleaf angiosperms. Leaf-level gas-exchange and morphological parameters were quantified in situ in the upper canopy of trees acclimated to high light conditions, spanning a wide range of ontogenetic stages from saplings (approximately 1 cm in stem diameter) to trees >60 cm d.b.h. and nearing their maximum lifespan, in three temperate deciduous tree species in central Ontario, Canada. Traits associated with growth performance, including leaf photosynthetic capacity (expressed on either an area, mass or leaf N basis), stomatal conductance, leaf size and leaf N content, generally showed a unimodal ('hump-shaped') pattern, with peak values at an intermediate ontogenetic stage. In contrast, leaf mass per area (LMA) and related morphological parameters (leaf thickness, leaf tissue density, leaf C content) increased monotonically with tree size, as did water-use efficiency; these monotonic relationships were well described by simple allometric functions of the form Y = aX(b). For traits showing unimodal patterns, tree size corresponding to the trait maximum differed markedly among traits: all three species showed a similar pattern in which the peak for leaf size occurred in trees approximately 2-6 cm d.b.h., followed by leaf chemical traits and photosynthetic capacity on a mass or leaf N basis and finally by photosynthetic capacity on a leaf area basis, which peaked approximately at the size of reproductive onset. It is argued that ontogenetic increases in photosynthetic capacity and related traits early in tree ontogeny are general among relatively shade-tolerant tree species that have a low capacity for leaf-level acclimation, as are declines in this set of traits late in tree ontogeny.

Fluorescent Staining of Tea Pathogenic Fungi in Tea Leaves Using Fluorescein-labeled Lectin

NASA Astrophysics Data System (ADS)

Yamada, Kengo; Yoshida, Katsuyuki; Sonoda, Ryoichi

Fluorochrome-labeled lectin, fluorescein conjugated wheat germ agglutinin (F-WGA) was applied to stain tea pathogenic fungi in tea leaf tissue. Infected leaves were fixed and decolorized with a mixture of ethanol and acetic acid, and cleared with 10% KOH for whole mount before staining with F-WGA. Hyphae of Pestalotiopsis longiseta, Pseudocercospora ocellata, Botrytis cinerea and Colletotrichum theae-sinensis fluoresced brightly in whole mount and sectioned samples of infected leaf tissue. In browned tissue, hyphae did not fluoresce frequently in whole mount sample. Autofluorescence of leaf tissue was strong in browned tissue of sections, it was removed by 10% KOH treatment before staining. Penetration hyphae of C. theae-sinensis in cell wall of trichome and hyphae in basal part of trichome did not fluoresced frequently. In whole mount samples of tea leaf infected with Exobasidium vexans and E. reticulatum, hymenia appeared on leaf surface fluoresced, but hyphae in leaf tissue did not fluoresce. In sectioned samples, hyphae fluoresced brightly when sections were treated with 10% KOH before staining.

Carbon Dioxide Metabolism in Leaf Epidermal Tissue 1

PubMed Central

Willmer, C. M.; Pallas, J. E.; Black, C. C.

1973-01-01

A number of plant species were surveyed to obtain pure leaf epidermal tissue in quantity. Commelina communis L. and Tulipa gesnariana L. (tulip) were chosen for further work. Chlorophyll a/b ratios of epidermal tissues were 2.41 and 2.45 for C. communis and tulip, respectively. Phosphoenolpyruvate carboxylase, ribulose-1,5-diphosphate carboxylase, malic enzyme, and NAD+ and NADP+ malate dehydrogenases were assayed with epidermal tissue and leaf tissue minus epidermal tissue. In both species, there was less ribulose 1,5-diphosphate than phosphoenolpyruvate carboxylase activity in epidermal tissue whether expressed on a protein or chlorophyll basis whereas the reverse was true for leaf tissue minus epidermal tissue. In both species, malic enzyme activities were higher in epidermal tissue than in the remaining leaf tissue when expressed on a protein or chlorophyll basis. In both species, NAD+ and NADP+ malate dehydrogenase activities were higher in the epidermal tissue when expressed on a chlorophyll basis; however, on a protein basis, the converse was true. Microautoradiography of C. communis epidermis and histochemical tests for keto acids suggested that CO2 fixation occurred predominantly in the guard cells. The significance and possible location of the enzymes are discussed in relation to guard cell metabolism. Images PMID:16658581

Variation in essential oil composition within individual leaves of sweet basil (Ocimum basilicum L.) is more affected by leaf position than by leaf age.

PubMed

Fischer, Ravit; Nitzan, Nadav; Chaimovitsh, David; Rubin, Baruch; Dudai, Nativ

2011-05-11

The aroma in sweet basil is a factor affecting the commercial value of the crop. In previous studies leaf age was considered to be a factor that influences the composition of essential oil (EO). In this study it was hypothesized that a single observation of the EO content in leaves from different positions on the main stem (young vs old) could predict the developmental changes in the plant during its life cycle. Plants harvested at week 16 demonstrated an exponential increase (R(2) = 0.92) in EO concentration in leaves on the main stem and lateral shoots, indicating higher EO concentrations in younger than in older leaves. Eugenol and methyleugenol predominated (28-77%) in the extract. Eugenol levels were higher in younger leaves (∼53%), and methyl-eugenol levels predominated in older leaves (∼68%). Linalool was lower in mature leaves than in younger leaves. This suggested that eugenol converted into methyleugenol and linalool decreased as leaf mature. However, in weekly monitored plants, the levels of these compounds in the EO had limited variation in the maturing leaf regardless of its position on the stem. This proposed that the EO composition in an individual leaf is mostly affected by the leaf position on the stem and not by its maturation process. Because leaf position is related to plant development, it is probable that the plant's physiological age at the time of leaf formation from the primordial tissue is the factor affecting the EO composition. It was concluded that interpretation of scientific observations should be carried out with caution and that hypotheses should be tested utilizing multifaceted approaches.

Contrasting cDNA-AFLP profiles between crown and leaf tissues of cold-acclimated wheat plants indicate differing regulatory circuitries for low temperature tolerance.

PubMed

Ganeshan, Seedhabadee; Sharma, Pallavi; Young, Lester; Kumar, Ashwani; Fowler, D Brian; Chibbar, Ravindra N

2011-03-01

Low-temperature (LT) tolerance in winter wheat (Triticum aestivum L.) is an economically important but complex trait. Four selected wheat genotypes, a winter hardy cultivar, Norstar, a tender spring cultivar, Manitou and two near-isogenic lines with Vrn-A1 (spring Norstar) and vrn-A1 (winter Manitou) alleles of Manitou and Norstar were cold-acclimated at 6°C and crown and leaf tissues were collected at 0, 2, 14, 21, 35, 42, 56 and 70 days of cold acclimation. cDNA-AFLP profiling was used to determine temporal expression profiles of transcripts during cold-acclimation in crown and leaf tissues, separately to determine if LT regulatory circuitries in crown and leaf tissues could be delineated using this approach. Screening 64 primer combinations identified 4,074 and 2,757 differentially expressed transcript-derived fragments (TDFs) out of which 38 and 16% were up-regulated as compared to 3 and 6% that were down-regulated in crown and leaf tissues, respectively. DNA sequencing of TDFs revealed sequences common to both tissues including genes coding for DEAD-box RNA helicase, choline-phosphate cytidylyltransferase and delta-1-pyrroline carboxylate synthetase. TDF specific to crown tissues included genes coding for phospahtidylinositol kinase, auxin response factor protein and brassinosteroid insensitive 1-associated receptor kinase. In leaf, genes such as methylene tetrahydrofolate reductase, NADH-cytochrome b5 reductase and malate dehydrogenase were identified. However, 30 and 14% of the DNA sequences from the crown and leaf tissues, respectively, were hypothetical or unknown proteins. Cluster analysis of up-, down-regulated and unique TDFs, DNA sequence and real-time PCR validation, infer that mechanisms operating in crown and leaf tissue in response to LT are differently regulated and warrant further studies.

Identification and expression of three new Nicotiana plumbaginifolia genes which encode isoforms of a plasma-membrane H(+)-ATPase, and one of which is induced by mechanical stress.

PubMed

Oufattole, M; Arango, M; Boutry, M

2000-04-01

To analyze in detail the multigene family encoding the plasma-membrane H(+)-ATPase (pma) in Nicotiana plumbaginifolia Viv., five new pma genes (pma 5-9) were isolated. Three of these (pma 6, 8, 9) were fully characterized and classified into new and independent subfamilies. Their cell-type expression was followed by the beta-glucuronidase (gusA) reporter-gene method. While the pma8-gusA transgene was not expressed in transgenic tobacco, expression of the two other transgenes (pma6- and pma9-gusA) was found to be restricted to particular cell types. In the vegetative tissues, pma6-gusA expression was limited to the head cells of the leaf short trichomes, involved in secretion, and to the cortical parenchyma of the young nodes where the developing leaves and axillary flowering stalks join the stem. In the latter tissues, gene expression was enhanced by mechanical stress, suggesting that H(+)-ATPase might be involved in the strength of the tissues and their resistance to mechanical trauma. The pma9-gusA transgene was mainly expressed in the apical meristem of adventitious roots and axillary buds as well as in the phloem tissues of the stem, in which expression depended on the developmental stage. In flowers, pma9-gusA expression was limited to the mature pollen grains and the young fertilized ovules, while that of pma6-gusA was identified in most of the organs. Reverse transcription-polymerase chain reaction of leaf and stem RNA confirmed the expression of pma 6 and 9, while pma8 was found to be expressed in both organs at a lower level. In conclusion, although pma 6 and 9 had a more restricted expression pattern than the previously characterized pma genes, they were nevertheless expressed in cell types in which H(+)-ATPase had not been previously detected.

Newly Identified Wild Rice Accessions Conferring High Salt Tolerance Might Use a Tissue Tolerance Mechanism in Leaf.

PubMed

Prusty, Manas R; Kim, Sung-Ryul; Vinarao, Ricky; Entila, Frederickson; Egdane, James; Diaz, Maria G Q; Jena, Kshirod K

2018-01-01

Cultivated rice ( Oryza sativa L.) is very sensitive to salt stress. So far a few rice landraces have been identified as a source of salt tolerance and utilized in rice improvement. These tolerant lines primarily use Na + exclusion mechanism in root which removes Na + from the xylem stream by membrane Na + and K + transporters, and resulted in low Na + accumulation in shoot. Identification of a new donor source conferring high salt tolerance is imperative. Wild relatives of rice having wide genetic diversity are regarded as a potential source for crop improvement. However, they have been less exploited against salt stress. Here, we simultaneously evaluated all 22 wild Oryza species along with the cultivated tolerant lines including Pokkali, Nona Bokra, and FL478, and sensitive check varieties under high salinity (240 mM NaCl). Based on the visual salt injury score, three species ( O . alta, O . latifolia , and O . coarctata ) and four species ( O . rhizomatis, O . eichingeri, O . minuta , and O . grandiglumis ) showed higher and similar level of tolerance compared to the tolerant checks, respectively. All three CCDD genome species exhibited salt tolerance, suggesting that the CCDD genome might possess the common genetic factors for salt tolerance. Physiological and biochemical experiments were conducted using the newly isolated tolerant species together with checks under 180 mM NaCl. Interestingly, all wild species showed high Na + concentration in shoot and low concentration in root unlike the tolerant checks. In addition, the wild-tolerant accessions showed a tendency of a high tissue tolerance in leaf, low malondialdehyde level in shoot, and high retention of chlorophyll in the young leaves. These results suggest that the wild species employ tissue tolerance mechanism to manage salt stress. Gene expression analyses of the key salt tolerance-related genes suggested that high Na + in leaf of wild species might be affected by OsHKT1;4 -mediated Na + exclusion in leaf and the following Na + sequestration in leaf might be occurring independent of tonoplast-localized OsNHX1. The newly isolated wild rice accessions will be valuable materials for both rice improvement to salinity stress and the study of salt tolerance mechanism in plants.

Distinct palisade tissue development processes promoted by leaf autonomous signalling and long-distance signalling in Arabidopsis thaliana.

PubMed

Munekage, Yuri Nakajima; Inoue, Shio; Yoneda, Yuki; Yokota, Akiho

2015-06-01

Plants develop palisade tissue consisting of cylindrical mesophyll cells located at the adaxial side of leaves in response to high light. To understand high light signalling in palisade tissue development, we investigated leaf autonomous and long-distance signal responses of palisade tissue development using Arabidopsis thaliana. Illumination of a developing leaf with high light induced cell height elongation, whereas illumination of mature leaves with high light increased cell density and suppressed cell width expansion in palisade tissue of new leaves. Examination using phototropin1 phototropin2 showed that blue light signalling mediated by phototropins was involved in cell height elongation of the leaf autonomous response rather than the cell density increase induced by long-distance signalling. Hydrogen peroxide treatment induced cylindrical palisade tissue cell formation in both a leaf autonomous and long-distance manner, suggesting involvement of oxidative signals. Although constitutive expression of transcription factors involved in systemic-acquired acclimation to excess light, ZAT10 and ZAT12, induced cylindrical palisade tissue cell formation, knockout of these genes did not affect cylindrical palisade tissue cell formation. We conclude that two distinct signalling pathways - leaf autonomous signalling mostly dependent on blue light signalling and long-distance signalling from mature leaves that sense high light and oxidative stress - control palisade tissue development in A. thaliana. © 2014 John Wiley & Sons Ltd.

Chemical and mechanical changes during leaf expansion of four woody species of dry Restinga woodland.

PubMed

Schlindwein, C C D; Fett-Neto, A G; Dillenburg, L R

2006-07-01

Young leaves are preferential targets for herbivores, and plants have developed different strategies to protect them. This study aimed to evaluate different leaf attributes of presumed relevance in protection against herbivory in four woody species (Erythroxylum argentinum, Lithrea brasiliensis, Myrciaria cuspidata, and Myrsine umbellata), growing in a dry restinga woodland in southern Brazil. Evaluation of leaf parameters was made through single-point sampling of leaves (leaf mass per area and leaf contents of nitrogen, carbon, and pigments) at three developmental stages and through time-course sampling of expanding leaves (area and strength). Leaves of M. umbellata showed the highest leaf mass per area (LMA), the largest area, and the longest expansion period. On the other extreme, Myrc. cuspidata had the smallest LMA and leaf size, and the shortest expansion period. Similarly to L. brasiliensis, it displayed red young leaves. None of the species showed delayed-greening, which might be related to the high-irradiance growth conditions. Nitrogen contents reduced with leaf maturity and reached the highest values in the young leaves of E. argentinum and Myrc. cuspidata and the lowest in M. umbellata. Each species seems to present a different set of protective attributes during leaf expansion. Myrciaria cuspidata appears to rely mostly on chemical defences to protect its soft leaves, and anthocyanins might play this role at leaf youth, while M. umbellata seems to invest more on mechanical defences, even at early stages of leaf growth, as well as on a low allocation of nitrogen to the leaves. The other species display intermediate characteristics.

Regulation of leaf hydraulics: from molecular to whole plant levels.

PubMed

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (K leaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in K leaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of K leaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.

Leaf trait dissimilarities between Dutch elm hybrids with a contrasting tolerance to Dutch elm disease.

PubMed

Durkovic, Jaroslav; Canová, Ingrid; Lagana, Rastislav; Kucerová, Veronika; Moravcík, Michal; Priwitzer, Tibor; Urban, Josef; Dvorák, Milon; Krajnáková, Jana

2013-02-01

Previous studies have shown that Ophiostoma novo-ulmi, the causative agent of Dutch elm disease (DED), is able to colonize remote areas in infected plants of Ulmus such as the leaf midrib and secondary veins. The objective of this study was to compare the performances in leaf traits between two Dutch elm hybrids 'Groeneveld' and 'Dodoens' which possess a contrasting tolerance to DED. Trait linkages were also tested with leaf mass per area (LMA) and with the reduced Young's modulus of elasticity (MOE) as a result of structural, developmental or functional linkages. Measurements and comparisons were made of leaf growth traits, primary xylem density components, gas exchange variables and chlorophyll a fluorescence yields between mature plants of 'Groeneveld' and 'Dodoens' grown under field conditions. A recently developed atomic force microscopy technique, PeakForce quantitative nanomechanical mapping, was used to reveal nanomechanical properties of the cell walls of tracheary elements such as MOE, adhesion and dissipation. 'Dodoens' had significantly higher values for LMA, leaf tissue thickness variables, tracheary element lumen area (A), relative hydraulic conductivity (RC), gas exchange variables and chlorophyll a fluorescence yields. 'Groeneveld' had stiffer cell walls of tracheary elements, and higher values for water-use efficiency and leaf water potential. Leaves with a large carbon and nutrient investment in LMA tended to have a greater leaf thickness and a higher net photosynthetic rate, but LMA was independent of RC. Significant linkages were also found between the MOE and some vascular traits such as RC, A and the number of tracheary elements per unit area. Strong dissimilarities in leaf trait performances were observed between the examined Dutch elm hybrids. Both hybrids were clearly separated from each other in the multivariate leaf trait space. Leaf growth, vascular and gas exchange traits in the infected plants of 'Dodoens' were unaffected by the DED fungus. 'Dodoens' proved to be a valuable elm germplasm for further breeding strategies.

Leaf spring made of fiber-reinforced resin

NASA Technical Reports Server (NTRS)

Hori, J.

1986-01-01

A leaf spring made of a matrix reinforced by at least two types of reinforcing fibers with different Young's modulus is described in this Japanese patent. At least two layers of reinforcing fibers are formed by partially arranging the reinforcing fibers toward the direction of the thickness of the leaf spring. A mixture of different types of reinforced fibers is used at the area of boundary between the two layers of reinforced fibers. The ratio of blending of each type of reinforced fiber is frequently changed to eliminate the parts where discontinuous stress may be applied to the leaf spring. The objective of this invention is to prevent the rapid change in Young's modulus at the boundary area between each layer of reinforced fibers in the leaf spring.

Exogenous Methyl Jasmonate Treatment Increases Glucosinolate Biosynthesis and Quinone Reductase Activity in Kale Leaf Tissue

PubMed Central

Ku, Kang-Mo; Jeffery, Elizabeth H.; Juvik, John A.

2014-01-01

Methyl jasmonate (MeJA) spray treatments were applied to the kale varieties ‘Dwarf Blue Curled Vates’ and ‘Red Winter’ in replicated field plantings in 2010 and 2011 to investigate alteration of glucosinolate (GS) composition in harvested leaf tissue. Aqueous solutions of 250 µM MeJA were sprayed to saturation on aerial plant tissues four days prior to harvest at commercial maturity. The MeJA treatment significantly increased gluconasturtiin (56%), glucobrassicin (98%), and neoglucobrassicin (150%) concentrations in the apical leaf tissue of these genotypes over two seasons. Induction of quinone reductase (QR) activity, a biomarker for anti-carcinogenesis, was significantly increased by the extracts from the leaf tissue of these two cultivars. Extracts of apical leaf tissues had greater MeJA mediated increases in phenolics, glucosinolate concentrations, GS hydrolysis products, and QR activity than extracts from basal leaf tissue samples. The concentration of the hydrolysis product of glucoraphanin, sulforphane was significantly increased in apical leaf tissue of the cultivar ‘Red Winter’ in both 2010 and 2011. There was interaction between exogenous MeJA treatment and environmental conditions to induce endogenous JA. Correlation analysis revealed that indole-3-carbanol (I3C) generated from the hydrolysis of glucobrassicin significantly correlated with QR activity (r = 0.800, P<0.001). Concentrations required to double the specific QR activity (CD values) of I3C was calculated at 230 µM, which is considerably weaker at induction than other isothiocyanates like sulforphane. To confirm relationships between GS hydrolysis products and QR activity, a range of concentrations of MeJA sprays were applied to kale leaf tissues of both cultivars in 2011. Correlation analysis of these results indicated that sulforaphane, NI3C, neoascorbigen, I3C, and diindolylmethane were all significantly correlated with QR activity. Thus, increased QR activity may be due to combined increases in phenolics (quercetin and kaempferol) and GS hydrolysis product concentrations rather than by individual products alone. PMID:25084454

Bole girdling affects metabolic properties and root, trunk and branch hydraulics of young ponderosa pine trees.

PubMed

Domec, Jean-Christophe; Pruyn, Michele L

2008-10-01

Effects of trunk girdling on seasonal patterns of xylem water status, water transport and woody tissue metabolic properties were investigated in ponderosa pine (Pinus ponderosa Dougl. ex P. Laws.) trees. At the onset of summer, there was a sharp decrease in stomatal conductance (g(s)) in girdled trees followed by a full recovery after the first major rainfall in September. Eliminating the root as a carbohydrate sink by girdling induced a rapid reversible reduction in g(s). Respiratory potential (a laboratory measure of tissue-level respiration) increased above the girdle (branches and upper trunk) and decreased below the girdle (lower trunk and roots) relative to control trees during the growing season, but the effect was reversed after the first major rainfall. The increase in branch respiratory potential induced by girdling suggests that the decrease in g(s) was caused by the accumulation of carbohydrates above the girdle, which is consistent with an observed increase in leaf mass per area in the girdled trees. Trunk girdling did not affect native xylem embolism or xylem conductivity. Both treated and control trunks experienced loss of xylem conductivity ranging from 10% in spring to 30% in summer. Girdling reduced xylem growth and sapwood to leaf area ratio, which in turn reduced branch leaf specific conductivity (LSC). The girdling-induced reductions in g(s) and transpiration were associated with a decrease in leaf hydraulic conductance. Two years after girdling, when root-to-shoot phloem continuity had been restored, girdled trees had a reduced density of new wood, which increased xylem conductivity and whole-tree LSC, but also vulnerability to embolism.

Protein profiling in potato (Solanum tuberosum L.) leaf tissues by differential centrifugation.

PubMed

Lim, Sanghyun; Chisholm, Kenneth; Coffin, Robert H; Peters, Rick D; Al-Mughrabi, Khalil I; Wang-Pruski, Gefu; Pinto, Devanand M

2012-04-06

Foliar diseases, such as late blight, result in serious threats to potato production. As such, potato leaf tissue becomes an important substrate to study biological processes, such as plant defense responses to infection. Nonetheless, the potato leaf proteome remains poorly characterized. Here, we report protein profiling of potato leaf tissues using a modified differential centrifugation approach to separate the leaf tissues into cell wall and cytoplasmic fractions. This method helps to increase the number of identified proteins, including targeted putative cell wall proteins. The method allowed for the identification of 1484 nonredundant potato leaf proteins, of which 364 and 447 were reproducibly identified proteins in the cell wall and cytoplasmic fractions, respectively. Reproducibly identified proteins corresponded to over 70% of proteins identified in each replicate. A diverse range of proteins was identified based on their theoretical pI values, molecular masses, functional classification, and biological processes. Such a protein extraction method is effective for the establishment of a highly qualified proteome profile.

The accumulation and localization of chalcone synthase in grapevine (Vitis vinifera L.).

PubMed

Wang, Huiling; Wang, Wei; Zhan, JiCheng; Yan, Ailing; Sun, Lei; Zhang, Guojun; Wang, Xiaoyue; Ren, Jiancheng; Huang, Weidong; Xu, Haiying

2016-09-01

Chalcone synthase (CHS, E.C.2.3.1.74) is the first committed enzyme in the flavonoid pathway. Previous studies have primarily focused on the cloning, expression and regulation of the gene at the transcriptional level. Little is yet known about the enzyme accumulation, regulation at protein level, as well as its localization in grapevine. In present study, the accumulation, tissue and subcellular localization of CHS in different grapevine tissues (Vitis vinifera L. Cabernet Sauvignon) were investigated via the techniques of Western blotting, immunohistochemical localization, immunoelectron microscopy and confocal microscopy. The results showed that CHS were mainly accumulated in the grape berry skin, leaves, stem tips and stem phloem, correlated with flavonoids accumulation. The accumulation of CHS is developmental dependent in grape berry skin and flesh. Immunohistochemical analysis revealed that CHS were primarily localized in the exocarp and vascular bundles of the fruits during berry development; in palisade, spongy tissues and vascular bundles of the leaves; in the primary phloem and pith ray in the stems; in the growth point, leaf primordium, and young leaves of leaf buds; and in the endoderm and primary phloem of grapevine roots. Furthermore, at the subcellular level, the cell wall, cytoplasm and nucleus localized patterns of CHS were observed in the grapevine vegetative tissue cells. Results above indicated that distribution of CHS in grapevine was organ-specific and tissue-specific. This work will provide new insight for the biosynthesis and regulation of diverse flavonoid compounds in grapevine. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Hypoglycemic activity of polysaccharide fractions containing beta-glucans from extracts of Rhynchelytrum repens (Willd.) C.E. Hubb., Poaceae.

PubMed

De Paula, A C C F F; Sousa, R V; Figueiredo-Ribeiro, R C L; Buckeridge, M S

2005-06-01

Beta-glucans are soluble fibers with physiological functions, such as interference with absorption of sugars and reduction of serum lipid levels. The objective of the present study was to analyze the distribution of beta-glucans in different tissues of the African grass species Rhynchelytrum repens and also to evaluate their hypoglycemic activity. Leaf blades, sheaths, stems, and young leaves of R. repens were submitted to extraction with 4 M KOH. Analysis of the fractions revealed the presence of arabinose, glucose, xylose, and traces of rhamnose and galactose. The presence of beta-glucan in these fractions was confirmed by hydrolyzing the polymers with endo-beta-glucanase from Bacillus subtilis, followed by HPLC analysis of the characteristic oligosaccharides produced. The 4 M KOH fractions from different tissues were subjected to gel permeation chromatography on Sepharose 4B, with separation of polysaccharides with different degrees of polymerization, the highest molecular mass (above 2000 kDa) being found in young leaves. The molecular mass of the leaf blade polymers was similar (250 kDa) to that of maize coleoptile beta-glucan used for comparison. The 4 M KOH fraction injected into rats with streptozotocin-induced diabetes showed hypoglycemic activity, reducing blood sugar to normal levels for approximately 24 h. This performance was better than that obtained with pure beta-glucan from barley, which decreased blood sugar levels for about 4 h. These results suggest that the activity of beta-glucans from R. repens is responsible for the use of this plant extract as a hypoglycemic drug in folk medicine.

Tissue- and environmental response-specific expression of 10 PP2C transcripts in Mesembryanthemum crystallinum.

PubMed

Miyazaki, S; Koga, R; Bohnert, H J; Fukuhara, T

1999-03-01

Ten transcripts (Mpc1-10) homologous to protein phosphatases of the 2C family have been isolated from the halophyte Mesembryanthemum crystallinum (common ice plant). Transcripts range in size from 1.6 to 2.6 kb, and encode proteins whose catalytic domains are between 24% and 62% identical to that of the Arabidopsis PP2C, ABI1. Transcript expression is tissue specific. Two isoforms are present only in roots (Mpc1 and Mpc5), three in young leaves (Mpc6, 8 and 9), two in old leaves (Mpc6 and Mpc8), and two in post-flowering leaves (Mpc8 and Mpc9). Mpc2 is strongly expressed in roots and also in seeds, meristematic tissues and mature flowers. Mpc3 is specific for leaf meristems, and Mpc4 is found in root and leaf meristems. Mpc7 is restricted to meristematic tissues. Mpc10 is only present in mature flowers. Mpc2 (in roots and leaves), Mpc5 (in roots) and Mpc8 (weakly in leaves) are induced by salinity stress and drought conditions with different kinetics in different tissues, but other Mpcs are downregulated by stress. Cold stress (4 degrees C) leads to a decline in Mpc5 and Mp6, but low temperature provoked a long-term (days) increase in Mpc2 levels in leaves and a transient increase (less than 24 h) in roots. Four full-length transcripts have been obtained. In each case, after over-expression in E. coli, the isolated proteins exhibited (Mg2+-dependent, okadeic acid-insensitive) protein phosphatase activity, although activity against 32P-phosphocasein varied among different PP2Cs. Determination of tissue developmental and stress response specificity of PP2C will facilitate functional studies of signal-transducing enzymes in this halophytic organism.

Proteaceae from severely phosphorus-impoverished soils extensively replace phospholipids with galactolipids and sulfolipids during leaf development to achieve a high photosynthetic phosphorus-use-efficiency.

PubMed

Lambers, Hans; Cawthray, Gregory R; Giavalisco, Patrick; Kuo, John; Laliberté, Etienne; Pearse, Stuart J; Scheible, Wolf-Rüdiger; Stitt, Mark; Teste, François; Turner, Benjamin L

2012-12-01

Proteaceae species in south-western Australia occur on severely phosphorus (P)-impoverished soils. They have very low leaf P concentrations, but relatively fast rates of photosynthesis, thus exhibiting extremely high photosynthetic phosphorus-use-efficiency (PPUE). Although the mechanisms underpinning their high PPUE remain unknown, one possibility is that these species may be able to replace phospholipids with nonphospholipids during leaf development, without compromising photosynthesis. For six Proteaceae species, we measured soil and leaf P concentrations and rates of photosynthesis of both young expanding and mature leaves. We also assessed the investment in galactolipids, sulfolipids and phospholipids in young and mature leaves, and compared these results with those on Arabidopsis thaliana, grown under both P-sufficient and P-deficient conditions. In all Proteaceae species, phospholipid levels strongly decreased during leaf development, whereas those of galactolipids and sulfolipids strongly increased. Photosynthetic rates increased from young to mature leaves. This shows that these species extensively replace phospholipids with nonphospholipids during leaf development, without compromising photosynthesis. A considerably less pronounced shift was observed in A. thaliana. Our results clearly show that a low investment in phospholipids, relative to nonphospholipids, offers a partial explanation for a high photosynthetic rate per unit leaf P in Proteaceae adapted to P-impoverished soils. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Growth reduction after defoliation is independent of CO2 supply in deciduous and evergreen young oaks.

PubMed

Schmid, Sandra; Palacio, Sara; Hoch, Günter

2017-06-01

Reduced productivity of trees after defoliation might be caused by limited carbon (C) availability. We investigated the combined effect of different atmospheric CO 2 concentrations (160, 280 and 560 ppm) and early season defoliation on the growth and C reserves (nonstructural carbohydrates (NSC)) of saplings of two oak species with different leaf habits (deciduous Quercus petraea and evergreen Quercus ilex). In both species, higher CO 2 supply significantly enhanced growth. Defoliation had a strong negative impact on growth (stronger for Q. ilex), but the relative reduction of growth caused by defoliation within each CO 2 treatment was very similar across all three CO 2 concentrations. Low CO 2 and defoliation led to decreased NSC tissue concentrations mainly in the middle of the growing season in Q. ilex, but not in Q. petraea. However, also in Q. ilex, NSC increased in woody tissues in defoliated and low-CO 2 saplings towards the end of the growing season. Although the saplings were C limited under these specific experimental conditions, growth reduction after defoliation was not directly caused by C limitation. Rather, growth of trees followed a strong allometric relationship between total leaf area and conductive woody tissue, which did not change across species, CO 2 concentrations and defoliation treatments. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The MADS-box gene SlMBP11 regulates plant architecture and affects reproductive development in tomato plants.

PubMed

Guo, Xuhu; Chen, Guoping; Naeem, Muhammad; Yu, Xiaohu; Tang, Boyan; Li, Anzhou; Hu, Zongli

2017-05-01

MADS-domain proteins are important transcription factors that are involved in many biological processes of plants. In the present study, SlMBP11, a member of the AGL15 subfamily, was cloned in tomato plants (Solanum lycopersicon M.). SlMBP11 is ubiquitously expressed in all of the tissues we examined, whereas the SlMBP11 transcription levels were significantly higher in reproductive tissues than in vegetative tissues. Plants exhibiting increased SlMBP11 levels displayed reduced plant height, leaf size, and internode length as well as a loss of dominance in young seedlings, highly branched growth from each leaf axil, and increased number of nodes and leaves. Moreover, overexpression lines also exhibited reproductive phenotypes, such as those having a shorter style and split ovary, leading to polycarpous fruits, while the wild type showed normal floral organization. In addition, delayed perianth senescence was observed in transgenic tomatoes. These phenotypes were further confirmed by analyzing the morphological, anatomical and molecular features of lines exhibiting overexpression. These results suggest that SlMBP11 plays an important role in regulating plant architecture and reproductive development in tomato plants. These findings add a new class of transcription factors to the group of genes controlling axillary bud growth and illuminate a previously uncharacterized function of MADS-box genes in tomato plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Antidiabetic Effect of Young and Old Ethanolic Leaf Extracts of Vernonia amygdalina: A Comparative Study

PubMed Central

Asante, Du-Bois; Effah-Yeboah, Emmanuel; Barnes, Precious; Abban, Heckel Amoabeng; Ameyaw, Elvis Ofori; Boampong, Johnson Nyarko; Ofori, Eric Gyamerah; Dadzie, Joseph Budu

2016-01-01

The young leaves of Vernonia amygdalina are often utilized as vegetable and for medicinal purpose compared to the old leaves. This study was designed to evaluate and compare the antidiabetic effects between ethanolic leaf extracts of old and young V. amygdalina on streptozotocin (STZ) induced diabetic rat for four weeks. Preliminary screening of both young and old ethanolic extracts revealed the presence of the same phytochemicals except flavonoids which was only present in the old V. amygdalina. Difference in antioxidant power between the young and old leaf extracts was statistically significant (p < 0.05). Both leaf extracts produced a significant (p < 0.05) antihyperglycaemic effect. Also results from treated rats revealed increasing effect in some haematological parameters. Similarly, the higher dose (300 mg/kg) of both extracts significantly (p < 0.05) reduced serum ALT, AST, and ALP levels as compared to the diabetic control rats. Results also showed significant (p < 0.05) decrease in LDL-C and VLDL-C in the extract-treated rats with a corresponding increase in HDL-C, as compared to the diabetic control rats. Moreover histopathological analysis revealed ameliorative effect of pathological insults induced by the STZ in the pancreas, liver, and spleen, most significantly the regeneration of the beta cells of the islets of Langerhans in treated rats. PMID:27294153

Water Potential in Excised Leaf Tissue

PubMed Central

Nelsen, Charles E.; Safir, Gene R.; Hanson, Andrew D.

1978-01-01

Leaf water potential (Ψleaf) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Ψleaf values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Ψleaf values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status. PMID:16660227

Tissue-specific changes of glutamine synthetase activity in oats after rhizosphere infestation by Pseudomonas syringae pv. tabaci. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knight, T.J.; Temple, S.; Sengupta-Gopalan, C.

1996-05-15

Oats (Avena sativa L. lodi) tolerant of rhizosphere infestation by Pseudomonas syringae pv. tabaci when challenged by the pathogen experience tissue-specific alterations of ammonia assimilatory capabilities. Altered ammonia assimilatory potentials between root and leaf tissue result from selective inactivation of glutamine synthetase (GS) by the toxin Tabtoxinine-B-lactam (TBL). Root GS is sensitive and leaf GSs are resistant to TBL inactivation. With prolonged challenge by the pathogen root GS activity decreases but leaf GS specific activity increase. Higher leaf GS activity is due to decreased rates of degradation rather than increased GS synthesis. Higher leaf GS activity and elevated levels ofmore » GS polypeptide appear to result from a limited interaction between GS and TBL leading to the accumulation of a less active but more stable GS holoenzyme. Tolerant challenged oats besides surviving rhizosphere infestation, experience enhanced growth. A strong correlation exists between leaf GS activity and whole plant fresh weight, suggesting that tissue-specific changes in ammonia assimilatory capability provides the plant a more efficient mechanism for uptake and utilization of nitrogen.« less

Regulation of leaf hydraulics: from molecular to whole plant levels

PubMed Central

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in Kleaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of Kleaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales. PMID:23874349

The enigma of effective pathlength for 18O enrichment in leaf water of conifers

NASA Astrophysics Data System (ADS)

Roden, J. S.; Kahmen, A.; Buchmann, N. C.; Siegwolf, R. T.

2013-12-01

The stable isotopes of oxygen (δ18O) in tree ring cellulose provide valuable proxy information about past environments and climate. Mechanistic models have been used to clarify the important drivers of isotope fractionation and help interpret δ18O variation in tree rings. A critical component to these models is an estimate of leaf water enrichment. However, standard models seldom accurately predict 18O enrichment in conifer needles and Péclet corrections often require effective pathlengths (L) that seem unreasonable from the perspective of needle morphology (>0.5 m). To analyze the potential role of path length on the Péclet effect in conifers we carried out experiments in controlled environment chambers. We exposed seedlings of six species of conifer (Abies alba, Larix decidua, Picea abies, Pinus cembra, P. sylvestris, Taxus bacata), that differ in needle morphology, to four different vapor pressure deficits (VPD), in order to modify transpiration rates (E) and leaf water 18O enrichment. Environmental and δ18O data (leaf, stem and chamber water vapor) were collected to parameterize leaf water models. Cross-sections of needles were sampled for an analysis of needle anatomy. Conifer needles have a single strand of vascular tissue making pathlength determinations through anatomical assessments possible. The six species differed in mesophyll distance (measured from endodermis to epidermis) and cell number, with Pinus and Picea species having the shortest distance and Abies and Taxus the longest (flat needle morphology). Other anatomical measures (transfusion distance, cell size etc.) did not differ significantly. A suberized strip was apparent in the endodermis of all species except Taxus and Abies. Conifer needles have a large proportion (from 0.2 to 0.4) of needle cross-sectional area in vascular tissues that may not be subject to evaporative enrichment. As expected, leaf water δ18O and E responded strongly to VPD and standard models (Craig-Gordon) overestimated leaf water δ18O. A single species-specific value for L could not be determined as the fractional difference between modeled and measured leaf water δ18O did not increase with E as theory predicts. Accounting for potentially unenriched water in vascular and transfusion tissues as well as a Péclet correction that allows the value for L to change with E (as in Song et al., 2013) produced accurate predictions of leaf water δ18O. Estimates of L (for a given E) were positively correlated with mean mesophyll thickness, which to our knowledge is the first time L has been related to a leaf anatomical measure. We repeated the experiment using young needles with much higher values for E, and found a continuing trend of reduced fractional difference with E, implying that Péclet corrections may need to be modified to predict conifer needle water over the range of needle phenology and physiology. Our study will help to better quantify effective pathlength and needle water δ18O in conifers, which are some of the most important organisms used for paleoclimate reconstruction.

Comparative Transcriptomics Unravel Biochemical Specialization of Leaf Tissues of Stevia for Diterpenoid Production1

PubMed Central

Kim, Mi Jung; Jin, Jingjing; Zheng, Junshi

2015-01-01

Stevia (Stevia rebaudiana) produces not only a group of diterpenoid glycosides known as steviol glycosides (SGs), but also other labdane-type diterpenoids that may be spatially separated from SGs. However, their biosynthetic routes and spatial distribution in leaf tissues have not yet been elucidated. Here, we integrate metabolome and transcriptome analyses of Stevia to explore the biosynthetic capacity of leaf tissues for diterpenoid metabolism. Tissue-specific chemical analyses confirmed that SGs were accumulated in leaf cells but not in trichomes. On the other hand, Stevia leaf trichomes stored other labdane-type diterpenoids such as oxomanoyl oxide and agatholic acid. RNA sequencing analyses from two different tissues of Stevia provided a comprehensive overview of dynamic metabolic activities in trichomes and leaf without trichomes. These metabolite-guided transcriptomics and phylogenetic and gene expression analyses clearly identified specific gene members encoding enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate pathway and the biosynthesis of steviol or other labdane-type diterpenoids. Additionally, our RNA sequencing analysis uncovered copalyl diphosphate synthase (SrCPS) and kaurene synthase1 (SrKS1) homologs, SrCPS2 and KS-like (SrKSL), which were specifically expressed in trichomes. In vitro and in planta assays showed that unlike SrCPS and SrKS1, SrCPS2 synthesized labda-13-en-8-ol diphosphate and successively catalyzed the formation of manoyl oxide and epi-manoyl oxide in combination with SrKSL. Our findings suggest that Stevia may have evolved to use distinct metabolic pathways to avoid metabolic interferences in leaf tissues for efficient production of diverse secondary metabolites. PMID:26438788

Newly Identified Wild Rice Accessions Conferring High Salt Tolerance Might Use a Tissue Tolerance Mechanism in Leaf

PubMed Central

Prusty, Manas R.; Kim, Sung-Ryul; Vinarao, Ricky; Entila, Frederickson; Egdane, James; Diaz, Maria G. Q.; Jena, Kshirod K.

2018-01-01

Cultivated rice (Oryza sativa L.) is very sensitive to salt stress. So far a few rice landraces have been identified as a source of salt tolerance and utilized in rice improvement. These tolerant lines primarily use Na+ exclusion mechanism in root which removes Na+ from the xylem stream by membrane Na+ and K+ transporters, and resulted in low Na+ accumulation in shoot. Identification of a new donor source conferring high salt tolerance is imperative. Wild relatives of rice having wide genetic diversity are regarded as a potential source for crop improvement. However, they have been less exploited against salt stress. Here, we simultaneously evaluated all 22 wild Oryza species along with the cultivated tolerant lines including Pokkali, Nona Bokra, and FL478, and sensitive check varieties under high salinity (240 mM NaCl). Based on the visual salt injury score, three species (O. alta, O. latifolia, and O. coarctata) and four species (O. rhizomatis, O. eichingeri, O. minuta, and O. grandiglumis) showed higher and similar level of tolerance compared to the tolerant checks, respectively. All three CCDD genome species exhibited salt tolerance, suggesting that the CCDD genome might possess the common genetic factors for salt tolerance. Physiological and biochemical experiments were conducted using the newly isolated tolerant species together with checks under 180 mM NaCl. Interestingly, all wild species showed high Na+ concentration in shoot and low concentration in root unlike the tolerant checks. In addition, the wild-tolerant accessions showed a tendency of a high tissue tolerance in leaf, low malondialdehyde level in shoot, and high retention of chlorophyll in the young leaves. These results suggest that the wild species employ tissue tolerance mechanism to manage salt stress. Gene expression analyses of the key salt tolerance-related genes suggested that high Na+ in leaf of wild species might be affected by OsHKT1;4-mediated Na+ exclusion in leaf and the following Na+ sequestration in leaf might be occurring independent of tonoplast-localized OsNHX1. The newly isolated wild rice accessions will be valuable materials for both rice improvement to salinity stress and the study of salt tolerance mechanism in plants. PMID:29740456

The relationships between leaf economics and hydraulic traits of woody plants depend on water availability.

PubMed

Yin, Qiulong; Wang, Lei; Lei, Maolin; Dang, Han; Quan, Jiaxin; Tian, Tingting; Chai, Yongfu; Yue, Ming

2018-04-15

Leaf economics and hydraulic traits are simultaneously involved in the process of trading water for CO 2 , but the relationships between these two suites of traits remain ambiguous. Recently, Li et al. (2015) reported that leaf economics and hydraulic traits were decoupled in five tropical-subtropical forests in China. We tested the hypothesis that the relationships between economics and hydraulic traits may depend on water availability. We analysed five leaf economics traits, four hydraulic traits and anatomical structures of 47 woody species on the Loess Plateau with poor water availability and compared those data with Li et al. (2015) obtained in tropical-subtropical regions with adequate water. The results showed that plants on the Loess Plateau tend to have higher leaf tissue density (TD), leaf nitrogen concentrations and venation density (VD) and lower stomatal guard cell length (SL) and maximum stomatal conductance to water vapour (g wmax ). VD showed positive correlations with leaf nitrogen concentrations, palisade tissue thickness (PT) and ratio of palisade tissue thickness to spongy tissue thickness (PT/ST). Principal component analysis (PCA) showed a result opposite from those of tropical-subtropical regions: leaf economics and hydraulic traits were coupled on the Loess Plateau. A stable correlation between these two suites of traits may be more cost-effective on the Loess Plateau, where water availability is poor. The correlation of leaf economics and hydraulic traits may be a type of adaptation mechanism in arid conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Leaf Age-Dependent Photoprotective and Antioxidative Response Mechanisms to Paraquat-Induced Oxidative Stress in Arabidopsis thaliana

PubMed Central

Moustaka, Julietta; Tanou, Georgia; Adamakis, Ioannis-Dimosthenis; Eleftheriou, Eleftherios P.; Moustakas, Michael

2015-01-01

Exposure of Arabidopsis thaliana young and mature leaves to the herbicide paraquat (Pq) resulted in a localized increase of hydrogen peroxide (H2O2) in the leaf veins and the neighboring mesophyll cells, but this increase was not similar in the two leaf types. Increased H2O2 production was concomitant with closed reaction centers (qP). Thirty min after Pq exposure despite the induction of the photoprotective mechanism of non-photochemical quenching (NPQ) in mature leaves, H2O2 production was lower in young leaves mainly due to the higher increase activity of ascorbate peroxidase (APX). Later, 60 min after Pq exposure, the total antioxidant capacity of young leaves was not sufficient to scavenge the excess reactive oxygen species (ROS) that were formed, and thus, a higher H2O2 accumulation in young leaves occurred. The energy allocation of absorbed light in photosystem II (PSII) suggests the existence of a differential photoprotective regulatory mechanism in the two leaf types to the time-course Pq exposure accompanied by differential antioxidant protection mechanisms. It is concluded that tolerance to Pq-induced oxidative stress is related to the redox state of quinone A (QA). PMID:26096005

Errors in Measuring Water Potentials of Small Samples Resulting from Water Adsorption by Thermocouple Psychrometer Chambers 1

PubMed Central

Bennett, Jerry M.; Cortes, Peter M.

1985-01-01

The adsorption of water by thermocouple psychrometer assemblies is known to cause errors in the determination of water potential. Experiments were conducted to evaluate the effect of sample size and psychrometer chamber volume on measured water potentials of leaf discs, leaf segments, and sodium chloride solutions. Reasonable agreement was found between soybean (Glycine max L. Merr.) leaf water potentials measured on 5-millimeter radius leaf discs and large leaf segments. Results indicated that while errors due to adsorption may be significant when using small volumes of tissue, if sufficient tissue is used the errors are negligible. Because of the relationship between water potential and volume in plant tissue, the errors due to adsorption were larger with turgid tissue. Large psychrometers which were sealed into the sample chamber with latex tubing appeared to adsorb more water than those sealed with flexible plastic tubing. Estimates are provided of the amounts of water adsorbed by two different psychrometer assemblies and the amount of tissue sufficient for accurate measurements of leaf water potential with these assemblies. It is also demonstrated that water adsorption problems may have generated low water potential values which in prior studies have been attributed to large cut surface area to volume ratios. PMID:16664367

Errors in measuring water potentials of small samples resulting from water adsorption by thermocouple psychrometer chambers.

PubMed

Bennett, J M; Cortes, P M

1985-09-01

The adsorption of water by thermocouple psychrometer assemblies is known to cause errors in the determination of water potential. Experiments were conducted to evaluate the effect of sample size and psychrometer chamber volume on measured water potentials of leaf discs, leaf segments, and sodium chloride solutions. Reasonable agreement was found between soybean (Glycine max L. Merr.) leaf water potentials measured on 5-millimeter radius leaf discs and large leaf segments. Results indicated that while errors due to adsorption may be significant when using small volumes of tissue, if sufficient tissue is used the errors are negligible. Because of the relationship between water potential and volume in plant tissue, the errors due to adsorption were larger with turgid tissue. Large psychrometers which were sealed into the sample chamber with latex tubing appeared to adsorb more water than those sealed with flexible plastic tubing. Estimates are provided of the amounts of water adsorbed by two different psychrometer assemblies and the amount of tissue sufficient for accurate measurements of leaf water potential with these assemblies. It is also demonstrated that water adsorption problems may have generated low water potential values which in prior studies have been attributed to large cut surface area to volume ratios.

Enzyme-Linked Immunosorbent Assay Testing of Shoots Grown In Vitro and the Use of Immunocapture-Reverse Transcription-Polymerase Chain Reaction Improve the Detection of Prunus necrotic ringspot virus in Rose.

PubMed

Moury, B; Cardin, L; Onesto, J P; Candresse, T; Poupet, A

2000-05-01

We developed and evaluated two different methods to improve the detection of the most prevalent virus of rose in Europe, Prunus necrotic ring-spot virus (PNRSV). Immunocapture-reverse transcription-polymerase chain reaction was estimated to be about 100 times more sensitive than double-antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) and showed an equivalent specificity. Based on the observation that PNRSV multiplies actively in young growing tissues (axillary shoots and cuttings), an in vitro culture method allowing rapid (about 15 days) and homogeneous development of dormant axillary buds with high virus titers was standardized. ELISA tests of these young shoots showed, in some cases, a 10(4) to 10(5) increase in sensitivity in comparison to adjacent leaf tissues from the rose mother plants. Between 21 and 98% (depending on the season) more samples were identified as positive by using ELISA on samples from shoot tips grown in vitro rather than on leaves collected directly from the PNRSV-infected mother plants. This simple method of growing shoot tips in vitro improved the confidence in the detection of PNRSV and eliminated problems in sampling appropriate tissues.

Leaf trait dissimilarities between Dutch elm hybrids with a contrasting tolerance to Dutch elm disease

PubMed Central

Ďurkovič, Jaroslav; Čaňová, Ingrid; Lagaňa, Rastislav; Kučerová, Veronika; Moravčík, Michal; Priwitzer, Tibor; Urban, Josef; Dvořák, Miloň; Krajňáková, Jana

2013-01-01

Background and Aims Previous studies have shown that Ophiostoma novo-ulmi, the causative agent of Dutch elm disease (DED), is able to colonize remote areas in infected plants of Ulmus such as the leaf midrib and secondary veins. The objective of this study was to compare the performances in leaf traits between two Dutch elm hybrids ‘Groeneveld’ and ‘Dodoens’ which possess a contrasting tolerance to DED. Trait linkages were also tested with leaf mass per area (LMA) and with the reduced Young's modulus of elasticity (MOE) as a result of structural, developmental or functional linkages. Methods Measurements and comparisons were made of leaf growth traits, primary xylem density components, gas exchange variables and chlorophyll a fluorescence yields between mature plants of ‘Groeneveld’ and ‘Dodoens’ grown under field conditions. A recently developed atomic force microscopy technique, PeakForce quantitative nanomechanical mapping, was used to reveal nanomechanical properties of the cell walls of tracheary elements such as MOE, adhesion and dissipation. Key Results ‘Dodoens’ had significantly higher values for LMA, leaf tissue thickness variables, tracheary element lumen area (A), relative hydraulic conductivity (RC), gas exchange variables and chlorophyll a fluorescence yields. ‘Groeneveld’ had stiffer cell walls of tracheary elements, and higher values for water-use efficiency and leaf water potential. Leaves with a large carbon and nutrient investment in LMA tended to have a greater leaf thickness and a higher net photosynthetic rate, but LMA was independent of RC. Significant linkages were also found between the MOE and some vascular traits such as RC, A and the number of tracheary elements per unit area. Conclusions Strong dissimilarities in leaf trait performances were observed between the examined Dutch elm hybrids. Both hybrids were clearly separated from each other in the multivariate leaf trait space. Leaf growth, vascular and gas exchange traits in the infected plants of ‘Dodoens’ were unaffected by the DED fungus. ‘Dodoens’ proved to be a valuable elm germplasm for further breeding strategies. PMID:23264236

Factors contributing to deep supercooling capability and cold survival in dwarf bamboo (Sasa senanensis) leaf blades.

PubMed

Ishikawa, Masaya; Oda, Asuka; Fukami, Reiko; Kuriyama, Akira

2014-01-01

Wintering Sasa senanensis, dwarf bamboo, is known to employ deep supercooling as the mechanism of cold hardiness in most of its tissues from leaves to rhizomes. The breakdown of supercooling in leaf blades has been shown to proceed in a random and scattered manner with a small piece of tissue surrounded by longitudinal and transverse veins serving as the unit of freezing. The unique cold hardiness mechanism of this plant was further characterized using current year leaf blades. Cold hardiness levels (LT20: the lethal temperature at which 20% of the leaf blades are injured) seasonally increased from August (-11°C) to December (-20°C). This coincided with the increases in supercooling capability of the leaf blades as expressed by the initiation temperature of low temperature exotherms (LTE) detected in differential thermal analyses (DTA). When leaf blades were stored at -5°C for 1-14 days, there was no nucleation of the supercooled tissue units either in summer or winter. However, only summer leaf blades suffered significant injury after prolonged supercooling of the tissue units. This may be a novel type of low temperature-induced injury in supercooled state at subfreezing temperatures. When winter leaf blades were maintained at the threshold temperature (-20°C), a longer storage period (1-7 days) increased lethal freezing of the supercooled tissue units. Within a wintering shoot, the second or third leaf blade from the top was most cold hardy and leaf blades at lower positions tended to suffer more injury due to lethal freezing of the supercooled units. LTE were shifted to higher temperatures (2-5°C) after a lethal freeze-thaw cycle. The results demonstrate that the tissue unit compartmentalized with longitudinal and transverse veins serves as the unit of supercooling and temperature- and time-dependent freezing of the units is lethal both in laboratory freeze tests and in the field. To establish such supercooling in the unit, structural ice barriers such as development of sclerenchyma and biochemical mechanisms to increase the stability of supercooling are considered important. These mechanisms are discussed in regard to ecological and physiological significance in winter survival.

Effects of spring prescribed fire on short-term, leaf-level photosynthesis and water use efficiency in longleaf pine

Treesearch

John K. Jackson; Dylan N. Dillaway; Michael C. Tyree; Mary Anne Sword Sayer

2015-01-01

Fire is a natural and important environmental disturbance influencing the structure, function, and composition of longleaf pine (Pinus palustris Mill.) ecosystems. However, recovery of young pines to leaf scorch may involve changes in leaf physiology, which could influence leaf water-use efficiency (WUE). This work is part of a larger seasonal...

The presence of cutan limits the interpretation of cuticular chemistry and structure: Ficus elastica leaf as an example.

PubMed

Guzmán-Delgado, Paula; Graça, José; Cabral, Vanessa; Gil, Luis; Fernández, Victoria

2016-06-01

Plant cuticles have been traditionally classified on the basis of their ultrastructure, with certain chemical composition assumptions. However, the nature of the plant cuticle may be misinterpreted in the prevailing model, which was established more than 150 years ago. Using the adaxial leaf cuticle of Ficus elastica, a study was conducted with the aim of analyzing cuticular ultrastructure, chemical composition and the potential relationship between structure and chemistry. Gradual chemical extractions and diverse analytical and microscopic techniques were performed on isolated leaf cuticles of two different stages of development (i.e. young and mature leaves). Evidence for the presence of cutan in F. elastica leaf cuticles has been gained after chemical treatments and tissue analysis by infrared spectroscopy and electron microscopy. Significant calcium, boron and silicon concentrations were also measured in the cuticle of this species. Such mineral elements which are often found in plant cell walls may play a structural role and their presence in isolated cuticles further supports the interpretation of the cuticle as the most external region of the epidermal cell wall. The complex and heterogeneous nature of the cuticle, and constraints associated with current analytical procedures may limit the chance for establishing a relationship between cuticle chemical composition and structure also in relation to organ ontogeny. © 2016 Scandinavian Plant Physiology Society.

Effect of pest management system on 'Empire' apple leaf phyllosphere populations

USDA-ARS?s Scientific Manuscript database

The phyllosphere of plant tissues is varied and dynamic. Pest management, time of sampling, proximity to immigration sources, tissue and tissue status such as leaf/fruit age and location within the canopy, and other environmental and biological factors interact to influence the composition and abun...

Water potential in excised leaf tissue: comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley.

PubMed

Nelsen, C E; Safir, G R; Hanson, A D

1978-01-01

Leaf water potential (Psi(leaf)) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi(leaf) values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi(leaf) values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.

Leaf blade versus petiole nutrient tests as predictors of nitrogen, phosphorus, and potassium status of ‘Pinot noir’ grapevines

USDA-ARS?s Scientific Manuscript database

Grape growers rely on tissues tests of leaf blades or petioles for routine monitoring of vine nutritional health and for diagnosing potential nutrient deficiency or toxicity. There has been a long standing debate as to which tissue better reflects the nutrient status of vines. A comparison of leaf b...

Comparative Transcriptomics Unravel Biochemical Specialization of Leaf Tissues of Stevia for Diterpenoid Production.

PubMed

Kim, Mi Jung; Jin, Jingjing; Zheng, Junshi; Wong, Limsoon; Chua, Nam-Hai; Jang, In-Cheol

2015-12-01

Stevia (Stevia rebaudiana) produces not only a group of diterpenoid glycosides known as steviol glycosides (SGs), but also other labdane-type diterpenoids that may be spatially separated from SGs. However, their biosynthetic routes and spatial distribution in leaf tissues have not yet been elucidated. Here, we integrate metabolome and transcriptome analyses of Stevia to explore the biosynthetic capacity of leaf tissues for diterpenoid metabolism. Tissue-specific chemical analyses confirmed that SGs were accumulated in leaf cells but not in trichomes. On the other hand, Stevia leaf trichomes stored other labdane-type diterpenoids such as oxomanoyl oxide and agatholic acid. RNA sequencing analyses from two different tissues of Stevia provided a comprehensive overview of dynamic metabolic activities in trichomes and leaf without trichomes. These metabolite-guided transcriptomics and phylogenetic and gene expression analyses clearly identified specific gene members encoding enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate pathway and the biosynthesis of steviol or other labdane-type diterpenoids. Additionally, our RNA sequencing analysis uncovered copalyl diphosphate synthase (SrCPS) and kaurene synthase1 (SrKS1) homologs, SrCPS2 and KS-like (SrKSL), which were specifically expressed in trichomes. In vitro and in planta assays showed that unlike SrCPS and SrKS1, SrCPS2 synthesized labda-13-en-8-ol diphosphate and successively catalyzed the formation of manoyl oxide and epi-manoyl oxide in combination with SrKSL. Our findings suggest that Stevia may have evolved to use distinct metabolic pathways to avoid metabolic interferences in leaf tissues for efficient production of diverse secondary metabolites. © 2015 American Society of Plant Biologists. All Rights Reserved.

Colonization and Movement of Xanthomonas fragariae in Strawberry Tissues.

PubMed

Wang, Hehe; McTavish, Christine; Turechek, William W

2018-06-01

Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry growing regions worldwide. To better understand how X. fragariae multiplies and moves in strawberry plants, a green fluorescent protein (GFP)-labeled strain was constructed and used to monitor the pathogen's presence in leaf, petiole, and crown tissue with fluorescence microscopy following natural and wound inoculation in three strawberry cultivars. Taqman PCR was used to quantify bacterial densities in these same tissues regardless of the presence of GFP signal. Results showed X. fragariae colonized leaf mesophyll, the top 1 cm portion of the petiole adjacent to the leaf blade, and was occasionally found colonizing xylem vessels down to the middle of the petioles. The colonization of vascular bundles and the limited systemic movement that was observed appeared to be a passive process, of which the frequency increased with wounding and direct infiltration of bacteria into leaf veins. X. fragariae was able to directly enter petioles and colonize the space under the epidermis. Systemic movement of the bacteria into crown and other uninoculated tissues was not detected visually by GFP. However, X. fragariae was occasionally detected in these tissues by qPCR, but at quantities very near the qPCR detection limit. Petiole tissue harboring bacteria introduced either by direct entry through natural openings or wounds, or by systemic movement from infected foliar tissue, likely serves as a main source of initial inoculum in field plantings.

Comparison of total phenolic content, scavenging activity and HPLC-ESI-MS/MS profiles of both young and mature leaves and stems of Andrographis paniculata.

PubMed

Chua, Lee Suan; Yap, Ken Choy; Jaganath, Indu Bala

2013-12-01

The total phenolic content and radical scavenging activity of Andrographis paniculata has been investigated to estimate the amount of phenolic compounds and diterpene lactones, respectively in the plant extracts. The stem extracts exhibited higher total phenolic content and scavenging activity than those of the leaf extracts from both young and mature plants. A range of 19.6-47.8 mg extract of A. paniculata from different parts of the plant is equivalent to the scavenging activity exhibited by one mg of standard Trolox. HPLC-ESI-MS/MS was also used to identify simultaneously the phytochemicals from the leaves and stems of both young and mature plant samples. Of the identified compounds, seven of the sixteen diterpene lactones, three of the six flavonoids, five of the six phenolic acids and two cyclic acids are reported here for the first time for this species. Multivariate statistical approaches such as Hierarchiral Component Analysis (HCA) and Principle Component Analysis (PCA) have clustered the plant extracts into the leaf and stem groups, regardless of plant age. Further classification based on the phytochemical profiles revealed that mostly phenolic acids and flavonoids were from the young leaf extracts, and diterpenoids and their glycosides from the mature leaf extracts. However, the phytochemical profiles for the stems of both young and mature plants were not significantly different as presented in the dendrogram of HCA and the score plot of PCA. The marker for mature plants might be the m/z 557 ion (dihydroxyl dimethyl 19-[(beta-D-glucopyranosyl)oxy]-19-oxo-ent-labda-8(17),13-dien-16,15-olide), whereas the m/z 521 ion (propyl neoandrographolide) could be the marker for leaf extracts.

Vertical leaf mass per area gradient of mature sugar maple reflects both height-driven increases in vascular tissue and light-driven increases in palisade layer thickness.

PubMed

Coble, Adam P; Cavaleri, Molly A

2017-10-01

A key trait used in canopy and ecosystem function modeling, leaf mass per area (LMA), is influenced by changes in both leaf thickness and leaf density (LMA = Thickness × Density). In tall trees, LMA is understood to increase with height through two primary mechanisms: (i) increasing palisade layer thickness (and thus leaf thickness) in response to light and/or (ii) reduced cell expansion and intercellular air space in response to hydrostatic constraints, leading to increased leaf density. Our objective was to investigate within-canopy gradients in leaf anatomical traits in order to understand environmental factors that influence leaf morphology in a sugar maple (Acer saccharum Marshall) forest canopy. We teased apart the effects of light and height on anatomical traits by sampling at exposed and closed canopies that had different light conditions at similar heights. As expected, palisade layer thickness responded strongly to cumulative light exposure. Mesophyll porosity, however, was weakly and negatively correlated with light and height (i.e., hydrostatic gradients). Reduced mesophyll porosity was not likely caused by limitations on cell expansion; in fact, epidermal cell width increased with height. Palisade layer thickness was better related to LMA, leaf density and leaf thickness than was mesophyll porosity. Vein diameter and fraction of vascular tissue also increased with height and LMA, density and thickness, revealing that greater investment in vascular and support tissue may be a third mechanism for increased LMA with height. Overall, decreasing mesophyll porosity with height was likely due to palisade cells expanding into the available air space and also greater investments in vascular and support tissue, rather than a reduction of cell expansion due to hydrostatic constraints. Our results provide evidence that light influences both palisade layer thickness and mesophyll porosity and indicate that hydrostatic gradients influence leaf vascular and support tissues in mature Acer saccharum trees. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Leaf-morphology-assisted selection for resistance to two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations (Dianthus caryophyllus L).

PubMed

Seki, Kousuke

2016-10-01

The development of a cultivar resistant to the two-spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. In the resistant and susceptible plants selected from an inbred population, a difference was recognised in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. The ability of mites to feed on the spongy tissue during an early life stage from hatching to adult emergence was critical. It was possible to select a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

9 CFR 319.702 - Lard, leaf lard.

Code of Federal Regulations, 2012 CFR

2012-01-01

... lard. (a) Lard is the fat rendered from clean and sound edible tissues from swine. The tissues may be... misbranding of the lard. The tissues shall be reasonably free from blood, and shall not include stomachs, livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

9 CFR 319.702 - Lard, leaf lard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... lard. (a) Lard is the fat rendered from clean and sound edible tissues from swine. The tissues may be... misbranding of the lard. The tissues shall be reasonably free from blood, and shall not include stomachs, livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

9 CFR 319.702 - Lard, leaf lard.

Code of Federal Regulations, 2014 CFR

2014-01-01

... lard. (a) Lard is the fat rendered from clean and sound edible tissues from swine. The tissues may be... misbranding of the lard. The tissues shall be reasonably free from blood, and shall not include stomachs, livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

9 CFR 319.702 - Lard, leaf lard.

Code of Federal Regulations, 2013 CFR

2013-01-01

... lard. (a) Lard is the fat rendered from clean and sound edible tissues from swine. The tissues may be... misbranding of the lard. The tissues shall be reasonably free from blood, and shall not include stomachs, livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

9 CFR 319.702 - Lard, leaf lard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... lard. (a) Lard is the fat rendered from clean and sound edible tissues from swine. The tissues may be... misbranding of the lard. The tissues shall be reasonably free from blood, and shall not include stomachs, livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Shengke; Xie, Ruohan; Wang, Haixin

Sedum alfredii is one of a few plant species known to hyperaccumulate cadmium (Cd). Uptake, localization, and tolerance of Cd at cellular levels in shoots were compared in hyperaccumulating (HE) and non-hyperaccumulating (NHE) ecotypes of Sedum alfredii. X-ray fluorescence images of Cd in stems and leaves showed only a slight Cd signal restricted within vascular bundles in the NHEs, while enhanced localization of Cd, with significant tissue- and age-dependent variations, was detected in HEs. In contrast to the vascular-enriched Cd in young stems, parenchyma cells in leaf mesophyll, stem pith and cortex tissues served as terminal storage sites for Cdmore » sequestration in HEs. Kinetics of Cd transport into individual leaf protoplasts of the two ecotypes showed little difference in Cd accumulation. However, far more efficient storage of Cd in vacuoles was apparent in HEs. Subsequent analysis of cell viability and hydrogen peroxide levels suggested that HE protoplasts exhibited higher resistance to Cd than those of NHE protoplasts. These results suggest that efficient sequestration into vacuoles, as opposed to rapid transport into parenchyma cells, is a pivotal process in Cd accumulation and homeostasis in shoots of HE S. alfredii. This is in addition to its efficient root-to-shoot translocation of Cd.« less

Impact of anatomical traits of maize (Zea mays L.) leaf as affected by nitrogen supply and leaf age on bundle sheath conductance.

PubMed

Retta, Moges; Yin, Xinyou; van der Putten, Peter E L; Cantre, Denis; Berghuijs, Herman N C; Ho, Quang Tri; Verboven, Pieter; Struik, Paul C; Nicolaï, Bart M

2016-11-01

The mechanism of photosynthesis in C 4 crops depends on the archetypal Kranz-anatomy. To examine how the leaf anatomy, as altered by nitrogen supply and leaf age, affects the bundle sheath conductance (g bs ), maize (Zea mays L.) plants were grown under three contrasting nitrogen levels. Combined gas exchange and chlorophyll fluorescence measurements were done on fully grown leaves at two leaf ages. The measured data were analysed using a biochemical model of C 4 photosynthesis to estimate g bs . The leaf microstructure and ultrastructure were quantified using images obtained from micro-computed tomography and microscopy. There was a strong positive correlation between g bs and leaf nitrogen content (LNC) while old leaves had lower g bs than young leaves. Leaf thickness, bundle sheath cell wall thickness and surface area of bundle sheath cells per unit leaf area (S b ) correlated well with g bs although they were not significantly affected by LNC. As a result, the increase of g bs with LNC was little explained by the alteration of leaf anatomy. In contrast, the combined effect of LNC and leaf age on S b was responsible for differences in g bs between young leaves and old leaves. Future investigations should consider changes at the level of plasmodesmata and membranes along the CO 2 leakage pathway to unravel LNC and age effects further. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Nitrate Reductase Activity and Polyribosomal Content of Corn (Zea mays L.) Having Low Leaf Water Potentials 1

PubMed Central

Morilla, Camila A.; Boyer, J. S.; Hageman, R. H.

1973-01-01

Desiccation of 8- to 13-day-old seedlings, achieved by withholding nutrient solution from the vermiculite root medium, caused a reduction in nitrate reductase activity of the leaf tissue. Activity declined when leaf water potentials decreased below −2 bars and was 25% of the control at a leaf water potential of −13 bars. Experiments were conducted to determine whether the decrease in nitrate reductase activity was due to reduced levels of nitrate in the tissue, direct inactivation of the enzyme by low leaf water potentials, or to changes in rates of synthesis or decay of the enzyme. Although tissue nitrate content decreased with the onset of desiccation, it did not continue to decline with tissue desiccation and loss of enzyme activity. Nitrate reductase activity recovered when the plants were rewatered with nitrate-free medium, suggesting that the nitrate in the plant was adequate for high nitrate reductase activity. The rate of decay of nitrate reductase activity from desiccated tissue was essentially identical to that of the control, in vivo or in vitro, regardless of the rapidity of desiccation of the tissue. Direct inactivation of the enzyme by the low water potentials was not detected. Polyribosomal content of the tissue declined with the decrease in water potential, prior to the decline in nitrate reductase activity. Changes in ribosomal profiles occurred during desiccation, regardless of whether the tissue had been excised or not and whether desiccation was rapid or slow. Reduction in polyribosomal content did not appear to be associated with changes in ribonuclease activity. Nitrate reductase activity and the polyribosomal content of the tissue recovered upon rewatering, following the recovery in water potential. The increase in polyribosomal content preceded the increase in nitrate reductase activity. Recovery of enzyme activity was prevented by cycloheximide. Based on these results, it appears that nitrate reductase activity was affected primarily by a decrease in the rate of enzyme synthesis at low leaf water potentials. PMID:16658419

A possible link between life and death of a xeric tree in desert.

PubMed

Xu, Gui-Qing; McDowell, Nate G; Li, Yan

2016-05-01

Understanding the interactions between drought and tree ontogeny or size remains an essential research priority because size-specific mortality patterns have large impacts on ecosystem structure and function, determine forest carbon storage capacity, and are sensitive to climatic change. Here we investigate a xerophytic tree species (Haloxylon ammodendron (C.A. Mey.)) with which the changes in biomass allocation with tree size may play an important role in size-specific mortality patterns. Size-related changes in biomass allocation, root distribution, plant water status, gas exchange, hydraulic architecture and non-structural carbohydrate reserves of this xerophytic tree species were investigated to assess their potential role in the observed U-shaped mortality pattern. We found that excessively negative water potentials (<-4.7MPa, beyond the P50leaf of -4.1MPa) during prolonged drought in young trees lead to hydraulic failure; while the imbalance of photoassimilate allocation between leaf and root system in larger trees, accompanied with declining C reserves (<2% dry matter across four tissues), might have led to carbon starvation. The drought-resistance strategy of this species is preferential biomass allocation to the roots to improve water capture. In young trees, the drought-resistance strategy is not well developed, and hydraulic failure appears to be the dominant driver of mortality during drought. With old trees, excess root growth at the expense of leaf area may lead to carbon starvation during prolonged drought. Our results suggest that the drought-resistance strategy of this xeric tree is closely linked to its life and death: well-developed drought-resistance strategy means life, while underdeveloped or overdeveloped drought-resistance strategy means death. Copyright © 2016 Elsevier GmbH. All rights reserved.

Ecology and ecophysiology of tree stems: corticular and wood photosynthesis.

PubMed

Pfanz, H; Aschan, G; Langenfeld-Heyser, R; Wittmann, C; Loose, M

2002-04-01

Below the outer peridermal or rhytidomal layers, most stems of woody plants possess greenish tissues. These chlorophyll-containing tissues (the chlorenchymes) within the stems are able to use the stem internal CO2 and the light penetrating the rhytidome to photoassimilate and produce sugars and starch. Although net photosynthetic uptake of CO2 is rarely found, stem internal re-fixation of CO2 in young twigs and branches may compensate for 60-90% of the potential respiratory carbon loss. Isolated chlorenchymal tissues reveal rather high rates of net photosynthesis (being up to 75% of the respective rates for leaf photosynthesis). Corticular photosynthesis is thus thought to be an effective mechanism for recapturing respiratory carbon dioxide before it diffuses out of the stem. Furthermore, chloroplasts of the proper wood or pith fraction also take part in stem internal photosynthesis. Although there has been no strong experimental evidence until now, we suggest that the oxygen evolved during wood or pith photosynthesis may play a decisive role in avoiding/reducing stem internal anaerobiosis.

Ecology and ecophysiology of tree stems: corticular and wood photosynthesis

NASA Astrophysics Data System (ADS)

Pfanz, H.; Aschan, G.; Langenfeld-Heyser, R.; Wittmann, C.; Loose, M.

2002-03-01

Below the outer peridermal or rhytidomal layers, most stems of woody plants possess greenish tissues. These chlorophyll-containing tissues (the chlorenchymes) within the stems are able to use the stem internal CO2 and the light penetrating the rhytidome to photoassimilate and produce sugars and starch. Although net photosynthetic uptake of CO2 is rarely found, stem internal re-fixation of CO2 in young twigs and branches may compensate for 60-90% of the potential respiratory carbon loss. Isolated chlorenchymal tissues reveal rather high rates of net photosynthesis (being up to 75% of the respective rates for leaf photosynthesis). Corticular photosynthesis is thus thought to be an effective mechanism for recapturing respiratory carbon dioxide before it diffuses out of the stem. Furthermore, chloroplasts of the proper wood or pith fraction also take part in stem internal photosynthesis. Although there has been no strong experimental evidence until now, we suggest that the oxygen evolved during wood or pith photosynthesis may play a decisive role in avoiding/reducing stem internal anaerobiosis.

Leaf chemical changes induced in Populus trichocarpa by enhanced UV-B radiation and concomitant effects on herbivory by Chrysomela scripta (Coleoptera: Chrysomelidae).

PubMed

Warren, Jeffrey M; Bassman, John H; Eigenbrode, Sanford

2002-11-01

To assess the potential impact of enhanced ultraviolet-B (UV-B) radiation over two trophic levels, we monitored key leaf chemical constituents and related changes in their concentration to dietary preference and performance of a specialist insect herbivore. Ramets of Populus trichocarpa Torr. & Gray (black cottonwood) were subjected to near zero (0X), ambient (1X) or twice ambient (2X) doses of biologically effective UV-B radiation (UV-B(BE)) in a randomized block design using either a square-wave (greenhouse) or a modulated (field) lamp system. After a 3-month treatment period, apparent photosynthesis was determined in situ and plants were harvested for biomass determination. Leaf subsamples were analyzed for nitrogen, sulfur, chlorophylls, UV-absorbing compounds and protein-precipitable tannins. Effects of changes in these constituents on feeding by Chrysomela scripta Fab. (cottonwood leaf beetle) were determined by (1) adult feeding preference trials and (2) larval growth rate trials. Enhanced UV-B(BE) radiation had minimal effects on photosynthesis, growth, leaf area and biomass distribution. In the greenhouse study, concentrations of foliar nitrogen and chlorophylls increased, but tannins decreased slightly in young leaves exposed to enhanced UV-B(BE) radiation. There were no significant effects on these parameters in the field study. The concentration of methanol-extractable foliar phenolics increased in plants grown with enhanced UV-B(BE) radiation in both the greenhouse and field studies. In feeding preference trials, adult C. scripta chose 2X-treated tissue almost twice as often as 1X-treated tissue in both greenhouse and field studies, but differences were not statistically significant (P = 0.12). In the field study, first instar larvae grown to adult eclosion on 2X-treated leaves had a significant (P < 0.001) reduction in consumption efficiency compared with larvae grown on 1X-treated leaves. We conclude that effects of enhanced UV-B(BE) radiation at the molecular-photochemical level can elicit significant responses at higher trophic levels that may ultimately affect forest canopy structure, plant competitive interactions and ecosystem-level processes.

Isolation and characterization of allelopathic volatiles from mugwort (Artemisia vulgaris).

PubMed

Barney, Jacob N; Hay, Anthony G; Weston, Leslie A

2005-02-01

Several volatile allelochemicals were identified and characterized from fresh leaf tissue of three distinct populations of the invasive perennial weed, mugwort (Artemisia vulgaris). A unique bioassay was used to demonstrate the release of volatile allelochemicals from leaf tissues. Leaf volatiles were trapped and analyzed via gas chromatography coupled with mass spectrometry. Some of the components identified were terpenes, including camphor, eucalyptol, alpha-pinene, and beta-pinene. Those commercially available were tested individually to determine their phytotoxicity. Concentrations of detectable volatiles differed in both absolute and relative proportions among the mugwort populations. The three mugwort populations consisted of a taller, highly branched population (ITH-1); a shorter, lesser-branched population (ITH-2) (both grown from rhizome fragments from managed landscapes); and a population grown from seed with lobed leaves (VT). Considerable interspecific variation existed in leaf morphology and leaf surface chemistry. Bioassays revealed that none of the individual monoterpenes could account for the observed phytotoxicity imparted by total leaf volatiles, suggesting a synergistic effect or activity of a component not tested. Despite inability to detect a single dominant phytotoxic compound, decreases in total terpene concentration with increase in leaf age correlated with decreases in phytotoxicity. The presence of bioactive terpenoids in leaf surface chemistry of younger mugwort tissue suggests a potential role for terpenoids in mugwort establishment and proliferation in introduced habitats.

Water potential in excised leaf tissue. Comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelsen, C.E.; Safir, G.R.; Hanson, A.D.

1978-01-01

Leaf water potential (Psi/sub leaf/) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi/sub leaf/ values from the dew point hygrometer were too high. Agreement was improvedmore » by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi/sub leaf/ values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.« less

Silk Gland Gene Expression during Larval-Pupal Transition in the Cotton Leaf Roller Sylepta derogata (Lepidoptera: Pyralidae)

PubMed Central

Su, Honghua; Cheng, Yuming; Wang, Zhongyang; Li, Zhong; Stanley, David; Yang, Yizhong

2015-01-01

The cotton leaf roller, Sylepta derogata, is a silk-producing insect pest. While young larvae feed on the underside of leaves, the older ones roll cotton leaves and feed on the leaf edges, which defoliates cotton plants. The larvae produce silk to stabilize the rolled leaf and to balloon from used to new leaves. Despite the significance of silk in the biology of pest insect species, there is virtually no information on the genes involved in their silk production. This is a substantial knowledge gap because some of these genes may be valuable targets for developing molecular pest management technologies. We addressed the gap by posing the hypothesis that silk gland gene expression changes during the transition from larvae to pupae. We tested our hypothesis using RNA-seq to investigate changes in silk gland gene expression at three developmental stages, 5th instar larvae (silk producing; 15,445,926 clean reads), prepupae (reduced silk producing; 13,758,154) and pupae (beyond silk producing; 16,787,792). We recorded 60,298 unigenes and mapped 50,158 (larvae), 48,415 (prepupae) and 46,623 (pupae) of them to the NCBI database. Most differentially expressed genes in the 5th instar larvae/prepupae libraries were relevant to nucleotide synthesis and maintenance of silk gland function. We identified down-regulated transcriptional factors and several genes involved in silk formation in the three libraries and verified the expression pattern of eight genes by qPCR. The developmental- and tissue-specific expression patterns of the fibroin light chain gene showed it was highly expressed during the larval silk-producing stage. We recorded highest expression of this gene in the larval silk gland, compared to other tissues, including midgut, hindgut, epidermis, Malpighian tubes, hemolymph and fat body. These data are a genetic resource to guide selection of key genes that may be targeted for in planta and other gene-silencing technologies for sustainable cotton agriculture. PMID:26352931

Silk Gland Gene Expression during Larval-Pupal Transition in the Cotton Leaf Roller Sylepta derogata (Lepidoptera: Pyralidae).

PubMed

Su, Honghua; Cheng, Yuming; Wang, Zhongyang; Li, Zhong; Stanley, David; Yang, Yizhong

2015-01-01

The cotton leaf roller, Sylepta derogata, is a silk-producing insect pest. While young larvae feed on the underside of leaves, the older ones roll cotton leaves and feed on the leaf edges, which defoliates cotton plants. The larvae produce silk to stabilize the rolled leaf and to balloon from used to new leaves. Despite the significance of silk in the biology of pest insect species, there is virtually no information on the genes involved in their silk production. This is a substantial knowledge gap because some of these genes may be valuable targets for developing molecular pest management technologies. We addressed the gap by posing the hypothesis that silk gland gene expression changes during the transition from larvae to pupae. We tested our hypothesis using RNA-seq to investigate changes in silk gland gene expression at three developmental stages, 5th instar larvae (silk producing; 15,445,926 clean reads), prepupae (reduced silk producing; 13,758,154) and pupae (beyond silk producing; 16,787,792). We recorded 60,298 unigenes and mapped 50,158 (larvae), 48,415 (prepupae) and 46,623 (pupae) of them to the NCBI database. Most differentially expressed genes in the 5th instar larvae/prepupae libraries were relevant to nucleotide synthesis and maintenance of silk gland function. We identified down-regulated transcriptional factors and several genes involved in silk formation in the three libraries and verified the expression pattern of eight genes by qPCR. The developmental- and tissue-specific expression patterns of the fibroin light chain gene showed it was highly expressed during the larval silk-producing stage. We recorded highest expression of this gene in the larval silk gland, compared to other tissues, including midgut, hindgut, epidermis, Malpighian tubes, hemolymph and fat body. These data are a genetic resource to guide selection of key genes that may be targeted for in planta and other gene-silencing technologies for sustainable cotton agriculture.

Effects of deoxynivalenol on content of chloroplast pigments in barley leaf tissues.

PubMed

Bushnell, W R; Perkins-Veazie, P; Russo, V M; Collins, J; Seeland, T M

2010-01-01

To understand further the role of deoxynivalenol (DON) in development of Fusarium head blight (FHB), we investigated effects of the toxin on uninfected barley tissues. Leaf segments, 1 to 1.2 cm long, partially stripped of epidermis were floated with exposed mesophyll in contact with DON solutions. In initial experiments with the leaf segments incubated in light, DON at 30 to 90 ppm turned portions of stripped tissues white after 48 to 96 h. The bleaching effect was greatly enhanced by addition of 1 to 10 mM Ca(2+), so that DON at 10 to 30 ppm turned virtually all stripped tissues white within 48 h. Content of chlorophylls a and b and of total carotenoid pigment was reduced. Loss of electrolytes and uptake of Evans blue indicated that DON had a toxic effect, damaging plasmalemmas in treated tissues before chloroplasts began to lose pigment. When incubated in the dark, leaf segments also lost electrolytes, indicating DON was toxic although the tissues remained green. Thus, loss of chlorophyll in light was due to photobleaching and was a secondary effect of DON, not required for toxicity. In contrast to bleaching effects, some DON treatments that were not toxic kept tissues green without bleaching or other signs of injury, indicating senescence was delayed compared with slow yellowing of untreated leaf segments. Cycloheximide, which like DON, inhibits protein synthesis, also bleached some tissues and delayed senescence of others. Thus, the effects of DON probably relate to its ability to inhibit protein synthesis. With respect to FHB, the results suggest DON may have multiple roles in host cells of infected head tissues, including delayed senescence in early stages of infection and contributing to bleaching and death of cells in later stages.

Boron accumulation and toxicity in hybrid poplar (Populus nigra × euramericana).

PubMed

Rees, Rainer; Robinson, Brett H; Menon, Manoj; Lehmann, Eberhard; Günthardt-Goerg, Madeleine S; Schulin, Rainer

2011-12-15

Poplars accumulate high B concentrations and are thus used for the phytomanagement of B contaminated soils. Here, we performed pot experiments in which Populus nigra × euramericana were grown on a substrate with B concentrations ranging from 13 to 280 mg kg(-1) as H(3)BO(3). Salix viminalis, Brassica juncea, and Lupinus albus were grown under some growing conditions for comparison. Poplar growth was unaffected at soil B treatment levels up to 93 mg kg(-1). Growth was progressively reduced at levels of 168 and 280 mg kg(-1). None of the other species survived at these substrate B levels. At leaf B concentrations <900 mg kg(-1) only <10% of the poplar leaf area showed signs of toxicity. Neutron radiography revealed that chlorotic leaf tissues had B concentrations of 1000-2000 mg kg(-1), while necrotic tissues had >2000 mg kg(-1). Average B concentrations of up to 3500 mg kg(-1) were found in leaves, while spots within leaves had concentrations >7000 mg kg(-1), showing that B accumulation in leaf tissue continued even after the onset of necrosis. The B accumulation ability of P. nigra × euramericana is associated with B hypertolerance in the living tissue and storage of B in dead leaf tissue.

Outside-Xylem Vulnerability, Not Xylem Embolism, Controls Leaf Hydraulic Decline during Dehydration.

PubMed

Scoffoni, Christine; Albuquerque, Caetano; Brodersen, Craig R; Townes, Shatara V; John, Grace P; Bartlett, Megan K; Buckley, Thomas N; McElrone, Andrew J; Sack, Lawren

2017-02-01

Leaf hydraulic supply is crucial to maintaining open stomata for CO 2 capture and plant growth. During drought-induced dehydration, the leaf hydraulic conductance (K leaf ) declines, which contributes to stomatal closure and, eventually, to leaf death. Previous studies have tended to attribute the decline of K leaf to embolism in the leaf vein xylem. We visualized at high resolution and quantified experimentally the hydraulic vulnerability of xylem and outside-xylem pathways and modeled their respective influences on plant water transport. Evidence from all approaches indicated that the decline of K leaf during dehydration arose first and foremost due to the vulnerability of outside-xylem tissues. In vivo x-ray microcomputed tomography of dehydrating leaves of four diverse angiosperm species showed that, at the turgor loss point, only small fractions of leaf vein xylem conduits were embolized, and substantial xylem embolism arose only under severe dehydration. Experiments on an expanded set of eight angiosperm species showed that outside-xylem hydraulic vulnerability explained 75% to 100% of K leaf decline across the range of dehydration from mild water stress to beyond turgor loss point. Spatially explicit modeling of leaf water transport pointed to a role for reduced membrane conductivity consistent with published data for cells and tissues. Plant-scale modeling suggested that outside-xylem hydraulic vulnerability can protect the xylem from tensions that would induce embolism and disruption of water transport under mild to moderate soil and atmospheric droughts. These findings pinpoint outside-xylem tissues as a central locus for the control of leaf and plant water transport during progressive drought. © 2017 The author(s). All Rights Reserved.

Developmental anatomy and immunocytochemistry reveal the neo-ontogenesis of the leaf tissues of Psidium myrtoides (Myrtaceae) towards the globoid galls of Nothotrioza myrtoidis (Triozidae).

PubMed

Carneiro, Renê G S; Oliveira, Denis C; Isaias, Rosy M S

2014-12-01

The temporal balance between hyperplasia and hypertrophy, and the new functions of different cell lineages led to cell transformations in a centrifugal gradient that determines the gall globoid shape. Plant galls develop by the redifferentiation of new cell types originated from those of the host plants, with new functional and structural designs related to the composition of cell walls and cell contents. Variations in cell wall composition have just started to be explored with the perspective of gall development, and are herein related to the histochemical gradients previously detected on Psidium myrtoides galls. Young and mature leaves of P. myrtoides and galls of Nothotrioza myrtoidis at different developmental stages were analysed using anatomical, cytometrical and immunocytochemical approaches. The gall parenchyma presents transformations in the size and shape of the cells in distinct tissue layers, and variations of pectin and protein domains in cell walls. The temporal balance between tissue hyperplasia and cell hypertrophy, and the new functions of different cell lineages led to cell transformations in a centrifugal gradient, which determines the globoid shape of the gall. The distribution of cell wall epitopes affected cell wall flexibility and rigidity, towards gall maturation. By senescence, it provided functional stability for the outer cortical parenchyma. The detection of the demethylesterified homogalacturonans (HGAs) denoted the activity of the pectin methylesterases (PMEs) during the senescent phase, and was a novel time-based detection linked to the increased rigidity of the cell walls, and to the gall opening. Current investigation firstly reports the influence of immunocytochemistry of plant cell walls over the development of leaf tissues, determining their neo-ontogenesis towards a new phenotype, i.e., the globoid gall morphotype.

Comparison of Photoacoustic Signals in Photosynthetic and Nonphotosynthetic Leaf Tissues of Variegated Pelargonium zonale

NASA Astrophysics Data System (ADS)

Veljović-Jovanović, S.; Vidović, M.; Morina, F.; Prokić, Lj.; Todorović, D. M.

2016-09-01

Green-white variegated leaves of Pelargonium zonale were studied using the photoacoustic method. Our aim was to characterize photosynthetically active green tissue and nonphotosynthetically active white tissue by the photoacoustic amplitude signals. We observed lower stomatal conductance and higher leaf temperature in white tissue than in green tissue. Besides these thermal differences, significantly higher absorbance in green tissue was based on chlorophyll and carotenoids which were absent in white tissue. However, optical properties of epidermal layers of both tissues were equal. The photoacoustic amplitude of white tissue was over four times higher compared to green tissue, which was correlated with lower stomatal conductance. In addition, at frequencies >700 Hz, the significant differences between the photoacoustic signals of green and white tissue were obtained. We identified the photoacoustic signal deriving from photosynthetic oxygen evolution in green tissue, using high intensity of red light modulated at 10 Hz. Moreover, the photoacoustic amplitude of green tissue increased progressively with time which corresponded to the period of induction of photosynthetic oxygen evolution. For the first time, very high frequencies (1 kHz to 5 kHz) were applied on leaf material.

Observation of Muntingia Calabura’s Leaf Extract as Feed Additive for Livestock Diet

NASA Astrophysics Data System (ADS)

Pujaningsih, R. I.; Sulistiyanto, B.; Sumarsih, S.

2018-02-01

Using of synthetic antioxidants in feedstuffs continuously can cause negative effect for the livestock. This study observed the constituent compounds of cherry leaf powder using format method of descriptive qualitative. Comparative study was done between young and old leaves to identify the content of antioxidant and antimicrobial. Based on the results of phytochemical tests that have been done, old cherry leaves contain compounds of flavonoids more than young cherry leaves. From the results of this study can be concluded that the results of old cherry leaf isolation using soxhlet extraction has antibacterial power against E. coli bacteria, and S. aureus at concentration of 75% have greater inhibitory ability.

Distribution of free and glycosylated sterols within Cycas micronesica plants

PubMed Central

Marler, Thomas E.; Shaw, Christopher A.

2010-01-01

Flour derived from Cycas micronesica seeds was once the dominant source of starch for Guam's residents. Cycad consumption has been linked to high incidence of human neurodegenerative diseases. We determined the distribution of the sterols stigmasterol and β-sitosterol and their derived glucosides stigmasterol β-d-glucoside and β-sitosterol β-d-glucoside among various plant parts because they have been identified in cycad flour and have been shown to elicit neurodegenerative outcomes. All four compounds were common in seeds, sporophylls, pollen, leaves, stems, and roots. Roots contained the greatest concentration of both free sterols, and photosynthetic leaflet tissue contained the greatest concentration of both steryl glucosides. Concentration within the three stem tissue categories was low compared to other organs. Reproductive sporophyll tissue contained free sterols similar to seeds, but greater concentration of steryl glucosides than seeds. One of the glucosides was absent from pollen. Concentration in young seeds was higher than old seeds as reported earlier, but concentration did not differ among age categories of leaf, sporophyll, or vascular tissue. The profile differences among the various tissues within these organs may help clarify the physiological role of these compounds. PMID:20157629

Insect herbivory in a mature Eucalyptus woodland canopy depends on leaf phenology but not CO2 enrichment.

PubMed

Gherlenda, Andrew N; Moore, Ben D; Haigh, Anthony M; Johnson, Scott N; Riegler, Markus

2016-10-19

Climate change factors such as elevated atmospheric carbon dioxide concentrations (e[CO 2 ]) and altered rainfall patterns can alter leaf composition and phenology. This may subsequently impact insect herbivory. In sclerophyllous forests insects have developed strategies, such as preferentially feeding on new leaf growth, to overcome physical or foliar nitrogen constraints, and this may shift under climate change. Few studies of insect herbivory at elevated [CO 2 ] have occurred under field conditions and none on mature evergreen trees in a naturally established forest, yet estimates for leaf area loss due to herbivory are required in order to allow accurate predictions of plant productivity in future climates. Here, we assessed herbivory in the upper canopy of mature Eucalyptus tereticornis trees at the nutrient-limited Eucalyptus free-air CO 2 enrichment (EucFACE) experiment during the first 19 months of CO 2 enrichment. The assessment of herbivory extended over two consecutive spring-summer periods, with a first survey during four months of the [CO 2 ] ramp-up phase after which full [CO 2 ] operation was maintained, followed by a second survey period from months 13 to 19. Throughout the first 2 years of EucFACE, young, expanding leaves sustained significantly greater damage from insect herbivory (between 25 and 32 % leaf area loss) compared to old or fully expanded leaves (less than 2 % leaf area loss). This preference of insect herbivores for young expanding leaves combined with discontinuous production of new foliage, which occurred in response to rainfall, resulted in monthly variations in leaf herbivory. In contrast to the significant effects of rainfall-driven leaf phenology, elevated [CO 2 ] had no effect on leaf consumption or preference of insect herbivores for different leaf age classes. In the studied nutrient-limited natural Eucalyptus woodland, herbivory contributes to a significant loss of young foliage. Leaf phenology is a significant factor that determines the level of herbivory experienced in this evergreen sclerophyllous woodland system, and may therefore also influence the population dynamics of insect herbivores. Furthermore, leaf phenology appears more strongly impacted by rainfall patterns than by e[CO 2 ]. e[CO 2 ] responses of herbivores on mature trees may only become apparent after extensive CO 2 fumigation periods.

Leaf hydraulics II: vascularized tissues.

PubMed

Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

2014-01-07

Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements. © 2013 Published by Elsevier Ltd. All rights reserved.

Leaf density explains variation in leaf mass per area in rice between cultivars and nitrogen treatments.

PubMed

Xiong, Dongliang; Wang, Dan; Liu, Xi; Peng, Shaobing; Huang, Jianliang; Li, Yong

2016-05-01

Leaf mass per area (LMA) is an important leaf trait; however, correlations between LMA and leaf anatomical features and photosynthesis have not been fully investigated, especially in cereal crops. The objectives of this study were (a) to investigate the correlations between LMA and leaf anatomical traits; and (b) to clarify the response of LMA to nitrogen supply and its effect on photosynthetic nitrogen use efficiency (PNUE). In the present study, 11 rice varieties were pot grown under sufficient nitrogen (SN) conditions, and four selected rice cultivars were grown under low nitrogen (LN) conditions. Leaf anatomical traits, gas exchange and leaf N content were measured. There was large variation in LMA across selected rice varieties. Regression analysis showed that the variation in LMA was more closely related to leaf density (LD) than to leaf thickness (LT). LMA was positively related to the percentage of mesophyll tissue area (%mesophyll), negatively related to the percentage of epidermis tissue area (%epidermis) and unrelated to the percentage of vascular tissue area (%vascular). The response of LMA to N supplementation was dependent on the variety and was also mainly determined by the response of LD to N. Compared with SN, photosynthesis was significantly decreased under LN, while PNUE was increased. The increase in PNUE was more critical in rice cultivars with a higher LMA under SN supply. Leaf density is the major cause of the variation in LMA across rice varieties and N treatments, and an increase in LMA under high N conditions would aggravate the decrease in PNUE. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Wettability, Polarity, and Water Absorption of Holm Oak Leaves: Effect of Leaf Side and Age1[OPEN

PubMed Central

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-01-01

Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

Potential Rapid Effects on Soil Organic Matter Characteristics and Chemistry Following a Change in Dominant Litter Inputs

NASA Astrophysics Data System (ADS)

Crow, S. E.; Filley, T.; Conyers, G.; Stott, D.; McCormick, M.; Whigham, D.; Taylor, D.

2006-12-01

Changes in vegetation structure are expected in forests globally under predicted future climate scenarios. Shifts in type or quantity of litter inputs, which will be associated with changes in plant community, may influence soil organic matter (SOM) characteristics. We altered litter inputs in a mixed-deciduous forest at the Smithsonian Environmental Research Center beginning in May 2004: litter removal, leaf amendment, and wood amendment plots were established in three old (120-150 y) and three young (50-70 y) forests. Plots were amended with wood and leaves collected locally from the dominant tree species, tulip poplar (Lirodendron tulipifera). 0-5 cm A horizon soil was collected in November 2005, 18 months after initial treatment, and physically fractionated first by dispersal in HMP and size separation (53 μm) to remove silts and clays then the >53 μm fraction by density (1.4 g cm-3) in SPT to separate the organic debris (light fraction, LF) from the mineral material. Soil with the greatest amount of C present within the LF came from the wood amendment treatment (35.2 ± 0.1%), followed by the leaf amendment (27.7 ± 0.0%) and the litter removal (24.5 ± 0.0%) treatments. In a pattern opposite of the other treatments, leaf amended soil from the old sites had less C within LF than the young. Potentially, a priming effect from the leaf addition at the old sites resulted in increased decomposition of soil LF. While at the young sites, invasive earthworms potentially provided a rapid, direct mode for incorporation of fresh leaf inputs into LF. Preliminary data indicate differences in lignin and cutin/suberin decay rates during litter decomposition between old and young sites. An investigation into the biopolymer composition of LF will determine whether altering litter inputs will ultimately influence SOM dynamics at both the old and young forest sites.

Glycine betaine accumulation, ionic and water relations of red-beet at contrasting levels of sodium supply

NASA Technical Reports Server (NTRS)

Subbarao, G. V.; Wheeler, R. M.; Levine, L. H.; Stutte, G. W.; Sager, J. C. (Principal Investigator)

2001-01-01

Exposure of plants to sodium (Na) and salinity may increase glycine betaine accumulation in tissues. To study this, red-beet cvs. Scarlet Supreme and Ruby Queen, were grown for 42 days in a growth chamber using a re-circulating nutrient film technique with 0.25 mmol/L K and either 4.75 mmol/L (control) or 54.75 mmol/L (saline) Na (as NaCl). Plants were harvested at weekly intervals and measurements were taken on leaf water relations, leaf photosynthetic rates, chlorophyll fluorescence, chlorophyll levels, glycine betaine levels, and tissue elemental composition. Glycine betaine accumulation increased under salinity and this accumulation correlated with higher tissue levels of Na in both cultivars. Na accounted for 80 to 90% of the total cation uptake under the saline treatment. At final harvest (42 days), K concentrations in laminae ranged from approximately 65-95 micromoles g-1 dry matter (DM), whereas Na in shoot tissue ranged from approximately 3000-4000 micromoles g-1. Leaf sap osmotic potential at full turgor [psi(s100)] increased as lamina Na content increased. Glycine betaine levels of leaf laminae showed a linear relationship with leaf sap [psi(s100)]. Chlorophyll levels, leaf photosynthetic rates, and chlorophyll fluorescence were not affected by Na levels. These results suggest that the metabolic tolerance to high levels of tissue Na in red-beet could be due to its ability to synthesize and regulate glycine betaine production, and to control partitioning of Na and glycine betaine between the vacuole and the cytoplasm.

Observations on anatomical aspects of the fruit, leaf and stem tissues of four Citrullus spp.

USDA-ARS?s Scientific Manuscript database

Morphological characteristics of the fruit, stem and leaf tissues of four species of Citrullus (L.) Schrad. were examined using standard histological methods. Plant materials included the cultivated watermelon (C. lanatus (Thunb.) Matsum. & Nakai) and three of its related species; C. colocynthis (...

Leaf tissue assay for lepidopteran pests of Bt cotton

USDA-ARS?s Scientific Manuscript database

Laboratory measurements of susceptibility to Bt toxins can be a poor indicator of the ability of an insect to survive on transgenic crops. We investigated the potential of using cotton leaf tissue for evaluating heliothine susceptibilities to two dual-gene Bt cottons. A preliminary study was conduct...

Impact of epidermal leaf mining by the aspen leaf miner (Phyllocnistis populiella) on the growth, physiology, and leaf longevity of quaking aspen.

Treesearch

Diane L. Wagner; Linda DeFoliart; Patricia Doak; Jenny Schneiderheinze

2008-01-01

The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant...

Three-dimensional radiation transfer modeling in a dicotyledon leaf

NASA Astrophysics Data System (ADS)

Govaerts, Yves M.; Jacquemoud, Stéphane; Verstraete, Michel M.; Ustin, Susan L.

1996-11-01

The propagation of light in a typical dicotyledon leaf is investigated with a new Monte Carlo ray-tracing model. The three-dimensional internal cellular structure of the various leaf tissues, including the epidermis, the palisade parenchyma, and the spongy mesophyll, is explicitly described. Cells of different tissues are assigned appropriate morphologies and contain realistic amounts of water and chlorophyll. Each cell constituent is characterized by an index of refraction and an absorption coefficient. The objective of this study is to investigate how the internal three-dimensional structure of the tissues and the optical properties of cell constituents control the reflectance and transmittance of the leaf. Model results compare favorably with laboratory observations. The influence of the roughness of the epidermis on the reflection and absorption of light is investigated, and simulation results confirm that convex cells in the epidermis focus light on the palisade parenchyma and increase the absorption of radiation.

Leaf water relations during summer water deficit: differential responses in turgor maintenance and variation in leaf structure among different plant communities in south-western Australia.

PubMed

Mitchell, Patrick J; Veneklaas, Erik J; Lambers, Hans; Burgess, Stephen S O

2008-12-01

We measured leaf water relations and leaf structural traits of 20 species from three communities growing along a topographical gradient. Our aim was to assess variation in seasonal responses in leaf water status and leaf tissue physiology between sites and among species in response to summer water deficit. Species from a ridge-top heath community showed the greatest reductions in pre-dawn leaf water potentials (Psi(leaf)) and stomatal conductance during summer; species from a valley-floor woodland and a midslope mallee community showed less reductions in these parameters. Heath species also displayed greater seasonal reduction in turgor-loss point (Psi(TLP)) than species from woodland or mallee communities. In general, species that had larger reductions in Psi(leaf) during summer showed significant shifts in either their osmotic potential at full turgor (Psi(pi 100); osmotic adjustment) or in tissue elasticity (epsilon(max)). Psi(pi 100) and epsilon(max) were negatively correlated, during both spring and summer, suggesting a trade-off between these different mechanisms to cope with water stress. Specific leaf area varied greatly among species, and was significantly correlated with seasonal changes in Psi(TLP) and pre-dawn Psi(leaf). These correlations suggest that leaf structure is a prerequisite for cellular mechanisms to be effective in adjusting to water deficit.

Gene expression profile analysis of Ligon lintless-1 (Li1) mutant reveals important genes and pathways in cotton leaf and fiber development.

PubMed

Ding, Mingquan; Jiang, Yurong; Cao, Yuefen; Lin, Lifeng; He, Shae; Zhou, Wei; Rong, Junkang

2014-02-10

Ligon lintless-1 (Li1) is a monogenic dominant mutant of Gossypium hirsutum (upland cotton) with a phenotype of impaired vegetative growth and short lint fibers. Despite years of research involving genetic mapping and gene expression profile analysis of Li1 mutant ovule tissues, the gene remains uncloned and the underlying pathway of cotton fiber elongation is still unclear. In this study, we report the whole genome-level deep-sequencing analysis of leaf tissues of the Li1 mutant. Differentially expressed genes in leaf tissues of mutant versus wild-type (WT) plants are identified, and the underlying pathways and potential genes that control leaf and fiber development are inferred. The results show that transcription factors AS2, YABBY5, and KANDI-like are significantly differentially expressed in mutant tissues compared with WT ones. Interestingly, several fiber development-related genes are found in the downregulated gene list of the mutant leaf transcriptome. These genes include heat shock protein family, cytoskeleton arrangement, cell wall synthesis, energy, H2O2 metabolism-related genes, and WRKY transcription factors. This finding suggests that the genes are involved in leaf morphology determination and fiber elongation. The expression data are also compared with the previously published microarray data of Li1 ovule tissues. Comparative analysis of the ovule transcriptomes of Li1 and WT reveals that a number of pathways important for fiber elongation are enriched in the downregulated gene list at different fiber development stages (0, 6, 9, 12, 15, 18dpa). Differentially expressed genes identified in both leaf and fiber samples are aligned with cotton whole genome sequences and combined with the genetic fine mapping results to identify a list of candidate genes for Li1. Copyright © 2013 Elsevier B.V. All rights reserved.

Interactive influence of leaf age, light intensity, and girdling on green ash foliar chemistry and emerald ash borer development.

PubMed

Chen, Yigen; Poland, Therese M

2009-07-01

Biotic and abiotic environmental factors affect plant nutritional quality and defensive compounds that confer plant resistance to herbivory. Influence of leaf age, light availability, and girdling on foliar nutrition and defense of green ash (Fraxinus pennsylvanica Marsh) was examined in this study. Longevity of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), adults reared on green ash foliage subjected to these factors was assayed. Mature leaves generally were more nutritious with greater amino acids and a greater ratio of protein to non-structural carbohydrate (P:C) than young leaves, in particular when trees were grown in shade. On the other hand, mature leaves had lower amounts of trypsin and chymotrypsin inhibitors, and total phenolics compared to young leaves. Lower defense of mature leaves alone, or along with higher nutritional quality may lead to increased survival and longevity of emerald ash borer feeding on mature leaves. Sunlight reduced amino acids and P:C ratio, irrespective of leaf age and girdling, and elevated total protein of young foliage, but not protein of mature leaves. Sunlight also dramatically increased all investigated defensive compounds of young, but not mature leaves. Girdling reduced green ash foliar nutrition, especially, of young leaves grown in shade and of mature leaves grown in sun. However emerald ash borer performance did not differ when fed leaves from trees grown in sun or shade, or from girdled or control trees. One explanation is that emerald ash borer reared on lower nutritional quality food may compensate for nutrient deficiency by increasing its consumption rate. The strong interactions among leaf age, light intensity, and girdling on nutrition and defense highlight the need for caution when interpreting data without considering possible interactions.

Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.

PubMed

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-09-01

Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. © 2014 American Society of Plant Biologists. All Rights Reserved.

Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny.

PubMed

Newhouse, Andrew E; Polin-McGuigan, Linda D; Baier, Kathleen A; Valletta, Kristia E R; Rottmann, William H; Tschaplinski, Timothy J; Maynard, Charles A; Powell, William A

2014-11-01

American chestnut (Castanea dentata) is a classic example of a native keystone species that was nearly eradicated by an introduced fungal pathogen. This report describes progress made toward producing a fully American chestnut tree with enhanced resistance to the blight fungus (Cryphonectria parasitica). The transgenic American chestnut 'Darling4,' produced through an Agrobacterium co-transformation procedure to express a wheat oxalate oxidase gene driven by the VspB vascular promoter, shows enhanced blight resistance at a level intermediate between susceptible American chestnut and resistant Chinese chestnut (Castanea mollissima). Enhanced resistance was identified first with a leaf-inoculation assay using young chestnuts grown indoors, and confirmed with traditional stem inoculations on 3- and 4-year-old field-grown trees. Pollen from 'Darling4' and other events was used to produce transgenic T1 seedlings, which also expressed the enhanced resistance trait in leaf assays. Outcrossed transgenic seedlings have several advantages over tissue-cultured plantlets, including increased genetic diversity and faster initial growth. This represents a major step toward the restoration of the majestic American chestnut. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Penetration of UV-A, UV-B, blue, and red light into leaf tissues of pecan measured by a fiber optic microprobe system

NASA Astrophysics Data System (ADS)

Qi, Yadong; Bai, Shuju; Vogelmann, Thomas C.; Heisler, Gordon M.

2003-11-01

The depth of light penetration from the adaxial surfaces of the mature leaves of pecan (Carya illinoensis) was measured using a fiber optic microprobe system at four wavelengths: UV-B (310nm), UV-A (360 nm), blue light (430nm), and red light (680nm). The average thickness of the leaf adaxial epidermal layer was 15um and the total leaf thickness was 219um. The patterns of the light attenuation by the leaf tissues exhibited strong wavelength dependence. The leaf adaxial epidermal layer was chiefly responsible for absorbing the UV-A UV-B radiation. About 98% of 310 nm light was steeply attenuated within the first 5 um of the adaxial epidermis; thus, very little UV-B radiation was transmitted to the mesophyll tissues where contain photosynthetically sensitive sites. The adaxial epidermis also attenuated 96% of the UV-A radiation. In contrast, the blue and red light penetrated much deeper and was gradually attenutated by the leaves. The mesophyll tissues attenuated 17% of the blue light and 42% of the red light, which were available for photosynthesis use. Since the epidermal layer absorbed nearly all UV-B light, it acted as an effective filter screening out the harmful radiation and protecting photosynthetically sensitive tissues from the UV-B damage. Therefore, the epidermal function of the UV-B screening effectiveness can be regarded as one of the UV-B protection mechanisms in pecan.

Lipid Biosynthesis and Protein Concentration Respond Uniquely to Phosphate Supply during Leaf Development in Highly Phosphorus-Efficient Hakea prostrata1[W][OPEN

PubMed Central

Kuppusamy, Thirumurugen; Giavalisco, Patrick; Arvidsson, Samuel; Stitt, Mark; Finnegan, Patrick M.; Scheible, Wolf-Rüdiger

2014-01-01

Hakea prostrata (Proteaceae) is adapted to severely phosphorus-impoverished soils and extensively replaces phospholipids during leaf development. We investigated how polar lipid profiles change during leaf development and in response to external phosphate supply. Leaf size was unaffected by a moderate increase in phosphate supply. However, leaf protein concentration increased by more than 2-fold in young and mature leaves, indicating that phosphate stimulates protein synthesis. Orthologs of known lipid-remodeling genes in Arabidopsis (Arabidopsis thaliana) were identified in the H. prostrata transcriptome. Their transcript profiles in young and mature leaves were analyzed in response to phosphate supply alongside changes in polar lipid fractions. In young leaves of phosphate-limited plants, phosphatidylcholine/phosphatidylethanolamine and associated transcript levels were higher, while phosphatidylglycerol and sulfolipid levels were lower than in mature leaves, consistent with low photosynthetic rates and delayed chloroplast development. Phosphate reduced galactolipid and increased phospholipid concentrations in mature leaves, with concomitant changes in the expression of only four H. prostrata genes, GLYCEROPHOSPHODIESTER PHOSPHODIESTERASE1, N-METHYLTRANSFERASE2, NONSPECIFIC PHOSPHOLIPASE C4, and MONOGALACTOSYLDIACYLGLYCEROL3. Remarkably, phosphatidylglycerol levels decreased with increasing phosphate supply and were associated with lower photosynthetic rates. Levels of polar lipids with highly unsaturated 32:x (x = number of double bonds in hydrocarbon chain) and 34:x acyl chains increased. We conclude that a regulatory network with a small number of central hubs underpins extensive phospholipid replacement during leaf development in H. prostrata. This hard-wired regulatory framework allows increased photosynthetic phosphorus use efficiency and growth in a low-phosphate environment. This may have rendered H. prostrata lipid metabolism unable to adjust to higher internal phosphate concentrations. PMID:25315604

Lipid biosynthesis and protein concentration respond uniquely to phosphate supply during leaf development in highly phosphorus-efficient Hakea prostrata.

PubMed

Kuppusamy, Thirumurugen; Giavalisco, Patrick; Arvidsson, Samuel; Sulpice, Ronan; Stitt, Mark; Finnegan, Patrick M; Scheible, Wolf-Rüdiger; Lambers, Hans; Jost, Ricarda

2014-12-01

Hakea prostrata (Proteaceae) is adapted to severely phosphorus-impoverished soils and extensively replaces phospholipids during leaf development. We investigated how polar lipid profiles change during leaf development and in response to external phosphate supply. Leaf size was unaffected by a moderate increase in phosphate supply. However, leaf protein concentration increased by more than 2-fold in young and mature leaves, indicating that phosphate stimulates protein synthesis. Orthologs of known lipid-remodeling genes in Arabidopsis (Arabidopsis thaliana) were identified in the H. prostrata transcriptome. Their transcript profiles in young and mature leaves were analyzed in response to phosphate supply alongside changes in polar lipid fractions. In young leaves of phosphate-limited plants, phosphatidylcholine/phosphatidylethanolamine and associated transcript levels were higher, while phosphatidylglycerol and sulfolipid levels were lower than in mature leaves, consistent with low photosynthetic rates and delayed chloroplast development. Phosphate reduced galactolipid and increased phospholipid concentrations in mature leaves, with concomitant changes in the expression of only four H. prostrata genes, GLYCEROPHOSPHODIESTER PHOSPHODIESTERASE1, N-METHYLTRANSFERASE2, NONSPECIFIC PHOSPHOLIPASE C4, and MONOGALACTOSYLDIACYLGLYCEROL3. Remarkably, phosphatidylglycerol levels decreased with increasing phosphate supply and were associated with lower photosynthetic rates. Levels of polar lipids with highly unsaturated 32:x (x = number of double bonds in hydrocarbon chain) and 34:x acyl chains increased. We conclude that a regulatory network with a small number of central hubs underpins extensive phospholipid replacement during leaf development in H. prostrata. This hard-wired regulatory framework allows increased photosynthetic phosphorus use efficiency and growth in a low-phosphate environment. This may have rendered H. prostrata lipid metabolism unable to adjust to higher internal phosphate concentrations. © 2014 American Society of Plant Biologists. All Rights Reserved.

Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids.

PubMed

Gaucher, Matthieu; Dugé de Bernonville, Thomas; Lohou, David; Guyot, Sylvain; Guillemette, Thomas; Brisset, Marie-Noëlle; Dat, James F

2013-06-01

Flavonoids, like other metabolites synthesized via the phenylpropanoid pathway, possess a wide range of biological activities including functions in plant development and its interaction with the environment. Dihydrochalcones (mainly phloridzin, sieboldin, trilobatin, phloretin) represent the major flavonoid subgroup in apple green tissues. Although this class of phenolic compounds is found in very large amounts in some tissues (≈200mg/g of leaf DW), their physiological significance remains unclear. In the present study, we highlight their tissue-specific localization in young growing shoots suggesting a specific role in important physiological processes, most notably in response to biotic stress. Indeed, dihydrochalcones could constitute a basal defense, in particular phloretin which exhibits a strong broad-range bactericidal and fungicidal activity. Our results also indicate that sieboldin forms complexes with iron with strong affinity, reinforcing its antioxidant properties and conferring to this dihydrochalcone a potential for iron seclusion and/or storage. The importance of localization and biochemical properties of dihydrochalcones are discussed in view of the apple tree defense strategy against both biotic and abiotic stresses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phenylalanine Is Required to Promote Specific Developmental Responses and Prevents Cellular Damage in Response to Ultraviolet Light in Soybean (Glycine max) during the Seed-to-Seedling Transition

PubMed Central

Sullivan, Joe H.; Muhammad, DurreShahwar; Warpeha, Katherine M.

2014-01-01

UV-radiation elicits a suite of developmental (photomorphogenic) and protective responses in plants, but responses early post-germination have received little attention, particularly in intensively bred plants of economic importance. We examined germination, hypocotyl elongation, leaf pubescence and subcellular responses of germinating and/or etiolated soybean (Glycine max (L.) Merr.) seedlings in response to treatment with discrete wavelengths of UV-A or UV-B radiation. We demonstrate differential responses of germinating/young soybean seedlings to a range of UV wavelengths that indicate unique signal transduction mechanisms regulate UV-initiated responses. We have investigated how phenylalanine, a key substrate in the phenylpropanoid pathway, may be involved in these responses. Pubescence may be a key location for phenylalanine-derived protective compounds, as UV-B irradiation increased pubescence and accumulation of UV-absorbing compounds within primary leaf pubescence, visualized by microscopy and absorbance spectra. Mass spectrometry analysis of pubescence indicated that sinapic esters accumulate in the UV-irradiated hairs compared to unirradiated primary leaf tissue. Deleterious effects of some UV-B wavelengths on germination and seedling responses were reduced or entirely prevented by inclusion of phenylalanine in the growth media. Key effects of phenylalanine were not duplicated by tyrosine or tryptophan or sucrose, nor is the specificity of response due to the absorbance of phenylalanine itself. These results suggest that in the seed-to-seedling transition, phenylalanine may be a limiting factor in the development of initial mechanisms of UV protection in the developing leaf. PMID:25549094

Tolerance of Cottonwood to Damage by Cottonwood Leaf Beetle

Treesearch

F. L. Oliveria; D. T. Cooper

1977-01-01

Wide variation in tolerance to the cottonwood leaf beetle was found in fourteen hundred eastern cottonwood clones, originating from 36 young natural stands along the Mississippi River from Memphis, Tennessee, to Baton Rouge, Louisiana. Expected genetic gains were large enough to justify further research.

Feeding Behaviour on Host Plants May Influence Potential Exposure to Bt Maize Pollen of Aglais Urticae Larvae (Lepidoptera, Nymphalidae).

PubMed

Lang, Andreas; Otto, Mathias

2015-08-31

Non-target butterfly larvae may be harmed by feeding on host plants dusted with Bt maize pollen. Feeding patterns of larvae and their utilization of host plants can affect the adverse Bt impact because the maize pollen is distributed unequally on the plant. In a field study, we investigated the feeding of larvae of the Small Tortoiseshell, Aglais urticae, on nettles, Urtica dioica. Young larvae used smaller host plants than older larvae. In general, the position of the larvae was in the top part of the host plant, but older larvae showed a broader vertical distribution on the nettles. Leaf blades and leaf tips were the plant parts most often consumed. Leaf veins were consumed but midribs were fed on to a lesser extent than other plant veins, particularly by young larvae. The feeding behavior of the larvae may increase possible exposure to Bt maize pollen because pollen densities are expected to be higher on the top parts and along leaf veins of nettles.

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus

DOE Office of Scientific and Technical Information (OSTI.GOV)

da Costa, Ricardo M. F.; Lee, Scott J.; Allison, Gordon G.

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transformmore » mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. In conclusion, it is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass samples, and sample variability could be mostly due to varying tissue contributions to total biomass.« less

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus

DOE PAGES

da Costa, Ricardo M. F.; Lee, Scott J.; Allison, Gordon G.; ...

2014-04-15

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transformmore » mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. In conclusion, it is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass samples, and sample variability could be mostly due to varying tissue contributions to total biomass.« less

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus.

PubMed

da Costa, Ricardo M F; Lee, Scott J; Allison, Gordon G; Hazen, Samuel P; Winters, Ana; Bosch, Maurice

2014-10-01

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transform mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. It is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass samples, and sample variability could be mostly due to varying tissue contributions to total biomass. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company.

Net primary production and phenology on a southern Appalachian watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Day, F.P. Jr.; Monk, C.D.

1977-01-01

Net primary production (NPP) is an important function of plant communities which has not often been examined seasonally in a forested ecosystem. The major objective of the study was to measure above-ground NPP seasonally and relate it to phenological activity on a hardwood forest watershed at Coweeta Hydrologic Laboratory, North Carolina. NPP was estimated as the increase in biomass, estimated from regression equations on diameter. Diameter increases were measured by venier tree bands. Phenological observations were made on bud break, leaf emergence, flowering, mature fruit, leaf senescence, and leaf fall. The species studied intensively were Acer rubrum, Quercus prinus, Caryamore » glabra, Cornus florida, and Liriodendron tulipifera. Liriodendron was found to be the most productive species per individual, but Quercus prinus was the most productive per unit ground area. The total watershed estimate of aboveground NPP was 8,754 kg ha/sup -1/yr/sup -1/ and included 47.9 percent leaves, 33.2 percent wood, 7.8 percent bark, 4.8 percent reproductive tissues, 4.2 percent loss to consumers, and 2.1 percent twigs. Increases in leaf biomass were most rapid in the spring, but woody tissue production peaked in June and continued through August. Since leaf production peaked in the spring, the plants' photosynthetic machinery was activated early in the growing season to support woody tissue production, which followed the period of rapid leaf growth, and reproductive activity. Flowering occurred during the leaf expansion period except for Acer rubrum, which flowered before leaf emergence. Fruit maturation occurred during late summer to early fall, when there were no additional biomass increases. Acer rubrum was an exception as its fruit matured during the period of leaf expansion.« less

Net primary production and phenology on a southern Appalachian watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Day, F.P. Jr.; Monk, C.D.

1977-10-01

Net primary production (NPP) is an important function of plant communities which has not often been examined seasonally in a forested ecosystem. The major objective of the study was to measure above-ground NPP seasonally and relate it to phenological activity on a hardwood forest watershed at Coweeta Hydrologic Laboratory, North Carolina. NPP was estimated as the increase in biomass, estimated from regression equations on diameter. Diameter increases were measured by vernier tree bands. Phenological observations were made on bud break, leaf emergence, flowering, mature fruit, leaf senescence, and leaf fall. The species studied intensively were Acer rubrum, Quercus prinus, Caryamore » glabra, Cornus florida, and Liriodendron tulipifera. Liriodendron was found to be the most productive species per individual, but Quercus prinus was the most productive per unit ground area. The total watershed estimate of aboveground NPP was 8,754 kg ha/sup -1/ yr/sup -1/ and included 47.9% leaves, 33.2% wood, 7.8% bark, 4.8% reproductive tissues, 4.2% loss to consumers, and 2.1% twigs. Increases in leaf biomass were most rapid in the spring, but woody tissue production peaked in June and continued through August. Since leaf production peaked in the spring, the plants' photosynthetic machinery was activated early in the growing season to support woody tissue production, which followed the period of rapid leaf growth, and reproductive activity. Flowering ocurred during the leaf expansion period except for Acer rubrum, which flowered before leaf emergence. Fruit maturation occurred during late summer to early fall, when there were no additional biomass increases. Acer rubrum was an exception as its fruit matured during the period of leaf expansion.« less

Expression of Ascorbic Acid Oxidase in Zucchini Squash (Cucurbita pepo L.).

PubMed

Lin, L S; Varner, J E

1991-05-01

The expression of ascorbic acid oxidase was studied in zucchini squash (Cucurbita pepo L.), one of the most abundant natural sources of the enzyme. In the developing fruit, specific activity of ascorbic acid oxidase was highest between 4 and 6 days after anthesis. Protein and mRNA levels followed the same trend as enzyme activity. Highest growth rate of the fruit occurred before 6 days after anthesis. Within a given fruit, ascorbic acid oxidase activity and mRNA level were highest in the epidermis, and lowest in the central placental region. In leaf tissue, ascorbic acid oxidase activity was higher in young leaves, and very low in old leaves. Within a given leaf, enzyme activity was highest in the fast-growing region (approximately the lower third of the blade), and lowest in the slow-growing region (near leaf apex). High expression of ascorbic acid oxidase at a stage when rapid growth is occurring (in both fruits and leaves), and localization of the enzyme in the fruit epidermis, where cells are under greatest tension during rapid growth in girth, suggest that ascorbic acid oxidase might be involved in reorganization of the cell wall to allow for expansion. Based on the known chemistry of dehydroascorbic acid, the end product of the ascorbic acid oxidase-catalyzed reaction, we have proposed several hypotheses to explain how dehydroascorbic acid might cause cell wall "loosening."

Outside-Xylem Vulnerability, Not Xylem Embolism, Controls Leaf Hydraulic Decline during Dehydration1[CC-BY

PubMed Central

Townes, Shatara V.; Bartlett, Megan K.; Buckley, Thomas N.; McElrone, Andrew J.; Sack, Lawren

2017-01-01

Leaf hydraulic supply is crucial to maintaining open stomata for CO2 capture and plant growth. During drought-induced dehydration, the leaf hydraulic conductance (Kleaf) declines, which contributes to stomatal closure and, eventually, to leaf death. Previous studies have tended to attribute the decline of Kleaf to embolism in the leaf vein xylem. We visualized at high resolution and quantified experimentally the hydraulic vulnerability of xylem and outside-xylem pathways and modeled their respective influences on plant water transport. Evidence from all approaches indicated that the decline of Kleaf during dehydration arose first and foremost due to the vulnerability of outside-xylem tissues. In vivo x-ray microcomputed tomography of dehydrating leaves of four diverse angiosperm species showed that, at the turgor loss point, only small fractions of leaf vein xylem conduits were embolized, and substantial xylem embolism arose only under severe dehydration. Experiments on an expanded set of eight angiosperm species showed that outside-xylem hydraulic vulnerability explained 75% to 100% of Kleaf decline across the range of dehydration from mild water stress to beyond turgor loss point. Spatially explicit modeling of leaf water transport pointed to a role for reduced membrane conductivity consistent with published data for cells and tissues. Plant-scale modeling suggested that outside-xylem hydraulic vulnerability can protect the xylem from tensions that would induce embolism and disruption of water transport under mild to moderate soil and atmospheric droughts. These findings pinpoint outside-xylem tissues as a central locus for the control of leaf and plant water transport during progressive drought. PMID:28049739

A rapid total reflection X-ray fluorescence protocol for micro analyses of ion profiles in Arabidopsis thaliana

NASA Astrophysics Data System (ADS)

Höhner, Ricarda; Tabatabaei, Samaneh; Kunz, Hans-Henning; Fittschen, Ursula

2016-11-01

The ion homeostasis of macro and micronutrients in plant cells and tissues is a fundamental requirement for vital biochemical pathways including photosynthesis. In nature, ion homeostasis is affected mainly by three processes: 1. Environmental stress factors, 2. Developmental effects, and 3. Loss or gain-of-function mutations in the plant genome. Here we present a rapid total reflection X-ray fluorescence (TXRF) protocol that allows for simultaneous quantification of several elements such as potassium (K), calcium (Ca), sulfur (S), manganese (Mn) and strontium (Sr) in Arabidopsis thaliana leaf specimens. Our procedure is cost-efficient and enables precise, robust and highly reproducible measurements on tissue samples as small as 0.3 mg dry weight. As shown here, we apply the TXRF procedure to detect accurately the early replacement of K by Na ions in leaves of plants exposed to soil salinity, a globally increasing abiotic stress factor. Furthermore, we were able to prove the existence of a leaf development-dependent ion gradient for K, Ca, and other divalent ions in A. thaliana; i.e. old leaves contain significantly lower K but higher Ca than young leaves. Lastly, we show that our procedure can be readily applied to reveal subtle differences in tissue-specific ion contents of plant mutants. We employed independent A. thaliana kea1kea2 loss-of-function mutants that lack KEA1 and KEA2, two highly active chloroplast K exchange proteins. We found significantly increased K levels specifically in kea1kea2 mutants, i.e. 55 mg ∗ g- 1 dry weight, compared to 40 mg ∗ g- 1 dry weight in wild type plants. The TXRF procedure can be supplemented with Flame atomic absorption (FAAS) and emission spectrometry (FAES) to expand the detection range to sodium (Na) and magnesium (Mg). Because of the small sample amounts required, this method is especially suited to probe individual leaves in single plants or even specific leaf areas. Therefore, TXRF represents a powerful method to gain detailed quantitative insights into I) the effect of environmental stress on plant ion homeostasis, II) ion gradients between plant tissues, and III) ion levels in plant mutants with compromised growth or heterogeneous phenotypes.

Indirect suppression of photosynthesis on individual leaves by arthropod herbivory

PubMed Central

Nabity, Paul D.; Zavala, Jorge A.; DeLucia, Evan H.

2009-01-01

Background Herbivory reduces leaf area, disrupts the function of leaves, and ultimately alters yield and productivity. Herbivore damage to foliage typically is assessed in the field by measuring the amount of leaf tissue removed and disrupted. This approach assumes the remaining tissues are unaltered, and plant photosynthesis and water balance function normally. However, recent application of thermal and fluorescent imaging technologies revealed that alterations to photosynthesis and transpiration propagate into remaining undamaged leaf tissue. Scope and Conclusions This review briefly examines the indirect effects of herbivory on photosynthesis, measured by gas exchange or chlorophyll fluorescence, and identifies four mechanisms contributing to the indirect suppression of photosynthesis in remaining leaf tissues: severed vasculature, altered sink demand, defence-induced autotoxicity, and defence-induced down-regulation of photosynthesis. We review the chlorophyll fluorescence and thermal imaging techniques used to gather layers of spatial data and discuss methods for compiling these layers to achieve greater insight into mechanisms contributing to the indirect suppression of photosynthesis. We also elaborate on a few herbivore-induced gene-regulating mechanisms which modulate photosynthesis and discuss the difficult nature of measuring spatial heterogeneity when combining fluorescence imaging and gas exchange technology. Although few studies have characterized herbivore-induced indirect effects on photosynthesis at the leaf level, an emerging literature suggests that the loss of photosynthetic capacity following herbivory may be greater than direct loss of photosynthetic tissues. Depending on the damage guild, ignoring the indirect suppression of photosynthesis by arthropods and other organisms may lead to an underestimate of their physiological and ecological impacts. PMID:18660492

Carbon and nitrogen dynamics of the intertidal seagrass, Zostera japonica, on the southern coast of the Korean peninsula

NASA Astrophysics Data System (ADS)

Kim, Jong-Hyeob; Kim, Seung Hyeon; Kim, Young Kyun; Lee, Kun-Seop

2016-12-01

Seagrasses require a large amount of nutrient assimilation to support high levels of production, and thus nutrient limitation for growth often occurs in seagrass habitats. Seagrasses can take up nutrients from both the water column and sediments. However, since seagrasses inhabiting in the intertidal zones are exposed to the air during low tide, the intertidal species may exhibit significantly different carbon (C) and nitrogen (N) dynamics compared to the subtidal species. To examine C and N dynamics of the intertidal seagrass, Zostera japonica, C and N content and stable isotope ratios of above- and below-ground tissues were measured monthly at the three intertidal zones in Koje Bay on the southern coast of Korea. The C and N content and stable isotope (δ13C and δ15N) ratios of seagrass tissues exhibited significant seasonal variations. Both leaf and rhizome C content were not significantly correlated with productivity. Leaf δ13C values usually exhibited negative correlations with leaf productivity. These results of tissue C content and δ13C values suggest that photosynthesis of Z. japonica in the study site was not limited by inorganic C supply, and sufficient inorganic C was provided from the atmosphere. The tissue N content usually exhibited negative correlations with leaf productivity except at the upper intertidal zone, suggesting that Z. japonica growth was probably limited by N availability during high growing season. In the upper intertidal zone, no correlations between leaf productivity and tissue elemental content and stable isotope ratios were observed due to the severely suppressed growth caused by strong desiccation stress.

The bionomics of the cottonwood leaf beetle, Chrysomela scripta Fab., on tissue culture hybrid poplars

Treesearch

T.R. Burkot; D.M. Benjamin

1977-01-01

Tissue culture methods are applied to poplars of the Aigeiros group in attempts to overcome premature decline thought to be associated with viral infections. Hybrid selections from such cultures outplanted in 1975 at the F. G. Wilson Nursery in Boscobel, Wisconsin subsequently were severely infested by the Cottonwood Leaf Beetle, Chrysomela scripta Fab. Beetle...

A model using marginal efficiency of investment to analyse carbon and nitrogen interactions in forested ecosystems

NASA Astrophysics Data System (ADS)

Thomas, R. Q.; Williams, M.

2014-12-01

Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System modelling community. Here we explore the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants using a new, simple model of ecosystem C-N cycling and interactions (ACONITE). ACONITE builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C:N, N fixation, and plant C use efficiency) based on the optimization of the marginal change in net C or N uptake associated with a change in allocation of C or N to plant tissues. We simulated and evaluated steady-state and transient ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C:N differed among the three ecosystem types (temperate deciduous < tropical evergreen < temperature evergreen), a result that compared well to observations from a global database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C:N. Also, a widely used linear leaf N-respiration relationship did not yield a realistic leaf C:N, while a more recently reported non-linear relationship simulated leaf C:N that compared better to the global trait database than the linear relationship. Overall, our ability to constrain leaf area index and allow spatially and temporally variable leaf C:N can help address challenges simulating these properties in ecosystem and Earth System models. Furthermore, the simple approach with emergent properties based on coupled C-N dynamics has potential for use in research that uses data-assimilation methods to integrate data on both the C and N cycles to improve C flux forecasts.

Antisense inhibition of tomato fruit sucrose synthase decreases fruit setting and the sucrose unloading capacity of young fruit.

PubMed Central

D'Aoust, M A; Yelle, S; Nguyen-Quoc, B

1999-01-01

The role of sucrose synthase (SuSy) in tomato fruit was studied in transgenic tomato (Lycopersicon esculentum) plants expressing an antisense fragment of fruit-specific SuSy RNA (TOMSSF) under the control of the cauliflower mosaic virus 35S promoter. Constitutive expression of the antisense RNA markedly inhibited SuSy activity in flowers and fruit pericarp tissues. However, inhibition was only slight in the endosperm and was undetectable in the embryo, shoot, petiole, and leaf tissues. The activity of sucrose phosphate synthase decreased in parallel with that of SuSy, but acid invertase activity did not increase in response to the reduced SuSy activity. The only effect on the carbohydrate content of young fruit was a slight reduction in starch accumulation. The in vitro sucrose import capacity of fruits was not reduced by SuSy inhibition at 23 days after anthesis, and the rate of starch synthesized from the imported sucrose was not lessened even when SuSy activity was decreased by 98%. However, the sucrose unloading capacity of 7-day-old fruit was substantially decreased in lines with low SuSy activity. In addition, the SuSy antisense fruit from the first week of flowering had a slower growth rate. A reduced fruit set, leading to markedly less fruit per plant at maturity, was observed for the plants with the least SuSy activity. These results suggest that SuSy participates in the control of sucrose import capacity of young tomato fruit, which is a determinant for fruit set and development. PMID:10590167

Highly Decorated Lignins in Leaf Tissues of the Canary Island Date Palm Phoenix canariensis1[OPEN

PubMed Central

Bartuce, Allison; Free, Heather C.A.; Smith, Bronwen G.

2017-01-01

The cell walls of leaf base tissues of the Canary Island date palm (Phoenix canariensis) contain lignins with the most complex compositions described to date. The lignin composition varies by tissue region and is derived from traditional monolignols (ML) along with an unprecedented range of ML conjugates: ML-acetate, ML-benzoate, ML-p-hydroxybenzoate, ML-vanillate, ML-p-coumarate, and ML-ferulate. The specific functions of such complex lignin compositions are unknown. However, the distribution of the ML conjugates varies depending on the tissue region, indicating that they may play specific roles in the cell walls of these tissues and/or in the plant’s defense system. PMID:28894022

Structural assessment of the impact of environmental constraints on Arabidopsis thaliana leaf growth: a 3D approach.

PubMed

Wuyts, Nathalie; Massonnet, Catherine; Dauzat, Myriam; Granier, Christine

2012-09-01

Light and soil water content affect leaf surface area expansion through modifications in epidermal cell numbers and area, while effects on leaf thickness and mesophyll cell volumes are far less documented. Here, three-dimensional imaging was applied in a study of Arabidopsis thaliana leaf growth to determine leaf thickness and the cellular organization of mesophyll tissues under moderate soil water deficit and two cumulative light conditions. In contrast to surface area, thickness was highly conserved in response to water deficit under both low and high cumulative light regimes. Unlike epidermal and palisade mesophyll tissues, no reductions in cell number were observed in the spongy mesophyll; cells had rather changed in volume and shape. Furthermore, leaf features of a selection of genotypes affected in leaf functioning were analysed. The low-starch mutant pgm had very thick leaves because of unusually large palisade mesophyll cells, together with high levels of photosynthesis and stomatal conductance. By means of an open stomata mutant and a 9-cis-epoxycarotenoid dioxygenase overexpressor, it was shown that stomatal conductance does not necessarily have a major impact on leaf dimensions and cellular organization, pointing to additional mechanisms for the control of CO(2) diffusion under high and low stomatal conductance, respectively. © 2012 Blackwell Publishing Ltd.

The site of water stress governs the pattern of ABA synthesis and transport in peanut

PubMed Central

Hu, Bo; Cao, Jiajia; Ge, Kui; Li, Ling

2016-01-01

Abscisic acid (ABA) is one of the most important phytohormones involved in stress responses in plants. However, knowledge of the effect on ABA distribution and transport of water stress at different sites on the plant is limited. In this study, water stress imposed on peanut leaves or roots by treatment with PEG 6000 is termed “leaf stress” or “root stress”, respectively. Immunoenzyme localization technolony was first used to detect ABA distribution in peanut. Under root stress, ABA biosynthesis and distribution level were all more pronounced in root than in leaf. However, ABA transport and the ability to induce stomatal closure were still better in leaf than in root during root stress; However, ABA biosynthesis initially increased in leaf, then rapidly accumulated in the vascular cambium of leaves and induced stomatal closure under leaf stress; ABA produced in root tissues was also transported to leaf tissues to maintain stomatal closure. The vascular system was involved in the coordination and integration of this complex regulatory mechanism for ABA signal accumulation. Water stress subject to root or leaf results in different of ABA biosynthesis and transport ability that trigger stoma close in peanut. PMID:27694957

Induction of direct and indirect plant responses by jasmonic acid, low spider mite densities, or a combination of jasmonic acid treatment and spider mite infestation.

PubMed

Gols, Rieta; Roosjen, Mara; Dijkman, Herman; Dicke, Marcel

2003-12-01

Jasmonic acid (JA) and the octadecanoid pathway are involved in both induced direct and induced indirect plant responses. In this study, the herbivorous mite, Tetranychus urticae, and its predator, Phytoseiulus persimilis, were given a choice between Lima bean plants induced by JA or spider mites and uninduced control plants. Infestation densities resulting in the induction of predator attractants were much lower than thus far assumed, i.e., predatory mites were significantly attracted to plants that were infested for 2 days with only one or four spider mites per plant. Phytoseiulus persimilis showed a density-dependent response to volatiles from plants that were infested with different numbers of spider mites. Similarly, treating plants with increasing concentrations of JA also led to increased attraction of P. persimilis. Moreover, the duration of spider mite infestation was positively correlated with the proportion of predators that were attracted to mite-infested plants. A pretreatment of the plants with JA followed by a spider mite infestation enhanced the attraction of P. persimilis to plant volatiles compared to attraction to volatiles from plants that were only infested with spider mites and did not receive a pretreatment with JA. The herbivore, T. urticae preferred leaf tissue that previously had been infested with conspecifics to uninfested leaf tissue. In the case of choice tests with JA-induced and control leaf tissue, spider mites slightly preferred control leaf tissue. When spider mites were given a choice between leaf discs induced by JA and leaf discs damaged by spider mite feeding, they preferred the latter. The presence of herbivore induced chemicals and/or spider mite products enhanced settlement of the mites, whereas treatment with JA seemed to impede settlement.

Visualisation by high resolution synchrotron X-ray phase contrast micro-tomography of gas films on submerged superhydrophobic leaves.

PubMed

Lauridsen, Torsten; Glavina, Kyriaki; Colmer, Timothy David; Winkel, Anders; Irvine, Sarah; Lefmann, Kim; Feidenhans'l, Robert; Pedersen, Ole

2014-10-01

Floods can completely submerge terrestrial plants but some wetland species can sustain O2 and CO2 exchange with the environment via gas films forming on superhydrophobic leaf surfaces. We used high resolution synchrotron X-ray phase contrast micro-tomography in a novel approach to visualise gas films on submerged leaves of common cordgrass (Spartina anglica). 3D tomograms enabled a hitherto unmatched level of detail regarding the micro-topography of leaf gas films. Gas films formed only on the superhydrophobic adaxial leaf side (water droplet contact angle, Φ=162°) but not on the abaxial side (Φ=135°). The adaxial side of the leaves of common cordgrass is plicate with a longitudinal system of parallel grooves and ridges and the vast majority of the gas film volume was found in large ∼180μm deep elongated triangular volumes in the grooves and these volumes were connected to each neighbouring groove via a fine network of gas tubules (∼1.7μm diameter) across the ridges. In addition to the gas film retained on the leaf exterior, the X-ray phase contrast micro-tomography also successfully distinguished gas spaces internally in the leaf tissues, and the tissue porosity (gas volume per unit tissue volume) ranged from 6.3% to 20.3% in tip and base leaf segments, respectively. We conclude that X-ray phase contrast micro-tomography is a powerful tool to obtain quantitative data of exterior gas features on biological samples because of the significant difference in electron density between air, biological tissues and water. Copyright © 2014 Elsevier Inc. All rights reserved.

Oxygen radical absorbance capacity (ORAC) and phenolic and anthocyanin concentrations in fruit and leaf tissues of highbush blueberry.

PubMed

Ehlenfeldt, M K; Prior, R L

2001-05-01

Antioxidant capacity, as measured by oxygen radical absorbance capacity (ORAC), and total phenolic and total anthocyanin contents were evaluated in fruit tissues of 87 highbush blueberry (Vacciniumcorymbosum L.) and species-introgressed highbush blueberry cultivars. ORAC and phenolic levels were evaluated in leaf tissues of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units, 1.79 mg/g (gallic acid equivalents), and 0.95 mg/g (cyanidin-3-glucoside equivalents), respectively. Cv. Rubel had the highest ORAC per gram of fresh weight values, at 31.1 units, and cv. Elliott had the highest values on the basis of ORAC per square centimeter of surface area. In leaf tissue, values for both ORAC and phenolics were significantly higher than in fruit tissue, with mean values of 490 ORAC units and 44.80 mg/g (gallic acid equivalents), respectively. Leaf ORAC had a low, but significant, correlation with fruit phenolics and anthocyanins, but not with fruit ORAC. An analysis of ORAC values versus calculated midparent values in 11 plants from the 87-cultivar group in which all parents were tested suggested that, across cultivars, ORAC inheritance is additive. An investigation of ORAC values in a family of 44 cv. Rubel x Duke seedlings showed negative epistasis for ORAC values, suggesting Rubel may have gene combinations contributing to ORAC that are broken up during hybridization.

Invasion of Solanum tuberosum L. by Aspergillus terreus: a microscopic and proteomics insight on pathogenicity.

PubMed

Louis, Bengyella; Waikhom, Sayanika Devi; Roy, Pranab; Bhardwaj, Pardeep Kumar; Singh, Mohendro Wakambam; Chandradev, Sharma K; Talukdar, Narayan Chandra

2014-06-10

Aspergillus terreus is one of the most harmful filamentous fungal pathogen of humans, animals and plants. Recently, researchers have discovered that A. terreus can cause foliar blight disease in potato (Solanum tuberosum L.). We used light and scanning electron microscopy, and performed proteomics analysis in an attempt to dissect the invasion process of A. terreus in this important crop. Microscopic study revealed that invasion of leaf tissue is marked by rapid germination of A. terreus phialidic conidia (PC) by 4 h after inoculation. By 8 h after inoculation, primary germ tubes from PC differentiated into irregular protuberance, often displayed stomata atropism, and failed to penetrate via the epidermal cells. Colonization of leaf tissues was associated with high rate of production of accessory conidia (AC). These analyses showed the occurrence of a unique opposing pattern of AC, tissue-specific and produced on melanized colonizing hyphae during the infection of leaf tissue. A significant proteome change hallmarked by differential expression of class I patatin, lipoxygenase, catalase-peroxidase complex, and cysteine proteinase inhibitor were observed during tuber colonization. These proteins are often involved in signal transduction pathways and crosstalk in pathogenic responses. A. terreus abundantly produced AC and multipolar germinating PC to invade potato leaf tissue. Additionally, A. terreus differentially induced enzymes in potato tuber during colonization which facilitates rapid disease development.

Invasion of Solanum tuberosum L. by Aspergillus terreus: a microscopic and proteomics insight on pathogenicity

PubMed Central

2014-01-01

Background Aspergillus terreus is one of the most harmful filamentous fungal pathogen of humans, animals and plants. Recently, researchers have discovered that A. terreus can cause foliar blight disease in potato (Solanum tuberosum L.). We used light and scanning electron microscopy, and performed proteomics analysis in an attempt to dissect the invasion process of A. terreus in this important crop. Results Microscopic study revealed that invasion of leaf tissue is marked by rapid germination of A. terreus phialidic conidia (PC) by 4 h after inoculation. By 8 h after inoculation, primary germ tubes from PC differentiated into irregular protuberance, often displayed stomata atropism, and failed to penetrate via the epidermal cells. Colonization of leaf tissues was associated with high rate of production of accessory conidia (AC). These analyses showed the occurrence of a unique opposing pattern of AC, tissue-specific and produced on melanized colonizing hyphae during the infection of leaf tissue. A significant proteome change hallmarked by differential expression of class I patatin, lipoxygenase, catalase-peroxidase complex, and cysteine proteinase inhibitor were observed during tuber colonization. These proteins are often involved in signal transduction pathways and crosstalk in pathogenic responses. Conclusion A. terreus abundantly produced AC and multipolar germinating PC to invade potato leaf tissue. Additionally, A. terreus differentially induced enzymes in potato tuber during colonization which facilitates rapid disease development. PMID:24917207

Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) Larval Performance on Eight Populus Clones

Treesearch

David R. Coyle; Joel D. McMillin; Richard B. Hall; Elwood R. Hart

2001-01-01

Abstract: The cottonwood leaf beetle, Chrysomela scripta F., is the most serious defoliator of young plantation-grown Populus in the eastern United States, yet there is a paucity of data on larval feeding performance across Populus clones used in tree breeding. Field experiments were conducted in 1998 and 1999...

How Does Alkali Aid Protein Extraction in Green Tea Leaf Residue: A Basis for Integrated Biorefinery of Leaves.

PubMed

Zhang, Chen; Sanders, Johan P M; Xiao, Ting T; Bruins, Marieke E

2015-01-01

Leaf protein can be obtained cost-efficiently by alkaline extraction, but overuse of chemicals and low quality of (denatured) protein limits its application. The research objective was to investigate how alkali aids protein extraction of green tea leaf residue, and use these results for further improvements in alkaline protein biorefinery. Protein extraction yield was studied for correlation to morphology of leaf tissue structure, protein solubility and hydrolysis degree, and yields of non-protein components obtained at various conditions. Alkaline protein extraction was not facilitated by increased solubility or hydrolysis of protein, but positively correlated to leaf tissue disruption. HG pectin, RGII pectin, and organic acids were extracted before protein extraction, which was followed by the extraction of cellulose and hemi-cellulose. RGI pectin and lignin were both linear to protein yield. The yields of these two components were 80% and 25% respectively when 95% protein was extracted, which indicated that RGI pectin is more likely to be the key limitation to leaf protein extraction. An integrated biorefinery was designed based on these results.

Feeding Behaviour on Host Plants May Influence Potential Exposure to Bt Maize Pollen of Aglais Urticae Larvae (Lepidoptera, Nymphalidae)

PubMed Central

Lang, Andreas; Otto, Mathias

2015-01-01

Non-target butterfly larvae may be harmed by feeding on host plants dusted with Bt maize pollen. Feeding patterns of larvae and their utilization of host plants can affect the adverse Bt impact because the maize pollen is distributed unequally on the plant. In a field study, we investigated the feeding of larvae of the Small Tortoiseshell, Aglais urticae, on nettles, Urtica dioica. Young larvae used smaller host plants than older larvae. In general, the position of the larvae was in the top part of the host plant, but older larvae showed a broader vertical distribution on the nettles. Leaf blades and leaf tips were the plant parts most often consumed. Leaf veins were consumed but midribs were fed on to a lesser extent than other plant veins, particularly by young larvae. The feeding behavior of the larvae may increase possible exposure to Bt maize pollen because pollen densities are expected to be higher on the top parts and along leaf veins of nettles. PMID:26463415

The hydrostatic gradient, not light availability, drives height-related variation in Sequoia sempervirens (Cupressaceae) leaf anatomy.

PubMed

Oldham, Alana R; Sillett, Stephen C; Tomescu, Alexandru M F; Koch, George W

2010-07-01

Leaves at the tops of most trees are smaller, thicker, and in many other ways different from leaves on the lowermost branches. This height-related variation in leaf structure has been explained as acclimation to differing light environments and, alternatively, as a consequence of hydrostatic, gravitational constraints on turgor pressure that reduce leaf expansion. • To separate hydrostatic effects from those of light availability, we used anatomical analysis of height-paired samples from the inner and outer tree crowns of tall redwoods (Sequoia sempervirens). • Height above the ground correlates much more strongly with leaf anatomy than does light availability. Leaf length, width, and mesophyll porosity all decrease linearly with height and help explain increases in leaf-mass-to-area ratio and decreases in both photosynthetic capacity and internal gas-phase conductance with increasing height. Two functional traits-leaf thickness and transfusion tissue-also increase with height and may improve water-stress tolerance. Transfusion tissue area increases enough that whole-leaf vascular volume does not change significantly with height in most trees. Transfusion tracheids become deformed with height, suggesting they may collapse under water stress and act as a hydraulic buffer that improves leaf water status and reduces the likelihood of xylem dysfunction. • That such variation in leaf structure may be caused more by gravity than by light calls into question use of the terms "sun" and "shade" to describe leaves at the tops and bottoms of tall tree crowns.

Elevated air humidity affects hydraulic traits and tree size but not biomass allocation in young silver birches (Betula pendula)

PubMed Central

Sellin, Arne; Rosenvald, Katrin; Õunapuu-Pikas, Eele; Tullus, Arvo; Ostonen, Ivika; Lõhmus, Krista

2015-01-01

As changes in air temperature, precipitation, and air humidity are expected in the coming decades, studies on the impact of these environmental shifts on plant growth and functioning are of major importance. Greatly understudied aspects of climate change include consequences of increasing air humidity on forest ecosystems, predicted for high latitudes. The main objective of this study was to find a link between hydraulic acclimation and shifts in trees’ resource allocation in silver birch (Betula pendula Roth) in response to elevated air relative humidity (RH). A second question was whether the changes in hydraulic architecture depend on tree size. Two years of application of increased RH decreased the biomass accumulation in birch saplings, but the biomass partitioning among aboveground parts (leaves, branches, and stems) remained unaffected. Increased stem Huber values (xylem cross-sectional area to leaf area ratio) observed in trees under elevated RH did not entail changes in the ratio of non-photosynthetic to photosynthetic tissues. The reduction of stem–wood density is attributable to diminished mechanical load imposed on the stem, since humidified trees had relatively shorter crowns. Growing under higher RH caused hydraulic conductance of the root system (KR) to increase, while KR (expressed per unit leaf area) decreased and leaf hydraulic conductance increased with tree size. Saplings of silver birch acclimate to increasing air humidity by adjusting plant morphology (live crown length, slenderness, specific leaf area, and fine-root traits) and wood density rather than biomass distribution among aboveground organs. The treatment had a significant effect on several hydraulic properties of the trees, while the shifts were largely associated with changes in tree size but not in biomass allocation. PMID:26528318

Retranslocation of foliar nutrients in evergreen tree species planted in a Mediterranean environment.

PubMed

Fife, D N; Nambiar, E K S; Saur, E

2008-02-01

Internal nutrient recycling through retranslocation (resorption) is important for meeting the nutrient demands of new tissue production in trees. We conducted a comparative study of nutrient retranslocation from leaves of five tree species from three genera grown in plantation forests for commercial or environmental purposes in southern Australia--Acacia mearnsii De Wild., Eucalyptus globulus Labill., E. fraxinoides H. Deane & Maiden, E. grandis W. Hill ex Maiden and Pinus radiata D. Don. Significant amounts of nitrogen, phosphorus and potassium were retranslocated during three phases of leaf life. In the first phase, retranslocation occurred from young leaves beginning 6 months after leaf initiation, even when leaves were physiologically most active. In the second phase, retranslocation occurred from mature green leaves during their second year, and in the third phase, retranslocation occurred during senescence before leaf fall. Nutrient retranslocation occurred mainly in response to new shoot production. The pattern of retranslocation was remarkably similar in the leaves of all study species (and in the phyllodes of Casuarina glauca Sieber ex Spreng.), despite their diverse genetics, leaf forms and growth rates. There was no net retranslocation of calcium in any of the species. The amounts of nutrients at the start of each pre-retranslocation phase had a strong positive relationship with the amounts subsequently retranslocated, and all species fitted a common relationship. The percentage reduction in concentration or content (retranslocation efficiency) at a particular growth phase is subject to many variables, even within a species, and is therefore not a meaningful measure of interspecific variation. It is proposed that the pattern of retranslocation and its governing factors are similar among species in the absence of interspecies competition for growth and crown structure which occurs in mixed species stands.

Effects of elevated atmospheric CO2 concentrations, clipping regimen and differential day/night atmospheric warming on tissue nitrogen concentrations of a perennial pasture grass

PubMed Central

Volder, Astrid; Gifford, Roger M.; Evans, John R.

2015-01-01

Forecasting the effects of climate change on nitrogen (N) cycling in pastures requires an understanding of changes in tissue N. We examined the effects of elevated atmospheric CO2 concentration, atmospheric warming and simulated grazing (clipping frequency) on aboveground and belowground tissue N concentrations and C : N ratios of a C3 pasture grass. Phalaris aquatica L. cv. ‘Holdfast’ was grown in the field in six transparent temperature gradient tunnels (18 × 1.5 × 1.5 m each), three at ambient atmospheric CO2 and three at 759 p.p.m. CO2. Within each tunnel, there were three air temperature treatments: ambient control, +2.2/+4.0 °C above ambient day/night warming and +3.0 °C continuous warming. A frequent and an infrequent clipping treatment were applied to each warming × CO2 combination. Green leaf N concentrations were decreased by elevated CO2 and increased by more frequent clipping. Both warming treatments increased leaf N concentrations under ambient CO2 concentrations, but did not significantly alter leaf N concentrations under elevated CO2 concentrations. Nitrogen resorption from leaves was decreased under elevated CO2 conditions as well as by more frequent clipping. Fine root N concentrations decreased strongly with increasing soil depth and were further decreased at the 10–60 cm soil depths by elevated CO2 concentrations. The interaction between the CO2 and warming treatments showed that leaf N concentration was affected in a non-additive manner. Changes in leaf C : N ratios were driven by changes in N concentration. Overall, the effects of CO2, warming and clipping treatments on aboveground tissue N concentrations were much greater than on belowground tissue. PMID:26272874

Nutrition versus defense: Why Myzus persicae (green peach aphid) prefers and performs better on young leaves of cabbage

PubMed Central

Cao, He-He; Zhang, Zhan-Feng; Wang, Xiao-Feng

2018-01-01

Plant leaves of different ages differ in nutrients and toxic metabolites and thus exhibit various resistance levels against insect herbivores. However, little is known about the influence of leaf ontogeny on plant resistance to phloem-feeding insects. In this study, we found that the green peach aphid, Myzus persicae, preferred to settle on young cabbage leaves compared with mature or old leaves, although young leaves contained the highest concentration of glucosinolates. Furthermore, aphids feeding on young leaves had higher levels of glucosinolates in their body, but aphids performed better on young leaves in terms of body weight and population growth. Phloem sap of young leaves had higher amino acid:sugar molar ratio than mature leaves, and aphids feeding on young leaves showed two times longer phloem feeding time and five times more honeydew excretion than on other leaves. These results indicate that aphids acquired the highest amount of nutrients and defensive metabolites when feeding on young cabbage leaves that are strong natural plant sinks. Accordingly, we propose that aphids generally prefer to obtain more nutrition rather than avoiding host plant defense, and total amount of nutrition that aphids could obtain is significantly influenced by leaf ontogeny or source-sink status of feeding sites. PMID:29684073

Enhanced Transgene Expression in Sugarcane by Co-Expression of Virus-Encoded RNA Silencing Suppressors

PubMed Central

Park, Jong-Won; Beyene, Getu; Buenrostro-Nava, Marco T.; Molina, Joe; Wang, Xiaofeng; Ciomperlik, Jessica J.; Manabayeva, Shuga A.; Alvarado, Veria Y.; Rathore, Keerti S.; Scholthof, Herman B.; Mirkov, T. Erik

2013-01-01

Post-transcriptional gene silencing is commonly observed in polyploid species and often poses a major limitation to plant improvement via biotechnology. Five plant viral suppressors of RNA silencing were evaluated for their ability to counteract gene silencing and enhance the expression of the Enhanced Yellow Fluorescent Protein (EYFP) or the β-glucuronidase (GUS) reporter gene in sugarcane, a major sugar and biomass producing polyploid. Functionality of these suppressors was first verified in Nicotiana benthamiana and onion epidermal cells, and later tested by transient expression in sugarcane young leaf segments and protoplasts. In young leaf segments co-expressing a suppressor, EYFP reached its maximum expression at 48–96 h post-DNA introduction and maintained its peak expression for a longer time compared with that in the absence of a suppressor. Among the five suppressors, Tomato bushy stunt virus-encoded P19 and Barley stripe mosaic virus-encoded γb were the most efficient. Co-expression with P19 and γb enhanced EYFP expression 4.6-fold and 3.6-fold in young leaf segments, and GUS activity 2.3-fold and 2.4-fold in protoplasts compared with those in the absence of a suppressor, respectively. In transgenic sugarcane, co-expression of GUS and P19 suppressor showed the highest accumulation of GUS levels with an average of 2.7-fold more than when GUS was expressed alone, with no detrimental phenotypic effects. The two established transient expression assays, based on young leaf segments and protoplasts, and confirmed by stable transgene expression, offer a rapid versatile system to verify the efficiency of RNA silencing suppressors that proved to be valuable in enhancing and stabilizing transgene expression in sugarcane. PMID:23799071

Developmental priming of stomatal sensitivity to abscisic acid by leaf microclimate.

PubMed

Pantin, Florent; Renaud, Jeanne; Barbier, François; Vavasseur, Alain; Le Thiec, Didier; Rose, Christophe; Bariac, Thierry; Casson, Stuart; McLachlan, Deirdre H; Hetherington, Alistair M; Muller, Bertrand; Simonneau, Thierry

2013-09-23

Plant water loss and CO2 uptake are controlled by valve-like structures on the leaf surface known as stomata. Stomatal aperture is regulated by hormonal and environmental signals. We show here that stomatal sensitivity to the drought hormone abscisic acid (ABA) is acquired during leaf development by exposure to an increasingly dryer atmosphere in the rosette plant Arabidopsis. Young leaves, which develop in the center of the rosette, do not close in response to ABA. As the leaves increase in size, they are naturally exposed to increasingly dry air as a consequence of the spatial arrangement of the leaves, and this triggers the acquisition of ABA sensitivity. Interestingly, stomatal ABA sensitivity in young leaves is rapidly restored upon water stress. These findings shed new light on how plant architecture and stomatal physiology have coevolved to optimize carbon gain against water loss in stressing environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Identification of Stevioside Using Tissue Culture-Derived Stevia (Stevia rebaudiana) Leaves

PubMed Central

Karim, Md. Ziaul; Uesugi, Daisuke; Nakayama, Noriyuki; Hossain, M. Monzur; Ishihara, Kohji; Hamada, Hiroki

2015-01-01

Stevioside is a natural sweetener from Stevia leaf, which is 300 times sweeter than sugar. It helps to reduce blood sugar levels dramatically and thus can be of benefit to diabetic people. Tissue culture is a very potential modern technology that can be used in large-scale disease-free stevia production throughout the year. We successfully produced stevia plant through in vitro culture for identification of stevioside in this experiment. The present study describes a potential method for identification of stevioside from tissue culture-derived stevia leaf. Stevioside in the sample was identified using HPLC by measuring the retention time. The percentage of stevioside content in the leaf samples was found to be 9.6%. This identification method can be used for commercial production and industrialization of stevia through in vitro culture across the world. PMID:28008268

Distribution of resveratrol and stilbene synthase in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon) and the effect of UV-C on its accumulation.

PubMed

Wang, Wei; Tang, Ke; Yang, Hao-Ru; Wen, Peng-Fei; Zhang, Ping; Wang, Hui-Ling; Huang, Wei-Dong

2010-01-01

Current research indicated that the resveratrol was mainly accumulated in the skin of grape berry, however, little is yet known about the distribution of resveratrol, as well as the regulation mechanism at protein level and the localization of stilbene synthase (malonyl-CoA:4-coumaroyl-CoA malonyltransferase; EC 2.3.1.95; STS), a key enzyme of resveratrol biosynthesis, in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon). Resveratrol, whose constitutive level ranged from 0.2 mg kg(-1) FW to 16.5 mg kg(-1) FW, could be detected in stem, axillary bud, shoot tip, petiole, root and leaf of grape plants. Among them, stem phloems presented the most abundant of resveratrol, and the leaves presented the lowest. Interestingly, the level of STS mRNA and protein were highest in grape leaves. And the analysis of immunohistochemical showed the tissue-specific distribution of STS in different organs, presenting the similar results compared with the amount of protein. And the subcellular localization revealed that the cell wall in different tissues processed the most golden particles representing STS. Subjecting to UV-C irradiation, resveratrol and STS were both intensely stimulated in grape leaves, with the similar response pattern. Results above indicated that distribution of resveratrol and STS in grape was organ-specific and tissue-specific. And the accumulation of resveratrol induced by UV-C was regulated by transcriptional and translational level of STS. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Metabolic Profiling and Physiological Analysis of a Novel Rice Introgression Line with Broad Leaf Size

PubMed Central

Zhao, Xiuqin; Zhang, Guilian; Wang, Yun; Zhang, Fan; Wang, Wensheng; Zhang, Wenhao; Fu, Binying; Xu, Jianlong; Li, Zhikang

2015-01-01

A rice introgression line, NIL-SS1, and its recurrent parent, Teqing, were used to investigate the influence of the introgression segment on plant growth. The current research showed NIL-SS1 had an increased flag leaf width, total leaf area, spikelet number per panicle and grain yield, but a decreased photosynthetic rate. The metabolite differences in NIL-SS1 and Teqing at different developmental stages were assessed using gas chromatography—mass spectrometry technology. Significant metabolite differences were observed across the different stages. NIL-SS1 increased the plant leaf nitrogen content, and the greatest differences between NIL-SS1 and Teqing occurred at the booting stage. Compared to Teqing, the metabolic phenotype of NIL-SS1 at the booting stage has closer association with those at the flowering stage. The introgression segment induced more active competition for sugars and organic acids (OAs) from leaves to the growing young spikes, which resulted in more spikelet number per plant (SNP). The results indicated the introgression segment could improve rice grain yield by increasing the SNP and total leaf area per plant, which resulted from the higher plant nitrogen content across growth stages and stronger competition for sugars and OAs of young spikes at the booting stage. PMID:26713754

Wasabi leaf extracts attenuate adipocyte hypertrophy through PPARγ and AMPK.

PubMed

Oowatari, Yasuo; Ogawa, Tetsuro; Katsube, Takuya; Iinuma, Kiyohisa; Yoshitomi, Hisae; Gao, Ming

2016-08-01

Hypertrophy of adipocytes in obese adipose tissues causes metabolic abnormality by adipocytokine dysregulation, which promotes type 2 diabetes mellitus, hypertension, and dyslipidemia. We investigated the effects of wasabi (Wasabia japonica Matsum) leaf extracts on metabolic abnormalities in SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP/ZF), which are a model of metabolic syndrome. Male SHRSP/ZF rats aged 7 weeks were divided into two groups: control and wasabi leaf extract (WLE) groups, which received water or oral treatment with 4 g/kg/day WLE for 6 weeks. WLE improved the body weight gain and high blood pressure in SHRSP/ZF rats, and the plasma triglyceride levels were significantly lower in the WLE group. Adipocyte hypertrophy was markedly prevented in adipose tissue. The expression of PPARγ and subsequent downstream genes was suppressed in the WLE group adipose tissues. Our data suggest that WLE inhibits adipose hypertrophy by suppressing PPARγ expression in adipose tissue and stimulating the AMPK activity by increased adiponectin.

Reduction of Cr(VI) to Cr(III) by wetland plants: Potential for in situ heavy metal detoxification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lytle, C.M.; Qian, J.H.; Hansen, D.

1998-10-15

Reduction of heavy metals in situ by plants may be a useful detoxification mechanism for phytoremediation. Using X-ray spectroscopy, the authors show that Eichhornia crassipes (water hyacinth), supplied with Cr(VI) in nutrient culture, accumulated nontoxic Cr(III) in root and shoot tissues. The reduction of Cr(VI) to Cr(III) appeared to occur in the fine lateral roots. The Cr(III) was subsequently translocated to leaf tissues. Extended X-ray absorption fine structure of Cr in leaf and petiole differed when compared to Cr in roots. In roots, Cr(III) was hydrated by water, but in petiole and more so in leaf, a portion of themore » Cr(III) may be bound to oxalate ligands. This suggests that E. crassipes detoxified Cr(VI) upon root uptake and transported a portion of the detoxified Cr to leaf tissues. Cr-rich crystalline structures were observed on the leaf surface. The chemical species of Cr in other plants, collected from wetlands that contained Cr(VI)-contaminated wastewater, was also found to be Cr(III). The authors propose that this plant-based reduction of Cr(VI) by E. crassipes has the potential to be used for the in situ detoxification of Cr(VI)-contaminated wastestreams.« less

[Characterization of kale (Brassica oberacea var acephala) under thallium stress by in situ attenuated total reflection FTIR].

PubMed

Yao, Yan; Zhang, Ping; Wang, Zhen-Chun; Chen, Yong-Heng

2009-01-01

The experiment was designed based on consumption of carbon dioxide through the photosynthesis of Brassica oberacea var acephala leaf, and the photosynthesis of kale leaf under thallium stress was investigated by in situ attenuated total reflection FTIR (in situ ATR-FTIR). The ATR-FTIR showed that the absorption peaks of leaves had no obvious difference between plants growing in thallium stress soil and plants growing in non-thallium pollution soil, and the strong peaks at 3,380 cm(-1) could be assigned to the absorption of water, carbohydrate, protein or amide; the strong peaks at 2,916 and 2,850 cm(-1) assigned to the absorption of carbohydrate or aliphatic compound; the peaks at 1,640 cm(-1) assigned to the absorption of water. However, as detected by the in situ ATR-FTIR, the double peaks (negative peaks) at 2,360 and 2,340 cm(-1) that are assigned to the absorption of CO2 appeared and became high gradually. It was showed that kale was carrying photosynthesis. At the same time, the carbon dioxide consumption speed of leaf under thallium stress was obviously larger than that of the blank It was expressed that photosynthesis under thallium stress was stronger than the blank All these represented that kale had certain tolerance to the heavy metal thallium. Meanwhile, the carbon dioxide consumption of grown-up leaf was more than that of young leaf whether or not under thallium stress. It was also indicated that the intensity of photosynthesis in grown-up leaf is higher than that in young leaf.

Tree Species Richness Promotes Invertebrate Herbivory on Congeneric Native and Exotic Tree Saplings in a Young Diversity Experiment.

PubMed

Wein, Annika; Bauhus, Jürgen; Bilodeau-Gauthier, Simon; Scherer-Lorenzen, Michael; Nock, Charles; Staab, Michael

2016-01-01

Tree diversity in forests is an important driver of ecological processes including herbivory. Empirical evidence suggests both negative and positive effects of tree diversity on herbivory, which can be, respectively, attributed to associational resistance or associational susceptibility. Tree diversity experiments allow testing for associational effects, but evidence regarding which pattern predominates is mixed. Furthermore, it is unknown if herbivory on tree species of native vs. exotic origin is influenced by changing tree diversity in a similar way, or if exotic tree species escape natural enemies, resulting in lower damage that is unrelated to tree diversity. To address these questions, we established a young tree diversity experiment in temperate southwestern Germany that uses high planting density (49 trees per plot; plot size 13 m2). The species pool consists of six congeneric species pairs of European and North American origin (12 species in total) planted in monocultures and mixtures (1, 2, 4, 6 species). We assessed leaf damage by leaf-chewing insects on more than 5,000 saplings of six broadleaved tree species. Plot-level tree species richness increased leaf damage, which more than doubled from monocultures to six-species mixtures, strongly supporting associational susceptibility. However, leaf damage among congeneric native and exotic species pairs was similar. There were marked differences in patterns of leaf damage across tree genera, and only the genera likely having a predominately generalist herbivore community showed associational susceptibility, irrespective of the geographical origin of a tree species. In conclusion, an increase in tree species richness in young temperate forests may result in associational susceptibility to feeding by generalist herbivores.

Step changes in leaf oil accumulation via iterative metabolic engineering.

PubMed

Vanhercke, Thomas; Divi, Uday K; El Tahchy, Anna; Liu, Qing; Mitchell, Madeline; Taylor, Matthew C; Eastmond, Peter J; Bryant, Fiona; Mechanicos, Anna; Blundell, Cheryl; Zhi, Yao; Belide, Srinivas; Shrestha, Pushkar; Zhou, Xue-Rong; Ral, Jean-Philippe; White, Rosemary G; Green, Allan; Singh, Surinder P; Petrie, James R

2017-01-01

Synthesis and accumulation of plant oils in the entire vegetative biomass offers the potential to deliver yields surpassing those of oilseed crops. However, current levels still fall well short of those typically found in oilseeds. Here we show how transcriptome and biochemical analyses pointed to a futile cycle in a previously established Nicotiana tabacum line, accumulating up to 15% (dry weight) of the storage lipid triacylglycerol in leaf tissue. To overcome this metabolic bottleneck, we either silenced the SDP1 lipase or overexpressed the Arabidopsis thaliana LEC2 transcription factor in this transgenic background. Both strategies independently resulted in the accumulation of 30-33% triacylglycerol in leaf tissues. Our results demonstrate that the combined optimization of de novo fatty acid biosynthesis, storage lipid assembly and lipid turnover in leaf tissue results in a major overhaul of the plant central carbon allocation and lipid metabolism. The resulting further step changes in oil accumulation in the entire plant biomass offers the possibility of delivering yields that outperform current oilseed crops. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Survival, dispersal, and potential soil-mediated suppression of Phytophthora ramorum in a California redwood-tanoak forest.

PubMed

Fichtner, E J; Lynch, S C; Rizzo, D M

2009-05-01

Because the role of soil inoculum of Phytophthora ramorum in the sudden oak death disease cycle is not well understood, this work addresses survival, chlamydospore production, pathogen suppression, and splash dispersal of the pathogen in infested forest soils. Colonized rhododendron and bay laurel leaf disks were placed in mesh sachets before transfer to the field in January 2005 and 2006. Sachets were placed under tanoak, bay laurel, and redwood at three vertical locations: leaf litter surface, litter-soil interface, and below the soil surface. Sachets were retrieved after 4, 8, 20, and 49 weeks. Pathogen survival was higher in rhododendron leaf tissue than in bay tissue, with >80% survival observed in rhododendron tissue after 49 weeks in the field. Chlamydospore production was determined by clearing infected tissue in KOH. Moist redwood-associated soils suppressed chlamydospore production. Rain events splashed inoculum as high as 30 cm from the soil surface, inciting aerial infection of bay laurel and tanoak. Leaf litter may provide an incomplete barrier to splash dispersal. This 2-year study illustrates annual P. ramorum survival in soil and the suppressive nature of redwood-associated soils to chlamydospore production. Infested soil may serve as primary inoculum for foliar infections by splash dispersal during rain events.

Leaf area and photosynthesis of newly emerged trifoliolate leaves are regulated by mature leaves in soybean.

PubMed

Wu, Yushan; Gong, Wanzhuo; Wang, Yangmei; Yong, Taiwen; Yang, Feng; Liu, Weigui; Wu, Xiaoling; Du, Junbo; Shu, Kai; Liu, Jiang; Liu, Chunyan; Yang, Wenyu

2018-03-29

Leaf anatomy and the stomatal development of developing leaves of plants have been shown to be regulated by the same light environment as that of mature leaves, but no report has yet been written on whether such a long-distance signal from mature leaves regulates the total leaf area of newly emerged leaves. To explore this question, we created an investigation in which we collected data on the leaf area, leaf mass per area (LMA), leaf anatomy, cell size, cell number, gas exchange and soluble sugar content of leaves from three soybean varieties grown under full sunlight (NS), shaded mature leaves (MS) or whole plants grown in shade (WS). Our results show that MS or WS cause a marked decline both in leaf area and LMA in newly developing leaves. Leaf anatomy also showed characteristics of shade leaves with decreased leaf thickness, palisade tissue thickness, sponge tissue thickness, cell size and cell numbers. In addition, in the MS and WS treatments, newly developed leaves exhibited lower net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (E), but higher carbon dioxide (CO 2 ) concentration in the intercellular space (Ci) than plants grown in full sunlight. Moreover, soluble sugar content was significantly decreased in newly developed leaves in MS and WS treatments. These results clearly indicate that (1) leaf area, leaf anatomical structure, and photosynthetic function of newly developing leaves are regulated by a systemic irradiance signal from mature leaves; (2) decreased cell size and cell number are the major cause of smaller and thinner leaves in shade; and (3) sugars could possibly act as candidate signal substances to regulate leaf area systemically.

Effects of salt stress on ion balance and nitrogen metabolism of old and young leaves in rice (Oryza sativa L.)

PubMed Central

2012-01-01

Background It is well known that salt stress has different effects on old and young tissues. However, it remains largely unexplored whether old and young tissues have different regulatory mechanism during adaptation of plants to salt stress. The aim of this study was to investigate whether salt stress has different effects on the ion balance and nitrogen metabolism in the old and young leaves of rice, and to compare functions of both organs in rice salt tolerance. Results Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl− in old leaves. The up-regulation of OsHKT1;1, OsHAK10 and OsHAK16 might contribute to accumulation of Na+ in old leaves under salt stress. In addition, lower expression of OsHKT1;5 and OsSOS1 in old leaves may decrease frequency of retrieving Na+ from old leaf cells. Under salt stress, old leaves showed higher concentration of NO3− content than young leaves. Up-regulation of OsNRT1;2, a gene coding nitrate transporter, might contribute to the accumulation of NO3− in the old leaves of salt stressed-rice. Salt stress clearly up-regulated the expression of OsGDH2 and OsGDH3 in old leaves, while strongly down-regulated expression of OsGS2 and OsFd-GOGAT in old leaves. Conclusions The down-regulation of OsGS2 and OsFd-GOGAT in old leaves might be a harmful response to excesses of Na+ and Cl−. Under salt stress, rice might accumulate Na+ and Cl− to toxic levels in old leaves. This might influence photorespiration process, reduce NH4+ production from photorespiration, and immediately down-regulate the expression of OsGS2 and OsFd-GOGAT in old leaves of salt stressed rice. Excesses of Na+ and Cl− also might change the pathway of NH4+ assimilation in old leaves of salt stressed rice plants, weaken GOGAT/GS pathway and elevate GDH pathway. PMID:23082824

Red (anthocyanic) leaf margins do not correspond to increased phenolic content in New Zealand Veronica spp.

PubMed Central

Hughes, Nicole M.; Smith, William K.; Gould, Kevin S.

2010-01-01

Background and Aims Red or purple coloration of leaf margins is common in angiosperms, and is found in approx. 25 % of New Zealand Veronica species. However, the functional significance of margin coloration is unknown. We hypothesized that anthocyanins in leaf margins correspond with increased phenolic content in leaf margins and/or the leaf entire, signalling low palatability or leaf quality to edge-feeding insects. Methods Five species of Veronica with red leaf margins, and six species without, were examined in a common garden. Phenolic content in leaf margins and interior lamina regions of juvenile and fully expanded leaves was quantified using the Folin–Ciocalteu assay. Proportions of leaf margins eaten and average lengths of continuous bites were used as a proxy for palatability. Key Results Phenolic content was consistently higher in leaf margins compared with leaf interiors in all species; however, neither leaf margins nor more interior tissues differed significantly in phenolic content with respects to margin colour. Mean phenolic content was inversely correlated with the mean length of continuous bites, suggesting effective deterrence of grazing. However, there was no difference in herbivore consumption of red and green margins, and the plant species with the longest continuous grazing patterns were both red-margined. Conclusions Red margin coloration was not an accurate indicator of total phenolic content in leaf margins or interior lamina tissue in New Zealand Veronica. Red coloration was also ineffective in deterring herbivory on the leaf margin, though studies controlling for variations in leaf structure and biochemistry (e.g. intra-specific studies) are needed before more precise conclusions can be drawn. It is also recommended that future studies focus on the relationship between anthocyanin and specific defence compounds (rather than general phenolic pools), and evaluate possible alternative functions of red margins in leaves (e.g. antioxidants, osmotic adjustment). PMID:20145003

Intraspecific Relationships among Wood Density, Leaf Structural Traits and Environment in Four Co-Occurring Species of Nothofagus in New Zealand

PubMed Central

Richardson, Sarah J.; Allen, Robert B.; Buxton, Rowan P.; Easdale, Tomás A.; Hurst, Jennifer M.; Morse, Christopher W.; Smissen, Rob D.; Peltzer, Duane A.

2013-01-01

Plant functional traits capture important variation in plant strategy and function. Recent literature has revealed that within-species variation in traits is greater than previously supposed. However, we still have a poor understanding of how intraspecific variation is coordinated among different traits, and how it is driven by environment. We quantified intraspecific variation in wood density and five leaf traits underpinning the leaf economics spectrum (leaf dry matter content, leaf mass per unit area, size, thickness and density) within and among four widespread Nothofagus tree species in southern New Zealand. We tested whether intraspecific relationships between wood density and leaf traits followed widely reported interspecific relationships, and whether variation in these traits was coordinated through shared responses to environmental factors. Sample sites varied widely in environmental variables, including soil fertility (25–900 mg kg–1 total P), precipitation (668–4875 mm yr–1), temperature (5.2–12.4 °C mean annual temperature) and latitude (41–46 °S). Leaf traits were strongly correlated with one another within species, but not with wood density. There was some evidence for a positive relationship between wood density and leaf tissue density and dry matter content, but no evidence that leaf mass or leaf size were correlated with wood density; this highlights that leaf mass per unit area cannot be used as a surrogate for component leaf traits such as tissue density. Trait variation was predicted by environmental factors, but not consistently among different traits; e.g., only leaf thickness and leaf density responded to the same environmental cues as wood density. We conclude that although intraspecific variation in wood density and leaf traits is strongly driven by environmental factors, these responses are not strongly coordinated among functional traits even across co-occurring, closely-related plant species. PMID:23527041

Field performance of Populus expressing somaclonal variation in resistance to Septoria musiva

Treesearch

M. E. Ostry; K. T. Ward

2003-01-01

Over 1500 trees from two hybrid poplar clones regenerated from tissue culture and expressing somatic variation in leaf disease resistance in a laboratory leaf disk bioassay were field-tested for 5-11 years to examine their resistance to Septoria leaf spot and canker and to assess their growth characteristics compared with the source clones....

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; An Nguyen, Thien; Alfano, Robert R.

2014-06-01

Two-photon (2P) excitation of the second singlet (S) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S2 state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf.

PubMed

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; Nguyen, Thien An; Alfano, Robert R

2014-06-01

Two-photon (2P) excitation of the second singlet (S₂) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S₂ state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S₂ state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

The effects of different UV-B radiation intensities on morphological and biochemical characteristics in Ocimum basilicum L.

PubMed

Sakalauskaitė, Jurga; Viskelis, Pranas; Dambrauskienė, Edita; Sakalauskienė, Sandra; Samuolienė, Giedrė; Brazaitytė, Aušra; Duchovskis, Pavelas; Urbonavičienė, Dalia

2013-04-01

The effects of short-term ultraviolet B (UV-B) irradiation on sweet basil (Ocimum basilicum L. cv. Cinnamon) plants at the 3-4 leaf pair and flowering stages were examined in controlled environment growth chambers. Plants were exposed to 0 (reference), 2 and 4 kJ UV-B m(-2) day(-1) over 7 days. Exposure of basil plants to supplementary UV-B light resulted in increased assimilating leaf area, fresh biomass and dry biomass. Stimulation of physiological functions in young basil plants under either applied UV-B dose resulted in increased total chlorophyll content but no marked variation in carotenoid content. At the flowering stage the chlorophyll and carotenoid contents of basil were affected by supplementary UV-B radiation, decreasing with enhanced UV-B exposure. Both total antioxidant activity (2,2-diphenyl-1-picrylhydrazyl free radical assay) and total phenolic compound content were increased by UV-B light supplementation. Young and mature basil plants differed in their ascorbic acid content, which was dependent on UV-B dose and plant age. UV-B radiation resulted in decreased nitrate content in young basil plants (3-4 leaf pair stage). These results indicate that the application of short-exposure UV-B radiation beneficially influenced both growth parameters and biochemical constituents in young and mature basil plants. © 2012 Society of Chemical Industry.

High frequency plant regeneration from leaf derived callus of high Δ9-tetrahydrocannabinol yielding Cannabis sativa L.

PubMed

Lata, Hemant; Chandra, Suman; Khan, Ikhlas A; Elsohly, Mahmoud A

2010-10-01

An efficient in vitro propagation protocol for rapidly producing Cannabis sativa plantlets from young leaf tissue was developed. Using gas chromatography-flame ionization detection (GC-FID), high THC yielding elite female clone of a drug-type CANNABIS variety (MX) was screened and its vegetatively propagated clones were used for micropropagation. Calli were induced from leaf explant on Murashige and Skoog medium supplemented with different concentrations (0.5, 1.0, 1.5, and 2.0 µM) of indole- 3-acetic acid (IAA), indole- 3- butyric acid (IBA), naphthalene acetic acid (NAA), and 2,4-dichlorophenoxy-acetic acid (2,4-D) in combination with 1.0 µM of thidiazuron (TDZ) for the production of callus. The optimum callus growth and maintenance was in 0.5 µM NAA plus 1.0 µM TDZ. The two-month-old calli were subcultured to MS media containing different concentrations of cytokinins (BAP, KN, TDZ). The rate of shoot induction and proliferation was highest in 0.5 µM TDZ. Of the various auxins (IAA, IBA, and NAA) tested, regenerated shoots rooted best on half strength MS medium (1/2 - MS) supplemented with 2.5 µM IBA. The rooted plantlets were successfully established in soil and grown to maturity with no gross variations in morphology and cannabinoids content at a survival rate of 95 % in the indoor growroom. © Georg Thieme Verlag KG Stuttgart · New York.

HOW to Identify and Control Black Walnut Mycosphaerella Leaf Spots

Treesearch

Kenneth J. Jr. Kessler; Linda B.H. Swanson

1985-01-01

This leaf-spot disease, caused by the fungus Mycosphaerella juglandis, attacks black walnut, Juglans nigra, and Persian walnut, J. regia. Thus far, the disease has been found in North Carolina, Georgia, Illinois, and Iowa. It is important in young walnut plantations, where it causes premature defoliation, thus reducing growth and nut production. Affected walnut trees...

Olive Leaf Extract Elevates Hepatic PPAR α mRNA Expression and Improves Serum Lipid Profiles in Ovariectomized Rats.

PubMed

Yoon, Leena; Liu, Ya-Nan; Park, Hyunjin; Kim, Hyun-Sook

2015-07-01

We hypothesized that olive leaf extract might alleviate dyslipidemia resulting from estrogen deficiency. Serum lipid profile and mRNA expression of the related genes in the liver and adipose tissue were analyzed after providing olive leaf extract (200 or 400 mg/kg body weight; n=7 for each group) to ovariectomized rats for 10 weeks. After 10 weeks' administration, the rats in the olive leaf extract-administered groups showed significantly lower levels of serum triglyceride and very-low-density lipoprotein (VLDL)-cholesterol compared with the rats in the control group, whereas the administration of olive leaf extract did not significantly change the elevated low-density lipoprotein cholesterol levels. In addition, administration of high dose of olive leaf extract significantly decreased the liver triglyceride and increased serum estradiol levels. mRNA expressions of peroxisome proliferator-activated receptor alpha (PPAR α) and acyl-CoA oxidase (ACO) were not affected by ovariectomy, however, administration of olive leaf extract significantly increased both PPAR α and ACO mRNA expression. Expression of adiponectin mRNA in adipose tissue was significantly decreased in the ovariectomized control group. Rats administered low-dose olive leaf extract showed significantly elevated adiponectin mRNA expression compared with rats in the ovariectomized control group. Even though dose-dependent effects were not observed in most of the measurements, these results suggest that genes involved in lipid metabolism may be regulated by olive leaf extract administration in ovariectomized rats.

Effect of Urtica dioica Leaf Alcoholic and Aqueous Extracts on the Number and the Diameter of the Islets in Diabetic Rats.

PubMed

Qujeq, Durdi; Tatar, Mohsen; Feizi, Farideh; Parsian, Hadi; Sohan Faraji, Alieh; Halalkhor, Sohrab

2013-01-01

Urtica dioica has been known as a plant that decreases blood glucose. Despite the importance of this plant in herbal medicine, relatively little research has been down on effects of this plant on islets yet. The objective of the current study was to evaluate the effect of dried Urtica dioica leaf alcoholic and aqueous extracts on the number and the diameter of the islets and histological parameters in streptozocin-induced diabetic rats. Six rats were used in each group. Group I: Normal rats were administered saline daily for 8 weeks. Group II: Diabetic rats were administered streptozotocin, 50 mg/kg of body weight; Group III: Diabetic rats were administered dried Urtica dioica leaf aqueous extracts for 8 weeks; Group IV: Diabetic rats were administered dried Urtica dioica leaf alcoholic extracts for 8 weeks. The animals, groups of diabetic and normal, were sacrificed by ether anaesthesia. Whole pancreas was dissected. The tissue samples were formalin fixed and paraffin embedded for microscopic examination. Histologic examination and grading were carried out on hematoxylin-eosin stained sections. The effects of administration of dried Urtica dioica leaf alcoholic and aqueous extracts to diabetic rats were determined by histopathologic examination. The pancreas from control rats showed normal pancreatic islets histoarchitecture. Our results also, indicate that the pancreas from diabetic rats show injury of pancreas tissue while the pancreas from diabetic rats treated with dried Urtica dioica leaf alcoholic and aqueous extracts show slight to moderate rearrangement of islets. According to our findings, dried Urtica dioica leaf alcoholic and aqueous extracts can cause a suitable repair of pancreatic tissue in streptozocin-induced diabetic experimental model.

Effect of Urtica dioica Leaf Alcoholic and Aqueous Extracts on the Number and the Diameter of the Islets in Diabetic Rats

PubMed Central

Qujeq, Durdi; Tatar, Mohsen; Feizi, Farideh; Parsian, Hadi; Sohan Faraji, Alieh; Halalkhor, Sohrab

2013-01-01

Urtica dioica has been known as a plant that decreases blood glucose. Despite the importance of this plant in herbal medicine, relatively little research has been down on effects of this plant on islets yet. The objective of the current study was to evaluate the effect of dried Urtica dioica leaf alcoholic and aqueous extracts on the number and the diameter of the islets and histological parameters in streptozocin-induced diabetic rats. Six rats were used in each group. Group I: Normal rats were administered saline daily for 8 weeks. Group II: Diabetic rats were administered streptozotocin, 50 mg/kg of body weight; Group III: Diabetic rats were administered dried Urtica dioica leaf aqueous extracts for 8 weeks; Group IV: Diabetic rats were administered dried Urtica dioica leaf alcoholic extracts for 8 weeks. The animals, groups of diabetic and normal, were sacrificed by ether anaesthesia. Whole pancreas was dissected. The tissue samples were formalin fixed and paraffin embedded for microscopic examination. Histologic examination and grading were carried out on hematoxylin-eosin stained sections. The effects of administration of dried Urtica dioica leaf alcoholic and aqueous extracts to diabetic rats were determined by histopathologic examination. The pancreas from control rats showed normal pancreatic islets histoarchitecture. Our results also, indicate that the pancreas from diabetic rats show injury of pancreas tissue while the pancreas from diabetic rats treated with dried Urtica dioica leaf alcoholic and aqueous extracts show slight to moderate rearrangement of islets. According to our findings, dried Urtica dioica leaf alcoholic and aqueous extracts can cause a suitable repair of pancreatic tissue in streptozocin-induced diabetic experimental model. PMID:24551786

The Distribution of Catalase Activity, Isozyme Protein, and Transcript in the Tissues of the Developing Maize Seedling 1

PubMed Central

Redinbaugh, Margaret G.; Sabre, Mara; Scandalios, John G.

1990-01-01

The catalase activity, CAT-2 and CAT-3 isozyme protein levels, and the steady-state mRNA levels for each of the three catalase genes were determined in the scutellum, root, epicotyl, and leaf of the developing maize (Zea mays L.) seedling. Catalase activity was highest in the scutellum, with 10-fold lower enzyme activity in the leaf and epicotyl. Very low levels of catalase activity were found in the root. The highest levels of CAT-2 protein were found in the scutellum, with about 10-fold lower levels in the green leaf. CAT-2 protein was present in trace amounts early in root development and no CAT-2 protein was detected in the epicotyl. Shortly after germination, CAT-3 protein was present at high levels in both the epicotyl and green leaf. With development, the amount of CAT-3 protein decreased slowly in the epicotyl and rapidly in the green leaf. Low levels of this isozyme were detected in the scutellum and root. The Cat1 transcript accumulated to low levels in all four tissues during the 14 day developmental period. High levels of the Cat2 transcript were found in the scutellum, with moderate levels of the mRNA in the green leaf. The Cat2 transcript levels were very low in the root and epicotyl. While the Cat3 mRNA level in the scutellum was low, high levels of the Cat3 transcript were detected in the root, epicotyl, and leaf. There was a positive correlation between the accumulation of a catalase isozyme and its transcript, indicating that the tissue specificity of maize catalase gene expression was regulated pretranslationally. Images Figure 3 Figure 4 PMID:16667285

Transient etiolation: protochlorophyll(ide) and chlorophyll forms in differentiating plastids of closed and breaking leaf buds of horse chestnut (Aesculus hippocastanum).

PubMed

Solymosi, Katalin; Bóka, Károly; Böddi, Béla

2006-08-01

An accompanying paper reports the accumulation of photoactive protochlorophyllide (Pchlide) in the innermost leaf primordia of buds of many tree species. In this paper, we describe plastid differentiation, changes in pigment concentrations and spectral properties of bud scales and leaf primordia of horse chestnut (Aesculus hippocastanum L.) from January until the end of bud break in April. The bud scales contained plastids with grana, stroma thylakoids characteristic of chloroplasts and large dense bodies within the stroma. In January, proplastids and young chloroplasts were present in the leaf primordia, and the fluorescence spectra of the primordia were similar to those of green leaves except for a minor band at 630 nm, indicative of a protochlorophyll(ide). During bud break, the pigment concentrations of the green bud scales and the outermost leaf primordia increased, and Pchlide forms with emission maxima at 633, 644 and 655 nm accumulated in the middle and innermost leaf primordia. Depending on the position of the leaf primordia within the bud, their plastids and their pigment concentrations varied. Etio-chloroplasts with prolamellar bodies (PLBs) and prothylakoids with developing grana were observed in the innermost leaves. Besides the above-mentioned Pchlide forms, the middle and innnermost leaf primordia contained only a Chl band with an emission maximum at 686 nm. The outermost leaf primordia contained etio-chloroplasts with well-developed grana and small, narrow-type PLBs. These outermost leaves contained only chlorophyll forms like the mature green leaves. No Pchlide accumulation was observed after bud break, indicating that etiolation of the innermost and middle leaves is transient. The Pchlide forms and the plastid types of the primordia in buds grown in nature were similar to those of leaves of dark-germinated seedlings and to those of the leaf primordia of dark-forced buds. We conclude that transient etiolation occurs under natural conditions. The formation of PLBs and etio-chloroplasts and the accumulation of the light-dependent NADPH:protochlorophyllide oxidoreductase are involved in the natural greening process and ontogenesis of young leaf primordia of horse chestnut buds.

Topical Olive Leaf Extract Improves Healing of Oral Mucositis in Golden Hamsters.

PubMed

Showraki, Najmeh; Mardani, Maryam; Emamghoreishi, Masoumeh; Andishe-Tadbir, Azadeh; Aram, Alireza; Mehriar, Peiman; Omidi, Mahmoud; Sepehrimanesh, Masood; Koohi-Hosseinabadi, Omid; Tanideh, Nader

2016-12-01

Oral mucositis (OM) is a common side effect of anti-cancer drugs and needs significant attention for its prevention. This study aimed to evaluate the healing effects of olive leaf extract on 5-fluorouracil-induced OM in golden hamster. OM was induced in 63 male golden hamsters by the combination of 5-fluorouracil injections (days 0, 5 and 10) and the abrasion of the cheek pouch (days 3 and 4). On day 12, hamsters were received topical olive leaf extract ointment, base of ointment, or no treatment (control) for 5 days. Histopathology evaluations, blood examinations, and tissue malondialdehyde level measurement were performed 1, 3 and 5 days after treatments. Histopathology score and tissue malondialdehyde level were significantly lower in olive leaf extract treated group in comparison with control and base groups ( p = 0.000). Significant decreases in white blood cell, hemoglobin, hematocrit , and mean corpuscular volume and an increase in mean corpuscular hemoglobin concentration were observed in olive leaf extract treated group in comparison with control and base groups ( p < 0.05). Our findings demonstrated that daily application of olive leaf extract ointment had healing effect on 5-fluorouracil induced OM in hamsters. Moreover, the beneficial effect of olive leaf extract on OM might be due to its antioxidant and anti-inflammatory properties.

Effects of transgenic Bt rice on growth, reproduction, and superoxide dismutase activity of Folsomia candida (Collembola: Isotomidae) in laboratory studies.

PubMed

Bai, Yaoyu; Yan, Ruihong; Ke, Xin; Ye, Gongyin; Huang, Fangneng; Luo, Yongming; Cheng, Jiaan

2011-12-01

Transgenic rice expressing Bacillus thuringiensis (Bt) CrylAb protein is expected to be commercialized in China in the near future. The use of Bt rice for controlling insect pests sparks intensive debates regarding its biosafety. Folsomia candida is an euedaphic species and is often used as a "standard" test organism in assessing effects of environmental pollutants on soil organisms. In this study, growth, development, reproduction, and superoxide dismutase activity (SOD) of F. candida were investigated in the laboratory for populations reared on leaf tissue or leaf-soil mixtures of two CrylAb rice lines and a non-Bt rice isoline. Two independent tests were performed: 1) a 35-d test using petri dishes containing yeast diet (positive control) or fresh rice leaf tissue, and 2) a 28-d test in soil-litter microcosms containing yeast or a mixture of soil and rice leaf tissue. Biological parameters measured in both tests were number of progeny production, population growth rate, and SOD activity. For the petri dish test, data measured also included insect body length and number of exuviation. There were no significant differences between the populations reared on Bt and non-Bt rice leaf tissue in all measured parameters in both tests and for both Bt rice lines, suggesting no significant effects of the CrylAb protein in Bt rice on F. candida in the laboratory studies. Results of this study should add additional biosafety proofs for use of Bt rice to manage rice pests in China.

Staining paraffin embedded sections of scald of barley before paraffin removal.

PubMed

Xi, K; Burnett, P A

1997-07-01

Staining of paraffin embedded sections with periodic acid-Schiff reagent and fast green before paraffin removal resulted in differentiation of barley seed and leaf tissue from fungal structures of Rhynchosporium secalis. Crystal violet, toluidine blue O and antiline blue also successfully stained fungal structures of R. secalis in barley leaf tissues. Staining of embedded sections before paraffin removal allows simple processing of a series of sections, saves time and reduces solvent consumption.

Effects of nutrient addition on leaf chemistry, morphology, and photosynthetic capacity of three bog shrubs

Treesearch

Jill L. Bubier; Rose Smith; Sari Juutinen; Tim R. Moore; Rakesh Minocha; Stephanie Long; Subash Minocha

2011-01-01

Plants in nutrient-poor environments typically have low foliar nitrogen (N) concentrations, long-lived tissues with leaf traits designed to use nutrients efficiently, and low rates of photosynthesis. We postulated that increasing N availability due to atmospheric deposition would increase photosynthetic capacity, foliar N, and specific leaf area (SLA) of bog shrubs. We...

Protoplast isolation and genetically true-to-type plant regeneration from leaf- and callus-derived protoplasts of Albizia julibrissin

Treesearch

Mohammad-Shafie Rahmani; Paula M. Pijut; Naghi Shabanian

2016-01-01

Protoplast isolation and subsequent plant regeneration of Albizia julibrissin was achieved from leaf and callus explants. Leaf tissue from 4 to 5-week-old in vitro seedlings was the best source for high-yield protoplast isolation. This approach produced 7.77 × 105 protoplasts (Pp) per gram fresh weight with 94 % viability;...

[Influence of simulated acid rain on nitrogen and phosphorus contents and their stoichiome-tric ratios of tea organs in a red soil region, China].

PubMed

Zhang, Yu Fei; Fang, Xiang Min; Chen, Fu Sheng; Zong, Ying Ying; Gu, Han Jiao; Hu, Xiao Fei

2017-04-18

A 25-year-old tea plantation in a typical red soil region was selected for an in situ simulated acid rain experiment treated by pH 4.5, 3.5, 2.5 and water (control, CK). Roots with different functions, leaves and twigs with different ages were collected to measure nitrogen (N) and phosphorus (P) contents in the third year after simulated acid rain treatment. The N/P and acid rain sensitivity coefficient of tea plant organs were also calculated. The results indicated that with the increase of acid rain intensity, the soil pH, NO 3 - -N and available P decreased, while the absorption root N content increased. Compared with the control, the N content in absorption root was increased by 32.9% under the treatment of pH 2.5. The P content in storage root significantly decreased with enhanced acid rain intensity, and the acid rain treatment significantly enhanced N/P of absorption root. Young and mature leaf N, P contents were not sensitive to different intensities of acid rain, but the mature leaf N/P was significantly increased under pH 3.5 treatment compared with the control. The effects of acid rain treatments differed with tea twig ages. Compared with the control, low intensity acid treatment (pH 4.5) significantly increased young twig N content and N/P, while no signi-ficant differences in old twig N content and N/P were observed among four acid rain treatments. Acid rain sensitivity coefficients of absorption root, young leaf and twig N contents were higher than that of storage root, old leaf and twig, respectively. And the storage root and leaf P had higher acid rain sensitivity coefficient than other tea organs. In sum, tea organs N content was sensitive to acid rain treatment, and moderate acid rain could increase young organ N content and N/P, and change the cycle and balance of N and P in tea plantation.

Mangifera indica L. leaf extract alleviates doxorubicin induced cardiac stress

PubMed Central

Bhatt, Laxit; Joshi, Viraj

2017-01-01

Aim: The study was undertaken to evaluate the cardioprotective effect of the alcoholic leaf extract of Mangifera indica L. against cardiac stress caused by doxorubicin (DOX). Materials and Methods: Rats were treated with 100 mg/kg of M. indica leaf extract (MILE) in alone and interactive groups for 21 days. Apart from the normal and MILE control groups, all the groups were subjected to DOX (15 mg/kg, i.p.) toxicity for 21 days and effects of different treatments were analyzed by changes in serum biomarkers, tissue antioxidant levels, electrocardiographic parameters, lipid profile, and histopathological evaluation. Results: The MILE treated group showed decrease in serum biomarker enzyme levels and increase in tissue antioxidants levels. Compared to DOX control group, MILE treated animals showed improvement in lipid profile, electrocardiographic parameters, histological score, and mortality. Conclusion: These findings clearly suggest the protective role of alcoholic leaf extract of M. indica against oxidative stress induced by DOX. PMID:28894627

The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance.

PubMed

Bhatt, A; Naidoo, Y; Nicholas, A

2010-01-01

The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM). This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.

De novo assembly and analysis of the Artemisia argyi transcriptome and identification of genes involved in terpenoid biosynthesis.

PubMed

Liu, Miaomiao; Zhu, Jinhang; Wu, Shengbing; Wang, Chenkai; Guo, Xingyi; Wu, Jiawen; Zhou, Meiqi

2018-04-11

Artemisia argyi Lev. et Vant. (A. argyi) is widely utilized for moxibustion in Chinese medicine, and the mechanism underlying terpenoid biosynthesis in its leaves is suggested to play an important role in its medicinal use. However, the A. argyi transcriptome has not been sequenced. Herein, we performed RNA sequencing for A. argyi leaf, root and stem tissues to identify as many as possible of the transcribed genes. In total, 99,807 unigenes were assembled by analysing the expression profiles generated from the three tissue types, and 67,446 of those unigenes were annotated in public databases. We further performed differential gene expression analysis to compare leaf tissue with the other two tissue types and identified numerous genes that were specifically expressed or up-regulated in leaf tissue. Specifically, we identified multiple genes encoding significant enzymes or transcription factors related to terpenoid synthesis. This study serves as a valuable resource for transcriptome information, as many transcribed genes related to terpenoid biosynthesis were identified in the A. argyi transcriptome, providing a functional genomic basis for additional studies on molecular mechanisms underlying the medicinal use of A. argyi.

Prevention of pink-pigmented methylotrophic bacteria (Methylohacterium mesophilicum) contamination of plant tissue cultures.

PubMed

Chanprame, S; Todd, J J; Widholm, J M

1996-12-01

Pink-pigmented facultative methylotrophic bacteria (PPFMs) have been found on the surfaces of leaves of most plants tested. We found PPFMs on the leaf surfaces of all 40 plants (38 species) tested and on soybean pods by pressing onto AMS medium with methanol as the sole carbon source. The abundance ranged from 0.5 colony forming unit (cfu) /cm(2) to 69.4 cfu/cm(2) on the leaf surfaces. PPFMs were found in homogenized leaf tissues of only 4 of the species after surface disinfestation with 1.05% sodium hypochlorite and were rarely found in cultures initiated from surface disinfested Datura innoxia leaves or inside surface disinfested soybean pods. Of 20 antibiotics tested for PPFM growth inhibition, rifampicin was the most effective and of seven others which also inhibited PPFM growth, cefotaxime should be the most useful due to the expected low plant cell toxicity. These antibiotics could be used in concert with common surface sterilization procedures to prevent the introduction or to eliminate PPFM bacteria in tissue cultures. Thus, while PPFMs are present on the surfaces of most plant tissues, surface disinfestation alone can effectively remove them so that uncontaminated tissue cultures can be initiated in most cases.

Developmental Role and Auxin Responsiveness of Class III Homeodomain Leucine Zipper Gene Family Members in Rice1[C][W][OA

PubMed Central

Itoh, Jun-Ichi; Hibara, Ken-Ichiro; Sato, Yutaka; Nagato, Yasuo

2008-01-01

Members of the Class III homeodomain leucine zipper (Class III HD-Zip) gene family are central regulators of crucial aspects of plant development. To better understand the roles of five Class III HD-Zip genes in rice (Oryza sativa) development, we investigated their expression patterns, ectopic expression phenotypes, and auxin responsiveness. Four genes, OSHB1 to OSHB4, were expressed in a localized domain of the shoot apical meristem (SAM), the adaxial cells of leaf primordia, the leaf margins, and the xylem tissue of vascular bundles. In contrast, expression of OSHB5 was observed only in phloem tissue. Plants ectopically expressing microRNA166-resistant versions of the OSHB3 gene exhibited severe defects, including the ectopic production of leaf margins, shoots, and radialized leaves. The treatment of seedlings with auxin quickly induced ectopic OSHB3 expression in the entire region of the SAM, but not in other tissues. Furthermore, this ectopic expression of OSHB3 was correlated with leaf initiation defects. Our findings suggest that rice Class III HD-Zip genes have conserved functions with their homologs in Arabidopsis (Arabidopsis thaliana), but have also acquired specific developmental roles in grasses or monocots. In addition, some Class III HD-Zip genes may regulate the leaf initiation process in the SAM in an auxin-dependent manner. PMID:18567825

Freezing avoidance by supercooling in Olea europaea cultivars: the role of apoplastic water, solute content and cell wall rigidity.

PubMed

Arias, Nadia S; Bucci, Sandra J; Scholz, Fabian G; Goldstein, Guillermo

2015-10-01

Plants can avoid freezing damage by preventing extracellular ice formation below the equilibrium freezing temperature (supercooling). We used Olea europaea cultivars to assess which traits contribute to avoid ice nucleation at sub-zero temperatures. Seasonal leaf water relations, non-structural carbohydrates, nitrogen and tissue damage and ice nucleation temperatures in different plant parts were determined in five cultivars growing in the Patagonian cold desert. Ice seeding in roots occurred at higher temperatures than in stems and leaves. Leaves of cold acclimated cultivars supercooled down to -13 °C, substantially lower than the minimum air temperatures observed in the study site. During winter, leaf ice nucleation and leaf freezing damage (LT50 ) occurred at similar temperatures, typical of plant tissues that supercool. Higher leaf density and cell wall rigidity were observed during winter, consistent with a substantial acclimation to sub-zero temperatures. Larger supercooling capacity and lower LT50 were observed in cold-acclimated cultivars with higher osmotically active solute content, higher tissue elastic adjustments and lower apoplastic water. Irreversible leaf damage was only observed in laboratory experiments at very low temperatures, but not in the field. A comparative analysis of closely related plants avoids phylogenetic independence bias in a comparative study of adaptations to survive low temperatures. © 2015 John Wiley & Sons Ltd.

Spatially Different Tissue-Scale Diffusivity Shapes ANGUSTIFOLIA3 Gradient in Growing Leaves.

PubMed

Kawade, Kensuke; Tanimoto, Hirokazu; Horiguchi, Gorou; Tsukaya, Hirokazu

2017-09-05

The spatial gradient of signaling molecules is pivotal for establishing developmental patterns of multicellular organisms. It has long been proposed that these gradients could arise from the pure diffusion process of signaling molecules between cells, but whether this simplest mechanism establishes the formation of the tissue-scale gradient remains unclear. Plasmodesmata are unique channel structures in plants that connect neighboring cells for molecular transport. In this study, we measured cellular- and tissue-scale kinetics of molecular transport through plasmodesmata in Arabidopsis thaliana developing leaf primordia by fluorescence recovery assays. These trans-scale measurements revealed biophysical properties of diffusive molecular transport through plasmodesmata and revealed that the tissue-scale diffusivity, but not the cellular-scale diffusivity, is spatially different along the leaf proximal-to-distal axis. We found that the gradient in cell size along the developmental axis underlies this spatially different tissue-scale diffusivity. We then asked how this diffusion-based framework functions in establishing a signaling gradient of endogenous molecules. ANGUSTIFOLIA3 (AN3) is a transcriptional co-activator, and as we have shown here, it forms a long-range signaling gradient along the leaf proximal-to-distal axis to determine a cell-proliferation domain. By genetically engineering AN3 mobility, we assessed each contribution of cell-to-cell movement and tissue growth to the distribution of the AN3 gradient. We constructed a diffusion-based theoretical model using these quantitative data to analyze the AN3 gradient formation and demonstrated that it could be achieved solely by the diffusive molecular transport in a growing tissue. Our results indicate that the spatially different tissue-scale diffusivity is a core mechanism for AN3 gradient formation. This provides evidence that the pure diffusion process establishes the formation of the long-range signaling gradient in leaf development. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Technetium-99 cycling in maple trees: characterization of changes in chemical form.

PubMed

Garten, C T; Lomax, R D

1989-08-01

Prior field studies near an old radioactive waste disposal site at Oak Ridge, TN, indicated that following root uptake, metabolism by deciduous trees rendered 99Tc less biogeochemically mobile than expected, based on chemistry of the pertechnetate (TcO-4) anion. Subsequently, the form of technetium (Tc) in maple tree (Acer sp.) sap, leaves, wood and forest leaf litter was characterized using one or more of the following methods: dialysis, physical fractionation, chemical extraction, gel permeation chromatography, enzymatic extraction, or thin layer chromatography (TLC) on silica gel. Chromatography (Sephadex G-25) of TcO-4 incubated in vitro with tree sap showed it to behave similar to TcO-4 anion. When labeled wood and leaf tissues were processed using a tissue homogenizer, 15% and 40%, respectively, of the Tc was solubilized into phosphate buffer. Most (65% to 80%) of the solubilized Tc passing a 0.45-micron filter also passed through an ultrafiltration membrane with a nominal molecular weight cutoff of 10,000 atomic mass units (amu). A majority (72% to 80%) of the Tc in wood could be chemically removed by successive extractions with ethanol, water and weak mineral acid. These same extractants removed only 23% to 31% of the Tc from maple leaves or forest floor leaf litter. Most of the Tc in leaves and leaf litter was removed only by strongly alkaline reagents typically used to release structural polysaccharides (hemicelluloses) from plant tissues. Chromatography (Sephadex G-25) of the ethanol-water extract from wood and the alkaline extract from leaves demonstrated that Tc in these extracts was not principally TcO-4 but was complexed with molecules greater than 1000 amu. Incubations of leaf and wood homogenates with protease approximately doubled the amount of Tc released from contaminated tissues. Ultrafiltration of protease-solubilized Tc from leaves and wood showed that 40% and 93%, respectively, of the Tc was less than 10,000 amu. TLC of the less than 10,000 amu fraction indicated the presence of TcO-4 in wood but not in leaves. In the leaf, TcO-4 is converted to less soluble forms apparently associated with structural components of leaf cell walls. This conversion explains why 99Tc is not easily leached by rainfall from tree foliage and why 99Tc appears to accumulate in forest floor leaf litter layers at the Oak Ridge study site.

A noncoding RNA transcribed from the AGAMOUS (AG) second intron binds to CURLY LEAF and represses AG expression in leaves.

PubMed

Wu, Hui-Wen; Deng, Shulin; Xu, Haiying; Mao, Hui-Zhu; Liu, Jun; Niu, Qi-Wen; Wang, Huan; Chua, Nam-Hai

2018-06-04

Dispersed H3K27 trimethylation (H3K27me3) of the AGAMOUS (AG) genomic locus is mediated by CURLY LEAF (CLF), a component of the Polycomb Repressive Complex (PRC) 2. Previous reports have shown that the AG second intron, which confers AG tissue-specific expression, harbors sequences targeted by several positive and negative regulators. Using RACE reverse transcription polymerase chain reaction, we found that the AG intron 2 encodes several noncoding RNAs. RNAi experiment showed that incRNA4 is needed for CLF repressive activity. AG-incRNA4RNAi lines showed increased leaf AG mRNA levels associated with a decrease of H3K27me3 levels; these plants displayed AG overexpression phenotypes. Genetic and biochemical analyses demonstrated that the AG-incRNA4 can associate with CLF to repress AG expression in leaf tissues through H3K27me3-mediated repression and to autoregulate its own expression level. The mechanism of AG-incRNA4-mediated repression may be relevant to investigations on tissue-specific expression of Arabidopsis MADS-box genes. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

Leaf economics and hydraulic traits are decoupled in five species-rich tropical-subtropical forests.

PubMed

Li, Le; McCormack, M Luke; Ma, Chengen; Kong, Deliang; Zhang, Qian; Chen, Xiaoyong; Zeng, Hui; Niinemets, Ülo; Guo, Dali

2015-09-01

Leaf economics and hydraulic traits are critical to leaf photosynthesis, yet it is debated whether these two sets of traits vary in a fully coordinated manner or there is room for independent variation. Here, we tested the relationship between leaf economics traits, including leaf nitrogen concentration and leaf dry mass per area, and leaf hydraulic traits including stomatal density and vein density in five tropical-subtropical forests. Surprisingly, these two suites of traits were statistically decoupled. This decoupling suggests that independent trait dimensions exist within a leaf, with leaf economics dimension corresponding to light capture and tissue longevity, and the hydraulic dimension to water-use and leaf temperature maintenance. Clearly, leaf economics and hydraulic traits can vary independently, thus allowing for more possible plant trait combinations. Compared with a single trait dimension, multiple trait dimensions may better enable species adaptations to multifarious niche dimensions, promote diverse plant strategies and facilitate species coexistence. © 2015 John Wiley & Sons Ltd/CNRS.

The Relationship between Anatomy and Photosynthetic Performance of Heterobaric Leaves1

PubMed Central

Nikolopoulos, Dimosthenis; Liakopoulos, Georgios; Drossopoulos, Ioannis; Karabourniotis, George

2002-01-01

Heterobaric leaves show heterogeneous pigmentation due to the occurrence of a network of transparent areas that are created from the bundle sheaths extensions (BSEs). Image analysis showed that the percentage of photosynthetically active leaf area (Ap) of the heterobaric leaves of 31 plant species was species dependent, ranging from 91% in Malva sylvestris to only 48% in Gynerium sp. Although a significant portion of the leaf surface does not correspond to photosynthetic tissue, the photosynthetic capacity of these leaves, expressed per unit of projected area (Pmax), was not considerably affected by the size of their transparent leaf area (At). This means that the photosynthetic capacity expressed per Ap (P*max) should increase with At. Moreover, the expression of P*max could be allowing the interpretation of the photosynthetic performance in relation to some critical anatomical traits. The P*max, irrespective of plant species, correlated with the specific leaf transparent volume (λt), as well as with the transparent leaf area complexity factor (CFAt), parameters indicating the volume per unit leaf area and length/density of the transparent tissues, respectively. Moreover, both parameters increased exponentially with leaf thickness, suggesting an essential functional role of BSEs mainly in thick leaves. The results of the present study suggest that although the Ap of an heterobaric leaf is reduced, the photosynthetic performance of each areole is increased, possibly due to the light transferring capacity of BSEs. This mechanism may allow a significant increase in leaf thickness and a consequent increase of the photosynthetic capacity per unit (projected) area, offering adaptive advantages in xerothermic environments. PMID:12011354

Herbivores alter plant-wind interactions by acting as a point mass on leaves and by removing leaf tissue.

PubMed

Kothari, Adit R; Burnett, Nicholas P

2017-09-01

In nature, plants regularly interact with herbivores and with wind. Herbivores can wound and alter the structure of plants, whereas wind can exert aerodynamic forces that cause the plants to flutter or sway. While herbivory has many negative consequences for plants, fluttering in wind can be beneficial for plants by facilitating gas exchange and loss of excess heat. Little is known about how herbivores affect plant motion in wind. We tested how the mass of an herbivore resting on a broad leaf of the tulip tree Liriodendron tulipifera , and the damage caused by herbivores, affected the motion of the leaf in wind. For this, we placed mimics of herbivores on the leaves, varying each herbivore's mass or position, and used high-speed video to measure how the herbivore mimics affected leaf movement and reconfiguration at two wind speeds inside a laboratory wind tunnel. In a similar setup, we tested how naturally occurring herbivore damage on the leaves affected leaf movement and reconfiguration. We found that the mass of an herbivore resting on a leaf can change that leaf's orientation relative to the wind and interfere with the ability of the leaf to reconfigure into a smaller, more streamlined shape. A large herbivore load slowed the leaf's fluttering frequency, while naturally occurring damage from herbivores increased the leaf's fluttering frequency. We conclude that herbivores can alter the physical interactions between wind and plants by two methods: (1) acting as a point mass on the plant while it is feeding and (2) removing tissue from the plant. Altering a plant's interaction with wind can have physical and physiological consequences for the plant. Thus, future studies of plants in nature should consider the effect of herbivory on plant-wind interactions, and vice versa.

Inside out: efflux of carbon dioxide from leaves represents more than leaf metabolism.

PubMed

Stutz, Samantha S; Anderson, Jeremiah; Zulick, Rachael; Hanson, David T

2017-05-17

High concentrations of inorganic carbon in the xylem, produced from root, stem, and branch respiration, travel via the transpiration stream and eventually exit the plant through distant tissues as CO2. Unlike previous studies that focused on the efflux of CO2 from roots and woody tissues, we focus on efflux from leaves and the potential effect on leaf respiration measurements. We labeled transported inorganic carbon, spanning reported xylem concentrations, with 13C and then manipulated transpiration rates in the dark in order to vary the rates of inorganic carbon supply to cut leaves from Brassica napus and Populus deltoides. We used tunable diode laser absorbance spectroscopy to directly measure the rate of gross 13CO2 efflux, derived from inorganic carbon supplied from outside of the leaf, relative to gross 12CO2 efflux generated from leaf cells. These experiemnts showed that 13CO2 efflux was dependent upon the rate of inorganic carbon supply to the leaf and the rate of transpiration. Our data show that the gross leaf efflux of xylem-transported CO2 is likely small in the dark when rates of transpiration are low. However, gross leaf efflux of xylem-transported CO2 could approach half the rate of leaf respiration in the light when transpiration rates and branch inorganic carbon concentrations are high, irrespective of the grossly different petiole morphologies in our experiment. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile light requirement.

PubMed

Houter, Nico C; Pons, Thijs L

2012-05-01

Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only slightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a/b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species' gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed.

L-Theanine Content and Related Gene Expression: Novel Insights into Theanine Biosynthesis and Hydrolysis among Different Tea Plant (Camellia sinensis L.) Tissues and Cultivars

PubMed Central

Liu, Zhi-Wei; Wu, Zhi-Jun; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

2017-01-01

L-Theanine content has tissues and cultivars specificity in tea plant (Camellia sinensis L.), the correlations of theanine metabolic related genes expression profiles with theanine contents were explored in this study. L-theanine contents in the bud and 1st leaf, 2nd leaf, 3rd leaf, old leaf, stem, and lateral root were determined by HPLC from three C. sinensis cultivars, namely ‘Huangjinya’, ‘Anjibaicha’, and ‘Yingshuang’, respectively. The theanine contents in leaves and root of ‘Huangjinya’ were the highest, followed by ‘Anjibaicha’, and ‘Yingshuang’. The theanine contents in the leaves reduced as the leaf mature gradually, and in stem were the least. Seventeen genes encoding enzymes involved in theanine metabolism were identified from GenBank and our tea transcriptome database, including CsTS1, CsTS2, CsGS1, CsGS2, CsGOGAT-Fe, CsGOGAT-NAD(P)H, CsGDH1, CsGDH2, CsALT, CsSAMDC, CsADC, CsCuAO, CsPAO, CsNiR, CsNR, CsGGT1, and CsGGT3. The transcript profiles of those seventeen genes in the different tissues of three tea plant cultivars were analyzed comparatively. Among the different cultivars, the transcript levels of most selected genes in ‘Huangjinya’ were significantly higher than that in the ‘Anjibaicha’ and ‘Yingshuang’. Among the different tissues, the transcript levels of CsTS2, CsGS1, and CsGDH2 almost showed positive correlation with the theanine contents, while the other genes showed negative correlation with the theanine contents in most cases. The theanine contents showed correlations with related genes expression levels among cultivars and tissues of tea plant, and were determined by the integrated effect of the metabolic related genes. PMID:28439281

Leaf colleters in Tontelea micrantha (Celastraceae, Salacioideae): ecological, morphological and structural aspects.

PubMed

Mercadante-Simões, Maria Olívia; Paiva, Elder Antônio Sousa

2013-08-01

The colleter secretion can be useful to protect plants of Cerrado (Brazilian savanna) biome during the long and pronounced dry season. This study describes the presence of colleters in Tontelea micrantha and represents the first record of these structures in Celastraceae. To investigate colleter structure and their secretory processes, young leaves were collected, fixed, and processed according to conventional techniques for light, and electron microscopy. Colleters were observed at the marginal teeth on the leaf. They produce mucilaginous secretions that spread over the leaf surface. After secretory phase, colleters abscise. The secretory epithelium is uniseriate and composed of elongated cells whose dense cytoplasm is rich in organelles. The ultrastructure of the secretory cells is compatible with the pectin-rich secretion. Observations of the young leaves surface revealed the presence of superficial hydrophilic secretion films that appeared to have the function of maintaining the water status of those organs. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Effects of Drought on Gene Expression in Maize Reproductive and Leaf Meristem Tissue Revealed by RNA-Seq1[W][OA

PubMed Central

Kakumanu, Akshay; Ambavaram, Madana M.R.; Klumas, Curtis; Krishnan, Arjun; Batlang, Utlwang; Myers, Elijah; Grene, Ruth; Pereira, Andy

2012-01-01

Drought stress affects cereals especially during the reproductive stage. The maize (Zea mays) drought transcriptome was studied using RNA-Seq analysis to compare drought-treated and well-watered fertilized ovary and basal leaf meristem tissue. More drought-responsive genes responded in the ovary compared with the leaf meristem. Gene Ontology enrichment analysis revealed a massive decrease in transcript abundance of cell division and cell cycle genes in the drought-stressed ovary only. Among Gene Ontology categories related to carbohydrate metabolism, changes in starch and Suc metabolism-related genes occurred in the ovary, consistent with a decrease in starch levels, and in Suc transporter function, with no comparable changes occurring in the leaf meristem. Abscisic acid (ABA)-related processes responded positively, but only in the ovaries. Related responses suggested the operation of low glucose sensing in drought-stressed ovaries. The data are discussed in the context of the susceptibility of maize kernel to drought stress leading to embryo abortion and the relative robustness of dividing vegetative tissue taken at the same time from the same plant subjected to the same conditions. Our working hypothesis involves signaling events associated with increased ABA levels, decreased glucose levels, disruption of ABA/sugar signaling, activation of programmed cell death/senescence through repression of a phospholipase C-mediated signaling pathway, and arrest of the cell cycle in the stressed ovary at 1 d after pollination. Increased invertase levels in the stressed leaf meristem, on the other hand, resulted in that tissue maintaining hexose levels at an “unstressed” level, and at lower ABA levels, which was correlated with successful resistance to drought stress. PMID:22837360

Becoming less tolerant with age: sugar maple, shade, and ontogeny.

PubMed

Sendall, Kerrie M; Lusk, Christopher H; Reich, Peter B

2015-12-01

Although shade tolerance is often assumed to be a fixed trait, recent work suggests ontogenetic changes in the light requirements of tree species. We determined the influence of gas exchange, biomass distribution, and self-shading on ontogenetic variation in the instantaneous aboveground carbon balance of Acer saccharum. We quantified the aboveground biomass distributions of 18 juveniles varying in height and growing in low light in a temperate forest understory in Minnesota, USA. Gas exchange rates of leaf and stem tissues were measured, and the crown architecture of each individual was quantified. The YPLANT program was used to estimate the self-shaded fraction of each crown and to model net leaf-level carbon gain. Leaf respiration and photosynthesis per gram of leaf tissue increased with plant size. In contrast, stem respiration rates per gram of stem tissue declined, reflecting a shift in the distribution of stem diameter sizes from smaller (with higher respiration) to larger diameter classes. However, these trends were outweighed by ontogenetic increases in self-shading (which reduces the net photosynthesis realized) and stem mass fraction (which increases the proportion of purely respiratory tissue) in terms of influence on net carbon exchange. As a result, net carbon gain per gram of aboveground plant tissue declined with increasing plant size, and the instantaneous aboveground light compensation point increased. When estimates of root respiration were included to model whole-plant carbon gain and light compensation points, relationships with plant size were even more pronounced. Our findings show how an interplay of gas exchange, self-shading, and biomass distribution shapes ontogenetic changes in shade tolerance.

Increased leaf angle1, a Raf-like MAPKKK that interacts with a nuclear protein family, regulates mechanical tissue formation in the Lamina joint of rice.

PubMed

Ning, Jing; Zhang, Baocai; Wang, Nili; Zhou, Yihua; Xiong, Lizhong

2011-12-01

Mitogen-activated protein kinase kinase kinases (MAPKKKs), which function at the top level of mitogen-activated protein kinase cascades, are clustered into three groups. However, no Group C Raf-like MAPKKKs have yet been functionally identified. We report here the characterization of a rice (Oryza sativa) mutant, increased leaf angle1 (ila1), resulting from a T-DNA insertion in a Group C MAPKKK gene. The increased leaf angle in ila1 is caused by abnormal vascular bundle formation and cell wall composition in the leaf lamina joint, as distinct from the mechanism observed in brassinosteroid-related mutants. Phosphorylation assays revealed that ILA1 is a functional kinase with Ser/Thr kinase activity. ILA1 is predominantly resident in the nucleus and expressed in the vascular bundles of leaf lamina joints. Yeast two-hybrid screening identified six closely related ILA1 interacting proteins (IIPs) of unknown function. Using representative IIPs, the interaction of ILA1 and IIPs was confirmed in vivo. IIPs were localized in the nucleus and showed transactivation activity. Furthermore, ILA1 could phosphorylate IIP4, indicating that IIPs may be the downstream substrates of ILA1. Microarray analyses of leaf lamina joints provided additional evidence for alterations in mechanical strength in ila1. ILA1 is thus a key factor regulating mechanical tissue formation at the leaf lamina joint.

Optimization of Protein Extraction and Two-Dimensional Electrophoresis Protocols for Oil Palm Leaf.

PubMed

Daim, Leona Daniela Jeffery; Ooi, Tony Eng Keong; Yusof, Hirzun Mohd; Majid, Nazia Abdul; Karsani, Saiful Anuar Bin

2015-08-01

Oil palm (Elaeis guineensis) is an important economic crop cultivated for its nutritional palm oil. A significant amount of effort has been undertaken to understand oil palm growth and physiology at the molecular level, particularly in genomics and transcriptomics. Recently, proteomics studies have begun to garner interest. However, this effort is impeded by technical challenges. Plant sample preparation for proteomics analysis is plagued with technical challenges due to the presence of polysaccharides, secondary metabolites and other interfering compounds. Although protein extraction methods for plant tissues exist, none work universally on all sample types. Therefore, this study aims to compare and optimize different protein extraction protocols for use with two-dimensional gel electrophoresis of young and mature leaves from the oil palm. Four protein extraction methods were evaluated: phenol-guanidine isothiocyanate, trichloroacetic acid-acetone precipitation, sucrose and trichloroacetic acid-acetone-phenol. Of these four protocols, the trichloroacetic acid-acetone-phenol method was found to give the highest resolution and most reproducible gel. The results from this study can be used in sample preparations of oil palm tissue for proteomics work.

Both heavy metal-amendment of soil and aphid-infestation increase Cd and Zn concentrations in phloem exudates of a metal-hyperaccumulating plant.

PubMed

Stolpe, Clemens; Giehren, Franziska; Krämer, Ute; Müller, Caroline

2017-07-01

Plants that are able to hyperaccumulate heavy metals show increased concentrations of these metals in their leaf tissue. However, little is known about the concentrations of heavy metals and of organic defence metabolites in the phloem sap of these plants in response to either heavy metal-amendment of the soil or biotic challenges such as aphid-infestation. In this study, we investigated the effects of heavy metal-exposure and of aphid-infestation on phloem exudate composition of the metal hyperaccumulator species Arabidopsis halleri L. O'Kane & Al-Shehbaz (Brassicaceae). The concentrations of elements and of organic defence compounds, namely glucosinolates, were measured in phloem exudates of young and old (mature) leaves of plants challenged either by amendment of the soil with cadmium and zinc and/or by an infestation with the generalist aphid Myzus persicae. Metal-amendment of the soil led to increased concentrations of Cd and Zn, but also of two other elements and one indole glucosinolate, in phloem exudates. This enhanced defence in the phloem sap of heavy metal-hyperaccumulating plants can thus potentially act as effective protection against aphids, as predicted by the elemental defence hypothesis. Aphid-infestation also caused enhanced Cd and Zn concentrations in phloem exudates. This result provides first evidence that metal-hyperaccumulating plants can increase heavy metal concentrations tissue-specifically in response to an attack by phloem-sucking herbivores. Overall, the concentrations of most elements, including the heavy metals, and glucosinolates were higher in phloem exudates of young leaves than in those of old leaves. This defence distribution highlights that the optimal defence theory, which predicts more valuable tissue to be better defended, is applicable for both inorganic and organic defences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cytokinin induced shoot regeneration and flowering of Scoparia dulcis L. (Scrophulariaceae)-an ethnomedicinal herb

PubMed Central

Premkumar, G; Sankaranarayanan, R; Jeeva, S; Rajarathinam, K

2011-01-01

Objective To develop an improved protocol for micropropagation of ethnomedicinally important Scoparia dulcis (S. dulcis) L. Methods Explants were inoculated on MS basal medium supplemented with kinetin and 6-benzylaminopurine for shoot bud induction. To enhance the shoot induction, various auxins like 3-indoleacetic acid or 3-indolebutyric acid or α-naphthylacetic acid were tested along with 2.32 M KI and 4.44 µM BAP. The regenerated shoots were rooted in half strength MS medium supplemented with various concentrations of IAA, IBA or NAA. After roots were developed, the plantlets were transplanted to pots filled with vermiculate and sand and kept in growth chamber with 70%–80% humidity under 16 h photoperiod. After acclimatization, the plantlets were transferred to the garden and survival percentage was calculated. Data were statistically analyzed and means were compared using Duncan's multiple range test (P<0.05). Results An in vitro method was developed to induce high frequency shoots regeneration from stem, mature leaf and young leaf explants of S. dulcis. Shoot induction on young leaf explants was most successful in MS medium supplemented with combination of two cytokinins (2.32 µM KI and 4.44 µM BAP) 2.85 µM IAA, 10% CM and 1 483.79 µM adenine sulfate. A single young leaf explant was capable of producing 59 shoots after 13 days of culture. Flower was induced in medium supplemented with combination of KI and BAP. Conclusions Cytokinins are the key factor to induce the direct shoot regeneration and flowering of S. dulcis. PMID:23569752

Cytokinin induced shoot regeneration and flowering of Scoparia dulcis L. (Scrophulariaceae)-an ethnomedicinal herb.

PubMed

Premkumar, G; Sankaranarayanan, R; Jeeva, S; Rajarathinam, K

2011-06-01

To develop an improved protocol for micropropagation of ethnomedicinally important Scoparia dulcis (S. dulcis) L. Explants were inoculated on MS basal medium supplemented with kinetin and 6-benzylaminopurine for shoot bud induction. To enhance the shoot induction, various auxins like 3-indoleacetic acid or 3-indolebutyric acid or α-naphthylacetic acid were tested along with 2.32 M KI and 4.44 µM BAP. The regenerated shoots were rooted in half strength MS medium supplemented with various concentrations of IAA, IBA or NAA. After roots were developed, the plantlets were transplanted to pots filled with vermiculate and sand and kept in growth chamber with 70%-80% humidity under 16 h photoperiod. After acclimatization, the plantlets were transferred to the garden and survival percentage was calculated. Data were statistically analyzed and means were compared using Duncan's multiple range test (P<0.05). An in vitro method was developed to induce high frequency shoots regeneration from stem, mature leaf and young leaf explants of S. dulcis. Shoot induction on young leaf explants was most successful in MS medium supplemented with combination of two cytokinins (2.32 µM KI and 4.44 µM BAP) 2.85 µM IAA, 10% CM and 1 483.79 µM adenine sulfate. A single young leaf explant was capable of producing 59 shoots after 13 days of culture. Flower was induced in medium supplemented with combination of KI and BAP. Cytokinins are the key factor to induce the direct shoot regeneration and flowering of S. dulcis.

Differential expressed protein in developing stages of Nepenthes gracilis Korth. pitcher.

PubMed

Pinthong, Krit; Chaveerach, Arunrat; Tanee, Tawatchai; Sudmoon, Runglawan; Mokkamul, Piya

2009-03-15

Nepenthes gracilis Korth. is a member of carnivorous plants in family Nepenthaceae. The plants have beautiful and economically important pitchers. It is interesting to study the protein(s) correlated with the pitcher. Crude proteins were extracted from leaf, leaf with developing pitcher and developed pitcher of the same plant and analyzed by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE). Two protein bands with molecular weights of 42.7 and 38 kDa were obtained from young leaf and leaf with developing pitcher, respectively. The 42.7 kDa protein was identified as phosphoglycerate kinase (PGK) by Liquid Chromatography Mass Spectrometry (LC-MS/MS), but the 38 kDa band is an unknown protein. Both proteins were differentially expressed in each developing stage of the pitcher, thus may be powerful candidates play role in development pathway of leaf and pitcher.

Cloning and function analysis of a drought-inducible gene associated with resistance to Curvularia leaf spot in maize.

PubMed

Zhu, Jiewei; Huang, Xiuli; Liu, Tong; Gao, Shigang; Chen, Jie

2012-08-01

ZmDIP was cloned and its function against Curvularia lunata was analyzed, according to a previous finding on a drought-inducible protein in resistant maize identified through MALDI-TOF-MS/MS. The ZmDIP expression varied in roots, leaf sheaths, and young, as well as old, leaves of different maize inbred lines. The ZmDIP transcript level changed in leaves over the course of time after inoculation with C. lunata. A prokaryotic expression analysis demonstrated that the gene can regulate the salt stress tolerance of Escherichia coli. The ZmDIP transient expression in the maize leaf showed that the gene was also linked to leaf resistance against the C. lunata infection. ZmDIP-mediated ROS and ABA signaling pathways were inferred to be closely associated with maize leaf resistance to the pathogen infection.

Stomatal oscillations in olive trees: analysis and methodological implications.

PubMed

López-Bernal, Alvaro; García-Tejera, Omar; Testi, Luca; Orgaz, Francisco; Villalobos, Francisco J

2018-04-01

Stomatal oscillations have long been disregarded in the literature despite the fact that the phenomenon has been described for a variety of plant species. This study aims to characterize the occurrence of oscillations in olive trees (Olea europaea L.) under different growing conditions and its methodological implications. Three experiments with young potted olives and one with large field-grown trees were performed. Sap flow measurements were always used to monitor the occurrence of oscillations, with additional determinations of trunk diameter variations and leaf-level stomatal conductance, photosynthesis and water potential also conducted in some cases. Strong oscillations with periods of 30-60 min were generally observed for young trees, while large field trees rarely showed significant oscillations. Severe water stress led to the disappearance of oscillations, but moderate water deficits occasionally promoted them. Simultaneous oscillations were also found for leaf stomatal conductance, leaf photosynthesis and trunk diameter, with the former presenting the highest amplitudes. The strong oscillations found in young potted olive trees preclude the use of infrequent measurements of stomatal conductance and related variables to characterize differences between trees of different cultivars or subjected to different experimental treatments. Under these circumstances, our results suggest that reliable estimates could be obtained using measurement intervals below 15 min.

Correlation of glucosinolate content to myrosinase activity in horseradish (Armoracia rusticana).

PubMed

Li, Xian; Kushad, Mosbah M

2004-11-17

Fully developed horseradish (Armoracia rusticana Gaertn., Mey., & Scherb.) roots from 27 accessions and leaves from a subset of 9 accessions were evaluated for glucosinolates and myrosinase enzyme activity. Eight different glucosinolates were detected (based on HPLC retention times as desulfoglucosinolates) in both root and leaf tissues. The sum of these glucosinolates, referred to as total, ranged from 2 to 296 micromol g(-1) of dry weight (DW) in both tissues. Four glucosinolates (sinigrin, glucobrassicin, neoglucobrassicin, and gluconasturtiin) were detected in major quantities. In fully developed roots, sinigrin concentration represented approximately 83%, gluconasturtiin approximately 11%, and glucobrassicin approximately 1% of the total glucosinolates. Approximately the same proportions of individual glucosinolates appeared in fully developed leaves, except that glucobrassicin was substituted by neoglucobrassicin and gluconasturtiin concentration was significantly lower (<1%). At least four other glucosinolates were detected in very small quantities (<1%) in both roots and leaves. Myrosinase (beta-thioglucoside glucohydrolase, EC 3.2.3.1) is the enzyme responsible for the hydrolysis of the parent glucosinolates into biologically active products. Very little is known about myrosinase activity and the correlation of its activity to total and individual glucosinolates in plant tissues. Significant differences in myrosinase activity were detected between the roots and leaves, ranging from 1.2 to 57.1 units g(-1) of DW. Data showed no correlation between myrosinase activity and total and/or individual glucosinolates in the roots. However, in the leaves, significant correlations were found between myrosinase activity and total glucosinolates (0.78 at P = 0.01) and between myrosinase activity and sinigrin (0.80 at P = 0.01). Glucosinolates content and myrosinase activity were also correlated in young and fully developed roots and leaves and during tissue crushing. Glucobrassicin concentration in the roots and neoglucobrassicin concentration in the leaves were significantly higher in young than in fully developed tissue. Crushing of the tissue resulted in rapid hydrolysis of sinigrin and glucobrassicin, as expected, from the presence of myrosinase. Likewise, myrosinase activity declined rapidly after crushing, perhaps due to inactivation by the reaction products and/or the depletion of its substrates.

Susceptibility of field populations of the fall armyworm (Lepidoptera: Noctuidae) from Florida and Puerto Rico to purified Cry1F protein and corn leaf tissue containing single and pyramided Bt genes

USDA-ARS?s Scientific Manuscript database

Larval survival of Cry1F-susceptible (FL), -resistant (PR and Cry1F-RR), and -heterozygous (FL x PR and Cry1F-RS) populations of the fall armyworm, Spodoptera frugiperda (J.E. Smith) to purified Cry1F protein and corn leaf tissue of seven Bacillus thuringiensis (Bt) corn hybrids and five non-Bt corn...

Vascular Streak Dieback of cacao in Southeast Asia and Melanesia: in planta detection of the pathogen and a new taxonomy.

PubMed

Samuels, Gary J; Ismaiel, Adnan; Rosmana, Ade; Junaid, Muhammad; Guest, David; McMahon, Peter; Keane, Philip; Purwantara, Agus; Lambert, Smilja; Rodriguez-Carres, Marianela; Cubeta, Marc A

2012-01-01

Vascular Streak Dieback (VSD) disease of cacao (Theobroma cacao) in Southeast Asia and Melanesia is caused by a basidiomycete (Ceratobasidiales) fungus Oncobasidium theobromae (syn. =Thanatephorus theobromae). The most characteristic symptoms of the disease are green-spotted leaf chlorosis or, commonly since about 2004, necrotic blotches, followed by senescence of leaves beginning on the second or third flush behind the shoot apex, and blackening of infected xylem in the vascular traces at the leaf scars resulting from the abscission of infected leaves. Eventually the shoot apex is killed and infected branches die. In susceptible cacao the fungus may grow through the xylem down into the main stem and kill a mature cacao tree. Infections in the stem of young plants prior to the formation of the first 3-4 lateral branches usually kill the plant. Basidiospores released from corticioid basidiomata developed on leaf scars or along cracks in the main vein of infected leaves infect young leaves. The pathogen commonly infects cacao but there are rare reports from avocado. As both crops are introduced to the region, the pathogen is suspected to occur asymptomatically in native vegetation. The pathogen is readily isolated but cultures cannot be maintained. In this study, DNA was extracted from pure cultures of O. theobromae obtained from infected cacao plants sampled from Indonesia. The internal transcribed spacer region (ITS), consisting of ITS1, 5.8S ribosomal RNA and ITS2, and a portion of nuclear large subunit (LSU) were sequenced. Phylogenetic analysis of ITS sequences placed O. theobromae sister to Ceratobasidium anastomosis groups AG-A, AG-Bo, and AG-K with high posterior probability. Therefore the new combination Ceratobasidium theobromae is proposed. A PCR-based protocol was developed to detect and identify C. theobromae in plant tissue of cacao enabling early detection of the pathogen in plants. A second species of Ceratobasidium, Ceratobasidium ramicola, identified through ITS sequence analysis, was isolated from VSD-affected cacao plants in Java, and is widespread in diseased cacao collected from Indonesia. Published by Elsevier Ltd.

Abscisic Acid Content, Transpiration, and Stomatal Conductance As Related to Leaf Age in Plants of Xanthium strumarium L.

PubMed

Raschke, K; Zeevaart, J A

1976-08-01

Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L. the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (+/-)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells.The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight.

Abscisic Acid Content, Transpiration, and Stomatal Conductance As Related to Leaf Age in Plants of Xanthium strumarium L. 1

PubMed Central

Raschke, Klaus; Zeevaart, Jan A. D.

1976-01-01

Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L. the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (±)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells. The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight. PMID:16659640

Mutation of the OsSAC1 Gene, which Encodes an Endoplasmic Reticulum Protein with an Unknown Function, Causes Sugar Accumulation in Rice Leaves.

PubMed

Zhu, Xiaoyan; Shen, Wenqiang; Huang, Junyang; Zhang, Tianquan; Zhang, Xiaobo; Cui, Yuanjiang; Sang, Xianchun; Ling, Yinghua; Li, Yunfeng; Wang, Nan; Zhao, Fangmin; Zhang, Changwei; Yang, Zhenglin; He, Guanghua

2018-03-01

Sugars are the most abundant organic compounds produced by plants, and can be used to build carbon skeletons and generate energy. The sugar accumulation 1 (OsSAC1) gene encodes a protein with an unknown function that exhibits four N-terminal transmembrane regions and two conserved domains of unknown function, DUF4220 and DUF594. OsSAC1 was found to be poorly and specifically expressed at the bottoms of young leaves and in the developing leaf sheaths. Subcellular location results showed that OsSAC1 was co-localized with ER:mCherry and targeted the endoplasmic reticulum (ER). OsSAC1 has been found to affect sugar partitioning in rice (Oryza sativa). I2/KI starch staining, ultrastructure observations and starch content measurements indicated that more and larger starch granules accumulated in ossac1 source leaves than in wild-type (WT) source leaves. Additionally, higher sucrose and glucose concentrations accumulated in the ossac1 source leaves than in WT source leaves, whereas lower sucrose and glucose concentrations were observed in the ossac1 young leaves and developing leaf sheaths than in those of the WT. Much greater expression of OsAGPL1 and OsAGPS1 (responsible for starch synthesis) and significantly less expression of OscFBP1, OscFBP2, OsSPS1 and OsSPS11 (responsible for sucrose synthesis) and OsSWEET11, OsSWEET14 and OsSUT1 (responsible for sucrose loading) occurred in ossac1 source leaves than in WT source leaves. A greater amount of the rice plasmodesmatal negative regulator OsGSD1 was detected in ossac1 young leaves and developing leaf sheaths than in those of the WT. These results suggest that ER-targeted OsSAC1 may indirectly regulate sugar partitioning in carbon-demanding young leaves and developing leaf sheaths.

Distribution and uptake dynamics of mercury in leaves of common deciduous tree species in Minnesota, U.S.A.

Treesearch

Aicam Laacouri; Edward A. Nater; Randall K. Kolka

2013-01-01

A sequential extraction technique for compartmentalizing mercury (Hg) in leaves was developed based on a water extraction of Hg from the leaf surface followed by a solvent extraction of the cuticle. The bulk of leaf Hg was found in the tissue compartment (90-96%) with lesser amounts in the surface and cuticle compartments. Total leaf concentrations of Hg varied among...

Elimination of two viruses which interact synergistically from sweetpotato by shoot tip culture and cryotherapy.

PubMed

Wang, Q C; Valkonen, J P T

2008-12-01

Sweet potato chlorotic stunt virus (SPCSV; Closteroviridae) and Sweet potato feathery mottle virus (SPFMV; Potyviridae) interact synergistically and cause severe diseases in co-infected sweetpotato plants (Ipomoea batatas). Sweetpotato is propagated vegetatively and virus-free planting materials are pivotal for sustainable production. Using cryotherapy, SPCSV and SPCSV were eliminated from all treated single-virus-infected and co-infected shoot tips irrespective of size (0.5-1.5mm including 2-4 leaf primordia). While shoot tip culture also eliminated SPCSV, elimination of SPFMV failed in 90-93% of the largest shoot tips (1.5mm) using this technique. Virus distribution to different leaf primordia and tissues within leaf primordia in the shoot apex and petioles was not altered by co-infection of the viruses in the fully virus-susceptible sweetpotato genotype used. SPFMV was immunolocalized to all types of tissues and up to the fourth-youngest leaf primordium. In contrast, SPCSV was detected only in the phloem and up to the fifth leaf primordium. Because only cells in the apical dome of the meristem and the two first leaf primordia survived cryotherapy, all data taken together could explain the results of virus elimination. The simple and efficient cryotherapy protocol developed for virus elimination can also be used for preparation of sweetpotato materials for long-term preservation.

Differential distribution of metals in tree tissues growing on reclaimed coal mine overburden dumps, Jharia coal field (India).

PubMed

Rana, Vivek; Maiti, Subodh Kumar

2018-04-01

Opencast bituminous coal mining invariably generates huge amount of metal-polluted waste rocks (stored as overburden (OB) dumps) and reclaimed by planting fast growing hardy tree species which accumulate metals in their tissues. In the present study, reclaimed OB dumps located in Jharia coal field (Jharkhand, India) were selected to assess the accumulation of selected metals (Pb, Zn, Mn, Cu and Co) in tissues (leaf, stem bark, stem wood, root bark and root wood) of two commonly planted tree species (Acacia auriculiformis A.Cunn. ex Benth. and Melia azedarach L.). In reclaimed mine soil (RMS), the concentrations of pseudo-total and available metals (DTPA-extractable) were found 182-498 and 196-1877% higher, respectively, than control soil (CS). The positive Spearman's correlation coefficients between pseudo-total concentration of Pb and Cu (r = 0.717; p < 0.05), Pb and Co (r = 0.650; p < 0.05), Zn and Mn (0.359), Cu and Co (r = 0.896; p < 0.01) suggested similar sources for Pb-Cu-Co and Mn-Zn. Among the five tree tissues considered, Pb selectively accumulated in root bark, stem bark and leaves; Zn and Mn in leaves; and Cu in root wood and stem wood. These results suggested metal accumulation to be "tissue-specific". The biological indices (BCF, TF leaf , TF stem bark and TF stem wood ) indicated variation in metal uptake potential of different tree tissues. The study indicated that A. auriculiformis could be employed for Mn phytoextraction (BCF, TF leaf , TF stem bark and TF stem wood  > 1). The applicability of both the trees in Cu phytostabilization (BCF > 1; TF leaf , TF stem bark and TF stem wood  < 1) was suggested. The study enhanced knowledge about the selection of tree species for the phytoremediation of coal mine OB dumps and specific tree tissues for monitoring metal pollution.

Young Children and A-Chains: The Acquisition of Hebrew Unaccusatives

ERIC Educational Resources Information Center

Friedmann, Na'ama

2007-01-01

SV sentences with unaccusative verbs like "The leaf fell" involve movement from object to subject position. This line of studies tested whether young children can produce this movement and whether they represent SV sentences with unaccusatives as derived by movement. In Hebrew, unaccusatives appear in both SV and VS orders. This optionality allows…

Photo-oxidative stress in emerging and senescing leaves: a mirror image?

PubMed

Juvany, Marta; Müller, Maren; Munné-Bosch, Sergi

2013-08-01

The life cycle of a leaf can be characterized as consisting of different stages: from primordial leaf initiation in the shoot apical meristem (SAM) to leaf senescence. Leaf development, from early leaf growth to senescence, is tightly controlled by plant development and the environment. Here, we primarily focus on summarizing current evidence indicating that photo-oxidative stress occurs at the two extremes of a leaf's lifespan. Some recent studies clearly indicate that--as happens in senescing leaves--emerging new leaves suffer from photo-oxidative stress, which suggests that oxidative stress plays a key role at both ends of the leaf life cycle. We discuss the causes and consequences of suffering from photo-oxidative stress during leaf development, paying attention to the particularities of this process at the two extremes of leaf development. Of particular importance is the current evidence showing mechanisms that maintain an adequate cellular reactive oxygen species/antioxidant (redox) balance that allows growth and prevents oxidative damage in young emerging leaves, while later on photo-oxidative stress induces cell death in senescing leaves. Also of interest is the fact that reductions in the efficiency of photosystem II photochemistry may not necessarily indicate photo-oxidative stress in emerging leaves. In this review, we summarize current knowledge of photoinhibition, photoprotection, and photo-oxidative stress at the two ends of the leaf life cycle: early leaf growth and leaf senescence.

Balancing photosynthetic light-harvesting and light-utilization capacities in potato leaf tissue during acclimation to different growth temperatures

NASA Technical Reports Server (NTRS)

Steffen, K. L.; Wheeler, R. M.; Arora, R.; Palta, J. P.; Tibbitts, T. W.

1995-01-01

We investigated the effect of temperature during growth and development on the relationship between light-harvesting capacity, indicated by chlorophyll concentration, and light-utilization potential, indicated by light- and bicarbonate-saturated photosynthetic oxygen evolution, in Solanum tuberosum L. cv. Norland. Clonal plantlets were transplanted and grown at 20 degrees C for 2 weeks before transfer to 12, 16, 20, 24 and 28 degrees C for 6 weeks. After 4 weeks of the temperature treatments, leaf tissue fresh weights per area were one-third higher in plants grown at 12 degrees C vs those grown at 28 degrees C. Conversely, chlorophyll content per area in tissue grown at 12 degrees C was less than one-half of that of tissue grown at 28 degrees C at 4 weeks. Photosynthetic capacity measured at a common temperature of 20 degrees C and expressed on a chlorophyll basis was inversely proportional to growth temperature. Leaf tissue from plants grown at 12 degrees C for 4 weeks had photosynthetic rates that were 3-fold higher on a chlorophyll basis than comparable tissue from plants grown at 28 degrees C. These results suggest that the relationship between light-harvesting capacity and light-utilization potential varies 3-fold in response to the growth temperatures examined. The role of this response in avoidance of photoinhibition is discussed.

VirtualLeaf: an open-source framework for cell-based modeling of plant tissue growth and development.

PubMed

Merks, Roeland M H; Guravage, Michael; Inzé, Dirk; Beemster, Gerrit T S

2011-02-01

Plant organs, including leaves and roots, develop by means of a multilevel cross talk between gene regulation, patterned cell division and cell expansion, and tissue mechanics. The multilevel regulatory mechanisms complicate classic molecular genetics or functional genomics approaches to biological development, because these methodologies implicitly assume a direct relation between genes and traits at the level of the whole plant or organ. Instead, understanding gene function requires insight into the roles of gene products in regulatory networks, the conditions of gene expression, etc. This interplay is impossible to understand intuitively. Mathematical and computer modeling allows researchers to design new hypotheses and produce experimentally testable insights. However, the required mathematics and programming experience makes modeling poorly accessible to experimental biologists. Problem-solving environments provide biologically intuitive in silico objects ("cells", "regulation networks") required for setting up a simulation and present those to the user in terms of familiar, biological terminology. Here, we introduce the cell-based computer modeling framework VirtualLeaf for plant tissue morphogenesis. The current version defines a set of biologically intuitive C++ objects, including cells, cell walls, and diffusing and reacting chemicals, that provide useful abstractions for building biological simulations of developmental processes. We present a step-by-step introduction to building models with VirtualLeaf, providing basic example models of leaf venation and meristem development. VirtualLeaf-based models provide a means for plant researchers to analyze the function of developmental genes in the context of the biophysics of growth and patterning. VirtualLeaf is an ongoing open-source software project (http://virtualleaf.googlecode.com) that runs on Windows, Mac, and Linux.

Low light and low ammonium are key factors for guayule leaf tissue shoot organogenesis and transformation.

PubMed

Dong, Niu; Montanez, Belen; Creelman, Robert A; Cornish, Katrina

2006-02-01

A new method has been developed for guayule tissue culture and transformation. Guayule leaf explants have a poor survival rate when placed on normal MS medium and under normal culture room light conditions. Low light and low ammonium treatment greatly improved shoot organogenesis and transformation from leaf tissues. Using this method, a 35S promoter driven BAR gene and an ubiquitin-3 promoter driven GUS gene (with intron) have been successfully introduced into guayule. These transgenic guayule plants were resistant to the herbicide ammonium-glufosinate and were positive to GUS staining. Molecular analysis showed the expected band and signal in all GUS positive transformants. The transformation efficiency with glufosinate selection ranged from 3 to 6%. Transformation with a pBIN19-based plasmid containing a NPTII gene and then selection with kanamycin also works well using this method. The ratio of kanamycin-resistant calli to total starting explants reached 50% in some experiments.

Plasticity of vulnerability to leaf hydraulic dysfunction during acclimation to drought in grapevines: an osmotic-mediated process.

PubMed

Martorell, Sebastian; Medrano, Hipolito; Tomàs, Magdalena; Escalona, José M; Flexas, Jaume; Diaz-Espejo, Antonio

2015-03-01

Previous studies have reported correlation of leaf hydraulic vulnerability with pressure-volume parameters related to cell turgor. This link has been explained on the basis of the effects of turgor on connectivity among cells and tissue structural integrity, which affect leaf water transport. In this study, we tested the hypothesis that osmotic adjustment to water stress would shift the leaf vulnerability curve toward more negative water potential (Ψ leaf ) by increasing turgor at low Ψ leaf . We measured leaf hydraulic conductance (K leaf ), K leaf vulnerability [50 and 80% loss of K leaf (P50 and P80 ); |Ψ leaf | at 50 and 80% loss of K leaf , respectively), bulk leaf water relations, leaf gas exchange and sap flow in two Vitis vinifera cultivars (Tempranillo and Grenache), under two water treatments. We found that P50 , P80 and maximum K leaf decreased seasonally by more than 20% in both cultivars and watering treatments. However, K leaf at 2 MPa increased threefold, while osmotic potential at full turgor and turgor loss point decreased. Our results indicate that leaf resistance to hydraulic dysfunction is seasonally plastic, and this plasticity may be mediated by osmotic adjustment. © 2014 Scandinavian Plant Physiology Society.

Comparative transcriptome analysis of different chemotypes elucidates withanolide biosynthesis pathway from medicinal plant Withania somnifera

PubMed Central

Gupta, Parul; Goel, Ridhi; Agarwal, Aditya Vikram; Asif, Mehar Hasan; Sangwan, Neelam Singh; Sangwan, Rajender Singh; Trivedi, Prabodh Kumar

2015-01-01

Withania somnifera is one of the most valuable medicinal plants synthesizing secondary metabolites known as withanolides. Despite pharmaceutical importance, limited information is available about the biosynthesis of withanolides. Chemo-profiling of leaf and root tissues of Withania suggest differences in the content and/or nature of withanolides in different chemotypes. To identify genes involved in chemotype and/or tissue-specific withanolide biosynthesis, we established transcriptomes of leaf and root tissues of distinct chemotypes. Genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis with their alternatively spliced forms and paralogous have been identified. Analysis suggests differential expression of large number genes among leaf and root tissues of different chemotypes. Study also identified differentially expressing transcripts encoding cytochrome P450s, glycosyltransferases, methyltransferases and transcription factors which might be involved in chemodiversity in Withania. Virus induced gene silencing of the sterol ∆7-reductase (WsDWF5) involved in the synthesis of 24-methylene cholesterol, withanolide backbone, suggests role of this enzyme in biosynthesis of withanolides. Information generated, in this study, provides a rich resource for functional analysis of withanolide-specific genes to elucidate chemotype- as well as tissue-specific withanolide biosynthesis. This genomic resource will also help in development of new tools for functional genomics and breeding in Withania. PMID:26688389

Response of plant nutrient stoichiometry to fertilization varied with plant tissues in a tropical forest

PubMed Central

Mo, Qifeng; Zou, Bi; Li, Yingwen; Chen, Yao; Zhang, Weixin; Mao, Rong; Ding, Yongzhen; Wang, Jun; Lu, Xiankai; Li, Xiaobo; Tang, Jianwu; Li, Zhian; Wang, Faming

2015-01-01

Plant N:P ratios are widely used as indices of nutrient limitation in terrestrial ecosystems, but the response of these metrics in different plant tissues to altered N and P availability and their interactions remains largely unclear. We evaluated changes in N and P concentrations, N:P ratios of new leaves (<1 yr), older leaves (>1 yr), stems and mixed fine roots of seven species after 3-years of an N and P addition experiment in a tropical forest. Nitrogen addition only increased fine root N concentrations. P addition increased P concentrations among all tissues. The N × P interaction reduced leaf and stem P concentrations, suggesting a negative effect of N addition on P concentrations under P addition. The reliability of using nutrient ratios as indices of soil nutrient availability varied with tissues: the stoichiometric metrics of stems and older leaves were more responsive indicators of changed soil nutrient availability than those of new leaves and fine roots. However, leaf N:P ratios can be a useful indicator of inter-specific variation in plant response to nutrients availability. This study suggests that older leaf is a better choice than other tissues in the assessment of soil nutrient status and predicting plant response to altered nutrients using nutrients ratios. PMID:26416169

Comparison of Ion Balance and Nitrogen Metabolism in Old and Young Leaves of Alkali-Stressed Rice Plants

PubMed Central

Wang, Huan; Wu, Zhihai; Han, Jiayu; Zheng, Wei; Yang, Chunwu

2012-01-01

Background Alkali stress is an important agricultural contaminant and has complex effects on plant metabolism. The aim of this study was to investigate whether the alkali stress has different effects on the growth, ion balance, and nitrogen metabolism in old and young leaves of rice plants, and to compare functions of both organs in alkali tolerance. Methodology/Principal Findings The results showed that alkali stress only produced a small effect on the growth of young leaves, whereas strongly damaged old leaves. Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl− in old leaves. The up-regulation of OsHKT1;1, OsAKT1, OsHAK1, OsHAK7, OsHAK10 and OsHAK16 may contribute to the larger accumulation of Na+ in old leaves under alkali stress. Alkali stress mightily reduced the NO3 − contents in both organs. As old leaf cells have larger vacuole, under alkali stress these scarce NO3 − was principally stored in old leaves. Accordingly, the expression of OsNRT1;1 and OsNRT1;2 in old leaves was up-regulated by alkali stress, revealing that the two genes might contribute to the accumulation of NO3 − in old leaves. NO3 − deficiency in young leaves under alkali stress might induce the reduction in OsNR1 expression and the subsequent lacking of NH4 +, which might be main reason for the larger down-regulation of OsFd-GOGAT and OsGS2 in young leaves. Conclusions/Significance Our results strongly indicated that, during adaptation of rice to alkali stress, young and old leaves have distinct mechanisms of ion balance and nitrogen metabolism regulation. We propose that the comparative studies of young and old tissues may be important for abiotic stress tolerance research. PMID:22655071

Evaluation of Three Protein-Extraction Methods for Proteome Analysis of Maize Leaf Midrib, a Compound Tissue Rich in Sclerenchyma Cells.

PubMed

Wang, Ning; Wu, Xiaolin; Ku, Lixia; Chen, Yanhui; Wang, Wei

2016-01-01

Leaf morphology is closely related to the growth and development of maize (Zea mays L.) plants and final kernel production. As an important part of the maize leaf, the midrib holds leaf blades in the aerial position for maximum sunlight capture. Leaf midribs of adult plants contain substantial sclerenchyma cells with heavily thickened and lignified secondary walls and have a high amount of phenolics, making protein extraction and proteome analysis difficult in leaf midrib tissue. In the present study, three protein-extraction methods that are commonly used in plant proteomics, i.e., phenol extraction, TCA/acetone extraction, and TCA/acetone/phenol extraction, were qualitatively and quantitatively evaluated based on 2DE maps and MS/MS analysis using the midribs of the 10th newly expanded leaves of maize plants. Microscopy revealed the existence of substantial amounts of sclerenchyma underneath maize midrib epidermises (particularly abaxial epidermises). The spot-number order obtained via 2DE mapping was as follows: phenol extraction (655) > TCA/acetone extraction (589) > TCA/acetone/phenol extraction (545). MS/MS analysis identified a total of 17 spots that exhibited 2-fold changes in abundance among the three methods (using phenol extraction as a control). Sixteen of the proteins identified were hydrophilic, with GRAVY values ranging from -0.026 to -0.487. For all three methods, we were able to obtain high-quality protein samples and good 2DE maps for the maize leaf midrib. However, phenol extraction produced a better 2DE map with greater resolution between spots, and TCA/acetone extraction produced higher protein yields. Thus, this paper includes a discussion regarding the possible reasons for differential protein extraction among the three methods. This study provides useful information that can be used to select suitable protein extraction methods for the proteome analysis of recalcitrant plant tissues that are rich in sclerenchyma cells.

Insights on the development, kinetics, and variation of photoinhibition using chlorophyll fluorescence imaging of a chilled, variegated leaf.

PubMed

Hogewoning, Sander W; Harbinson, Jeremy

2007-01-01

The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) under a moderate irradiance (120 micromol m-2 s-1). The individual leaves were divided into a shaded zone and two illuminated, chilled zones. The leaf tip and sometimes the leaf base were not chilled. Measurements of the dark-adapted Fv/Fm were made on the different leaf zones at the end of the chilling treatment, and then for several days thereafter to monitor recovery. Chilling up to 7 d in the dark did not affect PSII efficiency and visual appearance, whereas chilling in the light caused severe photoinhibition, sometimes followed by leaf necrosis. Photoinhibition increased with the duration of the chilling period, whereas, remarkably, chilling temperature had no effect. In the unchilled leaf tip, photoinhibition also occurred, whereas in the unchilled leaf base it did not. Whatever the leaf zone, photoinhibition became permanent if the mean value dropped below 0.4, although chlorosis and necrosis were associated solely with chilled illuminated tissue. Starch accumulated in the unchilled leaf tip, in contrast to the adjacent chilled irradiated zone. This suggests that photoinhibition was due to a secondary effect in the unchilled leaf tip (sink limitation), whereas it was a direct effect of chilling and irradiance in the chilled illuminated zones. The PSII efficiency and its coefficient of variation showed a unique negative linearity across all leaf zones and different tissue types. The slope of this curve was steeper for chilled leaves than it was for healthy, non-stressed leaves, suggesting that the coefficient of variation may be an important tool for assessing stress in leaves.

Climatic signals registered as Carbon isotopic values in Metasequoia leaf tissues: A statistical analysis

NASA Astrophysics Data System (ADS)

Yang, H.; Blais, B.; Perez, G.; Pagani, M.

2006-12-01

To examine climatic signals registered as carbon isotopic values in leaf tissues of C3 plants, we collected mature leaf tissues from sun and shade leaves of Metasequoia trees germinated from the 1947 batch of seeds from China and planted along a latitudinal gradient of the United States. Samples from 40 individual trees, along with fossilized material from the early Tertiary of the Canadian Arctic, were analyzed for C and concentration and isotopic values using EA-IRMS after the removal of free lipids. The generated datasets were then merged with climate data compiled from each tree site recorded as average values over the past thirty years (1971-2002, NOAA database). When the isotope data were cross plotted against each geographic and climatic indicator, Latitude, Mean Annual Temperature (MAT), Average Summer Mean Temperature (ASMT)(June-August), Mean Annual Precipitation (MAP), and Average Summer Mean Precipitation (ASMP) respectively correlation patterns were revealed. The best correlating trend was obtained between temperature parameters and C isotopic values, and this correlation is stronger in the northern leaf samples than the southern samples. We discovered a strong positive correlation between latitude and the offset of C isotopic values between shade and sun leaves. This investigation represents a comprehensive examination on climatic signals registered as C isotopic values on a single species that is marked by single genetic source. The results bear implications on paleoclimatic interpretations of C isotopic signals obtained from fossil plant tissues.

Age- and size-related changes in physiological characteristics and chemical composition of Acer pseudoplatanus and Fraxinus excelsior trees.

PubMed

Abdul-Hamid, Hazandy; Mencuccini, Maurizio

2009-01-01

Forest growth is an important factor both economically and ecologically, and it follows a predictable trend with age. Generally, growth accelerates as canopies develop in young forests and declines substantially soon after maximum leaf area is attained. The causes of this decline are multiple and may be linked to age- or size-related processes, or both. Our objective was to determine the relative effects of tree age and tree size on the physiological attributes of two broadleaf species. As age and size are normally coupled during growth, an approach based on grafting techniques to separate the effects of size from those of age was adopted. Genetically identical grafted seedlings were produced from scions taken from trees of four age classes, ranging from 4 to 162 years. We found that leaf-level net photosynthetic rate per unit of leaf mass and some other leaf structural and biochemical characteristics had decreased substantially with increasing size of the donor trees in the field, whereas other gas exchange parameters expressed on a leaf area basis did not. In contrast, these parameters remained almost constant in grafted seedlings, i.e., scions taken from donor trees with different meristematic ages show no age-related trend after they were grafted onto young rootstocks. In general, the results suggested that size-related limitations triggered the declines in photosynthate production and tree growth, whereas less evidence was found to support a role of meristematic age.

The cis-regulatory element CCACGTGG is involved in ABA and water-stress responses of the maize gene rab28.

PubMed

Pla, M; Vilardell, J; Guiltinan, M J; Marcotte, W R; Niogret, M F; Quatrano, R S; Pagès, M

1993-01-01

The maize gene rab28 has been identified as ABA-inducible in embryos and vegetative tissues. It is also induced by water stress in young leaves. The proximal promoter region contains the conserved cis-acting element CCACGTGG (ABRE) reported for ABA induction in other plant genes. Transient expression assays in rice protoplasts indicate that a 134 bp fragment (-194 to -60 containing the ABRE) fused to a truncated cauliflower mosaic virus promoter (35S) is sufficient to confer ABA-responsiveness upon the GUS reporter gene. Gel retardation experiments indicate that nuclear proteins from tissues in which the rab28 gene is expressed can interact specifically with this 134 bp DNA fragment. Nuclear protein extracts from embryo and water-stressed leaves generate specific complexes of different electrophoretic mobility which are stable in the presence of detergent and high salt. However, by DMS footprinting the same guanine-specific contacts with the ABRE in both the embryo and leaf binding activities were detected. These results indicate that the rab28 promoter sequence CCACGTGG is a functional ABA-responsive element, and suggest that distinct regulatory factors with apparent similar affinity for the ABRE sequence may be involved in the hormone action during embryo development and in vegetative tissues subjected to osmotic stress.

Detection of triterpene acids distribution in loquat (Eriobotrya japonica) leaf using hyperspectral imaging

NASA Astrophysics Data System (ADS)

Shi, Jiyong; Chen, Wu; Zou, Xiaobo; Xu, Yiwei; Huang, Xiaowei; Zhu, Yaodi; Shen, Tingting

2018-01-01

Hyperspectral images (431-962 nm) and partial least squares (PLS) were used to detect the distribution of triterpene acids within loquat (Eriobotrya japonica) leaves. 72 fresh loquat leaves in the young group, mature group and old group were collected for hyperspectral imaging; and triterpene acids content of the loquat leaves was analyzed using high performance liquid chromatography (HPLC). Then the spectral data of loquat leaf hyperspectral images and the triterpene acids content were employed to build calibration models. After spectra pre-processing and wavelength selection, an optimum calibration model (Rp = 0.8473, RMSEP = 2.61 mg/g) for predicting triterpene acids was obtained by synergy interval partial least squares (siPLS). Finally, spectral data of each pixel in the loquat leaf hyperspectral image were extracted and substituted into the optimum calibration model to predict triterpene acids content of each pixel. Therefore, the distribution map of triterpene acids content was obtained. As shown in the distribution map, triterpene acids are accumulated mainly in the leaf mesophyll regions near the main veins, and triterpene acids concentration of young group is less than that of mature and old groups. This study showed that hyperspectral imaging is suitable to determine the distribution of active constituent content in medical herbs in a rapid and non-invasive manner.

[Relationship between leaf anatomical structure and heat resistance of 15 Rhododendron cultivars].

PubMed

Shen, Hui Fei; Zhao, Bing; Xu, Jing Jing

2016-12-01

In this study, 17 anatomical structure indexes of 15 Rhododendron cultivars were mea-sured by scanning electron microscope (SEM). Leaf anatomical structure indexes were screened via coefficient of variation, analysis of correlation and hierarchical cluster analysis, and comprehensive evaluation on heat resistance for each cultivar was conducted by the subordinate function. The results showed that the leaves of Rhododendron cultivars were typical bifacial leaf and the epidermal anticlinal walls showed slightly sinuate. The stomata only distributed in the lower epidermis and the shape was ruleless. The anatomical structure indexes all reached a significant level difference among 15 cultivars (P<0.01), except for lower epidermis thickness (P<0.05). Thickness of lamina corneum, stomatal density, stomatal width, the thickness palisade tissue and looseness of leaf spongy tissue were the main factors related to the hardness, while other indexes, such as stomatal length, stoma aperture, stomatal opening, length and thickness of upper epidermis, length and thickness of lower epidermis, thickness of spongy tissue, the ratio of the palisade tissue to spongy tissue, tightness of leaf palisade tissue, leaf thickness and media thickness didn't show much effect on heat resistance. There were some differences among 15 cultivars in heat resistance, and the order was Rhododendron 'Song Jiang Da Tao Hong' > Rhododendron 'Zhuang Yuan Hong' > Rhododendron 'Lv Se Guang Hui' > Rhododendron 'Fen Zhen Zhu' > Rhododendron 'Wai Guo Hong' > Rhododendron 'Lan Yin' > Rhododendron 'Bi Zhi' >Rhododendron 'Da He Zhi Chun' > Rhododendron 'Guo Qi Hong' > Rhododendron 'Yu Ling Long' > Rhododendron 'Hong Shan Hu' > Rhododendron 'Ning Bo Hong' > Rhododendron 'Tao Ban Zhu Sha' > Rhododendron 'Ai Ding Bao' > Rhododendron 'Liu Qiu Hong'. According to the heat hardiness, the cultivars could be divided into 4 groups: R. 'Song Jiang Da Tao Hong', R. 'Zhuang Yuan Hong' and R. 'Lv Se Guang Hui' with high heat resistance, R. 'Fen Zhen Zhu', R. 'Wai Guo Hong', R. 'Lan Yin', R. 'Bi Zhi', R. 'Da He Zhi Chun', R. 'Guo Qi Hong' and R. 'Yu Ling Long' with medium heat resistance, R. 'Hong Shan Hu', R. 'Ning Bo Hong', R. 'Tao Ban Zhu Sha' and R. 'Ai Ding Bao' with lower heat resistance, R. 'Liu Qiu Hong' without heat resistance. However, the accurate heat hardiness evaluation of Rhododendron still needs to consider other factors, including morphological structure, physiological and biochemical indicators and genetic factor of heat resistance, the harmfulness of Rhododendron, and the recovery state after being injured by high temperature.

The TIE1 Transcriptional Repressor Links TCP Transcription Factors with TOPLESS/TOPLESS-RELATED Corepressors and Modulates Leaf Development in Arabidopsis[W

PubMed Central

Tao, Qing; Guo, Dongshu; Wei, Baoye; Zhang, Fan; Pang, Changxu; Jiang, Hao; Zhang, Jinzhe; Wei, Tong; Gu, Hongya; Qu, Li-Jia; Qin, Genji

2013-01-01

Leaf size and shape are mainly determined by coordinated cell division and differentiation in lamina. The CINCINNATA (CIN)-like TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors are key regulators of leaf development. However, the mechanisms that control TCP activities during leaf development are largely unknown. We identified the TCP Interactor containing EAR motif protein1 (TIE1), a novel transcriptional repressor, as a major modulator of TCP activities during leaf development. Overexpression of TIE1 leads to hyponastic and serrated leaves, whereas disruption of TIE1 causes epinastic leaves. TIE1 is expressed in young leaves and encodes a transcriptional repressor containing a C-terminal EAR motif, which mediates interactions with the TOPLESS (TPL)/TOPLESS-RELATED (TPR) corepressors. In addition, TIE1 physically interacts with CIN-like TCPs. We propose that TIE1 regulates leaf size and morphology by inhibiting the activities of TCPs through recruiting the TPL/TPR corepressors to form a tertiary complex at early stages of leaf development. PMID:23444332

Dependence of Plant Uptake and Diffusion of Polycyclic Aromatic Hydrocarbons on the Leaf Surface Morphology and Micro-structures of Cuticular Waxes

NASA Astrophysics Data System (ADS)

Li, Qingqing; Li, Yungui; Zhu, Lizhong; Xing, Baoshan; Chen, Baoliang

2017-04-01

The uptake of organic chemicals by plants is considered of great significance as it impacts their environmental transport and fate and threatens crop growth and food safety. Herein, the dependence of the uptake, penetration, and distribution of sixteen polycyclic aromatic hydrocarbons (PAHs) on the morphology and micro-structures of cuticular waxes on leaf surfaces was investigated. Plant surface morphologies and wax micro-structures were examined by scanning emission microscopy, and hydrophobicities of plant surfaces were monitored through contact angle measurements. PAHs in the cuticles and inner tissues were distinguished by sequential extraction, and the cuticle was verified to be the dominant reservoir for the accumulation of lipophilic pollutants. The interspecies differences in PAH concentrations cannot be explained by normalizing them to the plant lipid content. PAHs in the inner tissues became concentrated with the increase of tissue lipid content, while a generally negative correlation between the PAH concentration in cuticles and the epicuticular wax content was found. PAHs on the adaxial and abaxial sides of a leaf were differentiated for the first time, and the divergence between these two sides can be ascribed to the variations in surface morphologies. The role of leaf lipids was redefined and differentiated.

Physiological, vascular and nanomechanical assessment of hybrid poplar leaf traits in micropropagated plants and plants propagated from root cuttings: A contribution to breeding programs.

PubMed

Ďurkovič, Jaroslav; Husárová, Hana; Javoříková, Lucia; Čaňová, Ingrid; Šuleková, Miriama; Kardošová, Monika; Lukáčik, Ivan; Mamoňová, Miroslava; Lagaňa, Rastislav

2017-09-01

Micropropagated plants experience significant stress from rapid water loss when they are transferred from an in vitro culture to either greenhouse or field conditions. This is caused both by inefficient stomatal control of transpiration and the change to a higher light intensity and lower humidity. Understanding the physiological, vascular and biomechanical processes that allow micropropagated plants to modify their phenotype in response to environmental conditions can help to improve both field performance and plant survival. To identify changes between the hybrid poplar [Populus tremula × (Populus × canescens)] plants propagated from in vitro tissue culture and those from root cuttings, we assessed leaf performance for any differences in leaf growth, photosynthetic and vascular traits, and also nanomechanical properties of the tracheary element cell walls. The micropropagated plants showed significantly higher values for leaf area, leaf length, leaf width and leaf dry mass. The greater leaf area and leaf size dimensions resulted from the higher transpiration rate recorded for this stock type. Also, the micropropagated plants reached higher values for chlorophyll a fluorescence parameters and for the nanomechanical dissipation energy of tracheary element cell walls which may indicate a higher damping capacity within the primary xylem tissue under abiotic stress conditions. The performance of the plants propagated from root cuttings was superior for instantaneous water-use efficiency which signifies a higher acclimation capacity to stressful conditions during a severe drought particularly for this stock type. Similarities were found among the majority of the examined leaf traits for both vegetative plant origins including leaf mass per area, stomatal conductance, net photosynthetic rate, hydraulic axial conductivity, indicators of leaf midrib vascular architecture, as well as for the majority of cell wall nanomechanical traits. This research revealed that there were no drawbacks in the leaf physiological performance which could be attributed to the micropropagated plants of fast growing hybrid poplar. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Phytohormones signaling and crosstalk regulating leaf angle in rice.

PubMed

Luo, Xiangyu; Zheng, Jingsheng; Huang, Rongyu; Huang, Yumin; Wang, Houcong; Jiang, Liangrong; Fang, Xuanjun

2016-12-01

Leaf angle is an important agronomic trait in rice (Oryza sativa L.). It affects both the efficiency of sunlight capture and nitrogen reservoirs. The erect leaf phenotype is suited for high-density planting and thus increasing crop yields. Many genes regulate leaf angle by affecting leaf structure, such as the lamina joint, mechanical tissues, and the midrib. Signaling of brassinosteroids (BR), auxin (IAA), and gibberellins (GA) plays important roles in the regulation of lamina joint bending in rice. In addition, the biosynthesis and signaling of BR are known to have dominant effects on leaf angle development. In this review, we summarize the factors and genes associated with the development of leaf angle in rice, outline the regulatory mechanisms based on the signaling of BR, IAA, and GA, and discuss the contribution of crosstalk between BR and IAA or GA in the formation of leaf angle. Promising lines of research in the transgenic engineering of rice leaf angle to increase grain yield are proposed.

Leaf traits and herbivory levels in a tropical gymnosperm, Zamia stevensonii (Zamiaceae).

PubMed

Prado, Alberto; Sierra, Adriel; Windsor, Donald; Bede, Jacqueline C

2014-03-01

Slow-growing understory cycads invest heavily in defenses to protect the few leaves they produce annually. The Neotropical cycad Zamia stevensonii has chemical and mechanical barriers against insect herbivores. Mechanical barriers, such as leaf toughness, can be established only after the leaf has expanded. Therefore, chemical defenses may be important during leaf expansion. How changes in leaf traits affect the feeding activity of cycad specialist insects is unknown. We investigated leaf defenses and incidence of specialist herbivores on Z. stevensonii during the first year after leaf flush. Herbivore incidence, leaf production, and leaf traits that might affect herbivory-including leaf age, lamina thickness, resistance-to-fracture, work-to-fracture, trichome density, and chlorophyll, water, and toxic azoxyglycoside (AZG) content-were measured throughout leaf development. Principal component analysis and generalized linear models identified characteristics that may explain herbivore incidence. Synchronized leaf development in Z. stevensonii is characterized by quick leaf expansion and delayed greening. Specialist herbivores feed on leaves between 10 and 100 d after flush and damage ∼37% of all leaflets produced. Young leaves are protected by AZGs, but these defenses rapidly decrease as leaves expand. Leaves older than 100 d are protected by toughness. Because AZG concentrations drop before leaves become sufficiently tough, there is a vulnerable period during which leaves are susceptible to herbivory by specialist insects. This slow-growing gymnosperm invests heavily in constitutive defenses against highly specialized herbivores, underlining the convergence in defensive syndromes by major plant lineages.

Changes in water content and distribution in Quercus ilex leaves during progressive drought assessed by in vivo 1H magnetic resonance imaging

PubMed Central

2010-01-01

Background Drought is a common stressor in many regions of the world and current climatic global circulation models predict further increases in warming and drought in the coming decades in several of these regions, such as the Mediterranean basin. The changes in leaf water content, distribution and dynamics in plant tissues under different soil water availabilities are not well known. In order to fill this gap, in the present report we describe our study withholding the irrigation of the seedlings of Quercus ilex, the dominant tree species in the evergreen forests of many areas of the Mediterranean Basin. We have monitored the gradual changes in water content in the different leaf areas, in vivo and non-invasively, by 1H magnetic resonance imaging (MRI) using proton density weighted (ρw) images and spin-spin relaxation time (T2) maps. Results ρw images showed that the distal leaf area lost water faster than the basal area and that after four weeks of similar losses, the water reduction was greater in leaf veins than in leaf parenchyma areas and also in distal than in basal leaf area. There was a similar tendency in all different areas and tissues, of increasing T2 values during the drought period. This indicates an increase in the dynamics of free water, suggesting a decrease of cell membranes permeability. Conclusions The results indicate a non homogeneous leaf response to stress with a differentiated capacity to mobilize water between its different parts and tissues. This study shows that the MRI technique can be a useful tool to follow non-intrusively the in vivo water content changes in the different parts of the leaves during drought stress. It opens up new possibilities to better characterize the associated physiological changes and provides important information about the different responses of the different leaf areas what should be taken into account when conducting physiological and metabolic drought stress studies in different parts of the leaves during drought stress. PMID:20735815

Changes in water content and distribution in Quercus ilex leaves during progressive drought assessed by in vivo 1H magnetic resonance imaging.

PubMed

Sardans, Jordi; Peñuelas, Josep; Lope-Piedrafita, Silvia

2010-08-24

Drought is a common stressor in many regions of the world and current climatic global circulation models predict further increases in warming and drought in the coming decades in several of these regions, such as the Mediterranean basin. The changes in leaf water content, distribution and dynamics in plant tissues under different soil water availabilities are not well known. In order to fill this gap, in the present report we describe our study withholding the irrigation of the seedlings of Quercus ilex, the dominant tree species in the evergreen forests of many areas of the Mediterranean Basin. We have monitored the gradual changes in water content in the different leaf areas, in vivo and non-invasively, by 1H magnetic resonance imaging (MRI) using proton density weighted (rhow) images and spin-spin relaxation time (T2) maps. Rhow images showed that the distal leaf area lost water faster than the basal area and that after four weeks of similar losses, the water reduction was greater in leaf veins than in leaf parenchyma areas and also in distal than in basal leaf area. There was a similar tendency in all different areas and tissues, of increasing T2 values during the drought period. This indicates an increase in the dynamics of free water, suggesting a decrease of cell membranes permeability. The results indicate a non homogeneous leaf response to stress with a differentiated capacity to mobilize water between its different parts and tissues. This study shows that the MRI technique can be a useful tool to follow non-intrusively the in vivo water content changes in the different parts of the leaves during drought stress. It opens up new possibilities to better characterize the associated physiological changes and provides important information about the different responses of the different leaf areas what should be taken into account when conducting physiological and metabolic drought stress studies in different parts of the leaves during drought stress.

Evaluating relative contribution of osmotolerance and tissue tolerance mechanisms toward salinity stress tolerance in three Brassica species.

PubMed

Chakraborty, Koushik; Bose, Jayakumar; Shabala, Lana; Eyles, Alieta; Shabala, Sergey

2016-10-01

Three different species of Brassica, with differential salt sensitivity were used to understand physiological mechanisms of salt tolerance operating in these species and to evaluate the relative contribution of different strategies to cope with salt load. Brassica napus was the most tolerant species in terms of the overall performance, with Brassica juncea and Brassica oleracea being much more sensitive to salt stress with no obvious difference between them. While prominent reduction in net CO2 assimilation was observed in both sensitive species, physiological mechanisms beyond this reduction differed strongly. Brassica juncea plants possessed high osmotolerance and were able to maintain high transpiration rate but showed a significant reduction in leaf chlorophyll content and efficiency of leaf photochemistry. On the contrary, B. oleracea plants possessed the highest (among the three species) tissue tolerance but showed a very significant stomatal limitation of photosynthesis. Electrophysiological experiments revealed that the high tissue tolerance in B. oleracea was related to the ability of leaf mesophyll cells to maintain highly negative membrane potential in the presence of high apoplastic Na(+) . In addition to high osmotolerance, the most tolerant B. napus showed also lesser accumulation of toxic Na(+) and Cl(-) in the leaf, possessed moderate tissue tolerance and had a superior K(+) retention ability. Taken together, the results from this study indicate that the three Brassica species employ very different mechanisms to cope with salinity and, despite its overall sensitivity to salinity, B. oleracea could be recommended as a valuable 'donor' of tissue tolerance genes to confer this trait for marker-assisted breeding programs. © 2016 Scandinavian Plant Physiology Society.

Double-filter identification of vascular-expressed genes using Arabidopsis plants with vascular hypertrophy and hypotrophy.

PubMed

Ckurshumova, Wenzislava; Scarpella, Enrico; Goldstein, Rochelle S; Berleth, Thomas

2011-08-01

Genes expressed in vascular tissues have been identified by several strategies, usually with a focus on mature vascular cells. In this study, we explored the possibility of using two opposite types of altered tissue compositions in combination with a double-filter selection to identify genes with a high probability of vascular expression in early organ primordia. Specifically, we generated full-transcriptome microarray profiles of plants with (a) genetically strongly reduced and (b) pharmacologically vastly increased vascular tissues and identified a reproducible cohort of 158 transcripts that fulfilled the dual requirement of being underrepresented in (a) and overrepresented in (b). In order to assess the predictive value of our identification scheme for vascular gene expression, we determined the expression patterns of genes in two unbiased subsamples. First, we assessed the expression patterns of all twenty annotated transcription factor genes from the cohort of 158 genes and found that seventeen of the twenty genes were preferentially expressed in leaf vascular cells. Remarkably, fifteen of these seventeen vascular genes were clearly expressed already very early in leaf vein development. Twelve genes with published leaf expression patterns served as a second subsample to monitor the representation of vascular genes in our cohort. Of those twelve genes, eleven were preferentially expressed in leaf vascular tissues. Based on these results we propose that our compendium of 158 genes represents a sample that is highly enriched for genes expressed in vascular tissues and that our approach is particularly suited to detect genes expressed in vascular cell lineages at early stages of their inception. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The evaluation of long-term effects of cinnamon bark and olive leaf on toxicity induced by streptozotocin administration to rats.

PubMed

Onderoglu, S; Sozer, S; Erbil, K M; Ortac, R; Lermioglu, F

1999-11-01

The effects of cinnamon bark and olive leaf have been investigated on streptozotocin-induced tissue injury, and some biochemical and haematological changes in rats. The effects on glycaemia were also evaluated. Long-term administration of olive leaf caused significant improvement in tissue injury induced by streptozotocin treatment; the effect of cinnamon bark was less extent. No effects on blood glucose levels were detected. However, significant decreases in some increased biochemical and haematological parameters of streptozotocin-treated rats were observed. Aspartate aminotransferase, urea and cholesterol levels were significantly decreased by treatment with both plant materials, and alanine aminotransferase by treatment with olive leaf. Cinnamon bark also caused a significant decrease in platelet counts. In addition, any visible toxicity, except decrease in body weight gain, attributable to the long-term use of plant materials was not established in normal rats. The data indicate that long-term use of olive leaf and cinnamon bark may provide benefit against diabetic conditions. Determination of underlying mechanism(s) of beneficial effects, toxicity to other systems and clinical assessments of related plant materials are major topics requiring further studies.

A Rice PECTATE LYASE-LIKE Gene Is Required for Plant Growth and Leaf Senescence1[OPEN

PubMed Central

Leng, Yujia; Yang, Yaolong; Ren, Deyong; Dai, Liping; Wang, Yuqiong; Chen, Long; Tu, Zhengjun; Gao, Yihong; Zhu, Li; Hu, Jiang; Gao, Zhenyu; Guo, Longbiao; Lin, Yongjun

2017-01-01

To better understand the molecular mechanisms behind plant growth and leaf senescence in monocot plants, we identified a mutant exhibiting dwarfism and an early-senescence leaf phenotype, termed dwarf and early-senescence leaf1 (del1). Histological analysis showed that the abnormal growth was caused by a reduction in cell number. Further investigation revealed that the decline in cell number in del1 was affected by the cell cycle. Physiological analysis, transmission electron microscopy, and TUNEL assays showed that leaf senescence was triggered by the accumulation of reactive oxygen species. The DEL1 gene was cloned using a map-based approach. It was shown to encode a pectate lyase (PEL) precursor that contains a PelC domain. DEL1 contains all the conserved residues of PEL and has strong similarity with plant PelC. DEL1 is expressed in all tissues but predominantly in elongating tissues. Functional analysis revealed that mutation of DEL1 decreased the total PEL enzymatic activity, increased the degree of methylesterified homogalacturonan, and altered the cell wall composition and structure. In addition, transcriptome assay revealed that a set of cell wall function- and senescence-related gene expression was altered in del1 plants. Our research indicates that DEL1 is involved in both the maintenance of normal cell division and the induction of leaf senescence. These findings reveal a new molecular mechanism for plant growth and leaf senescence mediated by PECTATE LYASE-LIKE genes. PMID:28455404

Reversible Deformation of Transfusion Tracheids in Taxus baccata Is Associated with a Reversible Decrease in Leaf Hydraulic Conductance1[OPEN

PubMed Central

Zhang, Yong-Jiang; Rockwell, Fulton E.; Wheeler, James K.; Holbrook, N. Michele

2014-01-01

Declines in leaf hydraulic conductance (Kleaf) with increasing water stress have been attributed to cavitation of the leaf xylem. However, in the leaves of conifers, the reversible collapse of transfusion tracheids may provide an alternative explanation. Using Taxus baccata, a conifer species without resin, we developed a modified rehydration technique that allows the separation of declines in Kleaf into two components: one reversible and one irreversible upon relaxation of water potential to −1 MPa. We surveyed leaves at a range of water potentials for evidence of cavitation using cryo-scanning electron microscopy and quantified dehydration-induced structural changes in transfusion tracheids by cryo-fluorescence microscopy. Irreversible declines in Kleaf did not occur until leaf water potentials were more negative than −3 MPa. Declines in Kleaf between −2 and −3 MPa were reversible and accompanied by the collapse of transfusion tracheids, as evidenced by cryo-fluorescence microscopy. Based on cryo-scanning electron microscopy, cavitation of either transfusion or xylem tracheids did not contribute to declines in Kleaf in the reversible range. Moreover, the deformation of transfusion tracheids was quickly reversible, thus acting as a circuit breaker regulating the flux of water through the leaf vasculature. As transfusion tissue is present in all gymnosperms, the reversible collapse of transfusion tracheids may be a general mechanism in this group for the protection of leaf xylem from excessive loads generated in the living leaf tissue. PMID:24948828

A Rice PECTATE LYASE-LIKE Gene Is Required for Plant Growth and Leaf Senescence.

PubMed

Leng, Yujia; Yang, Yaolong; Ren, Deyong; Huang, Lichao; Dai, Liping; Wang, Yuqiong; Chen, Long; Tu, Zhengjun; Gao, Yihong; Li, Xueyong; Zhu, Li; Hu, Jiang; Zhang, Guangheng; Gao, Zhenyu; Guo, Longbiao; Kong, Zhaosheng; Lin, Yongjun; Qian, Qian; Zeng, Dali

2017-06-01

To better understand the molecular mechanisms behind plant growth and leaf senescence in monocot plants, we identified a mutant exhibiting dwarfism and an early-senescence leaf phenotype, termed dwarf and early-senescence leaf1 ( del1 ). Histological analysis showed that the abnormal growth was caused by a reduction in cell number. Further investigation revealed that the decline in cell number in del1 was affected by the cell cycle. Physiological analysis, transmission electron microscopy, and TUNEL assays showed that leaf senescence was triggered by the accumulation of reactive oxygen species. The DEL1 gene was cloned using a map-based approach. It was shown to encode a pectate lyase (PEL) precursor that contains a PelC domain. DEL1 contains all the conserved residues of PEL and has strong similarity with plant PelC. DEL1 is expressed in all tissues but predominantly in elongating tissues. Functional analysis revealed that mutation of DEL1 decreased the total PEL enzymatic activity, increased the degree of methylesterified homogalacturonan, and altered the cell wall composition and structure. In addition, transcriptome assay revealed that a set of cell wall function- and senescence-related gene expression was altered in del1 plants. Our research indicates that DEL1 is involved in both the maintenance of normal cell division and the induction of leaf senescence. These findings reveal a new molecular mechanism for plant growth and leaf senescence mediated by PECTATE LYASE-LIKE genes. © 2017 American Society of Plant Biologists. All Rights Reserved.

Olea europaea L. leaf extract and derivatives: antioxidant properties.

PubMed

Briante, Raffaella; Patumi, Maurizio; Terenziani, Stefano; Bismuto, Ettore; Febbraio, Ferdinando; Nucci, Roberto

2002-08-14

This paper reports a very simple and fast method to collect eluates with high amounts of hydroxytyrosol, biotransforming Olea europaea L. leaf extract by a thermophilic beta-glycosidase immobilized on chitosan. Some phenolic compounds in the leaf tissue and in the eluates obtained by biotransformation are identified. To propose the eluates as natural substances from a vegetal source, their antioxidant properties have been compared with those of the leaf extract from which they are originated. The eluates possess a higher concentration of simple phenols, characterized by a stronger antioxidant capacity, than those available in extra virgin olive oils and in many tablets of olive leaf extracts, commercially found as dietetic products and food integrators.

Does citrus leaf miner impair hydraulics and fitness of citrus host plants?

PubMed

Raimondo, Fabio; Trifilò, Patrizia; Gullo, Maria A Lo

2013-12-01

Gas exchange and hydraulic features were measured in leaves of three different Citrus species (Citrus aurantium L., Citrus limon L., Citrus  ×  paradisii Macfad) infested by Phyllocnistis citrella Staiton, with the aim to quantify the impact of this pest on leaf hydraulics and, ultimately, on plant fitness. Infested leaves were characterized by the presence on the leaf blade of typical snake-shaped mines and, in some cases, of a crumpled leaf blade. Light microscopy showed that leaf crumpling was induced by damage to the cuticular layer. In all three Citrus species examined: (a) the degree of infestation did not exceed 10% of the total surface area of infested plants; (b) control and infested leaves showed similar values of minimum diurnal leaf water potential, leaf hydraulic conductance and functional vein density; and (c) maximum diurnal values of stomatal conductance to water vapour, transpiration rate and photosynthetic rate (An) were similar in both control leaves and the green areas of infested leaves. A strong reduction of An was recorded only in mined leaf areas. Our data suggest that infestation with P. citrella does not cause conspicuous plant productivity reductions in young Citrus plants, at least not in the three Citrus species studied here.

Remote Sensing Plant Stress Using Combined Fluorescence and Reflectance Measurements for Early Detection of Defoliants within the Battlefield Environment

DTIC Science & Technology

2012-10-02

Sensing Imagery, Instituto de Agricultura Sostenible, Córdoba, Spain Young, D.R. 2007. Leaf to landscape in a barrier island environment.” Workshop...on Vegetation Stress Detection with Remote Sensing Imagery, Instituto de Agricultura Sostenible, Córdoba, Spain Young, D.R. and J.C. Naumann. 2007

Sampling throughfall and stemflow in young loblolly pine plantations

Treesearch

S.J. Zarnoch; D.A. Abrahamson; P.M. Dougherty

2002-01-01

Throughfall and stemflow estimates were obtained on a rain-event basis for small (0.09-hectare) plots established in a young loblolly pine (Pinus taeda L.) plantation in North Carolina. The plots were exposed to specific fertilization and irrigation treatments, which resulted in a wide range of basal areas and leaf area indices. Coefficients of variation were also...

Inhibition of a ubiquitously expressed pectin methyl esterase in Solanum tuberosum L. affects plant growth, leaf growth polarity, and ion partitioning.

PubMed

Pilling, J; Willmitzer, L; Bücking, H; Fisahn, J

2004-05-01

Two pectin methyl esterases (PMEs; EC 3.1.1.11) from Solanum tuberosum were isolated and their expression characterised. One partial clone ( pest1) was expressed in leaves and fruit tissue, while pest2 was a functional full-length clone and was expressed ubiquitously, with a preference for aerial organs. Potato plants were transformed with a chimeric antisense construct that was designed to simultaneously inhibit pest1 and pest2 transcript accumulation; however, reduction of mRNA levels was confined to pest2. The decrease in pest2 transcript was accompanied by up to 50% inhibition of total PME activity, which was probably due to the reduction of only one PME isoform. PME inhibition affected plant development as reflected by smaller stem elongation rates of selected transformants when compared with control plants, leading to a reduction in height throughout the entire course of development. Expansion rates of young developing leaves were measured simultaneously by two displacement transducers in the direction of the leaf tip (proximal-distal axis) and in the perpendicular direction (medial-lateral axis). Significant differences in leaf growth patterns were detected between wild-type and transgenic plants. We suggest that these visual phenotypes could be correlated with modifications of ion accumulation and partitioning within the transgenic plants. The ion-binding capacities of cell walls from PME-inhibited plants were specifically modified as they preferentially bound more sodium, but less potassium and calcium. X-ray microanalysis also indicated an increase in the concentration of several ions within the leaf apoplast of transgenic plants. Moreover, quantification of the total content of major cations revealed differences specific for a given element between the leaves of PME-inhibited and wild-type plants. Reduced growth rates might also be due to effects of PME inhibition on pectin metabolism, predominantly illustrated by an accumulation of galacturonic acid over other cell wall components.

Identification and transcript profiles of citrus growth-regulating factor genes involved in the regulation of leaf and fruit development.

PubMed

Liu, Xiao; Guo, Ling-Xia; Jin, Long-Fei; Liu, Yong-Zhong; Liu, Tao; Fan, Yu-Hua; Peng, Shu-Ang

2016-10-01

Growth-regulating factor (GRF) is an important protein in GA-mediated response, with key roles in plant growth and development. However, it is not known whether or how the GRF proteins in citrus to regulate organ size. In this study, nine citrus GRF genes (CsGRF1-9) were validated from the 'Anliu' sweet orange (AL, Citrus sinensis cv. Anliu) by PCR amplification. They all contain two conserved motifs (QLQ and WRC) and have 3-4 exons. The transcript levels of genes were detected by qRT-PCR. Transcript analysis showed that (1) CsGRF 1, 2, 5, 6, 7, and 9 expressed predominantly in young leaf, CsGRF 3 and 4 expressed predominantly in fruit immature juice sacs and CsGRF 8 expressed predominantly in root; (2) all citrus GRF genes had significantly higher expression in young leaves than mature leaf; (3) in juice sacs, the transcript levels of CsGRF1, 4, 5, 6, and 8 increased significantly while the transcript levels of CsGRF2, 3, 7, and 9 had no significant change from 80 DAF to 100 DAF. Besides, GA3 treatment did not affect the transcript levels of CsGRF5 and CsGRF6 but significantly increased the transcript levels of the other seven CsGRF genes in young leaves. These results suggested that all CsGRF genes involve in the leaf development, CsGRF1, 4, 5, 6, and 8 act developmentally whilst CsGRF2, 3, 7, and 9 play fundamental roles in fruit cell enlargement, which may be through GA pathway or GA-independent pathway.

Synergistic, additive and antagonistic impacts of drought and herbivory on Pinus sylvestris: leaf, tissue and whole-plant responses and recovery.

PubMed

Bansal, Sheel; Hallsby, Göran; Löfvenius, Mikael O; Nilsson, Marie-Charlotte

2013-05-01

Forests typically experience a mix of anthropogenic, natural and climate-induced stressors of different intensities, creating a mosaic of stressor combinations across the landscape. When multiple stressors co-occur, their combined impact on plant growth is often greater than expected based on single-factor studies (i.e., synergistic), potentially causing catastrophic dysfunction of physiological processes from an otherwise recoverable situation. Drought and herbivory are two stressors that commonly co-occur in forested ecosystems, and have the potential to 'overlap' in their impacts on various plant traits and processes. However, the combined impacts from these two stressors may not be predictable based on additive models from single-stressor studies. Moreover, the impacts and subsequent recovery may be strongly influenced by the relative intensities of each stressor. Here, we applied drought stress and simulated bark-feeding herbivory at three levels of intensity (control, moderate and severe) in a full factorial design on young Pinus sylvestris L. seedlings. We assessed if the combined effects from two stressors were additive (responses were equal to the sum of the single-factor effects), synergistic (greater than expected) or antagonistic (less than expected) on a suite of morphological and physiological traits at the leaf-, tissue- and whole-plant level. We additionally investigated whether recovery from herbivory was dependent on relief from drought. The two stressors had synergistic impacts on specific leaf area and water-use efficiency, additive effects on height and root-to-shoot ratios, but antagonistic effects on photosynthesis, conductance and, most notably, on root, shoot and whole-plant biomass. Nevertheless, the magnitude and direction of the combined impacts were often dependent on the relative intensities of each stressor, leading to many additive or synergistic responses from specific stressor combinations. Also, seedling recovery was far more dependent on the previous year's drought compared with the previous year's herbivory, demonstrating the influence of one stressor over another during recovery. Our study reveals for the first time, the importance of not only the presence or absence of drought and herbivory stressors, but also shows that their relative intensities are critical in determining the direction and magnitude of their impacts on establishing seedlings.

The use of stored carbon reserves in growth of temperate tree roots and leaf buds: Analyses using radiocarbon measurements and modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaudinski, J.B.; Torn, M.S.; Riley, W.J.

2009-02-01

Characterizing the use of carbon (C) reserves in trees is important for understanding regional and global C cycles, stress responses, asynchrony between photosynthetic activity and growth demand, and isotopic exchanges in studies of tree physiology and ecosystem C cycling. Using an inadvertent, whole-ecosystem radiocarbon ({sup 14}C) release in a temperate deciduous oak forest and numerical modeling, we estimated that the mean age of stored C used to grow both leaf buds and new roots is 0.7 years and about 55% of new-root growth annually comes from stored C. Therefore, the calculated mean age of C used to grow new-root tissuemore » is {approx}0.4 years. In short, new roots contain a lot of stored C but it is young in age. Additionally, the type of structure used to model stored C input is important. Model structures that did not include storage, or that assumed stored and new C mixed well (within root or shoot tissues) before being used for root growth, did not fit the data nearly as well as when a distinct storage pool was used. Consistent with these whole-ecosystem labeling results, the mean age of C in new-root tissues determined using 'bomb-{sup 14}C' in three additional forest sites in North America and Europe (one deciduous, two coniferous) was less than 1-2 years. The effect of stored reserves on estimated ages of fine roots is unlikely to be large in most natural abundance isotope studies. However, models of root C dynamics should take stored reserves into account, particularly for pulse-labeling studies and fast-cycling roots (<1 years).« less

Commander Young reviews clipboard notes and procedures on forward flight deck

NASA Image and Video Library

1981-04-14

STS001-07-540 (12-14 April 1981) --- Astronaut John W. Young, commander, is seated at his left side station in the flight deck of the space shuttle Columbia. He holds a loose-leaf book in which he recorded data during the flight. Soon after the launch phase of STS-1, astronauts Young and Robert L. Crippen, pilot, changed from their high altitude pressure garments into the light blue constant wear garment. Photo credit: NASA

The energetic and carbon economic origins of leaf thermoregulation.

PubMed

Michaletz, Sean T; Weiser, Michael D; McDowell, Nate G; Zhou, Jizhong; Kaspari, Michael; Helliker, Brent R; Enquist, Brian J

2016-08-22

Leaf thermoregulation has been documented in a handful of studies, but the generality and origins of this pattern are unclear. We suggest that leaf thermoregulation is widespread in both space and time, and originates from the optimization of leaf traits to maximize leaf carbon gain across and within variable environments. Here we use global data for leaf temperatures, traits and photosynthesis to evaluate predictions from a novel theory of thermoregulation that synthesizes energy budget and carbon economics theories. Our results reveal that variation in leaf temperatures and physiological performance are tightly linked to leaf traits and carbon economics. The theory, parameterized with global averaged leaf traits and microclimate, predicts a moderate level of leaf thermoregulation across a broad air temperature gradient. These predictions are supported by independent data for diverse taxa spanning a global air temperature range of ∼60 °C. Moreover, our theory predicts that net carbon assimilation can be maximized by means of a trade-off between leaf thermal stability and photosynthetic stability. This prediction is supported by globally distributed data for leaf thermal and photosynthetic traits. Our results demonstrate that the temperatures of plant tissues, and not just air, are vital to developing more accurate Earth system models.

Optimization of microwave-assisted extraction of flavonoids from young barley leaves

NASA Astrophysics Data System (ADS)

Gao, Tian; Zhang, Min; Fang, Zhongxiang; Zhong, Qifeng

2017-01-01

A central composite design combined with response surface methodology was utilized to optimise microwave-assisted extraction of flavonoids from young barley leaves. The results showed that using water as solvent, the optimum conditions of microwave-assisted extraction were extracted twice at 1.27 W g-1 microwave power and liquid-solid ratio 34.02 ml g-1 for 11.12 min. The maximum extraction yield of flavonoids (rutin equivalents) was 80.78±0.52%. Compared with conventional extraction method, the microwave-assisted extraction was more efficient as the extraction time was only 6.18% of conventional extraction, but the extraction yield of flavonoids was increased by 5.47%. The main flavonoid components from the young barley leaf extract were probably 33.36% of isoorientin-7-O-glueoside and 54.17% of isovitexin-7-O-glucoside, based on the HPLC-MS analysis. The barley leaf extract exhibited strong reducing power as well as the DPPH radical scavenging capacity.

Endophytic fungi reduce leaf-cutting ant damage to seedlings

PubMed Central

Bittleston, L. S.; Brockmann, F.; Wcislo, W.; Van Bael, S. A.

2011-01-01

Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (Ehigh) or low (Elow) densities of endophytes. The Ehigh seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the Elow treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from Elow relative to Ehigh seedlings and had a tendency to recruit more ants to Elow plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities. PMID:20610420

Leaf gas films contribute to rice (Oryza sativa) submergence tolerance during saline floods.

PubMed

Herzog, Max; Konnerup, Dennis; Pedersen, Ole; Winkel, Anders; Colmer, Timothy David

2018-05-01

Floods and salinization of agricultural land adversely impact global rice production. We investigated whether gas films on leaves of submerged rice delay salt entry during saline submergence. Two-week-old plants with leaf gas films (+GF) or with gas films experimentally removed (-GF) were submerged in artificial floodwater with 0 or 50 mm NaCl for up to 16 d. Gas films were present >9 d on GF plants after which gas films were diminished. Tissue ion analysis (Na + , Cl - and K + ) showed that gas films caused some delay of Na + entry, as leaf Na + concentration was 36-42% higher in -GF leaves than +GF leaves on days 1-5. However, significant net uptakes of Na + and Cl - , and K + net loss, occurred despite the presence of gas films, indicating the likely presence of some leaf-to-floodwater contact, so that the gas layer must not have completely separated the leaf surfaces from the water. Natural loss and removal of gas films resulted in severe declines in growth, underwater photosynthesis, chlorophyll a and tissue porosity. Submergence was more detrimental to leaf P N and growth than the additional effect of 50 mm NaCl, as salt did not significantly affect underwater P N at 200 μm CO 2 nor growth. © 2016 John Wiley & Sons Ltd.

USE OF NATIVE PLANTS FOR REMEDIATION OF TRICHLOROETHYLENE: I. DECIDUOUS TREES.

PubMed

Strycharz, S; Newman, L

2009-02-01

Phytoremediation of trichloroethylene (TCE) can be accomplished using fast-growing, deep-rooting trees. The most commonly used tree for phytoremediation of TCE has been the hybrid poplar. This study looks at native southeastern trees of the United States as alternatives to the use of hybrid poplar. The use of native trees for phytoremediation allows for simultaneous restoration of contaminated sites. A 2-mo, greenhouse-based study was conducted to determine if sycamore (Plantanus L.), eastern cottonwood (Populus deltoides), sweetgum (Liquidambar styraciflua L.), and willow (Salix sachalinensis) trees possess the ability to degrade TCE by assessing TCE metabolite formation in the plant tissue. In addition to the metabolic capabilities of each tree species, growth parameters were measured including change in height, water usage, total fresh weight of each tissue type, and calculated total leaf surface area. Willow trees had the greatest increase in height among all trees tested; however, at higher concentrations TCE inhibits growth. Sycamore trees had the highest overall leaf surface area and total biomass, which correlated with sycamore trees also having the highest average water usage over the course of the experiment. Carbon tubes used to sample transpiration gases from sycamore, sweetgum, and cottonwood trees did not contain detectable levels of TCE. Tenex sample collection tubes used to sample willow trees during TCE exposure showed average TCE concentrations of up to 0.354 ng TCE cm -2 leaf tissue. All exposed trees contained TCE in the root, stem, and leaf tissues. The concentration of TCE remaining in tissues at the conclusion of the experiment varied, with the highest levels found in the roots and the lowest levels found in the leaves. Metabolites were also observed in different tissue types of all trees tested. The highest concentrations of trichloroacetic acid were observed in the leaves of the sycamore trees and cottonwood trees. Based on the growth parameters tested and the ability to metabolize TCE, sycamore and native cottonwood species are the best candidates for phytoremediation from this study.

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle.

PubMed

Siegner, Ralf; Heuser, Stefan; Holtzmann, Ursula; Söhle, Jörn; Schepky, Andreas; Raschke, Thomas; Stäb, Franz; Wenck, Horst; Winnefeld, Marc

2010-08-05

The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated by a decrease in the ADD1/SREBP-1c signal. Importantly, our results demonstrated that a combination of lotus leaf extract solution and L-carnitine reduced triglyceride accumulation to a greater extent compared to incubation with either substance alone. Overall, our data demonstrate that a combination of lotus leaf extract and L-carnitine reduced triglyceride accumulation in human (pre)adipocytes by affecting different processes during the adipocyte life cycle. For this reason, this combination might represent a treatment option for obesity-related diseases.

Leaf gas exchange performance and the lethal water potential of five European species during drought.

PubMed

Li, Shan; Feifel, Marion; Karimi, Zohreh; Schuldt, Bernhard; Choat, Brendan; Jansen, Steven

2016-02-01

Establishing physiological thresholds to drought-induced mortality in a range of plant species is crucial in understanding how plants respond to severe drought. Here, five common European tree species were selected (Acer campestre L., Acer pseudoplatanus L., Carpinus betulus L., Corylus avellana L. and Fraxinus excelsior L.) to study their hydraulic thresholds to mortality. Photosynthetic parameters during desiccation and the recovery of leaf gas exchange after rewatering were measured. Stem vulnerability curves and leaf pressure-volume curves were investigated to understand the hydraulic coordination of stem and leaf tissue traits. Stem and root samples from well-watered and severely drought-stressed plants of two species were observed using transmission electron microscopy to visualize mortality of cambial cells. The lethal water potential (ψlethal) correlated with stem P99 (i.e., the xylem water potential at 99% loss of hydraulic conductivity, PLC). However, several plants that were stressed beyond the water potential at 100% PLC showed complete recovery during the next spring, which suggests that the ψlethal values were underestimated. Moreover, we observed a 1 : 1 relationship between the xylem water potential at the onset of embolism and stomatal closure, confirming hydraulic coordination between leaf and stem tissues. Finally, ultrastructural changes in the cytoplasm of cambium tissue and mortality of cambial cells are proposed to provide an alternative approach to investigate the point of no return associated with plant death. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Subtractive transcriptome analysis of leaf and rhizome reveals differentially expressed transcripts in Panax sokpayensis.

PubMed

Gurung, Bhusan; Bhardwaj, Pardeep K; Talukdar, Narayan C

2016-11-01

In the present study, suppression subtractive hybridization (SSH) strategy was used to identify rare and differentially expressed transcripts in leaf and rhizome tissues of Panax sokpayensis. Out of 1102 randomly picked clones, 513 and 374 high quality expressed sequenced tags (ESTs) were generated from leaf and rhizome subtractive libraries, respectively. Out of them, 64.92 % ESTs from leaf and 69.26 % ESTs from rhizome SSH libraries were assembled into different functional categories, while others were of unknown function. In particular, ESTs encoding galactinol synthase 2, ribosomal RNA processing Brix domain protein, and cell division cycle protein 20.1, which are involved in plant growth and development, were most abundant in the leaf SSH library. Other ESTs encoding protein KIAA0664 homologue, ubiquitin-activating enzyme e11, and major latex protein, which are involved in plant immunity and defense response, were most abundant in the rhizome SSH library. Subtractive ESTs also showed similarity with genes involved in ginsenoside biosynthetic pathway, namely farnesyl pyrophosphate synthase, squalene synthase, and dammarenediol synthase. Expression profiles of selected ESTs validated the quality of libraries and confirmed their differential expression in the leaf, stem, and rhizome tissues. In silico comparative analyses revealed that around 13.75 % of unigenes from the leaf SSH library were not represented in the available leaf transcriptome of Panax ginseng. Similarly, around 18.12, 23.75, 25, and 6.25 % of unigenes from the rhizome SSH library were not represented in available root/rhizome transcriptomes of P. ginseng, Panax notoginseng, Panax quinquefolius, and Panax vietnamensis, respectively, indicating a major fraction of novel ESTs. Therefore, these subtractive transcriptomes provide valuable resources for gene discovery in P. sokpayensis and would complement the available transcriptomes from other Panax species.

Potassium uptake and redistribution in Cabernet Sauvignon and Syrah grape tissues and its relationship with grape quality parameters.

PubMed

Ramos, María Concepción; Romero, María Paz

2017-08-01

The present study investigated the potassium (K) levels in petiole and other grape tissues during ripening in Vitis vinifera Shiraz and Cabernet Sauvignon, grown in areas with differences in vigour, as well as with and without leaf thinning. Potassium levels in petiole, seeds, skin and flesh were related to grape pH, acidity, berry weight and total soluble solids. Differences in K levels in petiole were in accordance with the differences in soil K. Leaf thinning gave rise to higher K levels in petiole but, in grape tissues, the differences were not significant in all samplings, with greater differences at the end of the growing cycle. Potassium levels per berry in grape tissues increased from veraison to harvest, with K mainly accumulated in skins and, to a lesser extent, in flesh. Potassium levels in flesh positively correlated with pH and total soluble solids, whereas the correlation with titratable acidity was negative. Grape juice pH and total soluble solids positively correlated with K, whereas titratable acidity correlated negatively. Leaf thinning increased K levels in petiole, although differences in K levels in grape tissues were not significant. This suggests the need to consider the K berry concentration when aiming to optimise K fertilisation programmes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Succession after fire: variation in \\delta13C of organic tissues and respired CO2 in boreal forests

NASA Astrophysics Data System (ADS)

Fessenden, J. E.; Li, H.; Mack, M.; Schuur, T.; Warren, S.; Randerson, J. T.

2001-12-01

Isotope ratios of carbon dioxide and leaf organic matter were measured in 5 neighboring forests of varying ages: 7, 14, 45, 140, and 160 years. These forests are composed primarily of black spruce (Picea Mariana) and quaking aspen (Populus tremuloides) with a shift in species dominance from aspen to spruce 50 years after fire disturbance. Research on the carbon isotope ratios of leaf material and CO2 was conducted to look for influences from species composition, forest age, and time after most recent burn. Samples of organic \\delta13C in whole leaf tissue were collected from the dominant species of each forest. Concurrent aboveground NPP measurements allowed us to estimate total ecosystem \\delta13C by providing a method for weighting \\delta13C of individual species and plant tissues. \\delta13CO2 and [CO2] were measured on canopy CO2 to determine the isotopic ratio of ecosystem respiration. The atmospheric results indicated that the \\delta13C of ecosystem respiration changes with successional stage. Specifically, the aspen dominating forests showed 13C depleted values relative to the spruce dominated forests. Organic results showed more 13C-enriched values with increased forest age and vegetation functional type. Specifically, oldest trees within the coniferous species had the most 13C-enriched values in leaf tissues. These results suggest that increases in the disturbance regime of northern boreal forests will lead to a decrease in the \\delta13C of ecosystem carbon with consequences for the atmospheric \\delta13C budget.

Diurnal Cycling Transcription Factors of Pineapple Revealed by Genome-Wide Annotation and Global Transcriptomic Analysis

PubMed Central

Sharma, Anupma; Wai, Ching Man; Ming, Ray

2017-01-01

Abstract Circadian clock provides fitness advantage by coordinating internal metabolic and physiological processes to external cyclic environments. Core clock components exhibit daily rhythmic changes in gene expression, and the majority of them are transcription factors (TFs) and transcription coregulators (TCs). We annotated 1,398 TFs from 67 TF families and 80 TCs from 20 TC families in pineapple, and analyzed their tissue-specific and diurnal expression patterns. Approximately 42% of TFs and 45% of TCs displayed diel rhythmic expression, including 177 TF/TCs cycling only in the nonphotosynthetic leaf tissue, 247 cycling only in the photosynthetic leaf tissue, and 201 cycling in both. We identified 68 TF/TCs whose cycling expression was tightly coupled between the photosynthetic and nonphotosynthetic leaf tissues. These TF/TCs likely coordinate key biological processes in pineapple as we demonstrated that this group is enriched in homologous genes that form the core circadian clock in Arabidopsis and includes a STOP1 homolog. Two lines of evidence support the important role of the STOP1 homolog in regulating CAM photosynthesis in pineapple. First, STOP1 responds to acidic pH and regulates a malate channel in multiple plant species. Second, the cycling expression pattern of the pineapple STOP1 and the diurnal pattern of malate accumulation in pineapple leaf are correlated. We further examined duplicate-gene retention and loss in major known circadian genes and refined their evolutionary relationships between pineapple and other plants. Significant variations in duplicate-gene retention and loss were observed for most clock genes in both monocots and dicots. PMID:28922793

Silica Deposition on the Leaves of Mir- and Earth-Grown Super Dwarf Wheat

NASA Technical Reports Server (NTRS)

Campbell, William F.; Bubenheim, David L.; Salisbury, Frank B.; Bingham, Gail E.; McManus, William R.; Biesinger, H. D.; Strickland, D. T.; Levinskikh, Maragarita; Sytchev, Vladimir N.; Podolsky, Igor

2000-01-01

Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis were used to investigate the nature of crystals deposited on leaves of Mir- and Earth-grown Super Dwarf wheat (Triticum aestivum L.) plants. Leaves from these plants exhibited dense and uniformly distributed crystals on leaf abaxial surfaces when viewed by SEM. Young leaves showed that crystals initially accumulated around the stomata on the adaxial surface, but became more dense and uniformly distributed as the leaves aged. EDX microanalyses of the Balkanine (a nutrient charged clinoptilolite zeolite) medium in which the wheat plants were grown showed an elemental pattern similar to that observed on the wheat leaves. The absence of N and P in the Balkanine suggests that they were completely utilized by the plants. Only Si and O were evident in the drying agent, Sorb-it-Silica (trademark), and perhaps could have accounted for some of the Si observed on the plant tissue.

Development of a rapid diagnostic assay for the detection of tomato chlorotic dwarf viroid based on isothermal reverse-transcription-recombinase polymerase amplification.

PubMed

Hammond, Rosemarie W; Zhang, Shulu

2016-10-01

A molecular diagnostic assay utilizing reverse transcription-recombinase polymerase amplification (RT-RPA) at an isothermal constant temperature of 39°C and target-specific primers and probe were developed for the rapid, sensitive, and specific detection of tomato chlorotic dwarf viroid (TCDVd) in infected leaf and seed tissues. The performance of the AmplifyRP(®) Acceler8™ RT-RPA diagnostic assay, utilizing a lateral flow strip contained within an amplicon detection chamber, was evaluated and the results were compared with a standard RT-PCR assay. The AmplifyRP(®) Acceler8™ assay was specific for TCDVd in leaf and seed tissues, its sensitivity was comparable to conventional RT-PCR in leaf tissues, and it does not require extensive sample purification, specialized equipment, or technical expertise. This is the first report utilizing an RT-RPA assay to detect viroids and the assay can be used both in the laboratory and in the field for TCDVd detection. Published by Elsevier B.V.

Systemic regulation of leaf anatomical structure, photosynthetic performance, and high-light tolerance in sorghum.

PubMed

Jiang, Chuang-Dao; Wang, Xin; Gao, Hui-Yuan; Shi, Lei; Chow, Wah Soon

2011-03-01

Leaf anatomy of C3 plants is mainly regulated by a systemic irradiance signal. Since the anatomical features of C4 plants are different from that of C3 plants, we investigated whether the systemic irradiance signal regulates leaf anatomical structure and photosynthetic performance in sorghum (Sorghum bicolor), a C4 plant. Compared with growth under ambient conditions (A), no significant changes in anatomical structure were observed in newly developed leaves by shading young leaves alone (YS). Shading mature leaves (MS) or whole plants (S), on the other hand, caused shade-leaf anatomy in newly developed leaves. By contrast, chloroplast ultrastructure in developing leaves depended only on their local light conditions. Functionally, shading young leaves alone had little effect on their net photosynthetic capacity and stomatal conductance, but shading mature leaves or whole plants significantly decreased these two parameters in newly developed leaves. Specifically, the net photosynthetic rate in newly developed leaves exhibited a positive linear correlation with that of mature leaves, as did stomatal conductance. In MS and S treatments, newly developed leaves exhibited severe photoinhibition under high light. By contrast, newly developed leaves in A and YS treatments were more resistant to high light relative to those in MS- and S-treated seedlings. We suggest that (1) leaf anatomical structure, photosynthetic capacity, and high-light tolerance in newly developed sorghum leaves were regulated by a systemic irradiance signal from mature leaves; and (2) chloroplast ultrastructure only weakly influenced the development of photosynthetic capacity and high-light tolerance. The potential significance of the regulation by a systemic irradiance signal is discussed.

Interpretation of the fluorescence signatures from vegetation

NASA Astrophysics Data System (ADS)

Buschmann, C.

Vegetation emits fluorescence as part of the energy taken up by absorption %of solar radiation from UV to the visible. This fluorescence consists of light with low intensity (only few percents of the reflected light) emitted from the leaves. The fluorescence emission of a green leaf is characterized by four bands with maxima in the blue (440 nm), green (520 nm), red (690 nm) and far red (740 nm) spectral region. The intensity of fluorescence in the maxima of the emission spectrum varies depending on the following six basic parameters which must be taken into account for the interpretation of fluorescence signatures from vegetation: (a) content of the fluorophores (ferulic acid, chlorophyll a), (b) temperature of the leaf, (c) penetration of excitation light into the leaf, (d) emission of fluorescence from the leaf (re-absorption inside the leaf tissue), (e) photosynthetic activity of the leaf, (f) non-radiative decay (heat production) parallel to the fluorescence The ratios between the intensities of the maxima (F440/F690, F440/F520, F690/F740) are used as characteristic fluorescence parameter. The wide range of changes of these ratios caused by differences in the leaf tissue (aerial interspaces, variegated/homogeneous green leaves), various types of stress (UV, photoinhibition, sun exposure, heat, water deficiency, N-deficiency) and chemicals (inhibitors, fertilizers) can be explained by changes of the six basic parameters. It will be shown that the interpretation of the fluorescence signatures, in most cases, must be based on a complex consideration of more than one of the basic parameters.

The influence of elevated CO2 on non-structural carbohydrate distribution and fructan accumulation in wheat canopies

NASA Technical Reports Server (NTRS)

Smart, D. R.; Chatterton, N. J.; Bugbee, B.

1994-01-01

We grew 2.4 m2 wheat canopies in a large growth chamber under high photosynthetic photon flux (1000 micromoles m-2 s-1) and using two CO2 concentrations, 360 and 1200 micromoles mol-1. Photosynthetically active radiation (400-700 nm) was attenuated slightly faster through canopies grown in 360 micromoles mol-1 than through canopies grown in 1200 micromoles mol-1, even though high-CO2 canopies attained larger leaf area indices. Tissue fractions were sampled from each 5-cm layer of the canopies. Leaf tissue sampled from the tops of canopies grown in 1200 micromoles mol-1 accumulated significantly more total non-structural carbohydrate, starch, fructan, sucrose, and glucose (p < 0.05) than for canopies grown in 360 micromoles mol-1. Non-structural carbohydrate did not significantly increase in the lower canopy layers of the elevated CO2 treatment. Elevated CO2 induced fructan synthesis in all leaf tissue fractions, but fructan formation was greatest in the uppermost leaf area. A moderate temperature reduction of 10 degrees C over 5 d increased starch, fructan and glucose levels in canopies grown in 1200 micromoles mol-1, but concentrations of sucrose and fructose decreased slightly or remained unchanged. Those results may correspond with the use of fructosyl-residues and release of glucose when sucrose is consumed in fructan synthesis.

Identification and Chacterization of new strains of Enterobacter spp. causing Mulberry (Morus alba) wilt disease in China

USDA-ARS?s Scientific Manuscript database

A new mulberry wilt disease (MWD) was recently identified in Hangzhou, Zhejiang province, China. Typical symptoms of the disease are dark brown discolorations in vascular tissues, leaf wilt, defoliation, and tree decline. Unlike the bacterial wilt disease caused by Ralstonia solanacearum, the leaf w...

Leaf, woody, and root biomass of Populus irrigated with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; D.R. Coyle; R.B. Hall

2007-01-01

Poplar (Populus spp.) trees can be utilized for ecological leachate disposal when applied as an irrigation source for managed tree systems. Our objective was to evaluate differences in tree height, diameter, volume, and biomass of leaf, stem, branch, and root tissues of Populus trees after two seasons of irrigation with municipal...

Theoretical and experimental errors for in situ measurements of plant water potential.

PubMed

Shackel, K A

1984-07-01

Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (-0.6 to -1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design.

Theoretical and Experimental Errors for In Situ Measurements of Plant Water Potential 1

PubMed Central

Shackel, Kenneth A.

1984-01-01

Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (−0.6 to −1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design. PMID:16663701

Leaves of field-grown mastic trees suffer oxidative stress at the two extremes of their lifespan.

PubMed

Juvany, Marta; Müller, Maren; Munné-Bosch, Sergi

2012-08-01

Leaf senescence is a complex phenomenon occurring in all plant species, but it is still poorly understood in plants grown in Mediterranean field conditions and well-adapted to harsh climatic conditions. To better understand the physiological processes underlying leaf senescence in mastic trees (Pistacia lentiscus L.), we evaluated leaf growth, water and N content, photosystem II (PSII) photochemistry, lipid peroxidation and levels of photosynthetic pigments, antioxidants, abscisic acid, and salicylic acid and jasmonic acid during the complete leaf lifespan, from early expansion to late senescence in relation to natural climatic conditions in the field. While mature leaves suffered from water and N deficit during late spring and summer, both young (emerging) and old (senescing) leaves were most sensitive to photo-oxidative stress, as indicated by reductions in the F(v)/F(m) ratio and enhanced lipid peroxidation during late autumn and winter. Reductions in the F(v)/F(m) ratio were associated with low α-tocopherol (vitamin E) levels, while very old, senescing leaves additionally showed severe anthocyanin losses. We have concluded that both young (emerging) and old (senescing) leaves suffer oxidative stress in mastic trees, which may be linked in part to suboptimal temperatures during late autumn and winter as well as to low vitamin E levels. © 2012 Institute of Botany, Chinese Academy of Sciences.

Effects of elevated atmospheric CO2 concentration on leaf dark respiration of Xanthium strumarium in light and in darkness

PubMed Central

Wang, Xianzhong; Lewis, James D.; Tissue, David T.; Seemann, Jeffrey R.; Griffin, Kevin L.

2001-01-01

Leaf dark respiration (R) is an important component of plant carbon balance, but the effects of rising atmospheric CO2 on leaf R during illumination are largely unknown. We studied the effects of elevated CO2 on leaf R in light (RL) and in darkness (RD) in Xanthium strumarium at different developmental stages. Leaf RL was estimated by using the Kok method, whereas leaf RD was measured as the rate of CO2 efflux at zero light. Leaf RL and RD were significantly higher at elevated than at ambient CO2 throughout the growing period. Elevated CO2 increased the ratio of leaf RL to net photosynthesis at saturated light (Amax) when plants were young and also after flowering, but the ratio of leaf RD to Amax was unaffected by CO2 levels. Leaf RN was significantly higher at the beginning but significantly lower at the end of the growing period in elevated CO2-grown plants. The ratio of leaf RL to RD was used to estimate the effect of light on leaf R during the day. We found that light inhibited leaf R at both CO2 concentrations but to a lesser degree for elevated (17–24%) than for ambient (29–35%) CO2-grown plants, presumably because elevated CO2-grown plants had a higher demand for energy and carbon skeletons than ambient CO2-grown plants in light. Our results suggest that using the CO2 efflux rate, determined by shading leaves during the day, as a measure for leaf R is likely to underestimate carbon loss from elevated CO2-grown plants. PMID:11226264

Effects of elevated atmospheric CO2 concentration on leaf dark respiration of Xanthium strumarium in light and in darkness.

PubMed

Wang, X; Lewis, J D; Tissue, D T; Seemann, J R; Griffin, K L

2001-02-27

Leaf dark respiration (R) is an important component of plant carbon balance, but the effects of rising atmospheric CO(2) on leaf R during illumination are largely unknown. We studied the effects of elevated CO(2) on leaf R in light (R(L)) and in darkness (R(D)) in Xanthium strumarium at different developmental stages. Leaf R(L) was estimated by using the Kok method, whereas leaf R(D) was measured as the rate of CO(2) efflux at zero light. Leaf R(L) and R(D) were significantly higher at elevated than at ambient CO(2) throughout the growing period. Elevated CO(2) increased the ratio of leaf R(L) to net photosynthesis at saturated light (A(max)) when plants were young and also after flowering, but the ratio of leaf R(D) to A(max) was unaffected by CO(2) levels. Leaf R(N) was significantly higher at the beginning but significantly lower at the end of the growing period in elevated CO(2)-grown plants. The ratio of leaf R(L) to R(D) was used to estimate the effect of light on leaf R during the day. We found that light inhibited leaf R at both CO(2) concentrations but to a lesser degree for elevated (17-24%) than for ambient (29-35%) CO(2)-grown plants, presumably because elevated CO(2)-grown plants had a higher demand for energy and carbon skeletons than ambient CO(2)-grown plants in light. Our results suggest that using the CO(2) efflux rate, determined by shading leaves during the day, as a measure for leaf R is likely to underestimate carbon loss from elevated CO(2)-grown plants.

Molecular Mechanisms of Phosphorus Metabolism and Transport during Leaf Senescence

PubMed Central

Stigter, Kyla A.; Plaxton, William C.

2015-01-01

Leaf senescence, being the final developmental stage of the leaf, signifies the transition from a mature, photosynthetically active organ to the attenuation of said function and eventual death of the leaf. During senescence, essential nutrients sequestered in the leaf, such as phosphorus (P), are mobilized and transported to sink tissues, particularly expanding leaves and developing seeds. Phosphorus recycling is crucial, as it helps to ensure that previously acquired P is not lost to the environment, particularly under the naturally occurring condition where most unfertilized soils contain low levels of soluble orthophosphate (Pi), the only form of P that roots can directly assimilate from the soil. Piecing together the molecular mechanisms that underpin the highly variable efficiencies of P remobilization from senescing leaves by different plant species may be critical for devising effective strategies for improving overall crop P-use efficiency. Maximizing Pi remobilization from senescing leaves using selective breeding and/or biotechnological strategies will help to generate P-efficient crops that would minimize the use of unsustainable and polluting Pi-containing fertilizers in agriculture. This review focuses on the molecular mechanisms whereby P is remobilized from senescing leaves and transported to sink tissues, which encompasses the action of hormones, transcription factors, Pi-scavenging enzymes, and Pi transporters. PMID:27135351

Metabolic engineering of biomass for high energy density: oilseed-like triacylglycerol yields from plant leaves

PubMed Central

Vanhercke, Thomas; El Tahchy, Anna; Liu, Qing; Zhou, Xue-Rong; Shrestha, Pushkar; Divi, Uday K; Ral, Jean-Philippe; Mansour, Maged P; Nichols, Peter D; James, Christopher N; Horn, Patrick J; Chapman, Kent D; Beaudoin, Frederic; Ruiz-López, Noemi; Larkin, Philip J; de Feyter, Robert C; Singh, Surinder P; Petrie, James R

2014-01-01

High biomass crops have recently attracted significant attention as an alternative platform for the renewable production of high energy storage lipids such as triacylglycerol (TAG). While TAG typically accumulates in seeds as storage compounds fuelling subsequent germination, levels in vegetative tissues are generally low. Here, we report the accumulation of more than 15% TAG (17.7% total lipids) by dry weight in Nicotiana tabacum (tobacco) leaves by the co-expression of three genes involved in different aspects of TAG production without severely impacting plant development. These yields far exceed the levels found in wild-type leaf tissue as well as previously reported engineered TAG yields in vegetative tissues of Arabidopsis thaliana and N. tabacum. When translated to a high biomass crop, the current levels would translate to an oil yield per hectare that exceeds those of most cultivated oilseed crops. Confocal fluorescence microscopy and mass spectrometry imaging confirmed the accumulation of TAG within leaf mesophyll cells. In addition, we explored the applicability of several existing oil-processing methods using fresh leaf tissue. Our results demonstrate the technical feasibility of a vegetative plant oil production platform and provide for a step change in the bioenergy landscape, opening new prospects for sustainable food, high energy forage, biofuel and biomaterial applications. PMID:24151938

Protective mechanisms and acclimation to solar ultraviolet-B radiation in Oenothera stricta

NASA Technical Reports Server (NTRS)

Robberecht, R.; Caldwell, M. M.

1981-01-01

Plant adaptations ameliorating or repairing the damaging effects of ultraviolet-B (UV-B) radiation on plant tissue were investigated. The degree of phenotype plasticity in UV protective mechanisms and acclimation in relation to the natural solar UV-B radiation flux and in an enhanced UV-B irradiance environment was also examined. Mechanisms by which plants avoid radiation, adaptations altering the path of radiation incident on the leaf, and repair processes were considered. Attenuation of UV-B by tissues, UV-B irradiation into the leaf, and the effects of UV-B on photosynthesis were investigated.

Hevea Linamarase—A Nonspecific β-Glycosidase 1

PubMed Central

Selmar, Dirk; Lieberei, Reinhard; Biehl, Böle; Voigt, Jürgen

1987-01-01

In the leaf tissue of the cyanogenic plant Hevea brasiliensis, which contains large amounts of linamarin, there is no specific linamarase. In Hevea leaves only one β-glucosidase is detectable. It is responsible for the cleavage of all β-glucosides and β-galactosides occurring in Hevea leaf tissue, including the cyanogenic glucoside linamarin. Therefore, the enzyme is referred to as a β-glycosidase instead of the term β-glucosidase. This β-glycosidase has a broad substrate spectrum and occurs in multiple forms. These homo-oligomeric forms are interconvertible by dissociation-association processes. The monomer is a single protein of 64 kilodaltons. PMID:16665288

Molecular Assessment of litter decay dynamics across old and young forest sites

NASA Astrophysics Data System (ADS)

Filley, T. R.; Crow, S.; Gamblin, D.; McCormick, M.; Whigham, D.; Taylor, D. L.

2006-12-01

The response of soil organic matter pools to changes in litter input, land cover, and ýinvertebrate activity is a research area of intensive study given the proposed impacts that ýrising CO2 and surface temperatures may have on forest productivity and distribution of ýinvasive species. In a mixed deciduous forest at the Smithsonian Environmental ýResearch Center litter amendment plots were established in old (120-150 y) and young ýý(50-70 y) forests. In May 2004, six plots were amended with locally collected ýLirodendron tulipifera wood (chipped) and leaves. At the same time, leaf and wood litter ýbag decomposition experiments on the sites were also started. Changes in the ýconcentration and composition of biopolymers, e.g. lignin and cutin/suberin, after ýapproximately four months of decay were tracked by alkaline CuO extraction. Resultant ýleaf and wood litter in the surface amendments was distinct between age groupings. ýYoung sites exhibited the greatest change in chemical character showing increased lignin ýand decreased cutin/suberin resulting in a cutin-poor residue. Minor changes to ýbiopolymer character were observed in older sites with residues exhibiting small but ýopposite trends to the young sites. In contrast, the litter bag studies exhibited little to no ývariation in chemistry with age of stand; although, generally leaf litter showed the ýgreatest age-related effect. These patterns in litter decay are consistent with both ýmicrobial activity and relative biomass of invasive earthworms; young forests exhibit ýrelatively higher activity of both phenol oxidase and B-glucosidase in the soil (0-5 cm) ýplots and greater biomass and relative abundance invasive earthworms. These results are ýimportant as they show how stand age and the presence of invertebrate species may have ýimportant controls on the impact that many global change drivers may have on forest soil ýand carbon exchange dynamics.ý

Leaf traits in parental and hybrid species of Sorbus (Rosaceae).

PubMed

Durkovic, Jaroslav; Kardosová, Monika; Canová, Ingrid; Lagana, Rastislav; Priwitzer, Tibor; Chorvát, Dusan; Cicák, Alojz; Pichler, Viliam

2012-09-01

Knowledge of functional leaf traits can provide important insights into the processes structuring plant communities. In the genus Sorbus, the generation of taxonomic novelty through reticulate evolution that gives rise to new microspecies is believed to be driven primarily by a series of interspecific hybridizations among closely related taxa. We tested hypotheses for dispersion of intermediacy across the leaf traits in Sorbus hybrids and for trait linkages with leaf area and specific leaf area. Here, we measured and compared the whole complex of growth, vascular, and ecophysiological leaf traits among parental (Sorbus aria, Sorbus aucuparia, Sorbus chamaemespilus) and natural hybrid (Sorbus montisalpae, Sorbus zuzanae) species growing under field conditions. A recently developed atomic force microscopy technique, PeakForce quantitative nanomechanical mapping, was used to characterize the topography of cell wall surfaces of tracheary elements and to map the reduced Young's modulus of elasticity. Intermediacy was associated predominantly with leaf growth traits, whereas vascular and ecophysiological traits were mainly parental-like and transgressive phenotypes. Larger-leaf species tended to have lower modulus of elasticity values for midrib tracheary element cell walls. Leaves with a biomass investment related to a higher specific leaf area had a lower density. Leaf area- and length-normalized theoretical hydraulic conductivity was related to leaf thickness. For the whole complex of examined leaf traits, hybrid microspecies were mosaics of parental-like, intermediate, and transgressive phenotypes. The high proportion of transgressive character expressions found in Sorbus hybrids implies that generation of extreme traits through transgressive segregation played a key role in the speciation process.

Molecular phylogenetics and evolution of host plant use in the Neotropical rolled leaf 'hispine' beetle genus Cephaloleia (Chevrolat) (Chrysomelidae: Cassidinae).

PubMed

McKenna, Duane D; Farrell, Brian D

2005-10-01

Here, we report the results of a species level phylogenetic study of Cephaloleia beetles designed to clarify relationships and patterns of host plant taxon and tissue use among species. Our study is based on up to 2088bp of mtDNA sequence data. Maximum parsimony, maximum likelihood, and Bayesian methods of phylogenetic inference consistently recover a monophyletic Cephaloleia outside of a basal clade of primarily palm feeding species (the 'Arecaceae-feeding clade'), and C. irregularis. In all three analyses, the 'Arecaceae-feeding clade' includes Cephaloleia spp. with unusual morphological features, and a few species currently placed in other cassidine genera and tribes. All three analyses also recover a clade that includes all Zingiberales feeding Cephaloleia and most Cephaloleia species (the 'Zingiberales-feeding clade'). Two notable clades are found within the 'Zingiberales-feeding clade.' One is comprised of beetles that normally feed only on the young rolled leaves of plants in the families Heliconiaceae and Marantaceae (the 'Heliconiaceae & Marantaceae-feeding clade'). The other is comprised of relative host tissue generalist, primarily Zingiberales feeding species (the 'generalist-feeding clade'). A few species in the 'generalist-feeding clade' utilize Cyperaceae or Poaceae as hosts. Overall, relatively basal Cephaloleia (e.g., the 'Arecaceae clade') feed on relatively basal monocots (e.g., Cyclanthaceae and Arecaceae), and relatively derived Cephaloleia (e.g., the 'Zingiberales-feeding clade') feed on relatively derived monocots (mostly in the order Zingiberales). Zingiberales feeding and specialization on young rolled Zingiberales leaves have each apparently evolved just once in Cephaloleia.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, Ziyu; Hooker, Brian S.; Anderson, Daniel B.

Optimization of Acidothermus cellulolyticus endoglucanase (E1) gene expression in transgenic potato (Solanum tuberosum L.) was examined in this study, where the E1 coding sequence was transcribed under control of a leaf specific promoter (tomato RbcS-3C) or the Mac promoter (a hybrid promoter of mannopine synthase promoter and cauliflower mosaic virus 35S promoter enhancer region). Average E1 activity in leaf extracts of potato transformants, in which E1 protein was targeted by a chloroplast signal peptide and an apoplast signal peptide were much higher than those by an E1 native signal peptide and a vacuole signal peptide. E1 protein accumulated up tomore » 2.6% of total leaf soluble protein, where E1 gene was under control of the RbcS-3C promoter, alfalfa mosaic virus 5-untranslated leader, and RbcS-2A signal peptide. E1 protein production, based on average E1 activity and E1 protein accumulation in leaf extracts, is higher in potato than those measured previously in transgenic tobacco bearing the same transgene constructs. Comparisons of E1 activity, protein accumulation, and relative mRNA levels showed that E1 expression under control of tomato RbcS-3C promoter was specifically localized in leaf tissues, while E1 gene was expressed in both leaf and tuber tissues under control of Mac promoter. This suggests dual-crop applications in which potato vines serve as enzyme production `bioreactors' while tubers are preserved for culinary applications.« less

PHANTASTICA regulates leaf polarity and petiole identity in Medicago truncatula

PubMed Central

Ge, Liangfa; Chen, Rujin

2014-01-01

Establishment of proper polarities along the adaxial-abaxial, proximodistal, and medial-lateral axes is a critical step for the expansion of leaves from leaf primordia. It has been shown that the MYB domain protein, ASYMMETRIC LEAVES1/ROUGH SHEATH2/PHANTASTICA (collectively named ARP) plays an important role in this process. Loss of function of ARP leads to severe leaf polarity defects, such as abaxialized or needle-like leaves. In addition to its role in leaf polarity establishment, we have recently shown that the Medicago truncatula ARP gene, MtPHAN, also plays a role in leaf petiole identity regulation. We show that a mutation of MtPHAN results in petioles acquiring characteristics of the motor organ, pulvinus, including small epidermal cells with extensive cell surface modifications and altered vascular tissue development. Taken together, our results reveal a previously unidentified function of ARP in leaf development. PMID:24603499

Oriented cell division shapes carnivorous pitcher leaves of Sarracenia purpurea

PubMed Central

Fukushima, Kenji; Fujita, Hironori; Yamaguchi, Takahiro; Kawaguchi, Masayoshi; Tsukaya, Hirokazu; Hasebe, Mitsuyasu

2015-01-01

Complex morphology is an evolutionary outcome of phenotypic diversification. In some carnivorous plants, the ancestral planar leaf has been modified to form a pitcher shape. However, how leaf development was altered during evolution remains unknown. Here we show that the pitcher leaves of Sarracenia purpurea develop through cell division patterns of adaxial tissues that are distinct from those in bifacial and peltate leaves, subsequent to standard expression of adaxial and abaxial marker genes. Differences in the orientation of cell divisions in the adaxial domain cause bifacial growth in the distal region and adaxial ridge protrusion in the middle region. These different growth patterns establish pitcher morphology. A computer simulation suggests that the cell division plane is critical for the pitcher morphogenesis. Our results imply that tissue-specific changes in the orientation of cell division underlie the development of a morphologically complex leaf. PMID:25774486

Oriented cell division shapes carnivorous pitcher leaves of Sarracenia purpurea.

PubMed

Fukushima, Kenji; Fujita, Hironori; Yamaguchi, Takahiro; Kawaguchi, Masayoshi; Tsukaya, Hirokazu; Hasebe, Mitsuyasu

2015-03-16

Complex morphology is an evolutionary outcome of phenotypic diversification. In some carnivorous plants, the ancestral planar leaf has been modified to form a pitcher shape. However, how leaf development was altered during evolution remains unknown. Here we show that the pitcher leaves of Sarracenia purpurea develop through cell division patterns of adaxial tissues that are distinct from those in bifacial and peltate leaves, subsequent to standard expression of adaxial and abaxial marker genes. Differences in the orientation of cell divisions in the adaxial domain cause bifacial growth in the distal region and adaxial ridge protrusion in the middle region. These different growth patterns establish pitcher morphology. A computer simulation suggests that the cell division plane is critical for the pitcher morphogenesis. Our results imply that tissue-specific changes in the orientation of cell division underlie the development of a morphologically complex leaf.

Determining past leaf-out times of New England's deciduous forests from herbarium specimens.

PubMed

Everill, Peter H; Primack, Richard B; Ellwood, Elizabeth R; Melaas, Eli K

2014-08-01

• There is great interest in studying leaf-out times of temperate forests because of the importance of leaf-out in controlling ecosystem processes, especially in the face of a changing climate. Remote sensing and modeling, combined with weather records and field observations, are increasing our knowledge of factors affecting variation in leaf-out times. Herbarium specimens represent a potential new source of information to determine whether the variation in leaf-out times observed in recent decades is comparable to longer time frames over past centuries.• Here we introduce the use of herbarium specimens as a method for studying long-term changes in leaf-out times of deciduous trees. We collected historical leaf-out data for the years 1834-2008 from common deciduous trees in New England using 1599 dated herbarium specimens with young leaves.• We found that leaf-out dates are strongly affected by spring temperature, with trees leafing out 2.70 d earlier for each degree C increase in mean April temperature. For each degree C increase in local temperature, trees leafed out 2.06 d earlier. Additionally, the mean response of leaf-out dates across all species and sites over time was 0.4 d earlier per decade. Our results are of comparable magnitude to results from studies using remote sensing and direct field observations.• Across New England, mean leaf-out dates varied geographically in close correspondence with those observed in studies using satellite data. This study demonstrates that herbarium specimens can be a valuable source of data on past leaf-out times of deciduous trees. © 2014 Botanical Society of America, Inc.

A model using marginal efficiency of investment to analyze carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)

NASA Astrophysics Data System (ADS)

Thomas, R. Q.; Williams, M.

2014-09-01

Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System Modeling community. However, there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C-N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) based on the outcome of assessments of the marginal change in net C or N uptake associated with a change in allocation of C or N to plant tissues. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous < tropical evergreen < temperature evergreen), a result that compared well to observations from a global database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP. Multiple parameters associated with photosynthesis, respiration, and N uptake influenced the rate of N fixation. Overall, our ability to constrain leaf area index and allow spatially and temporally variable leaf C : N can help address challenges simulating these properties in ecosystem and Earth System models. Furthermore, the simple approach with emergent properties based on coupled C-N dynamics has potential for use in research that uses data-assimilation methods to integrate data on both the C and N cycles to improve C flux forecasts.

Headwater riparian invertebrate communities associated with red alder and conifer wood and leaf litter in southeastern Alaska

USGS Publications Warehouse

LeSage, C.M.; Merritt, R.W.; Wipfli, M.S.

2005-01-01

We examined how management of young upland forests in southeastern Alaska affect riparian invertebrate taxa richness, density, and biomass, in turn, potentially influencing food abundance for fish and wildlife. Southeastern Alaska forests are dominated by coniferous trees including Sitka spruce (Picea sitchensis (Bong.) Carr.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), with mixed stands of red cedar (Thuja plicata Donn.). Red alder (Alnus rubra Bong.) is hypothesized to influence the productivity of young-growth conifer forests and through forest management may provide increased riparian invertebrate abundance. To compare and contrast invertebrate densities between coniferous and alder riparian habitats, leaf litter and wood debris (early and late decay classes) samples were collected along eleven headwater streams on Prince of Wales Island, Alaska, during the summers of 2000 and 2001. Members of Acarina and Collembola were the most abundant taxa collected in leaf litter with alder litter having significantly higher mean taxa richness than conifer litter. Members of Acarina were the most abundant group collected on wood debris and alder wood had significantly higher mean taxa richness and biomass than conifer wood. Alder wood debris in more advanced decay stages had the highest mean taxa richness and biomass, compared to other wood types, while conifer late decay wood debris had the highest densities of invertebrates. The inclusion of alder in young-growth conifer forests can benefit forest ecosystems by enhancing taxa richness and biomass of riparian forest invertebrates. ?? 2005 by the Northwest Scientific Association. All rights reserved.

Histopathological investigations of the infection process and propagule development of Phytophthora ramorumon rhododendron leaves

Treesearch

Marko Riedel; Sabine Werres; Marianne Elliott; Katie McKeever; Simon Shamoun

2012-01-01

Studies on the relationship between rhododendron and Phytophthora ramorum include the influence of wounds on leaf infection and on the development of leaf necrosis (De Dobbelaere et al. 2010; Denman et al. 2005), the influence of the inoculum type (Widmer 2009), and tissue colonization by P. ramorum (Brown and Brasier 2007;...

Somaclonal variation in hybrid poplars for resistance to Septoria leaf spot

Treesearch

M.E. Ostry; D. D. Skilling

1987-01-01

Tissue culture techniques have been used to obtain hybrid poplars with putative resistance to leaf spot caused by Septoria musiva from clones previously susceptible to the disease. Stem internode explants were used to obtain proliferating callus cultures. Adventitious bud formation and shoot proliferation were then induced. Elongated shoots were excised and rooted in a...

Diurnal Cycling Transcription Factors of Pineapple Revealed by Genome-Wide Annotation and Global Transcriptomic Analysis.

PubMed

Sharma, Anupma; Wai, Ching Man; Ming, Ray; Yu, Qingyi

2017-09-01

Circadian clock provides fitness advantage by coordinating internal metabolic and physiological processes to external cyclic environments. Core clock components exhibit daily rhythmic changes in gene expression, and the majority of them are transcription factors (TFs) and transcription coregulators (TCs). We annotated 1,398 TFs from 67 TF families and 80 TCs from 20 TC families in pineapple, and analyzed their tissue-specific and diurnal expression patterns. Approximately 42% of TFs and 45% of TCs displayed diel rhythmic expression, including 177 TF/TCs cycling only in the nonphotosynthetic leaf tissue, 247 cycling only in the photosynthetic leaf tissue, and 201 cycling in both. We identified 68 TF/TCs whose cycling expression was tightly coupled between the photosynthetic and nonphotosynthetic leaf tissues. These TF/TCs likely coordinate key biological processes in pineapple as we demonstrated that this group is enriched in homologous genes that form the core circadian clock in Arabidopsis and includes a STOP1 homolog. Two lines of evidence support the important role of the STOP1 homolog in regulating CAM photosynthesis in pineapple. First, STOP1 responds to acidic pH and regulates a malate channel in multiple plant species. Second, the cycling expression pattern of the pineapple STOP1 and the diurnal pattern of malate accumulation in pineapple leaf are correlated. We further examined duplicate-gene retention and loss in major known circadian genes and refined their evolutionary relationships between pineapple and other plants. Significant variations in duplicate-gene retention and loss were observed for most clock genes in both monocots and dicots. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Internalization of Escherichia coli O157:H7 gfp+ in rocket and Swiss chard baby leaves as affected by abiotic and biotic damage.

PubMed

Hartmann, R; Fricke, A; Stützel, H; Mansourian, S; Dekker, T; Wohanka, W; Alsanius, B

2017-07-01

Internalization of human pathogens in edible parts of vegetables eaten raw is a major concern, since once internalized they are protected from sanitizing treatments. In this study, we examined the invasion of gfp-labelled Escherichia coli O157:H7 into intact and biotically (infection with Xanthomonas campestris/Pseudomonas syringae) and abiotically (grating with silicon carbide) damaged leaves of wild rocket (Diplotaxis tenuifolia) and Swiss chard (Beta vulgaris subsp. cicla) using laser scanning confocal microscopy. Bacterial cells were found in internal locations of the tissue, irrespective of tissue health status. Contaminated leaf sections of biotically and abiotically damaged wild rocket leaves showed higher susceptibility to microbial invasion, while the pathogen was internalized in greater numbers into intact Swiss chard leaf sections when abiotically, but not biotically, damaged. The greatest differences were observed between the plant species; after surface sanitization, E. coli O157:H7 was still detected in wild rocket leaves, but not in Swiss chard leaves. Contamination of leafy vegetables with Escherichia coli O157:H7 is a growing problem, as reported outbreaks are increasing. However, establishment of this human pathogen in the phyllosphere is not completely understood. Using laser scanning confocal microscopy, we demonstrated that E. coli O157:H7gfp+ can invade plant tissue of Swiss chard and wild rocket leaves and that the bacterium is more sensitive to surface sanitization of Swiss chard leaves. Damage to leaf tissue promoted leaf invasion, but the nature of the damage (abiotic or biotic) and plant species had an impact. © 2017 The Society for Applied Microbiology.

Induction of wound-periderm-like tissue in Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) leaves as a defence response to high UV-B radiation levels

PubMed Central

Nascimento, Luana Beatriz dos Santos; Moreira, Nattacha dos Santos; Leal-Costa, Marcos Vinícius; Costa, Sônia Soares; Tavares, Eliana Schwartz

2015-01-01

Background and Aims UV-B radiation can be stressful for plants and cause morphological and biochemical changes. Kalanchoe pinnata is a CAM leaf-succulent species distributed in hot and dry regions, and is rich in flavonoids, which are considered to be protective against UV-B radiation. This study aims to verify if K. pinnata has morphological or anatomical responses as a strategy in response to high UV-B levels. Methods Kalanchoe pinnata plants of the same age were grown under white light (control) or white light plus supplemental UV-B radiation (5 h d–1). The plants were treated with the same photoperiod, photosynthetically active radiation, temperature and daily watering system. Fragments of the middle third of the leaf blade and petiole were dehydrated and then embedded in historesin and sectioned in a rotary microtome. Sections were stained with toluidine blue O and mounted in Entellan®. Microchemical analyses by optical microscopy were performed on fresh material with Sudan III, Sudan IV and phloroglucinol, and analysed using fluorescence microscopy. Key Results Supplemental UV-B radiation caused leaf curling and the formation of brown areas on the leaves. These brown areas developed into a protective tissue on the adaxial side of the leaf, but only in directly exposed regions. Anatomically, this protective tissue was similar to a wound-periderm, with outer layer cell walls impregnated with suberin and lignin. Conclusions This is the first report of wound-periderm formation in leaves in response to UV-B radiation. This protective tissue could be important for the survival of the species in desert regions under high UV-B stress conditions. PMID:26346722

Whole organ, venation and epidermal cell morphological variations are correlated in the leaves of Arabidopsis mutants.

PubMed

Pérez-Pérez, José Manuel; Rubio-Díaz, Silvia; Dhondt, Stijn; Hernández-Romero, Diana; Sánchez-Soriano, Joaquín; Beemster, Gerrit T S; Ponce, María Rosa; Micol, José Luis

2011-12-01

Despite the large number of genes known to affect leaf shape or size, we still have a relatively poor understanding of how leaf morphology is established. For example, little is known about how cell division and cell expansion are controlled and coordinated within a growing leaf to eventually develop into a laminar organ of a definite size. To obtain a global perspective of the cellular basis of variations in leaf morphology at the organ, tissue and cell levels, we studied a collection of 111 non-allelic mutants with abnormally shaped and/or sized leaves, which broadly represent the mutational variations in Arabidopsis thaliana leaf morphology not associated with lethality. We used image-processing techniques on these mutants to quantify morphological parameters running the gamut from the palisade mesophyll and epidermal cells to the venation, whole leaf and rosette levels. We found positive correlations between epidermal cell size and leaf area, which is consistent with long-standing Avery's hypothesis that the epidermis drives leaf growth. In addition, venation parameters were positively correlated with leaf area, suggesting that leaf growth and vein patterning share some genetic controls. Positional cloning of the genes affected by the studied mutations will eventually establish functional links between genotypes, molecular functions, cellular parameters and leaf phenotypes. © 2011 Blackwell Publishing Ltd.

Comparative Transcriptome Analysis of Chinary, Assamica and Cambod tea (Camellia sinensis) Types during Development and Seasonal Variation using RNA-seq Technology

NASA Astrophysics Data System (ADS)

Kumar, Ajay; Chawla, Vandna; Sharma, Eshita; Mahajan, Pallavi; Shankar, Ravi; Yadav, Sudesh Kumar

2016-11-01

Tea quality and yield is influenced by various factors including developmental tissue, seasonal variation and cultivar type. Here, the molecular basis of these factors was investigated in three tea cultivars namely, Him Sphurti (H), TV23 (T), and UPASI-9 (U) using RNA-seq. Seasonal variation in these cultivars was studied during active (A), mid-dormant (MD), dormant (D) and mid-active (MA) stages in two developmental tissues viz. young and old leaf. Development appears to affect gene expression more than the seasonal variation and cultivar types. Further, detailed transcript and metabolite profiling has identified genes such as F3‧H, F3‧5‧H, FLS, DFR, LAR, ANR and ANS of catechin biosynthesis, while MXMT, SAMS, TCS and XDH of caffeine biosynthesis/catabolism as key regulators during development and seasonal variation among three different tea cultivars. In addition, expression analysis of genes related to phytohormones such as ABA, GA, ethylene and auxin has suggested their role in developmental tissues during seasonal variation in tea cultivars. Moreover, differential expression of genes involved in histone and DNA modification further suggests role of epigenetic mechanism in coordinating global gene expression during developmental and seasonal variation in tea. Our findings provide insights into global transcriptional reprogramming associated with development and seasonal variation in tea.

Comparative Transcriptome Analysis of Chinary, Assamica and Cambod tea (Camellia sinensis) Types during Development and Seasonal Variation using RNA-seq Technology.

PubMed

Kumar, Ajay; Chawla, Vandna; Sharma, Eshita; Mahajan, Pallavi; Shankar, Ravi; Yadav, Sudesh Kumar

2016-11-17

Tea quality and yield is influenced by various factors including developmental tissue, seasonal variation and cultivar type. Here, the molecular basis of these factors was investigated in three tea cultivars namely, Him Sphurti (H), TV23 (T), and UPASI-9 (U) using RNA-seq. Seasonal variation in these cultivars was studied during active (A), mid-dormant (MD), dormant (D) and mid-active (MA) stages in two developmental tissues viz. young and old leaf. Development appears to affect gene expression more than the seasonal variation and cultivar types. Further, detailed transcript and metabolite profiling has identified genes such as F3'H, F3'5'H, FLS, DFR, LAR, ANR and ANS of catechin biosynthesis, while MXMT, SAMS, TCS and XDH of caffeine biosynthesis/catabolism as key regulators during development and seasonal variation among three different tea cultivars. In addition, expression analysis of genes related to phytohormones such as ABA, GA, ethylene and auxin has suggested their role in developmental tissues during seasonal variation in tea cultivars. Moreover, differential expression of genes involved in histone and DNA modification further suggests role of epigenetic mechanism in coordinating global gene expression during developmental and seasonal variation in tea. Our findings provide insights into global transcriptional reprogramming associated with development and seasonal variation in tea.

Plant-Adapted Escherichia coli Show Increased Lettuce Colonizing Ability, Resistance to Oxidative Stress and Chemotactic Response

PubMed Central

Dublan, Maria de los Angeles; Ortiz-Marquez, Juan Cesar Federico; Lett, Lina; Curatti, Leonardo

2014-01-01

Background Escherichia coli is a widespread gut commensal and often a versatile pathogen of public health concern. E. coli are also frequently found in different environments and/or alternative secondary hosts, such as plant tissues. The lifestyle of E. coli in plants is poorly understood and has potential implications for food safety. Methods/Principal Findings This work shows that a human commensal strain of E. coli K12 readily colonizes lettuce seedlings and produces large microcolony-like cell aggregates in leaves, especially in young leaves, in proximity to the vascular tissue. Our observations strongly suggest that those cell aggregates arise from multiplication of single bacterial cells that reach those spots. We showed that E. coli isolated from colonized leaves progressively colonize lettuce seedlings to higher titers, suggesting a fast adaptation process. E. coli cells isolated from leaves presented a dramatic rise in tolerance to oxidative stress and became more chemotactic responsive towards lettuce leaf extracts. Mutant strains impaired in their chemotactic response were less efficient lettuce colonizers than the chemotactic isogenic strain. However, acclimation to oxidative stress and/or minimal medium alone failed to prime E. coli cells for enhanced lettuce colonization efficiency. Conclusion/Significance These findings help to understand the physiological adaptation during the alternative lifestyle of E. coli in/on plant tissues. PMID:25313845

Does oolong tea (Camellia sinensis) made from a combination of leaf and stem smell more aromatic than leaf-only tea? Contribution of the stem to oolong tea aroma.

PubMed

Zeng, Lanting; Zhou, Ying; Fu, Xiumin; Mei, Xin; Cheng, Sihua; Gui, Jiadong; Dong, Fang; Tang, Jinchi; Ma, Shengzhou; Yang, Ziyin

2017-12-15

The raw materials used to make oolong tea (Camellia sinensis) are a combination of leaf and stem. Oolong tea made from leaf and stem is thought to have a more aromatic smell than leaf-only tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry oolong teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to oolong tea aroma. Copyright © 2017 Elsevier Ltd. All rights reserved.

Salt tolerance, salt accumulation, and ionic homeostasis in an epidermal bladder-cell-less mutant of the common ice plant Mesembryanthemum crystallinum.

PubMed

Agarie, Sakae; Shimoda, Toshifumi; Shimizu, Yumi; Baumann, Kathleen; Sunagawa, Haruki; Kondo, Ayumu; Ueno, Osamu; Nakahara, Teruhisa; Nose, Akihiro; Cushman, John C

2007-01-01

The aerial surfaces of the common or crystalline ice plant Mesembryanthemum crystallinum L., a halophytic, facultative crassulacean acid metabolism species, are covered with specialized trichome cells called epidermal bladder cells (EBCs). EBCs are thought to serve as a peripheral salinity and/or water storage organ to improve survival under high salinity or water deficit stress conditions. However, the exact contribution of EBCs to salt tolerance in the ice plant remains poorly understood. An M. crystallinum mutant lacking EBCs was isolated from plant collections mutagenized by fast neutron irradiation. Light and electron microscopy revealed that mutant plants lacked EBCs on all surfaces of leaves and stems. Dry weight gain of aerial parts of the mutant was almost half that of wild-type plants after 3 weeks of growth at 400 mM NaCl. The EBC mutant also showed reduced leaf succulence and leaf and stem water contents compared with wild-type plants. Aerial tissues of wild-type plants had approximately 1.5-fold higher Na(+) and Cl(-) content than the mutant grown under 400 mM NaCl for 2 weeks. Na(+) and Cl(-) partitioning into EBCs of wild-type plants resulted in lower concentrations of these ions in photosynthetically active leaf tissues than in leaves of the EBC-less mutant, particularly under conditions of high salt stress. Potassium, nitrate, and phosphate ion content decreased with incorporation of NaCl into tissues in both the wild type and the mutant, but the ratios of Na(+)/K(+) and Cl(-)/NO(3)(-)content were maintained only in the leaf and stem tissues of wild-type plants. The EBC mutant showed significant impairment in plant productivity under salt stress as evaluated by seed pod and seed number and average seed weight. These results clearly show that EBCs contribute to succulence by serving as a water storage reservoir and to salt tolerance by maintaining ion sequestration and homeostasis within photosynthetically active tissues of M. crystallinum.

Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

PubMed

He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

2013-10-01

Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing wetland to remediate high levels of perchlorate polluted water.

Preservation of Plant Biomolecules and the Relevance to the Interpretation of Paleoenvironmental Signals: Tertiary Metasequoia Fossils as Examples

NASA Astrophysics Data System (ADS)

Yang, H.; Leng, Q.

2004-12-01

The degradation and preservation of biomolecules in plant tissues not only affects the inference on paleoecology of ancient plants but also bears significance in the interpretation of paleoenvironmental signals. Using a combined SEM and geochemical approach, we are able to show the source, liability, and preservation of structural biopolymers from morphologically well-preserved Metasequoia tissues from three Tertiary deposits. We detected a continuum of biomolecular preservation in this evolutionarily-conserved conifer. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to solvent-extracted residues from both fossil leaf and wood remains in comparison with tissues from their living counterparts. The late Paleocene-early Eocene leaves from Ellesmere Island, Canadian Arctic Archipelago, exhibit the best quality of biochemical preservation and show pyrolysis products derived from labile biomolecules characterized by large amounts of polysaccharides. These labile biomolecules are the oldest record of these kinds so far characterized by the pyrolysis technology. The middle Eocene leaf tissues from Axel Heiberg Island, Canadian Arctic Archipelago, yielded slightly lesser amounts of polysaccharide moieties, but the lignin products are similar to those identified from the Ellesmere Island fossils. Compared with these Arctic materials, the Metasequoia leaves from Miocene Clarkia, Idaho, USA, show the lowest quality of molecular preservation, characterized by a dramatic reduction of polysaccharides. This continuum of relative quality of biomolecular preservation is further confirmed by SEM observations of transverse sections of these fossil leaves. The investigation revealed tissue-specific degradation, and our data support the in-situ polymerization hypothesis for the origin of long-chain homologous pairs of aliphatic n-alk-1-enes/n-alkanes as leaf alteration products. The preferential degradation and selective removal of polysaccharides may be significant in estimating plant paleo-productivity whereas the addition of aliphatic components to the leaf wax lipid pool may potentially contribute to the accuracy of compound specific isotope analysis using these lipid markers.

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle

PubMed Central

2010-01-01

Background The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. Methods For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Results Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated by a decrease in the ADD1/SREBP-1c signal. Importantly, our results demonstrated that a combination of lotus leaf extract solution and L-carnitine reduced triglyceride accumulation to a greater extent compared to incubation with either substance alone. Conclusions Overall, our data demonstrate that a combination of lotus leaf extract and L-carnitine reduced triglyceride accumulation in human (pre)adipocytes by affecting different processes during the adipocyte life cycle. For this reason, this combination might represent a treatment option for obesity-related diseases. PMID:20687953

Effects of branch height on leaf gas exchange, branch hydraulic conductance and branch sap flux in open-grown ponderosa pine.

PubMed

Hubbard, Robert M; Bond, Barbara J; Senock, Randy S; Ryan, Michael G

2002-06-01

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta13C) and ratios of leaf area to sapwood area within branches were dependent on branch height (10 and 25 m) within the crowns of four open-grown ponderosa pine (Pinus ponderosa Laws.) trees. We found no difference in leaf gas exchange or leaf specific hydraulic conductance from soil to leaf between the upper and lower canopy of our study trees. Branch sap flux per unit leaf area and per unit sapwood area did not differ between the 10- and 25-m canopy positions; however, branch sap flux per unit sapwood area at the 25-m position had consistently lower values. Branches at the 25-m canopy position had lower leaf to sapwood area ratios (0.17 m2 cm-2) compared with branches at the 10-m position (0.27 m2 cm-2) (P = 0.03). Leaf specific conductance of branches in the upper crown did not differ from that in the lower crown. Other studies at our site indicate lower hydraulic conductance, sap flux, whole-tree canopy conductance and photosynthesis in old trees compared with young trees. This study suggests that height alone may not explain these differences.

Loblolly pine grown under elevated CO2 affects early instar pine sawfly performance.

PubMed

Williams, R S; Lincoln, D E; Thomas, R B

1994-06-01

Seedlings of loblolly pine Pinus taeda (L.), were grown in open-topped field chambers under three CO 2 regimes: ambient, 150 μl l -1 CO 2 above ambient, and 300 μl l -1 CO 2 above ambient. A fourth, non-chambered ambient treatment was included to assess chamber effects. Needles were used in 96 h feeding trials to determine the performance of young, second instar larvae of loblolly pine's principal leaf herbivore, red-headed pine sawfly, Neodiprion lecontei (Fitch). The relative consumption rate of larvae significantly increased on plants grown under elevated CO 2 , and needles grown in the highest CO 2 regime were consumed 21% more rapidly than needles grown in ambient CO 2 . Both the significant decline in leaf nitrogen content and the substantial increase in leaf starch content contributed to a significant increase in the starch:nitrogen ratio in plants grown in elevated CO 2 . Insect consumption rate was negatively related to leaf nitrogen content and positively related to the starch:nitrogen ratio. Of the four volatile leaf monoterpenes measured, only β-pinene exhibited a significant CO 2 effect and declined in plants grown in elevated CO 2 . Although consumption changed, the relative growth rates of larvae were not different among CO 2 treatments. Despite lower nitrogen consumption rates by larvae feeding on the plants grown in elevated CO 2 , nitrogen accumulation rates were the same for all treatments due to a significant increase in nitrogen utilization efficiency. The ability of this insect to respond at an early, potentially susceptible larval stage to poorer food quality and declining levels of a leaf monoterpene suggest that changes in needle quality within pines in future elevated-CO 2 atmospheres may not especially affect young insects and that tree-feeding sawflies may respond in a manner similar to herb-feeding lepidopterans.

Hormones Restore Biomechanical Properties of the Vagina and Supportive Tissues After Surgical Menopause in Young Rats

PubMed Central

Moalli, Pamela A; Debes, Kristen M.; Meyn, Leslie A.; Howden, Nancy; Abramowitch, Steven D.

2010-01-01

Objective To determine the impact of hormones on the biomechanical properties of the vagina and its supportive tissues following surgical menopause in young vs middle aged rats. Methods Long-Evans rats [4-month virgin (N = 34), 4-month parous (N = 36), and 9-month parous (N = 34)], underwent ovariectomy (OVX) or sham surgery. OVX'd animals received hormones [estrogen (E2) or estrogen plus progesterone (E2 + P4)], placebo, or the Matrix Metalloproteinase inhibitor (CMT-8). Animals were sacrificed after 8 weeks and the biomechanical properties of the vagina and supportive tissues determined. Data was analyzed using a one-way analysis of variance and post-hoc tests. Results OVX induced a rapid decline in the biomechanical properties of pelvic tissues in young but not middle aged rats. Supplementation with E2, E2 + P4, or CMT-8 restored tissues of young rats to control levels with no effect on middle aged tissues. Parity did not impact tissue behavior. Conclusions OVX has a differential effect on the tissues of young vs middle aged rats. PMID:18395691

Dependency of branch diameter growth in young Acer trees on light availability and shoot elongation.

PubMed

Sone, Kosei; Noguchi, Ko; Terashima, Ichiro

2005-01-01

Many biomechanical and theoretical studies have been based on the pipe-model theory, according to which a tree is regarded as an assemblage of pipes, each having the same amount of leaf area or leaf mass. However, the physiological mechanisms underlying the theory have not been extensively examined, particularly at the branch level. We analyzed how branches and trunks thickened in nine young Acer mono Maxim. var. marmoratum (Nichols) Hara f. dissectum (Wesmael) Rehder. and A. rufinerve (Siebold & Zucc.) trees. In particular, we examined the roles of light, allocation of photosynthates and shoot heterogeneity. The cross-sectional area (A) of a branch was proportional to cumulative leaf mass or leaf area of the branch, and cumulative cross-sectional area of the daughter branches (SigmaA) above a branching point was equal to the A of the mother branch. These results indicate the validity of the pipe-model theory. However, the theory was invalid for current-year growth of branch cross-sectional area (DeltaA). The DeltaA/SigmaDeltaA for a branching point was greatest (nearly equal to 1) at the crown surface, decreased with crown depth, and tended to increase again at the trunk base, and DeltaA strongly depended on light interception and the yearly increment of leaves on the branch. We examined factors that influenced DeltaA with multiple regression analysis. The ratio of DeltaA of a branch to branch leaf area depended on both relative irradiance and mean current-year shoot length of the branch, suggesting that diameter growth of a branch is determined by the balance between supply of photosynthates, which depends on light interception by the branch, and demand for photosynthates, which is created by the high cambial activity associated with vigorous shoot elongation.

Leaf Selection by Two Bornean Colobine Monkeys in Relation to Plant Chemistry and Abundance

PubMed Central

Matsuda, Ikki; Tuuga, Augustine; Bernard, Henry; Sugau, John; Hanya, Goro

2013-01-01

Focusing on the chemical basis of dietary selection while investigating the nutritional ecology of animals helps understand their feeding biology. It is also important to consider food abundance/biomass while studying the mechanism of animal food selection. We studied leaf selection in two Bornean folivorous primates in relation to plant chemistry and abundance: proboscis monkeys inhabiting a secondary riverine forest and red leaf monkeys inhabiting a primary forest. Both species tended to prefer leaves containing higher protein levels, although more abundant plant species were chosen within the preferred species, probably to maximise energy gain per unit time. However, the two species showed clear differences in their detailed feeding strategy. Red leaf monkeys strictly chose to consume young leaves to adapt to the poor nutritional environment of the primary forest, whereas proboscis monkeys were not highly selective because of the better quality of its common food in the riverine forest. PMID:23695180

Do Aphids Alter Leaf Surface Temperature Patterns During Early Infestation?

PubMed Central

Cahon, Thomas; Caillon, Robin

2018-01-01

Arthropods at the surface of plants live in particular microclimatic conditions that can differ from atmospheric conditions. The temperature of plant leaves can deviate from air temperature, and leaf temperature influences the eco-physiology of small insects. The activity of insects feeding on leaf tissues, may, however, induce changes in leaf surface temperatures, but this effect was only rarely demonstrated. Using thermography analysis of leaf surfaces under controlled environmental conditions, we quantified the impact of presence of apple green aphids on the temperature distribution of apple leaves during early infestation. Aphids induced a slight change in leaf surface temperature patterns after only three days of infestation, mostly due to the effect of aphids on the maximal temperature that can be found at the leaf surface. Aphids may induce stomatal closure, leading to a lower transpiration rate. This effect was local since aphids modified the configuration of the temperature distribution over leaf surfaces. Aphids were positioned at temperatures near the maximal leaf surface temperatures, thus potentially experiencing the thermal changes. The feedback effect of feeding activity by insects on their host plant can be important and should be quantified to better predict the response of phytophagous insects to environmental changes. PMID:29538342

Leaf maximum photosynthetic rate and venation are linked by hydraulics.

PubMed

Brodribb, Tim J; Feild, Taylor S; Jordan, Gregory J

2007-08-01

Leaf veins are almost ubiquitous across the range of terrestrial plant diversity, yet their influence on leaf photosynthetic performance remains uncertain. We show here that specific physical attributes of the vascular plumbing network are key limiters of the hydraulic and photosynthetic proficiency of any leaf. Following the logic that leaf veins evolved to bypass inefficient water transport through living mesophyll tissue, we examined the hydraulic pathway beyond the distal ends of the vein system as a possible limiter of water transport in leaves. We tested a mechanistic hypothesis that the length of this final traverse, as water moves from veins across the mesophyll to where it evaporates from the leaf, governs the hydraulic efficiency and photosynthetic carbon assimilation of any leaf. Sampling 43 species across the breadth of plant diversity from mosses to flowering plants, we found that the post-vein traverse as determined by characters such as vein density, leaf thickness, and cell shape, was strongly correlated with the hydraulic conductivity and maximum photosynthetic rate of foliage. The shape of this correlation provided clear support for the a priori hypothesis that vein positioning limits photosynthesis via its influence on leaf hydraulic efficiency.

Endogenous electromagnetic fields in plant leaves: a new hypothesis for vascular pattern formation.

PubMed

Pietak, Alexis Mari

2011-06-01

Electromagnetic (EM) phenomena have long been implicated in biological development, but few detailed, practical mechanisms have been put forth to connect electromagnetism with morphogenetic processes. This work describes a new hypothesis for plant leaf veination, whereby an endogenous electric field forming as a result of a coherent Frohlich process, and corresponding to an EM resonant mode of the developing leaf structure, is capable of instigating leaf vascularisation. In order to test the feasibility of this hypothesis, a three-dimensional, EM finite-element model (FEM) of a leaf primordium was constructed to determine if suitable resonant modes were physically possible for geometric and physical parameters similar to those of developing leaf tissue. Using the FEM model, resonant EM modes with patterns of relevance to developing leaf vein modalities were detected. On account of the existence of shared geometric signatures in a leaf's vascular pattern and the electric field component of EM resonant modes supported by a developing leaf structure, further theoretical and experimental investigations are warranted. Significantly, this hypothesis is not limited to leaf vascular patterning, but may be applicable to a variety of morphogenetic phenomena in a number of living systems.

Maize YABBY Genes drooping leaf1 and drooping leaf2 Regulate Plant Architecture[OPEN

PubMed Central

Briggs, Sarah; Bradbury, Peter J.

2017-01-01

Leaf architecture directly influences canopy structure, consequentially affecting yield. We discovered a maize (Zea mays) mutant with aberrant leaf architecture, which we named drooping leaf1 (drl1). Pleiotropic mutations in drl1 affect leaf length and width, leaf angle, and internode length and diameter. These phenotypes are enhanced by natural variation at the drl2 enhancer locus, including reduced expression of the drl2-Mo17 allele in the Mo17 inbred. A second drl2 allele, produced by transposon mutagenesis, interacted synergistically with drl1 mutants and reduced drl2 transcript levels. The drl genes are required for proper leaf patterning, development and cell proliferation of leaf support tissues, and for restricting auricle expansion at the midrib. The paralogous loci encode maize CRABS CLAW co-orthologs in the YABBY family of transcriptional regulators. The drl genes are coexpressed in incipient and emergent leaf primordia at the shoot apex, but not in the vegetative meristem or stem. Genome-wide association studies using maize NAM-RIL (nested association mapping-recombinant inbred line) populations indicated that the drl loci reside within quantitative trait locus regions for leaf angle, leaf width, and internode length and identified rare single nucleotide polymorphisms with large phenotypic effects for the latter two traits. This study demonstrates that drl genes control the development of key agronomic traits in maize. PMID:28698237

Seismomorphogenesis: a novel approach to acclimatization of tissue culture regenerated plants.

PubMed

Sarmast, Mostafa Khoshhal; Salehi, Hassan; Khosh-Khui, Morteza

2014-12-01

Plantlets under in vitro conditions transferred to ex vivo conditions are exposed to biotic and abiotic stresses. Furthermore, in vitro regenerated plants are typically frail and sometimes difficult to handle subsequently increasing their risk to damage and disease; hence acclimatization of these plantlets is the most important step in tissue culture techniques. An experiment was conducted under in vitro conditions to study the effects of shaking duration (twice daily at 6:00 a.m. and 9:00 p.m. for 2, 4, 8, and 16 min at 250 rpm for 14 days) on Sansevieria trifasciata L. as a model plant. Results showed that shaking improved handling, total plant height, and leaf characteristics of the model plant. Forty-eight hours after 14 days of shaking treatments with increasing shaking time, leaf length decreased but proline content of leaf increased. However, 6 months after starting the experiment different results were observed. In explants that received 16 min of shaking treatment, leaf length and area and photosynthesis rate were increased compared with control plantlets. Six months after starting the experiment, control plantlets had 12.5 % mortality; however, no mortality was observed in other treated explants. The results demonstrated that shaking improved the explants' root length and number and as a simple, cost-effective, and non-chemical novel approach may be substituted for other prevalent acclimatization techniques used for tissue culture regenerated plantlets. Further studies with sensitive plants are needed to establish this hypothesis.

SU-E-T-331: Dosimetric Impact of Multileaf Collimator Leaf Width On Stereotactic Radiosurgery (SRS) RapidArc Treatment Plans for Single and Multiple Brain Metastases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hossain, S; Keeling, V; Ahmad, S

Purpose: To determine the effects of multileaf collimator (MLC) leaf width on normal-brain-tissue doses and dose conformity of SRS RapidArc treatment plans for brain tumors. Methods: Ten patients with 24 intracranial tumors (seven with 1–2 and three with 4–6 lesions) were planned using RapidArc for both Varian Millennium 120 MLC (5 mm leaf width) and high definition (HD) MLC (2.5 mm leaf width). Between 2 and 8 arcs were used with two full coplanar arcs and the rest non-coplanar half arcs. 6 MV beams were used and plans were optimized with a high priority to the Normal Tissue Objective (tomore » achieve dose conformity and sharp dose fall-off) and normal brain tissue. Calculation was done using AAA on a 1 mm grid size. The prescription dose ranged from 14–22 Gy. Plans were normalized such that 99% of the target received the prescription dose. Identical beam geometries, optimizations, calculations, and normalizations were used for both plans. Paddick Conformity Index (PCI), V4, V8 and V12 Gy for normal brain tissue and Integral Dose were used for analysis. Results: In all cases, HD MLC plans performed better in sparing normal brain tissue, achieving a higher PCI with a lower Integral Dose. The average PCI for all 24 targets was 0.75±0.23 and 0.70±0.23 (p ≤0.0015) for HD MLC and Millennium MLC plans, respectively. The average ratio of normal brain doses for Millennium MLC to HD MLC plans was 1.30±0.16, 1.27±0.15, and 1.31±0.18 for the V4, V8, and V12, respectively. The differences in normal brain dose for all criteria were statistically significant with p-value < 0.02. On average Millennium MLC plans had a 16% higher integral dose than HD MLC plans. Conclusion: Significantly better dose conformity with reduced volume of normal brain tissue and integral dose was achieved with HD MLC plans compared to Millennium MLC plans.« less

Factors Affecting Leaf Selection by Foregut-fermenting Proboscis Monkeys: New Insight from in vitro Digestibility and Toughness of Leaves

PubMed Central

Matsuda, Ikki; Clauss, Marcus; Tuuga, Augustine; Sugau, John; Hanya, Goro; Yumoto, Takakazu; Bernard, Henry; Hummel, Jürgen

2017-01-01

Free-living animals must make dietary choices in terms of chemical and physical properties, depending on their digestive physiology and availability of food resources. Here we comprehensively evaluated the dietary choices of proboscis monkeys (Nasalis larvatus) consuming young leaves. We analysed the data for leaf toughness and digestibility measured by an in vitro gas production method, in addition to previously reported data on nutrient composition. Leaf toughness, in general, negatively correlated with the crude protein content, one of the most important nutritional factors affecting food selection by leaf-eating primates. This result suggests that leaf toughness assessed by oral sensation might be a proximate cue for its protein content. We confirmed the importance of the leaf chemical properties in terms of preference shown by N. larvatus; leaves with high protein content and low neutral detergent fibre levels were preferred to those of the common plant species. We also found that these preferred leaves were less tough and more digestible than the alternatives. Our in vitro results also suggested that N. larvatus were little affected by secondary plant compounds. However, the spatial distribution pattern of plant species was the strongest factor explaining the selection of the preferred leaf species. PMID:28211530

Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto.

PubMed

Souza, Marcelo C de; Bueno, Paula C P; Morellato, Leonor P C; Habermann, Gustavo

2015-01-01

The cerrado's flora comprises aluminum-(Al) accumulating and non-accumulating plants, which coexist on acidic and Al-rich soils with low fertility. Despite their existence, the ecological importance or biological strategies of these functional groups have been little explored. We evaluated the leaf flushing patterns of both groups throughout a year; leaf concentrations of N, P, K, Ca, Mg, S, Al, total flavonoids and polyphenols; as well as the specific leaf area (SLA) on young and mature leaves within and between the groups. In Al-accumulating plants, leaf flushed throughout the year, mainly in May and September; for non-accumulating plants, leaf flushing peaked at the dry-wet seasons transition. However, these behaviors could not be associated with strategies for building up concentrations of defense compounds in leaves of any functional groups. Al-accumulating plants showed low leaf nutrient concentrations, while non-accumulating plants accumulated more macronutrients and produced leaves with high SLA since the juvenile leaf phase. This demonstrates that the increase in SLA is slower in Al-accumulating plants that are likely to achieve SLA values comparable to the rest of the plant community only in the wet season, when sunlight capture is important for the growth of new branches.

The mechanism of improved aeration due to gas films on leaves of submerged rice.

PubMed

Verboven, Pieter; Pedersen, Ole; Ho, Quang Tri; Nicolai, Bart M; Colmer, Timothy D

2014-10-01

Some terrestrial wetland plants, such as rice, have super-hydrophobic leaf surfaces which retain a gas film when submerged. O2 movement through the diffusive boundary layer (DBL) of floodwater, gas film and stomata into leaf mesophyll was explored by means of a reaction-diffusion model that was solved in a three-dimensional leaf anatomy model. The anatomy and dark respiration of leaves of rice (Oryza sativa L.) were measured and used to compute O2 fluxes and partial pressure of O2 (pO2 ) in the DBL, gas film and leaf when submerged. The effects of floodwater pO2 , DBL thickness, cuticle permeability, presence of gas film and stomatal opening were explored. Under O2 -limiting conditions of the bulk water (pO2  < 10 kPa), the gas film significantly increases the O2 flux into submerged leaves regardless of whether stomata are fully or partly open. With a gas film, tissue pO2 substantially increases, even for the slightest stomatal opening, but not when stomata are completely closed. The effect of gas films increases with decreasing cuticle permeability. O2 flux and tissue pO2 decrease with increasing DBL thickness. The present modelling analysis provides a mechanistic understanding of how leaf gas films facilitate O2 entry into submerged plants. © 2014 John Wiley & Sons Ltd.

Stomatal responses to changes in vapor pressure deficit reflect tissue-specific differences in hydraulic conductance.

PubMed

Ocheltree, T W; Nippert, J B; Prasad, P V V

2014-01-01

The vapor pressure deficit (D) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water vapor (g(wv)) in response to increasing D, limiting the ability of plants to assimilate carbon. The sensitivity of g(wv) to changes in D varies among species and has been correlated with the hydraulic conductance of leaves (K(leaf) ), but the hydraulic conductance of other tissues has also been implicated in plant responses to changing D. Among the 19 grass species, we found that K(leaf) was correlated with the hydraulic conductance of large longitudinal veins (K(lv), r(2) = 0.81), but was not related to K(root) (r(2) = 0.01). Stomatal sensitivity to D was correlated with K(leaf) relative to total leaf area (r(2) = 0.50), and did not differ between C3 and C4 species. Transpiration (E) increased in response to D, but 8 of the 19 plants showed a decline in E at high D, indicative of an 'apparent feedforward' response. For these individuals, E began to decline at lower values of D in plants with low K(root) (r(2) = 0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand. © 2013 John Wiley & Sons Ltd.

Nutritional Ecology of Wood-Feeing Coleoptrea Lepidoptera and Hymenoptera

Treesearch

Haack Robert A.; Frank Slansky Jr.

1987-01-01

Woody tissues are produced by each of the approximately 44,000 species of trees, shrubs, and woody vines found worldwide (Hickin, 1975). Most woody tissues are tougher, drier, and nutritionally poorer than leaf tissue when considered as a sustrate for insect growth and development (Slansky and Scriber, 195). Nevertheless, many insects have evolved to live and feed in...

Temporal processes that contribute to nonlinearity in vegetation responses to ozone exposure and dose

Treesearch

Robert L. Heath; Allen S. Lefohn; Robert C. Musselman

2009-01-01

Ozone interacts with plant tissue through distinct temporal processes. Sequentially, plants are exposed to ambient O3 hat (1) moves through the leaf boundary layer, (2) is taken up into plant tissue primarily through stomata, and (3) undergoes chemical interaction within plant tissue, first by initiating alterations and then as part of plant...

The influence of leaf anatomy on the internal light environment and photosynthetic electron transport rate: exploration with a new leaf ray tracing model

PubMed Central

Xiao, Yi; Tholen, Danny; Zhu, Xin-Guang

2016-01-01

Leaf photosynthesis is determined by biochemical properties and anatomical features. Here we developed a three-dimensional leaf model that can be used to evaluate the internal light environment of a leaf and its implications for whole-leaf electron transport rates (J). This model includes (i) the basic components of a leaf, such as the epidermis, palisade and spongy tissues, as well as the physical dimensions and arrangements of cell walls, vacuoles and chloroplasts; and (ii) an efficient forward ray-tracing algorithm, predicting the internal light environment for light of wavelengths between 400 and 2500nm. We studied the influence of leaf anatomy and ambient light on internal light conditions and J. The results show that (i) different chloroplasts can experience drastically different light conditions, even when they are located at the same distance from the leaf surface; (ii) bundle sheath extensions, which are strips of parenchyma, collenchyma or sclerenchyma cells connecting the vascular bundles with the epidermis, can influence photosynthetic light-use efficiency of leaves; and (iii) chloroplast positioning can also influence the light-use efficiency of leaves. Mechanisms underlying leaf internal light heterogeneity and implications of the heterogeneity for photoprotection and for the convexity of the light response curves are discussed. PMID:27702991

Metabolic engineering of biomass for high energy density: oilseed-like triacylglycerol yields from plant leaves.

PubMed

Vanhercke, Thomas; El Tahchy, Anna; Liu, Qing; Zhou, Xue-Rong; Shrestha, Pushkar; Divi, Uday K; Ral, Jean-Philippe; Mansour, Maged P; Nichols, Peter D; James, Christopher N; Horn, Patrick J; Chapman, Kent D; Beaudoin, Frederic; Ruiz-López, Noemi; Larkin, Philip J; de Feyter, Robert C; Singh, Surinder P; Petrie, James R

2014-02-01

High biomass crops have recently attracted significant attention as an alternative platform for the renewable production of high energy storage lipids such as triacylglycerol (TAG). While TAG typically accumulates in seeds as storage compounds fuelling subsequent germination, levels in vegetative tissues are generally low. Here, we report the accumulation of more than 15% TAG (17.7% total lipids) by dry weight in Nicotiana tabacum (tobacco) leaves by the co-expression of three genes involved in different aspects of TAG production without severely impacting plant development. These yields far exceed the levels found in wild-type leaf tissue as well as previously reported engineered TAG yields in vegetative tissues of Arabidopsis thaliana and N. tabacum. When translated to a high biomass crop, the current levels would translate to an oil yield per hectare that exceeds those of most cultivated oilseed crops. Confocal fluorescence microscopy and mass spectrometry imaging confirmed the accumulation of TAG within leaf mesophyll cells. In addition, we explored the applicability of several existing oil-processing methods using fresh leaf tissue. Our results demonstrate the technical feasibility of a vegetative plant oil production platform and provide for a step change in the bioenergy landscape, opening new prospects for sustainable food, high energy forage, biofuel and biomaterial applications. © 2013 CSIRO. Plant Biotechnology Journal published by Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Within-plant distribution of onion thrips (Thysanoptera: Thripidae) in onions.

PubMed

Mo, Jianhua; Munro, Scott; Boulton, Alan; Stevens, Mark

2008-08-01

Two aspects of the within-plant distribution of Thrips tabaci Lindeman (Thysanoptera: Thripidae) on onion, Allium cepa L., plants were investigated: 1) diurnal variations in the distribution of adults and larvae between basal and upper sections of onion leaves, and 2) between-leaf and within-leaf distribution of the eggs. The diurnal investigations showed that higher proportions of larvae than of adults congregated at the basal sections of plants, particularly when plants were young and thrips density was low. As plants matured and thrips density increased, the larvae became more dispersed. Regardless of plant size, there were always more adults in the upper than basal plant sections. There were no clear time-windows during the 24-h diurnal cycle when more thrips were in the upper plant parts. T. tabaci eggs were laid everywhere in the plant. Leaves of intermediate ages had more eggs than older or younger leaves. Within leaves, the white leaf sheath received the least eggs and leaf tips received slightly more eggs than leaf sheaths. The highest egg density was found between the green leaf base and the leaf tips. Regardless of plant size, more than half of all eggs were laid above the basal sections. The percentage increased to >95% in mature plants. Except when plants were small the outer leaves were preferred over inner leaves and upper leaf sections preferred over lower leaf sections as egg-laying sites by adults. Implications of the results in the management of T. tabaci are discussed.

Adding a Piece to the Leaf Epidermal Cell Shape Puzzle.

PubMed

von Wangenheim, Daniel; Wells, Darren M; Bennett, Malcolm J

2017-11-06

The jigsaw puzzle-shaped pavement cells in the leaf epidermis collectively function as a load-bearing tissue that controls organ growth. In this issue of Developmental Cell, Majda et al. (2017) shed light on how the jigsaw shape can arise from localized variations in wall stiffness between adjacent epidermal cells. Copyright © 2017 Elsevier Inc. All rights reserved.

A Simple Method for Rapid Depletion of Rubisco from Soybean (Glycine max) Leaf for Proteomic Analysis of Lower Abundance Proteins

USDA-ARS?s Scientific Manuscript database

2-DE analysis of complex plant proteomes has limited dynamic resolution because only abundant proteins can be detected. Proteomic assessment of the low abundance proteins within leaf tissue is difficult when it is comprised of 30 – 50% of the CO2 fixation enzyme Rubisco. Resolution can be improved t...

The plant economics spectrum is structured by leaf habits and growth forms across subtropical species.

PubMed

Zhao, Yan-Tao; Ali, Arshad; Yan, En-Rong

2017-02-01

The plant economics spectrum that integrates the combination of leaf and wood syndromes provides a useful framework for the examination of species strategies at the whole-plant level. However, it remains unclear how species that differ in leaf habits and growth forms are integrated within the plant economics spectrum in subtropical forests. We measured five leaf and six wood traits across 58 subtropical plant species, which represented two leaf habits (evergreen vs deciduous) and two growth forms (tree vs shrub) in eastern China. Principal component analysis (PCA) was employed separately to construct the leaf (LES), wood (WES) and whole-plant (WPES) economics spectra. Leaf and wood traits are highly intra- and intercorrelated, thus defining not only the LES and WES, but also a WPES. Multi-trait variations in PCAs revealed that the traits which were representative of the acquisitive strategy, i.e., cheap tissue investment and rapid returns on that investment, were clustered at one end, while traits that represented the conservative strategy, i.e., expensive tissue investment and slower returns, were clustered at other end in each of the axes of the leaf and wood syndromes (PC1-axis) and the plant height strategy (PC2-axis). The local WPES, LES and WES were tightly correlated with each other. Evergreens shaped the conservative side, while deciduous species structured the acquisitive side of the WPES and LES. With respect to plant height strategies, trees formulated the acquisitive side and shrub species made up the conservative side of the WPES, LES and WES. In conclusion, our results suggested that the LES and WES were coordinated to a WPES for subtropical species. The finding of this local spectrum of plant form and function would be beneficial for modeling nutrient fluxes and species compositions in the changing climate, but also for understanding species strategies in an evolutionary context. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Changes in photosynthetic performance and antioxidative strategies during maturation of Norway maple (Acer platanoides L.) leaves.

PubMed

Lepeduš, Hrvoje; Gaća, Vlatka; Viljevac, Marija; Kovač, Spomenka; Fulgosi, Hrvoje; Simić, Domagoj; Jurković, Vlatka; Cesar, Vera

2011-04-01

Different structural and functional changes take place during leaf development. Since some of them are highly connected to oxidative metabolism, regulation of reactive oxygen species (ROS) abundance is required. Most of the reactive oxygen species ROS in plant cells are produced in chloroplasts as a result of highly energetic reactions of photosynthesis. The aim of our study was to examine the changes in concentration of oxidative stress parameters (TBARS - thiobarbituric acid-reacting substances and protein carbonyls) as well as antioxidative strategies during development of maple (Acer platanoides L.) leaves in the light of their enhanced photosynthetic performance. We reveal that biogenesis of the photosynthetic apparatus during maple leaf maturation corresponded with oxidative damage of lipids, but not proteins. In addition, antioxidative responses in young leaves differed from that in older leaves. Young leaves had high values of non-photochemical quenching (NPQ) and catalase (CAT, EC 1.11.1.6) activity which declined during the maturation process. Developing leaves were characterized by an increase in TBARS level, the content of non-enzymatic antioxidants as well as ascorbate peroxidase activity (APX, EC 1.11.1.11), while the content of protein carbonyls decreased with leaf maturation. Fully developed leaves had the highest lipid peroxidation level accompanied by a maximum in ascorbic acid content and superoxide dismutase activity (SOD, EC1.15.1.1). These observations imply completely different antioxidative strategies during leaf maturation enabling them to perform their basic function. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Distribution of calmodulin in pea seedlings: immunocytochemical localization in plumules and root apices

NASA Technical Reports Server (NTRS)

Dauwalder, M.; Roux, S. J.; Hardison, L.

1986-01-01

Immunofluorescence techniques have been used to study the distribution of calmodulin in several tissues in young etiolated pea (Pisum sativum L.) seedlings. A fairly uniform staining was seen in the nucleoplasm and background cytoplasm of most cell types. Cell walls and nucleoli were not stained. In addition, patterned staining reactions were seen in many cells. In cells of the plumule, punctate staining of the cytoplasm was common, and in part this stain appeared to be associated with the plastids. A very distinctive staining of amyloplasts was seen in the columella of the root cap. Staining associated with cytoskeletal elements could be shown in division stages. By metaphase, staining of the spindle region was quite evident. In epidermal cells of the stem and along the underside of the leaf there was an intense staining of the vacuolar contents. Guard cells lacked this vacuolar stain. Vacuolar staining was sometimes seen in cells of the stele, but the most distinctive pattern in the stele was associated with young conducting cells of the xylem. These staining patterns are consistent with the idea that the interactions of plastids and the cytoskeletal may be one of the Ca(2+)-mediated steps in the response of plants to environmental stimuli. Nuclear functions may also be controlled, at least in part, by Ca2+.

Impact of proline application on cadmium accumulation, mineral nutrition and enzymatic antioxidant defense system of Olea europaea L. cv Chemlali exposed to cadmium stress.

PubMed

Zouari, Mohamed; Ben Ahmed, Chedlia; Elloumi, Nada; Bellassoued, Khaled; Delmail, David; Labrousse, Pascal; Ben Abdallah, Ferjani; Ben Rouina, Bechir

2016-06-01

Proline plays an important role in plant response to various environmental stresses. However, its involvement in mitigation of heavy metal stress in plants remains elusive. In this study, we examined the effectiveness of exogenous proline (10 and 20 mM) in alleviating cadmium induced inhibitory effects in young olive plants (Olea europaea L. cv. Chemlali) exposed to two Cd levels (10 and 30 mg CdCl2 kg(-1) soil). The Cd treatment induced substantial accumulation of Cd in both root and leaf tissues and a decrease in gas exchange, photosynthetic pigments contents, uptake of essential elements (Ca, Mg and K) and plant biomass. Furthermore, an elevation of antioxidant enzymes activities (superoxide dismutase, catalase, glutathione peroxydase) and proline content in association with relatively high amounts of hydrogen peroxide, thiobarbituric acid reactive substances and electrolyte leakage were observed. Interestingly, the application of exogenous proline alleviated the oxidative damage induced by Cd accumulation. In fact, Cd-stressed olive plants treated with proline showed an increase of antioxidant enzymes activities, photosynthetic activity, nutritional status, plant growth and oil content of olive fruit. Generally, it seems that proline supplementation alleviated the deleterious effects of young olive plants exposed to Cd stress. Copyright © 2016 Elsevier Inc. All rights reserved.

The dependence of leaf hydraulic conductance on irradiance during HPFM measurements: any role for stomatal response?

PubMed

Tyree, Melvin T; Nardini, Andrea; Salleo, Sebastiano; Sack, Lawren; El Omari, Bouchra

2005-02-01

This paper examines the dependence of whole leaf hydraulic conductance to liquid water (K(L)) on irradiance when measured with a high pressure flowmeter (HPFM). During HPFM measurements, water is perfused into leaves faster than it evaporates hence water infiltrates leaf air spaces and must pass through stomates in the liquid state. Since stomates open and close under high versus low irradiance, respectively, the possibility exists that K(L) might change with irradiance if stomates close tightly enough to restrict water movement. However, the dependence of K(L) on irradiance could be due to a direct effect of irradiance on the hydraulic properties of other tissues in the leaf. In the present study, K(L) increased with irradiance for 6 of the 11 species tested. Whole leaf conductance to water vapour, g(L), was used as a proxy for stomatal aperture and the time-course of changes in K(L) and g(L) was studied during the transition from low to high irradiance and from high to low irradiance. Experiments showed that in some species K(L) changes were not paralleled by g(L) changes. Measurements were also done after perfusion of leaves with ABA which inhibited the g(L) response to irradiance. These leaves showed the same K(L) response to irradiance as control leaves. These experimental results and theoretical calculations suggest that the irradiance dependence of K(L) is more consistent with an effect on extravascular (and/or vascular) tissues rather than stomatal aperture. Irradiance-mediated stimulation of aquaporins or hydrogel effects in leaf tracheids may be involved.

Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species

PubMed Central

2013-01-01

Background Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. Results We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. Conclusion Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield. PMID:24083555

High invertase activity in tomato reproductive organs correlates with enhanced sucrose import into, and heat tolerance of, young fruit

PubMed Central

Li, Zhimiao; Palmer, William M.; Martin, Antony P.; Wang, Rongqing; Rainsford, Frederick; Jin, Ye; Patrick, John W.; Yang, Yuejian; Ruan, Yong-Ling

2012-01-01

Heat stress can cause severe crop yield losses by impairing reproductive development. However, the underlying mechanisms are poorly understood. We examined patterns of carbon allocation and activities of sucrose cleavage enzymes in heat-tolerant (HT) and -sensitive (HS) tomato (Solanum lycopersicum L.) lines subjected to normal (control) and heat stress temperatures. At the control temperature of 25/20 °C (day/night) the HT line exhibited higher cell wall invertase (CWIN) activity in flowers and young fruits and partitioned more sucrose to fruits but less to vegetative tissues as compared to the HS line, independent of leaf photosynthetic capacity. Upon 2-, 4-, or 24-h exposure to day or night temperatures of 5 °C or more above 25/20 °C, cell wall (CWIN) and vacuolar invertases (VIN), but not sucrose synthase (SuSy), activities in young fruit of the HT line were significantly higher than those of the HS line. The HT line had a higher level of transcript of a CWIN gene, Lin7, in 5-day fruit than the HS line under control and heat stress temperatures. Interestingly, heat induced transcription of an invertase inhibitor gene, INVINH1, but reduced its protein abundance. Transcript levels of LePLDa1, encoding phospholipase D, which degrades cell membranes, was less in the HT line than in the HS line after exposure to heat stress. The data indicate that high invertase activity of, and increased sucrose import into, young tomato fruit could contribute to their heat tolerance through increasing sink strength and sugar signalling activities, possibly regulating a programmed cell death pathway. PMID:22105847

High invertase activity in tomato reproductive organs correlates with enhanced sucrose import into, and heat tolerance of, young fruit.

PubMed

Li, Zhimiao; Palmer, William M; Martin, Antony P; Wang, Rongqing; Rainsford, Frederick; Jin, Ye; Patrick, John W; Yang, Yuejian; Ruan, Yong-Ling

2012-02-01

Heat stress can cause severe crop yield losses by impairing reproductive development. However, the underlying mechanisms are poorly understood. We examined patterns of carbon allocation and activities of sucrose cleavage enzymes in heat-tolerant (HT) and -sensitive (HS) tomato (Solanum lycopersicum L.) lines subjected to normal (control) and heat stress temperatures. At the control temperature of 25/20 °C (day/night) the HT line exhibited higher cell wall invertase (CWIN) activity in flowers and young fruits and partitioned more sucrose to fruits but less to vegetative tissues as compared to the HS line, independent of leaf photosynthetic capacity. Upon 2-, 4-, or 24-h exposure to day or night temperatures of 5 °C or more above 25/20 °C, cell wall (CWIN) and vacuolar invertases (VIN), but not sucrose synthase (SuSy), activities in young fruit of the HT line were significantly higher than those of the HS line. The HT line had a higher level of transcript of a CWIN gene, Lin7, in 5-day fruit than the HS line under control and heat stress temperatures. Interestingly, heat induced transcription of an invertase inhibitor gene, INVINH1, but reduced its protein abundance. Transcript levels of LePLDa1, encoding phospholipase D, which degrades cell membranes, was less in the HT line than in the HS line after exposure to heat stress. The data indicate that high invertase activity of, and increased sucrose import into, young tomato fruit could contribute to their heat tolerance through increasing sink strength and sugar signalling activities, possibly regulating a programmed cell death pathway.

Leaf Tissue C:N and Soil N are Modified by Growing Season and Goose Grazing Phenology in a Sub-Arctic Coastal Wetland of Western Alaska

NASA Astrophysics Data System (ADS)

Choi, R. T.; Beard, K. H.; Leffler, A. J.; Schmutz, J. A.; Welker, J. M.

2014-12-01

Climate change in Arctic wetlands is resulting in a widening phenological mismatch between the onset of the growing season and the arrival and hatch date of migratory geese, the primary consumers in the system. During the past three decades, the growing season has advanced but geese have not advanced arrival or hatch date at the same rate. Geese now arrive into a system that has been growing longer than in the past with potential changes in forage quality because sedges have their highest nutrient density shortly following emergence. One potential concomitant result of this phenological gap is altered carbon to nitrogen ratio (C:N) of leaf tissue being returned to the ecosystem as feces that is more N-poor. Altering the C:N of these inputs can further influence C and N cycling in the system. We examine the influence of advanced growing season and different arrival times by black brant on leaf and soil C:N ratio and soil N-form. Our experiment consists of six blocks with nine study plots each. Half the plots are warmed to advance the growing season. Two plots each receive early, typical, late, and no grazing; one plot is a control that is not warmed and grazing is natural. Leaf tissue was collected to determine C and N concentration using an elemental analyzer. Anion and cation exchange membranes were used to monitor inorganic N forms in soil; samples were analyzed via fluorescence following extraction. Soil water collected from lysimeters was analyzed for organic N. Warming advanced plant growth between one and two weeks and resulted in higher C:N of leaf tissue Geese maintained 'grazing lawns', areas of exceptionally short vegetation, where plants had high N compared to non-grazed areas. Grazing early in the season promoted higher N content of leaves and soil while grazing late had little influence on N. The timing of the growing season and grazing both have important implications for C and N in this system.

Drought, Abscisic Acid and Transpiration Rate Effects on the Regulation of PIP Aquaporin Gene Expression and Abundance in Phaseolus vulgaris Plants

PubMed Central

AROCA, RICARDO; FERRANTE, ANTONIO; VERNIERI, PAOLO; CHRISPEELS, MAARTEN J.

2006-01-01

• Background and Aims Drought causes a decline of root hydraulic conductance, which aside from embolisms, is governed ultimately by aquaporins. Multiple factors probably regulate aquaporin expression, abundance and activity in leaf and root tissues during drought; among these are the leaf transpiration rate, leaf water status, abscisic acid (ABA) and soil water content. Here a study is made of how these factors could influence the response of aquaporin to drought. • Methods Three plasma membrane intrinsic proteins (PIPs) or aquaporins were cloned from Phaseolus vulgaris plants and their expression was analysed after 4 d of water deprivation and also 1 d after re-watering. The effects of ABA and of methotrexate (MTX), an inhibitor of stomatal opening, on gene expression and protein abundance were also analysed. Protein abundance was examined using antibodies against PIP1 and PIP2 aquaporins. At the same time, root hydraulic conductance (L), transpiration rate, leaf water status and ABA tissue concentration were measured. • Key Results None of the treatments (drought, ABA or MTX) changed the leaf water status or tissue ABA concentration. The three treatments caused a decline in the transpiration rate and raised PVPIP2;1 gene expression and PIP1 protein abundance in the leaves. In the roots, only the drought treatment raised the expression of the three PIP genes examined, while at the same time diminishing PIP2 protein abundance and L. On the other hand, ABA raised both root PIP1 protein abundance and L. • Conclusions The rise of PvPIP2;1 gene expression and PIP1 protein abundance in the leaves of P. vulgaris plants subjected to drought was correlated with a decline in the transpiration rate. At the same time, the increase in the expression of the three PIP genes examined caused by drought and the decline of PIP2 protein abundance in the root tissues were not correlated with any of the parameters measured. PMID:17028296

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in high nitrite excretion and NO emission from leaf and root tissue.

PubMed

Lea, Unni S; Ten Hoopen, Floor; Provan, Fiona; Kaiser, Werner M; Meyer, Christian; Lillo, Cathrine

2004-05-01

In wild-type Nicotiana plumbaginifolia Viv. and other higher plants, nitrate reductase (NR) is regulated at the post-translational level and is rapidly inactivated in response to, for example, a light-to-dark transition. This inactivation is caused by phosphorylation of a conserved regulatory serine residue, Ser 521 in tobacco, and interaction with divalent cations or polyamines, and 14-3-3 proteins. The physiological importance of the post-translational NR modulation is presently under investigation using a transgenic N. plumbaginifolia line. This line expresses a mutated tobacco NR where Ser 521 has been changed into aspartic acid (Asp) by site-directed mutagenesis, resulting in a permanently active NR enzyme. When cut leaves or roots of this line (S(521)) were placed in darkness in a buffer containing 50 mM KNO(3), nitrite was excreted from the tissue at rates of 0.08-0.2 micromol (g FW)(-1) h(-1) for at least 5 h. For the control transgenic plant (C1), which had the regulatory serine of NR intact, nitrite excretion was low and halted completely after 1-3 h. Without nitrate in the buffer in which the tissue was immersed, nitrite excretion was also low for S(521), although 20-40 micromol (g FW)(-1) nitrate was present inside the tissue. Apparently, stored nitrate was not readily available for reduction in darkness. Leaf tissue and root segments of S(521) also emitted much more nitric oxide (NO) than the control. Importantly, NO emission from leaf tissue of S(521) was higher in the dark than in the light, opposite to what was usually observed when post-translational NR modulation was operating.

BOREAS TE-23 Canopy Architecture and Spectral Data from Hemispherical Photographs

NASA Technical Reports Server (NTRS)

Rich, Paul M.; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

2000-01-01

The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-23 (Terrestrial Ecology) team collected hemispherical photographs in support of its efforts to characterize and interpret information on estimates of canopy architecture and radiative transfer properties for most BOREAS study sites. Various Old Aspen (OA), Old Black Spruce (OBS), Old Jack Pine (OJP), Young Jack Pine (YJP), and Young Aspen (YA) sites in the boreal forest were measured from May to August 1994. The hemispherical photographs were used to derive values of leaf area index (LAI), leaf angle, gap fraction, and clumping index. This documentation describes these derived values. The derived data are stored in tabular ASCII files. The hemispherical photographs are stored in the original set of 42 CD-ROMs that were supplied by TE-23. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Leaf water 18 O and 2 H enrichment along vertical canopy profiles in a broadleaved and a conifer forest tree.

PubMed

Bögelein, Rebekka; Thomas, Frank M; Kahmen, Ansgar

2017-07-01

Distinguishing meteorological and plant-mediated drivers of leaf water isotopic enrichment is prerequisite for ecological interpretations of stable hydrogen and oxygen isotopes in plant tissue. We measured input and leaf water δ 2 H and δ 18 O as well as micrometeorological and leaf morpho-physiological variables along a vertical gradient in a mature angiosperm (European beech) and gymnosperm (Douglas fir) tree. We used these variables and different enrichment models to quantify the influence of Péclet and non-steady state effects and of the biophysical drivers on leaf water enrichment. The two-pool model accurately described the diurnal variation of leaf water enrichment. The estimated unenriched water fraction was linked to leaf dry matter content across the canopy heights. Non-steady state effects and reduced stomatal conductance caused a higher enrichment of Douglas fir compared to beech leaf water. A dynamic effect analyses revealed that the light-induced vertical gradients of stomatal conductance and leaf temperature outbalanced each other in their effects on evaporative enrichment. We conclude that neither vertical canopy gradients nor the Péclet effect is important for estimates and interpretation of isotopic leaf water enrichment in hypostomatous trees. Contrarily, species-specific non-steady state effects and leaf temperatures as well as the water vapour isotope composition need careful consideration. © 2017 John Wiley & Sons Ltd.

Comparison of Glucosinolate Profiles in Different Tissues of Nine Brassica Crops.

PubMed

Bhandari, Shiva Ram; Jo, Jung Su; Lee, Jun Gu

2015-08-31

Glucosinolate (GSL) profiles and concentrations in various tissues (seeds, sprouts, mature root, and shoot) were determined and compared across nine Brassica species, including cauliflower, cabbage, broccoli, radish, baemuchae, pakchoi, Chinese cabbage, leaf mustard, and kale. The compositions and concentrations of individual GSLs varied among crops, tissues, and growth stages. Seeds had highest total GSL concentrations in most of crops, whereas shoots had the lowest GSL concentrations. Aliphatic GSL concentrations were the highest in seeds, followed by that in sprouts, shoots, and roots. Indole GSL concentration was the highest in the root or shoot tissues in most of the crops. In contrast, aromatic GSL concentrations were highest in roots. Of the nine crops examined, broccoli exhibited the highest total GSL concentration in seeds (110.76 µmol·g(-1)) and sprouts (162.19 µmol·g(-1)), whereas leaf mustard exhibited the highest total GSL concentration in shoots (61.76 µmol·g(-1)) and roots (73.61 µmol·g(-1)). The lowest GSL concentrations were observed in radish across all tissues examined.

Fundamental trade-offs generating the worldwide leaf economics spectrum.

PubMed

Shipley, Bill; Lechowicz, Martin J; Wright, Ian; Reich, Peter B

2006-03-01

Recent work has identified a worldwide "economic" spectrum of correlated leaf traits that affects global patterns of nutrient cycling and primary productivity and that is used to calibrate vegetation-climate models. The correlation patterns are displayed by species from the arctic to the tropics and are largely independent of growth form or phylogeny. This generality suggests that unidentified fundamental constraints control the return of photosynthates on investments of nutrients and dry mass in leaves. Using novel graph theoretic methods and structural equation modeling, we show that the relationships among these variables can best be explained by assuming (1) a necessary trade-off between allocation to structural tissues versus liquid phase processes and (2) an evolutionary tradeoff between leaf photosynthetic rates, construction costs, and leaf longevity.

Rumen Bacterial Degradation of Forage Cell Walls Investigated by Electron Microscopy

PubMed Central

Akin, Danny E.; Amos, Henry E.

1975-01-01

The association of rumen bacteria with specific leaf tissues of the forage grass Kentucky-31 tall fescue (Festuca arundinacea Schreb.) during in vitro degradation was investigated by transmission and scanning electron microscopy. Examination of degraded leaf cross-sections revealed differential rates of tissue degradation in that the cell walls of the mesophyll and pholem were degraded prior to those of the outer bundle sheath and epidermis. Rumen bacteria appeared to degrade the mesophyll, in some cases, and phloem without prior attachment to the plant cell walls. The degradation of bundle sheath and epidermal cell walls appeared to be preceded by attachment of bacteria to the plant cell wall. Ultrastructural features apparently involved in the adhesion of large cocci to plant cells were observed by transmission and scanning electron microscopy. The physical association between plant and rumen bacterial cells during degradation apparently varies with tissue types. Bacterial attachment, by extracellular features in some microorganisms, is required prior to degradation of the more resistant tissues. Images PMID:16350017

Tibiofemoral Contact Mechanics with Horizontal Cleavage Tear and Resection of the Medial Meniscus in the Human Knee.

PubMed

Koh, Jason L; Yi, Seung Jin; Ren, Yupeng; Zimmerman, Todd A; Zhang, Li-Qun

2016-11-02

The meniscus is known to increase the contact area and decrease contact pressure in the tibiofemoral compartments of the knee. Radial tears of the meniscal root attachment along with partial resections of the torn meniscal tissue decrease the contact area and increase pressure; however, there is a lack of information on the effects of a horizontal cleavage tear (HCT) and partial leaf meniscectomy of such tears on tibiofemoral contact pressure and contact area. Twelve fresh-frozen human cadaveric knees were tested under 10 conditions: 5 serial conditions of posterior medial meniscectomy (intact meniscus, HCT, repaired HCT, inferior leaf resection, and resection of both inferior and superior leaves), each at 2 knee flexion angles (0° and 60°) under an 800-N axial load. Tekscan sensors (model 4000) were used to measure the contact pressure and contact area. HCT and HCT repair resulted in small changes in the contact area and an increase in contact pressure compared with the intact condition. Resection of the inferior leaf resulted in significantly decreased contact area (to a mean 82.3% of the intact condition at 0° of flexion and 81.8% at 60° of flexion; p < 0.05) and increased peak contact pressure (a mean 36.3% increase at 0° flexion and 43.2% increase at 60° flexion; p < 0.05) in the medial compartment. Further resection of the remaining superior leaf resulted in additional significant decreases in contact area (to a mean 60.1% of the intact condition at 0° of flexion and 49.7% at 60° of flexion; p < 0.05) and increases in peak contact pressure (a mean 79.2% increase at 0° of flexion and 74.9% increase at 60° of flexion; p < 0.05). Resection of meniscal tissue forming the inferior leaf of an HCT resulted in substantially decreased contact area and increased contact pressure. Additional resection of the superior leaf resulted in a further significant decrease in contact area and increase in contact pressure in the medial compartment. Repair or minimal resection of meniscal tissue of an HCT may be preferred to complete leaf resection to maintain knee tibiofemoral contact mechanics. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

A quantitative analysis of phenotypic variations of Metrosideros polymorpha within and across populations along environmental gradients on Mauna Loa, Hawaii.

PubMed

Tsujii, Yuki; Onoda, Yusuke; Izuno, Ayako; Isagi, Yuji; Kitayama, Kanehiro

2016-04-01

Metrosideros polymorpha, a dominant tree species in the Hawaiian Islands, shows an extreme phenotypic polymorphism both across gradients of climatic/edaphic conditions and within populations, making it a potentially useful model species for evolutionary study. In order to understand how the phenotypic diversity is maintained within populations as well as across populations, we examined the diversities of several leaf and stem functional traits across five elevations and two soil substrates on the volcanic mountain of Mauna Loa, on the island of Hawaii. Leaf dry mass per area (LMA), a key leaf functional trait, was particularly focused on and analyzed in relation to its underlying components-namely, tissue LMA and trichome LMA (LMA = tissue LMA + trichome LMA). Across populations, tissue LMA increased linearly with elevation while trichome LMA showed unimodal patterns with elevation, which were better correlated with temperature and rainfall, respectively. Substantial phenotypic variations were also found within populations. Interestingly, the variations of tissue LMA were often negatively correlated to trichome LMA within populations, which contrasts with the cross-populations pattern, where a strong positive correlation between tissue LMA and trichome LMA was found. This suggests that phenotypic variations within populations were substantially influenced by local ecological processes. Soil depth (an indicator of local water availability) and tree size (an indicator of colonized timing) modestly explained the within-population variations, implying other local environmental factors and/or random processes are also important in local phenotypic diversity. This study provides an insight about how phenotypic diversity of plant species is maintained from local to landscape levels.

Leaf hydraulics I: scaling transport properties from single cells to tissues.

PubMed

Rockwell, Fulton E; Michele Holbrook, N; Stroock, Abraham D

2014-01-07

In leaf tissues, water may move through the symplast or apoplast as a liquid, or through the airspace as vapor, but the dominant path remains in dispute. This is due, in part, to a lack of models that describe these three pathways in terms of experimental variables. We show that, in plant water relations theory, the use of a hydraulic capacity in a manner analogous to a thermal capacity, though it ignores mechanical interactions between cells, is consistent with a special case of the more general continuum mechanical theory of linear poroelasticity. The resulting heat equation form affords a great deal of analytical simplicity at a minimal cost: we estimate an expected error of less than 12%, compared to the full set of equations governing linear poroelastic behavior. We next consider the case for local equilibrium between protoplasts, their cell walls, and adjacent air spaces during isothermal hydration transients to determine how accurately simple volume averaging of material properties (a 'composite' model) describes the hydraulic properties of leaf tissue. Based on typical hydraulic parameters for individual cells, we find that a composite description for tissues composed of thin walled cells with air spaces of similar size to the cells, as in photosynthetic tissues, is a reasonable preliminary assumption. We also expect isothermal transport in such cells to be dominated by the aquaporin-mediated cell-to-cell path. In the non-isothermal case, information on the magnitude of the thermal gradients is required to assess the dominant phase of water transport, liquid or vapor. © 2013 Published by Elsevier Ltd. All rights reserved.

Leaf-Cutter Ant Fungus Gardens Are Biphasic Mixed Microbial Bioreactors That Convert Plant Biomass to Polyols with Biotechnological Applications

PubMed Central

Somera, Alexandre F.; Lima, Adriel M.; dos Santos-Neto, Álvaro J.; Lanças, Fernando M.

2015-01-01

Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology. PMID:25911490

Leaf-cutter ant fungus gardens are biphasic mixed microbial bioreactors that convert plant biomass to polyols with biotechnological applications.

PubMed

Somera, Alexandre F; Lima, Adriel M; Dos Santos-Neto, Álvaro J; Lanças, Fernando M; Bacci, Maurício

2015-07-01

Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Proline accumulation in lemongrass (Cymbopogon flexuosus Stapf.) due to heavy metal stress.

PubMed

Handique, G K; Handique, A K

2009-03-01

Toxic heavy metals viz. lead, mercury and cadmium induced differential accumulation of proline in lemongrass (Cymbopogon flexuosus Stapf.) grown in soil amended with 50, 100, 200, 350 and 500 mg kg(-1) of the metals have been studied. Proline accumulation was found to be metal specific, organ specific and linear dose dependant. Further, proline accumulation following short term exposure (two months after transplantation) was higher than long term exposure (nine months after transplantation). Proline accumulation following short term exposure was 2.032 to 3.839 micro moles g(-1) for cadmium (50-200 mg kg(-1)); the corresponding range for mercury was 1.968 to 5.670 micro moles g(-1) and 0.830 to 4.567 micro moles g(-1) for lead (50-500 mg kg(-1) for mercury and lead). Proline accumulation was consistently higher in young tender leaf than old leaf, irrespective of the metal or duration of exposure. For cadmium treatment proline level was 2.032 to 3.839 micro moles g(-1) for young leaves while the corresponding value for old leaf was 1.728 to 2.396 micro moles g(-1) following short term exposure. The same trend was observed for the other two metals and duration of exposure. For control set proline accumulation in root was 0.425 micro moles g(-1) as against 0.805 and 0.533 micro moles g(-1) in young and old leaves respectively indicating that proline accumulation in root are lower than leaves, under both normal and stressed condition.

Studies on the nitrate reductase activities of the fruit and the source leaf in pepper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Achhireddy, N.R.; Beevers, L.; Fletcher, J.S.

Nitrate reductase (NR) activity (NO/sub 2//sup -/ produced in the dark and under anaerobic conditions) of 30-day-old fruit of Capsicum annuum L. was 2.2% that in tissues of a single leaf adjacent to each fruit (33 vs. 1500 nmoles/hr-g fresh weight). The optimal NR activity in one source leaf could only account for about 17% of the fruit's total nitrogen accumulation, while the fruit's own NR activity was almost negligible. Covered and uncovered fruits did not differ significantly in NR activities. 19 references, 1 figure, 1 table.

Psychrometric Measurement of Leaf Water Potential: Lack of Error Attributable to Leaf Permeability.

PubMed

Barrs, H D

1965-07-02

A report that low permeability could cause gross errors in psychrometric determinations of water potential in leaves has not been confirmed. No measurable error from this source could be detected for either of two types of thermocouple psychrometer tested on four species, each at four levels of water potential. No source of error other than tissue respiration could be demonstrated.

The Photosynthesis, Na+/K+ Homeostasis and Osmotic Adjustment of Atriplex canescens in Response to Salinity

PubMed Central

Pan, Ya-Qing; Guo, Huan; Wang, Suo-Min; Zhao, Bingyu; Zhang, Jin-Lin; Ma, Qing; Yin, Hong-Ju; Bao, Ai-Ke

2016-01-01

Atriplex canescens (fourwing saltbush) is a C4 perennial fodder shrub with excellent resistance to salinity. However, the mechanisms underlying the salt tolerance in A. canescens are poorly understood. In this study, 5-weeks-old A. canescens seedlings were treated with various concentrations of external NaCl (0–400 mM). The results showed that the growth of A. canescens seedlings was significantly stimulated by moderate salinity (100 mM NaCl) and unaffected by high salinity (200 or 400 mM NaCl). Furthermore, A. canescens seedlings showed higher photosynthetic capacity under NaCl treatments (except for 100 mM NaCl treatment) with significant increases in net photosynthetic rate and water use efficiency. Under saline conditions, the A. canescens seedlings accumulated more Na+ in either plant tissues or salt bladders, and also retained relatively constant K+ in leaf tissues and bladders by enhancing the selective transport capacity for K+ over Na+ (ST value) from stem to leaf and from leaf to bladder. External NaCl treatments on A. canescens seedlings had no adverse impact on leaf relative water content, and this resulted from lower leaf osmotic potential under the salinity conditions. The contribution of Na+ to the leaf osmotic potential (Ψs) was sharply enhanced from 2% in control plants to 49% in plants subjected to 400 mM NaCl. However, the contribution of K+ to Ψs showed a significant decrease from 34% (control) to 9% under 400 mM NaCl. Interestingly, concentrations of betaine and free proline showed significant increase in the leaves of A. canescens seedlings, these compatible solutes presented up to 12% of contribution to Ψs under high salinity. These findings suggest that, under saline environments, A. canescens is able to enhance photosynthetic capacity, increase Na+ accumulation in tissues and salt bladders, maintain relative K+ homeostasis in leaves, and use inorganic ions and compatible solutes for osmotic adjustment which may contribute to the improvement of water status in plant. PMID:27379134

Accumulation of Pb and Cu heavy metals in sea water, sediment, and leaf and root tissue of Enhalus sp. in the seagrass bed of Banten Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fauziah, Faiza, E-mail: faiza.fauziah@gmail.com; Choesin, Devi N., E-mail: faiza.fauziah@gmail.com

2014-03-24

Banten Bay in Indonesia is a coastal area which has been highly affected by human activity. Previous studies have reported the presence of lead (Pb) and copper (Cu) heavy metals in the seawater of this area. This study was conducted to measure the accumulation of Pb and Cu in seawater, sediment, leaf tissue, and root tissue of the seagrass species Enhalus sp. Sampling was conducted at two observation stations in Banten Bay: Station 1 (St.1) was located closer to the coastline and to industrial plants as source of pollution, while Station 2 (St.2) was located farther away offshore. At eachmore » station, three sampling points were established by random sampling. Field sampling was conducted at two different dates, i.e., on 29 May 2012 and 30 June 2012. Samples were processed by wet ashing using concentrated HNO{sub 3} acid and measured using Atomic Absorption Spectrometry (AAS). Accumulation of Pb was only detected in sediment samples in St.1, while Cu was detected in all samples. Average concentrations of Cu in May were as follows: sediment St.1 = 0.731 ppm, sediment St.2 = 0.383 ppm, seawater St.1 = 0.163 ppm, seawater St.2 = 0.174 ppm, leaf St.1 = 0.102 ppm, leaf St.2 = 0.132 ppm, root St.1= 0.139 ppm, and root St.2 = 0.075 ppm. Average measurements of Cu in June were: sediment St.1 = 0.260 ppm, leaf St.1 = 0.335 ppm, leaf St.2 = 0.301 ppm, root St.1= 0.047 ppm, and root St.2 = 0.060 ppm. In June, Cu was undetected in St.2 sediment and seawater at both stations. In May, Cu concentration in seawater exceeded the maximum allowable threshold for water as determined by the Ministry of the Environment. Spatial and temporal variation in Pb and Cu accumulation were most probably affected by distance from source and physical conditions of the environment (e.g., water current and mixing)« less

Morinda citrifolia leaves enhance osteogenic differentiation and mineralization of human periodontal ligament cells.

PubMed

Boonanantanasarn, Kanitsak; Janebodin, Kajohnkiart; Suppakpatana, Prapan; Arayapisit, Tawepong; Rodsutthi, Jit-aree; Chunhabundit, Panjit; Boonanuntanasarn, Surintorn; Sripairojthikoon, Wanida

2012-01-01

This present study investigated the potential of Morinda citrifolia leaf aqueous extract to induce osteogenic differentiation and matrix mineralization of human periodontal ligament (hPDL) cells. Human periodontal ligament cells were cultured in complete medium, ascorbic acid with β-glycerophosphate, or Morinda citrifolia leaf aqueous extract. Morinda citrifolia leaf aqueous extract significantly increased alkaline phosphatase activity compared to culturing in complete medium or ascorbic acid with β-glycerophosphate. Matrixcontaining mineralized nodules were formed only when the cells were cultured in the presence of Morinda citrifolia leaf aqueous extract. These nodules showed positive alizarin red S staining and were rich in calcium and phosphorus according to energy dispersive X-ray analysis. In conclusion, Morinda citrifolia leaf extract promoted osteogenic differentiation and matrix mineralization in human periodontal ligament cells, a clear indication of the therapeutic potential of Morinda citrifolia leaves in bone and periodontal tissue regeneration.

Morinda citrifolia leaves enhance osteogenic differentiation and mineralization of human periodontal ligament cells.

PubMed

Boonanantanasarn, Kanitsak; Janebodin, Kajohnkiart; Suppakpatana, Prapan; Arayapisit, Tawepong; Rodsutthi, Jit-aree; Chunhabundit, Panjit; Boonanuntanasarn, Surintorn; Sripairojthikoon, Wanida

2014-01-01

This present study investigated the potential of Morinda citrifolia leaf aqueous extract to induce osteogenic differentiation and matrix mineralization of human periodontal ligament (hPDL) cells. Human periodontal ligament cells were cultured in complete medium, ascorbic acid with β-glycerophosphate, or Morinda citrifolia leaf aqueous extract. Morinda citrifolia leaf aqueous extract significantly increased alkaline phosphatase activity compared to culturing in complete medium or ascorbic acid with β-glycerophosphate. Matrixcontaining mineralized nodules were formed only when the cells were cultured in the presence of Morinda citrifolia leaf aqueous extract. These nodules showed positive alizarin red S staining and were rich in calcium and phosphorus according to energy dispersive X-ray analysis. In conclusion, Morinda citrifolia leaf extract promoted osteogenic differentiation and matrix mineralization in human periodontal ligament cells, a clear indication of the therapeutic potential of Morinda citrifolia leaves in bone and periodontal tissue regeneration.

Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice

PubMed Central

Kim, Sung-Il; Song, Jong Tae; Jeong, Jin-Yong; Seo, Hak Soo

2016-01-01

Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects. PMID:26879887

A growing Leaf as a Sheet of an Active Solid

NASA Astrophysics Data System (ADS)

Sharon, Eran

A growing leaf is a thin sheet of active solid, which expands while obeying the laws of mechanics. The effective rheology of this active solid is nontrivial, allowing the leaf to increase its area by orders of magnitude, keeping its ''proper'' geometry. The questions of what the characteristics of the leaf growth field are and how it is regulated without any central ''headquarter'' are still open. I will present measurements of natural leaf growth with high time and space resolution. These show that the growth is a highly fluctuating process in both time and space. We suggest that the entire statistics of the growth field, not just its averages contain information important for the understanding of growth regulation. In another set of experiments we measure the effect of mechanical stress on deformation and growth. The measured effective rheology is viscoelastic with time varying parameters, indicating remodeling of the tissue in response to extended application of mechanical stress.

Developmental validation of a Cannabis sativa STR multiplex system for forensic analysis.

PubMed

Howard, Christopher; Gilmore, Simon; Robertson, James; Peakall, Rod

2008-09-01

A developmental validation study based on recommendations of the Scientific Working Group on DNA Analysis Methods (SWGDAM) was conducted on a multiplex system of 10 Cannabis sativa short tandem repeat loci. Amplification of the loci in four multiplex reactions was tested across DNA from dried root, stem, and leaf sources, and DNA from fresh, frozen, and dried leaf tissue with a template DNA range of 10.0-0.01 ng. The loci were amplified and scored consistently for all DNA sources when DNA template was in the range of 10.0-1.0 ng. Some allelic dropout and PCR failure occurred in reactions with lower template DNA amounts. Overall, amplification was best using 10.0 ng of template DNA from dried leaf tissue indicating that this is the optimal source material. Cross species amplification was observed in Humulus lupulus for three loci but there was no allelic overlap. This is the first study following SWGDAM validation guidelines to validate short tandem repeat markers for forensic use in plants.

Effects of the Topical Application of Hydroalcoholic Leaf Extract of Oncidium flexuosum Sims. (Orchidaceae) and Microcurrent on the Healing of Wounds Surgically Induced in Wistar Rats

PubMed Central

de Gaspi, Fernanda Oliveira de G.; Foglio, Mary Ann; de Carvalho, João Ernesto; Santos, Gláucia Maria T.; Testa, Milene; Passarini, José Roberto; de Moraes, Cristiano Pedroso; Esquisatto, Marcelo A. Marreto; Mendonça, Josué S.; Mendonça, Fernanda A. Sampaio

2011-01-01

This study evaluated the wound healing activity of hydroalcoholic leaf extract of Oncidium flexuosum Sims. (Orchidaceae), an important native plant of Brazil, combined or not with microcurrent stimulation. Wistar rats were randomly divided into four groups of nine animals: control (C), topical application of the extract (OF), treated with a microcurrent (10 μA/2 min) (MC), and topical application of the extract plus microcurrent (OF + MC). Tissue samples were obtained 2, 6, and 10 days after injury and submitted to structural and morphometric analysis. The simultaneous application of OF + MC was found to be highly effective in terms of the parameters analyzed (P < .05), with positive effects on the area of newly formed tissue, number of fibroblasts, number of newly formed blood vessels, and epithelial thickness. Morphometric data confirmed the structural findings. The O. flexuosum leaf extract contains active compounds that speed the healing process, especially when applied simultaneously with microcurrent stimulation. PMID:21716707

Ruta graveolens Extracts and Metabolites against Spodoptera frugiperda.

PubMed

Ayil-Gutiérrez, Benjamin A; Villegas-Mendoza, Jesús M; Santes-Hernndez, Zuridai; Paz-González, Alma D; Mireles-Martínez, Maribel; Rosas-García, Ninfa M; Rivera, Gildardo

2015-11-01

The biological activity of Ruta graveolens leaf tissue extracts obtained with different solvents (ethyl acetate, ethanol, and water) and metabolites (psoralen, 2- undecanone and rutin) against Spodoptera frugiperda was evaluated. Metabolites levels in extracts were quantified by HPLC and GC. Ethyl acetate and ethanol extracts showed 94% and 78% mortality, respectively. Additionally, psoralen metabolite showed a high mortality as cypermethrin. Metabolite quantification in extracts shows the presence of 2-undecanone (87.9 µmoles mg(-1) DW), psoralen (3.6 µmoles mg(-1) DW) and rutin (0.001 pmoles mg(-1) DW). We suggest that these concentrations of 2-undecanone and psoralen in R. graveolens leaf tissue extracts could be responsible for S. frugiperda mortality.

Protein expression in Arabidopsis thaliana after chronic clinorotation

NASA Technical Reports Server (NTRS)

Piastuch, W. C.; Brown, C. S.

1995-01-01

Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional SDS PAGE and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

Resistance mechanisms and their difference between the root and leaf of Microsorum pteropus - A novel potential aquatic cadmium hyperaccumulator.

PubMed

Lan, Xin-Yu; Yang, Bin; Yan, Yun-Yun; Li, Xin-Yuan; Xu, Fu-Liu

2018-03-01

Microsorum pteropus (M. pteropus), an aquatic Polypodiaceae fern, was identified as a novel potential cadmium (Cd) hyperaccumulator in our previous study. This study reveals the Cd-resistance mechanisms and their difference between the root and leaf of M. pteropus based on analyses of photosynthesis, antioxidant systems and gene expression. A high level of Cd at 500μM was used to treat the samples to test the effects of this compound. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA) and flavonoids were used as indicators for antioxidant system changes. Five chlorophyll fluorescent parameters including the maximal photochemical efficiency of photosystem II (F v /F m ), effective quantum yield of photosystem II (Y(II)), photochemical quenching (qP), nonphotochemical quenching (qN) and electron transport rate (ETR) were measured to determine the photosynthetic changes. RNA-sequencing analysis was used to study the changes in gene expression. The results showed that after exposure to high levels of Cd, the concentrations of enzymatic oxidants (SOD and POD) were significantly increased, while the MDA levels were significantly decreased. There were no significant changes for the chlorophyll fluorescent parameters during Cd stress, which indicates that M. pteropus is highly effective at protecting itself. Certain functional genes, including photosystem genes and secondary metabolites, had significantly altered levels of expression. Different Cd-resistance mechanisms were found between the root and leaf tissues of M. pteropus. The root tissues of M. pteropus resist Cd damage using antioxidants, while its leaf tissues mainly protect themselves using photosystem self-protection. Copyright © 2017 Elsevier B.V. All rights reserved.

Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

NASA Astrophysics Data System (ADS)

Benner, Ronald; Hatcher, Patrick G.; Hedges, John I.

1990-07-01

Changes in the chemical composition of mangrove ( Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed.

Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

USGS Publications Warehouse

Benner, R.; Hatcher, P.G.; Hedges, J.I.

1990-01-01

Changes in the chemical composition of mangrove (Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed. ?? 1990.

Light controls phospholipase A2α and β gene expression in Citrus sinensis

PubMed Central

Liao, Hui-Ling; Burns, Jacqueline K.

2010-01-01

The low-molecular weight secretory phospholipase A2α (CssPLA2α) and β (CsPLA2β) cloned in this study exhibited diurnal rhythmicity in leaf tissue of Citrus sinensis. Only CssPLA2α displayed distinct diurnal patterns in fruit tissues. CssPLA2α and CsPLA2β diurnal expression exhibited periods of approximately 24 h; CssPLA2α amplitude averaged 990-fold in the leaf blades from field-grown trees, whereas CsPLA2β amplitude averaged 6.4-fold. Diurnal oscillation of CssPLA2α and CsPLA2β gene expression in the growth chamber experiments was markedly dampened 24 h after transfer to continuous light or dark conditions. CssPLA2α and CsPLA2β expressions were redundantly mediated by blue, green, red and red/far-red light, but blue light was a major factor affecting CssPLA2α and CsPLA2β expression. Total and low molecular weight CsPLA2 enzyme activity closely followed diurnal changes in CssPLA2α transcript expression in leaf blades of seedlings treated with low intensity blue light (24 μmol m−2 s−1). Compared with CssPLA2α basal expression, CsPLA2β expression was at least 10-fold higher. Diurnal fluctuation and light regulation of PLA2 gene expression and enzyme activity in citrus leaf and fruit tissues suggests that accompanying diurnal changes in lipophilic second messengers participate in the regulation of physiological processes associated with phospholipase A2 action. PMID:20388744

The influence of leaf anatomy on the internal light environment and photosynthetic electron transport rate: exploration with a new leaf ray tracing model.

PubMed

Xiao, Yi; Tholen, Danny; Zhu, Xin-Guang

2016-11-01

Leaf photosynthesis is determined by biochemical properties and anatomical features. Here we developed a three-dimensional leaf model that can be used to evaluate the internal light environment of a leaf and its implications for whole-leaf electron transport rates (J). This model includes (i) the basic components of a leaf, such as the epidermis, palisade and spongy tissues, as well as the physical dimensions and arrangements of cell walls, vacuoles and chloroplasts; and (ii) an efficient forward ray-tracing algorithm, predicting the internal light environment for light of wavelengths between 400 and 2500nm. We studied the influence of leaf anatomy and ambient light on internal light conditions and J The results show that (i) different chloroplasts can experience drastically different light conditions, even when they are located at the same distance from the leaf surface; (ii) bundle sheath extensions, which are strips of parenchyma, collenchyma or sclerenchyma cells connecting the vascular bundles with the epidermis, can influence photosynthetic light-use efficiency of leaves; and (iii) chloroplast positioning can also influence the light-use efficiency of leaves. Mechanisms underlying leaf internal light heterogeneity and implications of the heterogeneity for photoprotection and for the convexity of the light response curves are discussed. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Overcoming seed dormancy using gibberellic acid and the performance of young Syagrus coronata plants under severe drought stress and recovery.

PubMed

Medeiros, Maria J; Oliveira, Marciel T; Willadino, Lilia; Santos, Mauro G

2015-12-01

Syagrus coronata, a native palm tree of the Brazilian semi-arid region, exhibits low germinability due to seed dormancy. This study aimed to increase the germinability, analyze the morphology of seedlings and evaluate the performance of young plants under a water deficit. We used immersion in water and gibberellic acid (GA3) as pyrene (seed with endocarp) pre-germination treatments, and we analyzed the water relations, gas exchange, chlorophyll fluorescence and carbon balance components of young plants under drought and rehydration conditions. The immersion of pyrenes in 0.3 mM GA3 solution for 24 h enhanced the emergence and survival of plants and the emergence rate index. The germination of S. coronata is of the remote tubular type, and seedling growth originates with the protrusion of the cotyledon petiole, followed by the subsequent emergence of the root, leaf sheaths and eophyll. The plants exhibited high tolerance to no irrigation for 37 days, which was attributed to strong stomatal control, a higher proportion of energy dissipation and a higher content of photoprotective pigments. Despite the reduced stomatal conductance (regardless of soil water availability), the photosynthetic rate remained high throughout the day, which indicated a low correlation between these two parameters. After rehydration, we observed that both the leaf water content and photosynthesis recovered, which showed an absence of irreversible damage of the photosynthetic apparatus. The use of 0.3 mM GA3 is recommended as a treatment for overcoming seed dormancy in this species. Young S. coronata plants showed high tolerance during drought and resilience after rehydration by adjusting their leaf metabolism, which could explain the endemism of this species in semi-arid regions and its ability to remain evergreen throughout the year. Furthermore, with high photosynthetic rate in the most favorable time of day, even under drought stress. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Tissue distribution comparison between healthy and fatty liver rats after oral administration of hawthorn leaf extract.

PubMed

Yin, Jingjing; Qu, Jianguo; Zhang, Wenjie; Lu, Dongrui; Gao, Yucong; Ying, Xixiang; Kang, Tingguo

2014-05-01

Hawthorn leaves, a well-known traditional Chinese medicine, have been widely used for treating cardiovascular and fatty liver diseases. The present study aimed to investigate the therapeutic basis treating fatty liver disease by comparing the tissue distribution of six compounds of hawthorn leaf extract (HLE) in fatty liver rats and healthy rats after oral administration at first day, half month and one month, separately. Therefore, a sensitive and specific HPLC method with internal standard was developed and validated to determine chlorogenic acid, vitexin-4''-O-glucoside, vitexin-2''-O-rhamnoside, vitexin, rutin and hyperoside in the tissues including heart, liver, spleen, kidney, stomach and intestine. The results indicated that the six compounds in HLE presented some bioactivity in treating rat fatty liver as the concentrations of the six compounds varied significantly in inter- and intragroup comparisons (healthy and/or fatty liver group). Copyright © 2013 John Wiley & Sons, Ltd.

Plant tissue and the color infrared record

NASA Technical Reports Server (NTRS)

Pease, R. W.

1969-01-01

Green plant tissue should not be considered as having a uniguely high near-infrared reflectance but rather a low visual reflectance. Leaf tissue without chloroplasts appears to reflect well both visual and near infrared wavelengths. The sensitometry of color infrared film is such that a spectral imbalance strongly favoring infrared reflection is necessary to yield a red record. It is the absorption of visual light by chlorophyll that creates the imbalance that makes the typical red record for plants possible. Reflectance measurements of leaves that have been chemically blanched or which have gone into natural chloride decline strongly suggests that it is the rise in the visual reflectance that is most important in removing the imbalance and degrading the red CIR record. The role of water in leaves appears to be that of rendering epidermal membranes translucent so that the underlying chlorophyll controls the reflection rather than the leaf surface.

Proteomic Analysis Reveals the Leaf Color Regulation Mechanism in Chimera Hosta “Gold Standard” Leaves

PubMed Central

Yu, Juanjuan; Zhang, Jinzheng; Zhao, Qi; Liu, Yuelu; Chen, Sixue; Guo, Hongliang; Shi, Lei; Dai, Shaojun

2016-01-01

Leaf color change of variegated leaves from chimera species is regulated by fine-tuned molecular mechanisms. Hosta “Gold Standard” is a typical chimera Hosta species with golden-green variegated leaves, which is an ideal material to investigate the molecular mechanisms of leaf variegation. In this study, the margin and center regions of young and mature leaves from Hosta “Gold Standard”, as well as the leaves from plants after excess nitrogen fertilization were studied using physiological and comparative proteomic approaches. We identified 31 differentially expressed proteins in various regions and development stages of variegated leaves. Some of them may be related to the leaf color regulation in Hosta “Gold Standard”. For example, cytosolic glutamine synthetase (GS1), heat shock protein 70 (Hsp70), and chloroplastic elongation factor G (cpEF-G) were involved in pigment-related nitrogen synthesis as well as protein synthesis and processing. By integrating the proteomics data with physiological results, we revealed the metabolic patterns of nitrogen metabolism, photosynthesis, energy supply, as well as chloroplast protein synthesis, import and processing in various leaf regions at different development stages. Additionally, chloroplast-localized proteoforms involved in nitrogen metabolism, photosynthesis and protein processing implied that post-translational modifications were crucial for leaf color regulation. These results provide new clues toward understanding the mechanisms of leaf color regulation in variegated leaves. PMID:27005614

Assessment of nutrient remobilization through structural changes of palisade and spongy parenchyma in oilseed rape leaves during senescence.

PubMed

Sorin, Clément; Musse, Maja; Mariette, François; Bouchereau, Alain; Leport, Laurent

2015-02-01

Differential palisade and spongy parenchyma structural changes in oilseed rape leaf were demonstrated. These dismantling processes were linked to early senescence events and associated to remobilization processes. During leaf senescence, an ordered cell dismantling process allows efficient nutrient remobilization. However, in Brassica napus plants, an important amount of nitrogen (N) in fallen leaves is associated with low N remobilization efficiency (NRE). The leaf is a complex organ mainly constituted of palisade and spongy parenchyma characterized by different structures and functions concerning water relations and carbon fixation. The aim of the present study was to demonstrate a specific structural evolution of these parenchyma throughout natural senescence in B. napus, probably linked to differential nutrient remobilization processes. The study was performed on 340 leaves from 32 plants during an 8-week development period under controlled growing conditions. Water distribution and status at the cellular level were investigated by low-field proton nuclear magnetic resonance (NMR), while light and electron microscopy were used to observe cell and plast structure. Physiological parameters were determined on all leaves studied and used as indicators of leaf development and remobilization progress. The results revealed a process of hydration and cell enlargement of leaf tissues associated with senescence. Wide variations were observed in the palisade parenchyma while spongy cells changed only very slightly. The major new functional information revealed was the link between the early senescence events and specific tissue dismantling processes.

Community structures and antagonistic activities of the bacteria associated with surface-sterilized pepper plants grown in different field soils.

PubMed

Kang, Sin Ae; Han, Jae Woo; Kim, Beom Seok

2016-12-01

Endophytic bacteria may act individually or in consortia in controlling certain plant diseases. In this study, pepper plants (Capsicum annuum L. cv. Nokkwang) were cultivated in glasshouse conditions using field soils collected from two different geographic locations, Deokso (DS) and Gwangyang (GY) in Korea. Community structure and antifungal activity of pepper endophytic bacteria were analyzed using culture-independent (PCR-DGGE) and culture-dependent (plating) methods, respectively. Dissimilarities were observed between DGGE profiles of DS and GY samples at all plant tissues. However, sequencing of the major DGGE bands revealed an enrichment of Firmicutes in the leaves of plants propagated in either soil. Similar results were observed with the culturable assays. Firmicutes dominated the isolates from both leaf samples, DS leaf (100 %) and GY leaf (83.3 %), although the genus compositions of DS leaf and GY leaf isolates were different. We assessed the antifungal activity of each isolate recovered to better understand the potential role that these endophytic bacteria may play. Of the 27 representative isolates from DS plant samples, 17 isolates (63.0 %) had antagonistic activity against at least one of the fungi tested. Seventeen isolates from GY plant samples (58.6 %) displayed antagonistic properties. The results show that the endophytic communities differ in the same plant species when propagated in different soils. Exploring the internal tissues of plants growing in diverse soil environments could be a way to find potential candidates for biocontrol agents.

Model for the role of auxin polar transport in patterning of the leaf adaxial-abaxial axis.

PubMed

Shi, Jianmin; Dong, Jiaqiang; Xue, Jingshi; Wang, Hua; Yang, Zhongnan; Jiao, Yuling; Xu, Lin; Huang, Hai

2017-11-01

Leaf adaxial-abaxial polarity refers to the two leaf faces, which have different types of cells performing distinct biological functions. In 1951, Ian Sussex reported that when an incipient leaf primordium was surgically isolated by an incision across the vegetative shoot apical meristem (SAM), a radialized structure without an adaxial domain would form. This led to the proposal that a signal, now called the Sussex signal, is transported from the SAM to emerging primordia to direct leaf adaxial-abaxial patterning. It was recently proposed that instead of the Sussex signal, polar transport of the plant hormone auxin is critical in leaf polarity formation. However, how auxin polar transport functions in the process is unknown. Through live imaging, we established a profile of auxin polar transport in and around young leaf primordia. Here we show that auxin polar transport in lateral regions of an incipient primordium forms auxin convergence points. We demonstrated that blocking auxin polar transport in the lateral regions of the incipient primordium by incisions abolished the auxin convergence points and caused abaxialized leaves to form. The lateral incisions also blocked the formation of leaf middle domain and margins and disrupted expression of the middle domain/margin-associated marker gene WUSCHEL-RELATED HOMEOBOX 1 (SlWOX1). Based on these results we propose that the auxin convergence points are required for the formation of leaf middle domain and margins, and the functional middle domain and margins ensure leaf adaxial-abaxial polarity. How middle domain and margins function in the process is discussed. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Construction Costs and Physico-chemical Properties of the Assimilatory Organs of Nepenthes Species in Northern Borneo

PubMed Central

Osunkoya, Olusegun O.; Daud, Siti Dayanawati; Di-Giusto, Bruno; Wimmer, Franz L.; Holige, Thippeswamy M.

2007-01-01

Background and Aims Species of the Nepenthaceae family are under-represented in studies of leaf traits and the consequent view of mineral nutrition and limitation in carnivorous plants. This study is aimed to complement existing data on leaf traits of carnivorous plants. Methods Physico-chemical properties, including construction costs (CC), of the assimilatory organs (leaf and pitcher) of a guild of lowland Nepenthes species inhabiting heath and/or peat swamp forests of Brunei, Northern Borneo were determined. Key Results Stoichiometry analyses indicate that Nepenthes species are nitrogen limited. Most traits vary appreciably across species, but greater variations exist between the assimilatory organs. Organ mass per unit area, dry matter tissue concentration (density), nitrogen (N), phosphorus (P), carbon, heat of combustion (Hc) and CC values were higher in the leaf relative to the pitcher, while organ thickness, potassium (K) and ash showed the opposite trend. Cross-species correlations indicate that joint rather than individual consideration of the leaf and the pitcher give better predictive relationships between variables, signalling tight coupling and functional interdependence of the two assimilatory organs. Across species, mass-based CC did not vary with N or P, but increases significantly with tissue density, carbon and Hc, and decreases with K and ash contents. Area-based CC gave the same trends (though weaker in strength) in addition to a significant positive correlation with tissue mass per unit area. Conclusions The lower CC value for the pitcher is in agreement with the concept of low marginal cost for carnivory relative to conventional autotrophy. The poor explanatory power of N, P or N : P ratio with CC suggests that factors other than production of expensive photosynthetic machinery (which calls for a high N input), including concentrations of lignin, wax/lipids or osmoregulatory ions like K+, may give a better explanation of the CC variation across Nepenthes species. PMID:17452380

Leaf and root glucosinolate profiles of Chinese cabbage (Brassica rapa ssp. pekinensis) as a systemic response to methyl jasmonate and salicylic acid elicitation.

PubMed

Zang, Yun-xiang; Ge, Jia-li; Huang, Ling-hui; Gao, Fei; Lv, Xi-shan; Zheng, Wei-wei; Hong, Seung-beom; Zhu, Zhu-jun

2015-08-01

Glucosinolates (GSs) are an important group of defensive phytochemicals mainly found in Brassicaceae. Plant hormones jasmonic acid (JA) and salicylic acid (SA) are major regulators of plant response to pathogen attack. However, there is little information about the interactive effect of both elicitors on inducing GS biosynthesis in Chinese cabbage (Brassica rapa ssp. pekinensis). In this study, we applied different concentrations of methyl jasmonate (MeJA) and/or SA onto the leaf and root of Chinese cabbage to investigate the time-course interactive profiles of GSs. Regardless of the site of the elicitation and the concentrations of the elicitors, the roots accumulated much more GSs and were more sensitive and more rapidly responsive to the elicitors than leaves. Irrespective of the elicitation site, MeJA had a greater inducing and longer lasting effect on GS accumulation than SA. All three components of indole GS (IGS) were detected along with aliphatic and aromatic GSs. However, IGS was a major component of total GSs that accumulated rapidly in both root and leaf tissues in response to MeJA and SA elicitation. Neoglucobrassicin (neoGBC) did not respond to SA but to MeJA in leaf tissue, while it responded to both SA and MeJA in root tissue. Conversion of glucobrassicin (GBC) to neoGBC occurred at a steady rate over 3 d of elicitation. Increased accumulation of 4-methoxy glucobrassicin (4-MGBC) occurred only in the root irrespective of the type of elicitors and the site of elicitation. Thus, accumulation of IGS is a major metabolic hallmark of SA- and MeJA-mediated systemic response systems. SA exerted an antagonistic effect on the MeJA-induced root GSs irrespective of the site of elicitation. However, SA showed synergistic and antagonistic effects on the MeJA-induced leaf GSs when roots and leaves are elicitated for 3 d, respectively.

Chemometrics in biomonitoring: Distribution and correlation of trace elements in tree leaves.

PubMed

Deljanin, Isidora; Antanasijević, Davor; Bjelajac, Anđelika; Urošević, Mira Aničić; Nikolić, Miroslav; Perić-Grujić, Aleksandra; Ristić, Mirjana

2016-03-01

The concentrations of 15 elements were measured in the leaf samples of Aesculus hippocastanum, Tilia spp., Betula pendula and Acer platanoides collected in May and September of 2014 from four different locations in Belgrade, Serbia. The objective was to assess the chemical characterization of leaf surface and in-wax fractions, as well as the leaf tissue element content, by analyzing untreated, washed with water and washed with chloroform leaf samples, respectively. The combined approach of self-organizing networks (SON) and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) aided by Geometrical Analysis for Interactive Aid (GAIA) was used in the interpretation of multiple element loads on/in the tree leaves. The morphological characteristics of the leaf surfaces and the elemental composition of particulate matter (PM) deposited on tree leaves were studied by using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) detector. The results showed that the amounts of retained and accumulated element concentrations depend on several parameters, such as chemical properties of the element and morphological properties of the leaves. Among the studied species, Tilia spp. was found to be the most effective in the accumulation of elements in leaf tissue (70% of the total element concentration), while A. hippocastanum had the lowest accumulation (54%). After water and chloroform washing, the highest percentages of removal were observed for Al, V, Cr, Cu, Zn, As, Cd and Sb (>40%). The PROMETHEE/SON ranking/classifying results were in accordance with the results obtained from the GAIA clustering techniques. The combination of the techniques enabled extraction of additional information from datasets. Therefore, the use of both the ranking and clustering methods could be a useful tool to be applied in biomonitoring studies of trace elements. Copyright © 2015 Elsevier B.V. All rights reserved.

Physical and mechanical properties of spinach for whole-surface online imaging inspection

NASA Astrophysics Data System (ADS)

Tang, Xiuying; Mo, Chang Y.; Chan, Diane E.; Peng, Yankun; Qin, Jianwei; Yang, Chun-Chieh; Kim, Moon S.; Chao, Kuanglin

2011-06-01

The physical and mechanical properties of baby spinach were investigated, including density, Young's modulus, fracture strength, and friction coefficient. The average apparent density of baby spinach leaves was 0.5666 g/mm3. The tensile tests were performed using parallel, perpendicular, and diagonal directions with respect to the midrib of each leaf. The test results showed that the mechanical properties of spinach are anisotropic. For the parallel, diagonal, and perpendicular test directions, the average values for the Young's modulus values were found to be 2.137MPa, 1.0841 MPa, and 0.3914 MPa, respectively, and the average fracture strength values were 0.2429 MPa, 0.1396 MPa, and 0.1113 MPa, respectively. The static and kinetic friction coefficient between the baby spinach and conveyor belt were researched, whose test results showed that the average coefficients of kinetic and maximum static friction between the adaxial (front side) spinach leaf surface and conveyor belt were 1.2737 and 1.3635, respectively, and between the abaxial (back side) spinach leaf surface and conveyor belt were 1.1780 and 1.2451 respectively. These works provide the basis for future development of a whole-surface online imaging inspection system that can be used by the commercial vegetable processing industry to reduce food safety risks.

Extraction of high-quality DNA from ethanol-preserved tropical plant tissues.

PubMed

Bressan, Eduardo A; Rossi, Mônica L; Gerald, Lee T S; Figueira, Antonio

2014-04-24

Proper conservation of plant samples, especially during remote field collection, is essential to assure quality of extracted DNA. Tropical plant species contain considerable amounts of secondary compounds, such as polysaccharides, phenols, and latex, which affect DNA quality during extraction. The suitability of ethanol (96% v/v) as a preservative solution prior to DNA extraction was evaluated using leaves of Jatropha curcas and other tropical species. Total DNA extracted from leaf samples stored in liquid nitrogen or ethanol from J. curcas and other tropical species (Theobroma cacao, Coffea arabica, Ricinus communis, Saccharum spp., and Solanum lycopersicon) was similar in quality, with high-molecular-weight DNA visualized by gel electrophoresis. DNA quality was confirmed by digestion with EcoRI or HindIII and by amplification of the ribosomal gene internal transcribed spacer region. Leaf tissue of J. curcas was analyzed by light and transmission electron microscopy before and after exposure to ethanol. Our results indicate that leaf samples can be successfully preserved in ethanol for long periods (30 days) as a viable method for fixation and conservation of DNA from leaves. The success of this technique is likely due to reduction or inactivation of secondary metabolites that could contaminate or degrade genomic DNA. Tissue conservation in 96% ethanol represents an attractive low-cost alternative to commonly used methods for preservation of samples for DNA extraction. This technique yields DNA of equivalent quality to that obtained from fresh or frozen tissue.

Extraction of high-quality DNA from ethanol-preserved tropical plant tissues

PubMed Central

2014-01-01

Background Proper conservation of plant samples, especially during remote field collection, is essential to assure quality of extracted DNA. Tropical plant species contain considerable amounts of secondary compounds, such as polysaccharides, phenols, and latex, which affect DNA quality during extraction. The suitability of ethanol (96% v/v) as a preservative solution prior to DNA extraction was evaluated using leaves of Jatropha curcas and other tropical species. Results Total DNA extracted from leaf samples stored in liquid nitrogen or ethanol from J. curcas and other tropical species (Theobroma cacao, Coffea arabica, Ricinus communis, Saccharum spp., and Solanum lycopersicon) was similar in quality, with high-molecular-weight DNA visualized by gel electrophoresis. DNA quality was confirmed by digestion with EcoRI or HindIII and by amplification of the ribosomal gene internal transcribed spacer region. Leaf tissue of J. curcas was analyzed by light and transmission electron microscopy before and after exposure to ethanol. Our results indicate that leaf samples can be successfully preserved in ethanol for long periods (30 days) as a viable method for fixation and conservation of DNA from leaves. The success of this technique is likely due to reduction or inactivation of secondary metabolites that could contaminate or degrade genomic DNA. Conclusions Tissue conservation in 96% ethanol represents an attractive low-cost alternative to commonly used methods for preservation of samples for DNA extraction. This technique yields DNA of equivalent quality to that obtained from fresh or frozen tissue. PMID:24761774

Histopathological assessment of the infection of maize leaves by Fusarium graminearum, F. proliferatum, and F. verticillioides.

PubMed

Nguyen, Thi Thanh Xuan; Dehne, Heinz-Wilhelm; Steiner, Ulrike

2016-09-01

Young maize plants were inoculated on unfolded mature leaves and on folded immature leaves with Fusarium graminearum, Fusarium proliferatum, and Fusarium verticillioides suspensions. Infection and symptom development of disease on these asymptomatic mature leaves and immature leaves were then documented. Subcuticular infection was found by the three Fusarium species on both symptomatic and symptomless leaves. The three Fusarium species penetrated the stomata of immature leaves by the formation of appressoria-like structures, infection cushions or by direct penetration. Infection by the three species of Fusarium via stomata is reported here for the first time. The superficial hyphae and re-emerging hyphae of the three species produced conidia. The macroconidia of F. graminearum produced secondary macroconidia and F. proliferatum formed microconidia inside the leaf tissues that sporulated through stomata and trichomes. The infection of maize leaves by the three species of Fusarium and their sporulation may contribute inoculum to cob and kernel infection. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

The Last Step in Cocaine Biosynthesis Is Catalyzed by a BAHD Acyltransferase[OPEN

PubMed Central

Schmidt, Gregor Wolfgang; Porta, Tiffany; Reichelt, Michael; Luck, Katrin; Torre, José Carlos Pardo; Dolke, Franziska; Varesio, Emmanuel; Hopfgartner, Gérard; Gershenzon, Jonathan

2015-01-01

The esterification of methylecgonine (2-carbomethoxy-3β-tropine) with benzoic acid is the final step in the biosynthetic pathway leading to the production of cocaine in Erythoxylum coca. Here we report the identification of a member of the BAHD family of plant acyltransferases as cocaine synthase. The enzyme is capable of producing both cocaine and cinnamoylcocaine via the activated benzoyl- or cinnamoyl-Coenzyme A thioesters, respectively. Cocaine synthase activity is highest in young developing leaves, especially in the palisade parenchyma and spongy mesophyll. These data correlate well with the tissue distribution pattern of cocaine as visualized with antibodies. Matrix-assisted laser-desorption ionization mass spectral imaging revealed that cocaine and cinnamoylcocaine are differently distributed on the upper versus lower leaf surfaces. Our findings provide further evidence that tropane alkaloid biosynthesis in the Erythroxylaceae occurs in the above-ground portions of the plant in contrast with the Solanaceae, in which tropane alkaloid biosynthesis occurs in the roots. PMID:25406120

Structural equation modeling of PAHs in ambient air, dust fall, soil, and cabbage in vegetable bases of Northern China.

PubMed

Zhang, YunHui; Hou, DeYi; Xiong, GuanNan; Duan, YongHong; Cai, ChuanYang; Wang, Xin; Li, JingYa; Tao, Shu; Liu, WenXin

2018-08-01

A series of field samples including ambient air (gaseous and particulate phases), dust fall, surface soil, rhizosphere soil and cabbage tissues (leaf, root and core), were collected in vegetable bases near a large coking manufacturer in Shanxi Province, Northern China, during a harvest season. A factor analysis was employed to apportion the emission sources of polycyclic aromatic hydrocarbons (PAHs), and the statistical results indicated coal combustion was the dominant emission source that accounted for different environmental media and cabbage tissues, while road traffic, biomass burning and the coking industry contributed to a lesser extent. A structural equation model was first developed to quantitatively explore the transport pathways of PAHs from surrounding media to cabbage tissues. The modeling results showed that PAHs in ambient air were positively associated with those in dust fall, and a close relationship was also true for PAHs in dust fall and in surface soil due to air-soil exchange process. Furthermore, PAHs in surface soil were correlated with those in rhizosphere soil and in the cabbage leaf with the path coefficients of 0.83 and 0.39, respectively. PAHs in the cabbage leaf may dominantly contribute to the accumulation of PAHs in the edible part of cabbages. Copyright © 2018 Elsevier Ltd. All rights reserved.

Changes in Cell Wall Polysaccharides Associated With Growth 1

PubMed Central

Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1968-01-01

Changes in the polysaccharide composition of Phaseolus vulgaris, P. aureus, and Zea mays cell walls were studied during the first 28 days of seedling development using a gas chromatographic method for the analysis of neutral sugars. Acid hydrolysis of cell wall material from young tissues liberates rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose which collectively can account for as much as 70% of the dry weight of the wall. Mature walls in fully expanded tissues of these same plants contain less of these constituents (10%-20% of dry wt). Gross differences are observed between developmental patterns of the cell wall in the various parts of a seedling, such as root, stem, and leaf. The general patterns of wall polysaccharide composition change, however, are similar for analogous organs among the varieties of a species. Small but significant differences in the rates of change in sugar composition were detected between varieties of the same species which exhibited different growth patterns. The cell walls of species which are further removed phylogenetically exhibit even more dissimilar developmental patterns. The results demonstrate the dynamic nature of the cell wall during growth as well as the quantitative and qualitative exactness with which the biosynthesis of plant cell walls is regulated. PMID:16656862

Carbon isotope fractionation in the mangrove Avicennia marina has implications for food web and blue carbon research

NASA Astrophysics Data System (ADS)

Kelleway, Jeffrey J.; Mazumder, Debashish; Baldock, Jeffrey A.; Saintilan, Neil

2018-05-01

The ratio of stable isotopes of carbon (δ13C) is commonly used to track the flow of energy among individuals and ecosystems, including in mangrove forests. Effective use of this technique requires understanding of the spatial variability in δ13C among primary producer(s) as well as quantification of the isotopic fractionations that occur as C moves within and among ecosystem components. In this experiment, we assessed δ13C variation in the cosmopolitan mangrove Avicennia marina across four sites of varying physico-chemical conditions across two estuaries. We also compared the isotopic values of five distinct tissue types (leaves, woody stems, cable roots, pneumatophores and fine roots) in individual plants. We found a significant site effect (F3, 36 = 15.78; P < 0.001) with mean leaf δ13C values 2.0‰ more depleted at the lowest salinity site compared to the other locations. There was a larger within-plant fractionation effect, however, with leaf samples (mean ± SE = -29.1 ± 0.2) more depleted in 13C than stem samples (-27.1 ± 0.1), while cable root (-25. 8 ± 0.1), pneumatophores (-25.7 ± 0.1) and fine roots (-26.0 ± 0.2) were more enriched in 13C relative to both aboveground tissue types (F4, 36 = 223.45; P < 0.001). The within-plant δ13C fractionation we report for A. marina is greater than that reported in most other ecosystems. This has implications for studies of estuarine carbon cycling. The consistent and large size of the fractionation from leaf to woody stem (∼2.0‰) and mostly consistent fractionation from leaf to root tissues (>3.0‰) means that it may now be possible to partition the individual contributions of various mangrove tissues to estuarine food webs. Similarly, the contributions of mangrove leaves, woody debris and belowground sources to blue carbon stocks might also be quantified. Above all, however, our results emphasize the importance of considering appropriate mangrove tissue types when using δ13C to trace carbon cycling in estuarine systems.

Efficacy of Neem Extract and Three Antimicrobial Agents Incorporated into Tissue Conditioner in Inhibiting the Growth of C. Albicans and S. Mutans

PubMed Central

Barua, Dikshita Ray; Varghese, Rana Kalappattil

2017-01-01

Introduction Denture stomatitis is an inflammatory condition which compromises the mucosal surface beneath dentures. The aetiology of denture stomatitis is usually multifactorial which varies from trauma from ill fitting denture to poor immune system. There are evidences that denture stomatitis is an outcome of multispecies biofilms that include Candida albicans and Streptococcus mutans. Tissue conditioners are found to be more susceptible to colonisation by micro-organisms. Aim The purpose of this study was to compare the efficacy of neem leaf extract and three other antimicrobial agents incorporated in a tissue conditioner against both Candida albicans and Streptococcus mutans. Materials and Methods Standard strain of Candida albicans and Streptococcus mutans were inoculated into Sabouraud Dextrose broth and Mitis-Salivarius-Bacitracin broth respectively incubated at 37°C. Tissue conditioner (Viscogel) mixed with two different concentrations of ketoconazole, nystatin and chlorhexidine diacetate (5%, 10% w/w) and neem leaf extract (7.5% w/w and 15% w/w) and control group (plain tissue conditioner) were placed into punch hole (6 mm diameter) agar plate inoculated with Candida albicans and Streptococcus mutans. A total of 216 samples were prepared for both Candida albicans and Streptococcus mutans. Mean Inhibition Diameter (MID) across each punch holes were measured in millimetres at 24 hours and seven days and data were statistically analysed using Kruskal Wallis test followed by Mann-Whitney U test. Results Both ketoconazole and nystatin (10% w/w) showed maximum inhibition of 32 mm and mean of 31.75 followed by 15% w/w neem leaf extract with an inhibition of 21 mm and mean of 20.67 after 24 hours against Candida albicans whereas chlorhexidine diacetate (10% w/w) showed mean of 25.67 followed by chlorhexidine diacetate (5% w/w) and neem extract (15% w/w) which showed mean of 24.17 and 23.67 respectively against Streptococcus mutans. Conclusion Neem leaf extract exhibited considerable potential to be an efficacious antimicrobial agent against both Candida albicans and Streptococcus mutans. PMID:28658918

Contribution of aboveground plant respiration to carbon cycling in a Bornean tropical rainforet

NASA Astrophysics Data System (ADS)

Katayama, Ayumi; Tanaka, Kenzo; Ichie, Tomoaki; Kume, Tomonori; Matsumoto, Kazuho; Ohashi, Mizue; Kumagai, Tomo'omi

2014-05-01

Bornean tropical rainforests have a different characteristic from Amazonian tropical rainforests, that is, larger aboveground biomass caused by higher stand density of large trees. Larger biomass may cause different carbon cycling and allocation pattern. However, there are fewer studies on carbon allocation and each component in Bornean tropical rainforests, especially for aboveground plant respiration, compared to Amazonian forests. In this study, we measured woody tissue respiration and leaf respiration, and estimated those in ecosystem scale in a Bornean tropical rainforest. Then, we examined carbon allocation using the data of soil respiration and aboveground net primary production obtained from our previous studies. Woody tissue respiration rate was positively correlated with diameter at breast height (dbh) and stem growth rate. Using the relationships and biomass data, we estimated woody tissue respiration in ecosystem scale though methods of scaling resulted in different estimates values (4.52 - 9.33 MgC ha-1 yr-1). Woody tissue respiration based on surface area (8.88 MgC ha-1 yr-1) was larger than those in Amazon because of large aboveground biomass (563.0 Mg ha-1). Leaf respiration rate was positively correlated with height. Using the relationship and leaf area density data at each 5-m height, leaf respiration in ecosystem scale was estimated (9.46 MgC ha-1 yr-1), which was similar to those in Amazon because of comparable LAI (5.8 m2 m-2). Gross primary production estimated from biometric measurements (44.81 MgC ha-1 yr-1) was much higher than those in Amazon, and more carbon was allocated to woody tissue respiration and total belowground carbon flux. Large tree with dbh > 60cm accounted for about half of aboveground biomass and aboveground biomass increment. Soil respiration was also related to position of large trees, resulting in high soil respiration rate in this study site. Photosynthesis ability of top canopy for large trees was high and leaves for the large trees accounted for 30% of total, which can lead high GPP. These results suggest that large trees play considerable role in carbon cycling and make a distinctive carbon allocation in the Bornean tropical rainforest.

Physiological studies in young Eucalyptus stands in southern India and their use in estimating forest transpiration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, J.M.; Rosier, P.T.W.; Murthy, K.V.

1992-12-31

Stomatal conductance, leaf water potential and leaf area index were measured in adjacent plantations of Eucalyptus camaldulensis and Eucalyptus tereticornis at Puradal, near Shimoga, Karnataka, southern India. The data were collected in a range of climatic conditions during a two year period immediately following plantation establishment. Physiological differences between the two species were small and confined largely to leaf area index. Stomatal conductance was highest in the post-monsoon period and declined to minimum values immediately prior to the onset of the monsoon, with the lowest conductances observed after the plantations had been established for more than one year. Stomatal conductance,more » leaf area index and above-canopy meteorological data were combined in a multi-layer transpiration model and used to calculate hourly values of transpiration from the two species. Rates of transpiration up to 6 mm d{sup {minus}1} were estimated for the post-monsoon period but fell to below 1 mm d{sup {minus}1} prior to the monsoon.« less

A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors

PubMed Central

Redkar, Amey; Hoser, Rafal; Schilling, Lena; Zechmann, Bernd; Krzymowska, Magdalena; Walbot, Virginia; Doehlemann, Gunther

2015-01-01

The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize. PMID:25888589

Carbon nanofibers arrays: A novel tool for microdelivery of biomolecules to plants

DOE PAGES

Davern, Sandra M.; McKnight, Timothy E.; Kalluri, Udaya C.; ...

2016-04-27

Effective methods for delivering bioprobes into the cells of intact plants are essential for investigating diverse biological processes. Increasing research on trees, such as Populus spp., for bioenergy applications is driving the need for techniques that work well with tree species. This report introduces vertically aligned carbon nanofiber (VACNF) arrays as a new tool for microdelivery of labeled molecules to Populus leaf tissue and whole plants. We demonstrated that VACNFs penetrate the leaf surface to deliver sub-microliter quantities of solution containing fluorescent or radiolabeled molecules into Populus leaf cells. Importantly, VACNFs proved to be gentler than abrasion with carborundum, amore » common way to introduce material into leaves. Unlike carborundum, VACNFs did not disrupt cell or tissue integrity, nor did they induce production of hydrogen peroxide, a typical wound response. We show that femtomole to picomole quantities of labeled molecules (fluorescent dyes, small proteins and dextran), ranging from 0.5–500 kDa, can be introduced by VACNFs, and we demonstrate the use of the approach to track delivered probes from their site of introduction on the leaf to distal plant regions. VACNF arrays thus offer an attractive microdelivery method for the introduction of biomolecules and other probes into trees and potentially other types of plants.« less

Carbon nanofibers arrays: A novel tool for microdelivery of biomolecules to plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davern, Sandra M.; McKnight, Timothy E.; Kalluri, Udaya C.

Effective methods for delivering bioprobes into the cells of intact plants are essential for investigating diverse biological processes. Increasing research on trees, such as Populus spp., for bioenergy applications is driving the need for techniques that work well with tree species. This report introduces vertically aligned carbon nanofiber (VACNF) arrays as a new tool for microdelivery of labeled molecules to Populus leaf tissue and whole plants. We demonstrated that VACNFs penetrate the leaf surface to deliver sub-microliter quantities of solution containing fluorescent or radiolabeled molecules into Populus leaf cells. Importantly, VACNFs proved to be gentler than abrasion with carborundum, amore » common way to introduce material into leaves. Unlike carborundum, VACNFs did not disrupt cell or tissue integrity, nor did they induce production of hydrogen peroxide, a typical wound response. We show that femtomole to picomole quantities of labeled molecules (fluorescent dyes, small proteins and dextran), ranging from 0.5–500 kDa, can be introduced by VACNFs, and we demonstrate the use of the approach to track delivered probes from their site of introduction on the leaf to distal plant regions. VACNF arrays thus offer an attractive microdelivery method for the introduction of biomolecules and other probes into trees and potentially other types of plants.« less

Spectral changes in conifers subjected to air pollution and water stress: Experimental studies

NASA Technical Reports Server (NTRS)

Westman, Walter E.; Price, Curtis V.

1988-01-01

The roles of leaf anatomy, moisture and pigment content, and number of leaf layers on spectral reflectance in healthy, pollution-stressed, and water-stressed conifer needles were examined experimentally. Jeffrey pine (Pinus jeffreyi) and giant sequoia (Sequoiadendron gigantea) were exposed to ozone and acid mist treatments in fumigation chambers; red pine (Pinus resinosa) needles were artificially dried. Infrared reflectance from stacked needles rose with free water loss. In an air-drying experiment, cell volume reductions induced by loss of turgor caused near-infrared reflectance (TM band 4) to drop after most free water was lost. Under acid mist fumigation, stunting of tissue development similarly reduced band 4 reflectance. Both artificial drying and pollutant fumigation caused a blue shift of the red edge of spectral reflectance curves in conifers, attributable to chlorophyll denaturation. Thematic mapper band ratio 4/3 fell and 5/4 rose with increasing pollution stress on artificial drying. Loss of water by air-drying, freeze-drying, or oven-drying enhanced spectral features, due in part to greater scattering and reduced water absorption. Grinding of the leaf tissue further enhanced the spectral features by increasing reflecting surfaces and path length. In a leaf-stacking experiment, an asymptote in visible and infrared reflectance was reached at 7-8 needle layers of red pine.

Carbon Nanofiber Arrays: A Novel Tool for Microdelivery of Biomolecules to Plants

PubMed Central

Davern, Sandra M.; McKnight, Timothy E.; Morrell-Falvey, Jennifer L.; Shpak, Elena D.; Kalluri, Udaya C.; Jelenska, Joanna; Greenberg, Jean T.; Mirzadeh, Saed

2016-01-01

Effective methods for delivering bioprobes into the cells of intact plants are essential for investigating diverse biological processes. Increasing research on trees, such as Populus spp., for bioenergy applications is driving the need for techniques that work well with tree species. This report introduces vertically aligned carbon nanofiber (VACNF) arrays as a new tool for microdelivery of labeled molecules to Populus leaf tissue and whole plants. We demonstrated that VACNFs penetrate the leaf surface to deliver sub-microliter quantities of solution containing fluorescent or radiolabeled molecules into Populus leaf cells. Importantly, VACNFs proved to be gentler than abrasion with carborundum, a common way to introduce material into leaves. Unlike carborundum, VACNFs did not disrupt cell or tissue integrity, nor did they induce production of hydrogen peroxide, a typical wound response. We show that femtomole to picomole quantities of labeled molecules (fluorescent dyes, small proteins and dextran), ranging from 0.5–500 kDa, can be introduced by VACNFs, and we demonstrate the use of the approach to track delivered probes from their site of introduction on the leaf to distal plant regions. VACNF arrays thus offer an attractive microdelivery method for the introduction of biomolecules and other probes into trees and potentially other types of plants. PMID:27119338

Quantitative photoacoustic elastography of Young's modulus in humans

NASA Astrophysics Data System (ADS)

Hai, Pengfei; Zhou, Yong; Gong, Lei; Wang, Lihong V.

2017-03-01

Elastography can noninvasively map the elasticity distribution of biological tissue, which is often altered in pathological states. In this work, we report quantitative photoacoustic elastography (QPAE), capable of measuring Young's modulus of human tissue in vivo. By combining photoacoustic elastography with a stress sensor having known stress-strain behavior, QPAE can simultaneously measure strain and stress, from which Young's modulus is calculated. We first applied QPAE to quantify the Young's modulus of tissue-mimicking agar phantoms with different concentrations. The measured values fitted well with both the empirical expectations based on the agar concentrations and those measured in independent standard compression tests. We then demonstrated the feasibility of QPAE by measuring the Young's modulus of human skeletal muscle in vivo. The data showed a linear relationship between muscle stiffness and loading. The results proved that QPAE can noninvasively quantify the absolute elasticity of biological tissue, thus enabling longitudinal imaging of tissue elasticity. QPAE can be exploited for both preclinical biomechanics studies and clinical applications.

Cell wall accumulation of fluorescent proteins derived from a trans-Golgi cisternal membrane marker and paramural bodies in interdigitated Arabidopsis leaf epidermal cells.

PubMed

Akita, Kae; Kobayashi, Megumi; Sato, Mayuko; Kutsuna, Natsumaro; Ueda, Takashi; Toyooka, Kiminori; Nagata, Noriko; Hasezawa, Seiichiro; Higaki, Takumi

2017-01-01

In most dicotyledonous plants, leaf epidermal pavement cells develop jigsaw puzzle-like shapes during cell expansion. The rapid growth and complicated cell shape of pavement cells is suggested to be achieved by targeted exocytosis that is coordinated with cytoskeletal rearrangement to provide plasma membrane and/or cell wall materials for lobe development during their morphogenesis. Therefore, visualization of membrane trafficking in leaf pavement cells should contribute an understanding of the mechanism of plant cell morphogenesis. To reveal membrane trafficking in pavement cells, we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes, in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of pavement cell borders and guard cell ends during leaf expansion. Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated pavement cells and guard cell ends in young leaf epidermis. In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes. These results suggested possible heterogeneity of the curved regions of plasma membranes, implying a relationship with pavement cell morphogenesis.

Induction of wound-periderm-like tissue in Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) leaves as a defence response to high UV-B radiation levels.

PubMed

Nascimento, Luana Beatriz dos Santos; Moreira, Nattacha dos Santos; Leal-Costa, Marcos Vinícius; Costa, Sônia Soares; Tavares, Eliana Schwartz

2015-10-01

UV-B radiation can be stressful for plants and cause morphological and biochemical changes. Kalanchoe pinnata is a CAM leaf-succulent species distributed in hot and dry regions, and is rich in flavonoids, which are considered to be protective against UV-B radiation. This study aims to verify if K. pinnata has morphological or anatomical responses as a strategy in response to high UV-B levels. Kalanchoe pinnata plants of the same age were grown under white light (control) or white light plus supplemental UV-B radiation (5 h d(-1)). The plants were treated with the same photoperiod, photosynthetically active radiation, temperature and daily watering system. Fragments of the middle third of the leaf blade and petiole were dehydrated and then embedded in historesin and sectioned in a rotary microtome. Sections were stained with toluidine blue O and mounted in Entellan®. Microchemical analyses by optical microscopy were performed on fresh material with Sudan III, Sudan IV and phloroglucinol, and analysed using fluorescence microscopy. Supplemental UV-B radiation caused leaf curling and the formation of brown areas on the leaves. These brown areas developed into a protective tissue on the adaxial side of the leaf, but only in directly exposed regions. Anatomically, this protective tissue was similar to a wound-periderm, with outer layer cell walls impregnated with suberin and lignin. This is the first report of wound-periderm formation in leaves in response to UV-B radiation. This protective tissue could be important for the survival of the species in desert regions under high UV-B stress conditions. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ginkgo biloba L. leaf extract offers multiple mechanisms in bridling N-methylnitrosourea - mediated experimental colorectal cancer.

PubMed

Ahmed, Hanaa H; El-Abhar, Hanan S; Hassanin, Elsayed Abdul Khalik; Abdelkader, Noha F; Shalaby, Mohamed B

2017-11-01

In Egypt, colorectal cancer (CRC) is the 6th cancer in both gender and CRC rates are high in subjects under 40 years of age. This study goaled to determine the development of CRC using relevant biochemical markers and to elucidate the potent mechanism of Ginkgo biloba L. leaf extract in retrogression of experimental CRC. Adult male Sprague-Dawley rats were administered N-methylnitrosourea (N-MNU; 2mg in 0.5ml water/rat) intrarectally thrice a week for five weeks to induce CRC, followed by treatment with either 5-fluorouracil (5-FU; 12.5mg/kg, i.p.) or Ginkgo biloba L. leaf extract in a dose of 0.675 and 1.35g/kg, p.o. respectively. The developed tumor enhanced plasma TGF-β, and Bcl 2 , serum EGF, CEA, CCSA, and MMP-7 significantly. Also, gene expression analysis showed significant upregulation of colonic β-Catenin, K-ras and C-myc genes. Besides, immunohistochemical findings revealed significant increase in COX-2, cyclin D1 and survivin content in colon tissue. These data were further supported by the histological observations. Ginkgo biloba L. leaf extract-treated rats; particularly those treated with dose of 1.35g/kg, exhibited significant reduction in the aforementioned parameters and improvement in the histological organization of the colon tissue. The therapeutic effect of Ginkgo biloba L. leaf extract was comparable with that mediated by 5-FU. The current research proved that Ginkgo biloba L. leaf extract could suppress tumor cell proliferation, promote apoptosis, and mitigat inflammation in vivo. The amelioration of these key events might be linked with the inhibition of Wnt/β-Catenin signaling module. The outcomes of the present investigation encourage the use of Ginkgo biloba L. leaf extract as a complementary and alternative therapeutic approach to abate CRC. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley.

PubMed

Hasanuzzaman, Md; Davies, Noel W; Shabala, Lana; Zhou, Meixue; Brodribb, Tim J; Shabala, Sergey

2017-06-19

While most water loss from leaf surfaces occurs via stomata, part of this loss also occurs through the leaf cuticle, even when the stomata are fully closed. This component, termed residual transpiration, dominates during the night and also becomes critical under stress conditions such as drought or salinity. Reducing residual transpiration might therefore be a potentially useful mechanism for improving plant performance when water availability is reduced (e.g. under saline or drought stress conditions). One way of reducing residual transpiration may be via increased accumulation of waxes on the surface of leaf. Residual transpiration and wax constituents may vary with leaf age and position as well as between genotypes. This study used barley genotypes contrasting in salinity stress tolerance to evaluate the contribution of residual transpiration to the overall salt tolerance, and also investigated what role cuticular waxes play in this process. Leaves of three different positions (old, intermediate and young) were used. Our results show that residual transpiration was higher in old leaves than the young flag leaves, correlated negatively with the osmolality, and was positively associated with the osmotic and leaf water potentials. Salt tolerant varieties transpired more water than the sensitive variety under normal growth conditions. Cuticular waxes on barley leaves were dominated by primary alcohols (84.7-86.9%) and also included aldehydes (8.90-10.1%), n-alkanes (1.31-1.77%), benzoate esters (0.44-0.52%), phytol related compounds (0.22-0.53%), fatty acid methyl esters (0.14-0.33%), β-diketones (0.07-0.23%) and alkylresorcinols (1.65-3.58%). A significant negative correlation was found between residual transpiration and total wax content, and residual transpiration correlated significantly with the amount of primary alcohols. Both leaf osmolality and the amount of total cuticular wax are involved in controlling cuticular water loss from barley leaves under well irrigated conditions. A significant and negative relationship between the amount of primary alcohols and a residual transpiration implies that some cuticular wax constituents act as a water barrier on plant leaf surface and thus contribute to salinity stress tolerance. It is suggested that residual transpiration could be a fundamental mechanism by which plants optimize water use efficiency under stress conditions.

A model using marginal efficiency of investment to analyse carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)

NASA Astrophysics Data System (ADS)

Thomas, R. Q.; Williams, M.

2014-04-01

Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System modelling community. However there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C-N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) using emergent constraints provided by marginal returns on investment for C and/or N allocation. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous < tropical evergreen < temperature evergreen), a result that compared well to observations from a global database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. Also, a widely used linear leaf N-respiration relationship did not yield a realistic leaf C : N, while a more recently reported non-linear relationship performed better. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP. Multiple parameters associated with photosynthesis, respiration, and N uptake influenced the rate of N fixation. Overall, our ability to constrain leaf area index and have spatially and temporally variable leaf C : N helps address challenges for ecosystem and Earth System models. Furthermore, the simple approach with emergent properties based on coupled C-N dynamics has potential for use in research that uses data-assimilation methods to integrate data on both the C and N cycles to improve C flux forecasts.

Expression of genomic AtCYCD2;1 in Arabidopsis induces cell division at smaller cell sizes: implications for the control of plant growth.

PubMed

Qi, Ruhu; John, Peter Crook Lloyd

2007-07-01

The Arabidopsis (Arabidopsis thaliana) CYCD2;1 gene introduced in genomic form increased cell formation in the Arabidopsis root apex and leaf, while generating full-length mRNA, raised CDK/CYCLIN enzyme activity, reduced G1-phase duration, and reduced size of cells at S phase and division. Other cell cycle genes, CDKA;1, CYCLIN B;1, and the cDNA form of CYCD2;1 that produced an aberrantly spliced mRNA, produced smaller or zero increases in CDK/CYCLIN activity and did not increase the number of cells formed. Plants with a homozygous single insert of genomic CYCD2;1 grew with normal morphology and without accelerated growth of root or shoot, not providing evidence that cell formation or CYCLIN D2 controls growth of postembryonic vegetative tissues. At the root apex, cells progressed normally from meristem to elongation, but their smaller size enclosed less growth and a 40% reduction in final size of epidermal and cortical cells was seen. Smaller elongated cell size inhibited endoreduplication, indicating a cell size requirement. Leaf cells were also smaller and more numerous during proliferation and epidermal pavement and palisade cells attained 59% and 69% of controls, whereas laminas reached normal size. Autonomous control of expansion was therefore not evident in abundant cell types that formed tissues of root or leaf. Cell size was reduced by a greater number formed in a tissue prior to cell and tissue expansion. Initiation and termination of expansion did not correlate with cell dimension or number and may be determined by tissue-wide signals acting across cellular boundaries.

Determination of diagnostic standards on saturated soil extracts for cut roses grown in greenhouses.

PubMed

Franco-Hermida, John Jairo; Quintero, María Fernanda; Cabrera, Raúl Iskander; Guzman, José Miguel

2017-01-01

This work comprises the theoretical determination and validation of diagnostic standards for the analysis of saturated soil extracts for cut rose flower crops (Rosa spp.) growing in the Bogota Plateau, Colombia. The data included 684 plant tissue analyses and 684 corresponding analyses of saturated soil extracts, all collected between January 2009 and June 2013. The tissue and soil samples were selected from 13 rose farms, and from cultivars grafted on the 'Natal Briar' rootstock. These concurrent samples of soil and plant tissues represented 251 production units (locations) of approximately 10,000 m2 distributed across the study area. The standards were conceived as a tool to improve the nutritional balance in the leaf tissue of rose plants and thereby define the norms for expressing optimum productive potential relative to nutritional conditions in the soil. To this end, previously determined diagnostic standard for rose leaf tissues were employed to obtain rates of foliar nutritional balance at each analyzed location and as criteria for determining the diagnostic norms for saturated soil extracts. Implementing this methodology to foliar analysis, showed a higher significant correlation for diagnostic indices. A similar behavior was observed in saturated soil extracts analysis, becoming a powerful tool for integrated nutritional diagnosis. Leaf analyses determine the most limiting nutrients for high yield and analyses of saturated soil extracts facilitate the possibility of correcting the fertigation formulations applied to soils or substrates. Recommendations are proposed to improve the balance in soil-plant system with which the possibility of yield increase becomes more probable. The main recommendations to increase and improve rose crop flower yields would be: continuously check pH values of SSE, reduce the amounts of P, Fe, Zn and Cu in fertigation solutions and carefully analyze the situation of Mn in the soil-plant system.

[Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.

PubMed

Zhu, Duo Ju; Wen, Zhong Ming; Zhang, Jing; Tao, Yu; Zeng, Hong Wen; Tang, Yang

2018-02-01

To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FR ic , FE ve , FD iv , FD is , Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.

Protoplast isolation, transient transformation of leaf mesophyll protoplasts and improved Agrobacterium-mediated leaf disc infiltration of Phaseolus vulgaris: tools for rapid gene expression analysis.

PubMed

Nanjareddy, Kalpana; Arthikala, Manoj-Kumar; Blanco, Lourdes; Arellano, Elizabeth S; Lara, Miguel

2016-06-24

Phaseolus vulgaris is one of the most extensively studied model legumes in the world. The P. vulgaris genome sequence is available; therefore, the need for an efficient and rapid transformation system is more imperative than ever. The functional characterization of P. vulgaris genes is impeded chiefly due to the non-amenable nature of Phaseolus sp. to stable genetic transformation. Transient transformation systems are convenient and versatile alternatives for rapid gene functional characterization studies. Hence, the present work focuses on standardizing methodologies for protoplast isolation from multiple tissues and transient transformation protocols for rapid gene expression analysis in the recalcitrant grain legume P. vulgaris. Herein, we provide methodologies for the high-throughput isolation of leaf mesophyll-, flower petal-, hypocotyl-, root- and nodule-derived protoplasts from P. vulgaris. The highly efficient polyethylene glycol-mannitol magnesium (PEG-MMG)-mediated transformation of leaf mesophyll protoplasts was optimized using a GUS reporter gene. We used the P. vulgaris SNF1-related protein kinase 1 (PvSnRK1) gene as proof of concept to demonstrate rapid gene functional analysis. An RT-qPCR analysis of protoplasts that had been transformed with PvSnRK1-RNAi and PvSnRK1-OE vectors showed the significant downregulation and ectopic constitutive expression (overexpression), respectively, of the PvSnRK1 transcript. We also demonstrated an improved transient transformation approach, sonication-assisted Agrobacterium-mediated transformation (SAAT), for the leaf disc infiltration of P. vulgaris. Interestingly, this method resulted in a 90 % transformation efficiency and transformed 60-85 % of the cells in a given area of the leaf surface. The constitutive expression of YFP further confirmed the amenability of the system to gene functional characterization studies. We present simple and efficient methodologies for protoplast isolation from multiple P. vulgaris tissues. We also provide a high-efficiency and amenable method for leaf mesophyll transformation for rapid gene functional characterization studies. Furthermore, a modified SAAT leaf disc infiltration approach aids in validating genes and their functions. Together, these methods help to rapidly unravel novel gene functions and are promising tools for P. vulgaris research.

The oxygen isotope enrichment of leaf-exported assimilates--does it always reflect lamina leaf water enrichment?

PubMed

Gessler, Arthur; Brandes, Elke; Keitel, Claudia; Boda, Sonja; Kayler, Zachary E; Granier, André; Barbour, Margaret; Farquhar, Graham D; Treydte, Kerstin

2013-10-01

The oxygen stable isotope composition of plant organic matter (OM) (particularly of wood and cellulose in the tree ring archive) is valuable in studies of plant-climate interaction, but there is a lack of information on the transfer of the isotope signal from the leaf to heterotrophic tissues. We studied the oxygen isotopic composition and its enrichment above source water of leaf water over diel courses in five tree species covering a broad range of life forms. We tracked the transfer of the isotopic signal to leaf water-soluble OM and further to phloem-transported OM. Observed leaf water evaporative enrichment was consistent with values predicted from mechanistic models taking into account nonsteady-state conditions. While leaf water-soluble OM showed the expected (18)O enrichment in all species, phloem sugars were less enriched than expected from leaf water enrichment in Scots pine (Pinus sylvestris), European larch (Larix decidua) and Alpine ash (Eucalyptus delegatensis). Oxygen atom exchange with nonenriched water during phloem loading and transport, as well as a significant contribution of assimilates from bark photosynthesis, can explain these phloem (18)O enrichment patterns. Our results indicate species-specific uncoupling between the leaf water and the OM oxygen isotope signal, which is important for the interpretation of tree ring data. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

How to pattern a leaf.

PubMed

Bolduc, N; O'Connor, D; Moon, J; Lewis, M; Hake, S

2012-01-01

Leaf development presents a tremendous resource for tackling the question of patterning in biology. Leaves can be simple or highly dissected. They may have elaborated parts such as the tendrils of a pea leaf or the rolled blade of a carnivorous pitcher plant. Despite the variation in size, shape, and function, all leaves initiate in the same manner: from the flanks of a meristem. The maize leaf is useful for analysis of patterning due to the wealth of mutants and the distinct tissues along the proximal distal axis. The blade is distal, the sheath is proximal, and the ligule forms at the blade/sheath boundary. Establishment of this boundary involves the transcription factors LIGULELESS1 and LIGULELESS2 and the kinase LIGULELESS NARROW. The meristem-specific protein KNOTTED1 (KN1) binds and modulates the lg2 gene. Given the localization of KN1 at the proximal end of the leaf from the time of inception, we hypothesize that KN1 has a role in establishing the very proximal end of the leaf, whereas an auxin maximum guides the growing distal tip.

Leaf water potentials measured with a pressure chamber.

PubMed

Boyer, J S

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within +/- 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements.The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer.

Leaf Water Potentials Measured with a Pressure Chamber

PubMed Central

Boyer, J. S.

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within ± 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements. The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer. PMID:16656476

Elemental micro-PIXE mapping of hypersensitive lesions in Lagenaria sphaerica (Cucurbitaceae) resistant to Sphaerotheca fuliginea (powdery mildew)

NASA Astrophysics Data System (ADS)

Weiersbye-Witkowski, I. M.; Przybylowicz, W. J.; Straker, C. J.; Mesjasz-Przybylowicz, J.

1997-07-01

Genotypes of the Southern African cucurbit, Lagenaria sphaerica, that are resistant to powdery-mildew ( Sphaerotheca fuliginea) exhibit foliar hypersensitive (HS) lesions on inoculation with this fungal pathogen. Elemental distributions across radially symmetrical HS lesions, surrounding unlesioned leaf tissue and uninoculated leaf tissue, were obtained using the true elemental imaging system (Dynamic Analysis) of the NAC Van de Graaff nuclear microprobe. Raster scans of 3 MeV protons were complemented by simultaneous PIXE and BS point analyses. The composition of cellulose (C 6H 10O 5) was used as constant matrix composition for scans, and the sample thickness was found from BS spectra. Si and elements heavier than Ca contributed to matrix composition within HS lesions and the locally elevated Ca raised the limits of detection for some trace metals of interest. In comparison to uninoculated tissue, inoculated tissue was characterised by higher overall concentrations of all measured elements except Cu. Fully developed, 6 day-old HS lesions and the surrounding tissue could be divided into five zones, centred on the fungal infection site. Each zone was characterized by distinct local elemental distributions (either depletion, or accumulation to potentially phytotoxic levels).

Factors modulating cottongrass seedling growth stimulation to enhanced nitrogen and carbon dioxide: compensatory tradeoffs in leaf dynamics and allocation to meet potassium-limited growth.

PubMed

Siegenthaler, Andy; Buttler, Alexandre; Grosvernier, Philippe; Gobat, Jean-Michel; Nilsson, Mats B; Mitchell, Edward A D

2013-02-01

Eriophorum vaginatum is a characteristic species of northern peatlands and a keystone plant for cutover bog restoration. Understanding the factors affecting E. vaginatum seedling establishment (i.e. growth dynamics and allocation) under global change has practical implications for the management of abandoned mined bogs and restoration of their C-sequestration function. We studied the responses of leaf dynamics, above- and belowground biomass production of establishing seedlings to elevated CO(2) and N. We hypothesised that nutrient factors such as limitation shifts or dilutions would modulate growth stimulation. Elevated CO(2) did not affect biomass, but increased the number of young leaves in spring (+400 %), and the plant vitality (i.e. number of green leaves/total number of leaves) (+3 %), both of which were negatively correlated to [K(+)] in surface porewater, suggesting a K-limited production of young leaves. Nutrient ratios in green leaves indicated either N and K co-limitation or K limitation. N addition enhanced the number of tillers (+38 %), green leaves (+18 %), aboveground and belowground biomass (+99, +61 %), leaf mass-to-length ratio (+28 %), and reduced the leaf turnover (-32 %). N addition enhanced N availability and decreased [K(+)] in spring surface porewater. Increased tiller and leaf production in July were associated with a doubling in [K(+)] in surface porewater suggesting that under enhanced N production is K driven. Both experiments illustrate the importance of tradeoffs in E. vaginatum growth between: (1) producing tillers and generating new leaves, (2) maintaining adult leaves and initiating new ones, and (3) investing in basal parts (corms) for storage or in root growth for greater K uptake. The K concentration in surface porewater is thus the single most important factor controlling the growth of E. vaginatum seedlings in the regeneration of selected cutover bogs.

Cytological and ultrastructural preservation in Eocene Metasequoia leaves from the Canadian High Arctic.

PubMed

Schoenhut, Karimah; Vann, David R; Lepage, Ben A

2004-06-01

The ultrastructural examination by transmission electron microscopy of 45-million-year-old mummified leaves of Metasequoia extracted from the Upper Coal member of the Buchanan Lake Formation in Napartulik on Axel Heiberg Island revealed the preservation of intact chloroplasts and chloroplast components. Abundant tanniferous cell inclusions may indicate that the 3-mo period of constant daylight during the Artic summer induced high concentrations of tannins in the leaf tissues, which may have arrested microbial degradation of the litter. Quantified differences in the extent of chloroplast preservation through a vertical section of the lignite suggest that short-term shifts in the depositional environment took place, perhaps influencing the exposure of the leaf tissues to conditions that would either promote or inhibit decomposition.

Protein expression in Arabidopsis thaliana after chronic clinorotation

NASA Technical Reports Server (NTRS)

Piastuch, William C.; Brown, Christopher S.

1994-01-01

Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional sodium doedocyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

Epidermal Micromorphology and Mesophyll Structure of Populus euphratica Heteromorphic Leaves at Different Development Stages

PubMed Central

Liu, Yubing; Li, Xinrong; Chen, Guoxiong; Li, Mengmeng; Liu, Meiling; Liu, Dan

2015-01-01

Leaf epidermal micromorphology and mesophyll structure during the development of Populus euphratica heteromorphic leaves, including linear, lanceolate, ovate, dentate ovate, dentate rhombic, dentate broad-ovate and dentate fan-shaped leaves, were studied by using electron and light microscopy. During development of heteromorphic leaves, epidermal appendages (wax crystals and trichomes) and special cells (mucilage cells and crystal idioblasts) increased in all leaf types while chloroplast ultrastructure and stomatal characters show maximum photosynthetic activity in dentate ovate and rhombic leaves. Also, functional analysis by subordinate function values shows that the maximum adaptability to adverse stress was exhibited in the broad type of mature leaves. The 12 heteromorphic leaf types are classified into three major groups by hierarchical cluster analysis: young, developing and mature leaves. Mature leaves can effectively obtain the highest stress resistance by combining the protection of xerophytic anatomy from drought stress, regulation of water uptake in micro-environment by mucilage and crystal idioblasts, and assistant defense of transpiration reduction through leaf epidermal appendages, which improves photosynthetic activity under arid desert conditions. Our data confirms that the main leaf function is differentiated during the developing process of heteromorphic leaves. PMID:26356300

Epidermal Micromorphology and Mesophyll Structure of Populus euphratica Heteromorphic Leaves at Different Development Stages.

PubMed

Liu, Yubing; Li, Xinrong; Chen, Guoxiong; Li, Mengmeng; Liu, Meiling; Liu, Dan

2015-01-01

Leaf epidermal micromorphology and mesophyll structure during the development of Populus euphratica heteromorphic leaves, including linear, lanceolate, ovate, dentate ovate, dentate rhombic, dentate broad-ovate and dentate fan-shaped leaves, were studied by using electron and light microscopy. During development of heteromorphic leaves, epidermal appendages (wax crystals and trichomes) and special cells (mucilage cells and crystal idioblasts) increased in all leaf types while chloroplast ultrastructure and stomatal characters show maximum photosynthetic activity in dentate ovate and rhombic leaves. Also, functional analysis by subordinate function values shows that the maximum adaptability to adverse stress was exhibited in the broad type of mature leaves. The 12 heteromorphic leaf types are classified into three major groups by hierarchical cluster analysis: young, developing and mature leaves. Mature leaves can effectively obtain the highest stress resistance by combining the protection of xerophytic anatomy from drought stress, regulation of water uptake in micro-environment by mucilage and crystal idioblasts, and assistant defense of transpiration reduction through leaf epidermal appendages, which improves photosynthetic activity under arid desert conditions. Our data confirms that the main leaf function is differentiated during the developing process of heteromorphic leaves.

Water retained in tall Cryptomeria japonica leaves as studied by infrared micro-spectroscopy.

PubMed

Azuma, Wakana; Nakashima, Satoru; Yamakita, Eri; Ishii, H Roaki; Kuroda, Keiko

2017-10-01

Recent studies in the tallest tree species suggest that physiological and anatomical traits of tree-top leaves are adapted to water-limited conditions. In order to examine water retention mechanism of leaves in a tall tree, infrared (IR) micro-spectroscopy was conducted on mature leaf cross-sections of tall Cryptomeria japonica D. Don from four different heights (51, 43, 31 and 19 m). We measured IR transmission spectra and mainly analyzed OH (3700-3000 cm-1) and C-O (1190-845 cm-1) absorption bands, indicating water molecules and sugar groups, respectively. The changes in IR spectra of leaf sections from different heights were compared with bulk-leaf hydraulics. Both average OH band area of the leaf sections and leaf water content were larger in the upper-crown, while osmotic potential at saturation did not vary with height, suggesting higher dissolved sugar contents of upper-crown leaves. As cell-wall is the main cellular structure of leaves, we inferred that larger average C-O band area of upper-crown leaves reflected higher content of structural polysaccharides such as cellulose, hemicellulose and pectin. Infrared micro-spectroscopic imaging showed that the OH and C-O band areas are large in the vascular bundle, transfusion tissue and epidermis. Infrared spectra of individual tissue showed that much more water is retained in vascular bundle and transfusion tissue than mesophyll. These results demonstrate that IR micro-spectroscopy is a powerful tool for visualizing detailed, quantitative information on the spatial distribution of chemical substances within plant tissues, which cannot be done using conventional methods like histochemical staining. The OH band could be well reproduced by four Gaussian OH components around 3530 (free water: long H bond), 3410 (pectin-like OH species), 3310 (cellulose-like OH species) and 3210 (bound water: short H bond) cm-1, and all of these OH components were higher in the upper crown while their relative proportions did not vary with height. Based on the spectral analyses, we inferred that polysaccharides play a key role in biomolecular retention of water in leaves of tall C. japonica. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

NADPH Thioredoxin Reductase C Is Localized in Plastids of Photosynthetic and Nonphotosynthetic Tissues and Is Involved in Lateral Root Formation in Arabidopsis[W

PubMed Central

Kirchsteiger, Kerstin; Ferrández, Julia; Pascual, María Belén; González, Maricruz; Cejudo, Francisco Javier

2012-01-01

Plastids are organelles present in photosynthetic and nonphotosynthetic plant tissues. While it is well known that thioredoxin-dependent redox regulation is essential for leaf chloroplast function, little is known of the redox regulation in plastids of nonphotosynthetic tissues, which cannot use light as a direct source of reducing power. Thus, the question remains whether redox regulation operates in nonphotosynthetic plastid function and how it is integrated with chloroplasts for plant growth. Here, we show that NADPH-thioredoxin reductase C (NTRC), previously reported as exclusive to green tissues, is also expressed in nonphotosynthetic tissues of Arabidopsis thaliana, where it is localized to plastids. Moreover, we show that NTRC is involved in maintaining the redox homeostasis of plastids also in nonphotosynthetic organs. To test the relationship between plastids of photosynthetic and nonphotosynthetic tissues, transgenic plants were obtained with redox homeostasis restituted exclusively in leaves or in roots, through the expression of NTRC under the control of organ-specific promoters in the ntrc mutant. Our results show that fully functional root amyloplasts are not sufficient for root, or leaf, growth, but fully functional chloroplasts are necessary and sufficient to support wild-type rates of root growth and lateral root formation. PMID:22505729

NADPH thioredoxin reductase C is localized in plastids of photosynthetic and nonphotosynthetic tissues and is involved in lateral root formation in Arabidopsis.

PubMed

Kirchsteiger, Kerstin; Ferrández, Julia; Pascual, María Belén; González, Maricruz; Cejudo, Francisco Javier

2012-04-01

Plastids are organelles present in photosynthetic and nonphotosynthetic plant tissues. While it is well known that thioredoxin-dependent redox regulation is essential for leaf chloroplast function, little is known of the redox regulation in plastids of nonphotosynthetic tissues, which cannot use light as a direct source of reducing power. Thus, the question remains whether redox regulation operates in nonphotosynthetic plastid function and how it is integrated with chloroplasts for plant growth. Here, we show that NADPH-thioredoxin reductase C (NTRC), previously reported as exclusive to green tissues, is also expressed in nonphotosynthetic tissues of Arabidopsis thaliana, where it is localized to plastids. Moreover, we show that NTRC is involved in maintaining the redox homeostasis of plastids also in nonphotosynthetic organs. To test the relationship between plastids of photosynthetic and nonphotosynthetic tissues, transgenic plants were obtained with redox homeostasis restituted exclusively in leaves or in roots, through the expression of NTRC under the control of organ-specific promoters in the ntrc mutant. Our results show that fully functional root amyloplasts are not sufficient for root, or leaf, growth, but fully functional chloroplasts are necessary and sufficient to support wild-type rates of root growth and lateral root formation.

Ecophysiological responses of a young blue gum (Eucalyptus globulus) plantation to weed control.

PubMed

Eyles, Alieta; Worledge, Dale; Sands, Peter; Ottenschlaeger, Maria L; Paterson, Steve C; Mendham, Daniel; O'Grady, Anthony P

2012-08-01

Early weed control may improve the growth of forest plantations by influencing soil water and nutrient availability. To understand eucalypt growth responses to weed control, we examined the temporal responses of leaf gas-exchange, leaf nitrogen concentration (N) and water status of 7-month-old Eucalyptus globulus L. trees in a paired-plot field trial. In addition, we monitored the growth, leaf N and water status of the competing vegetation in the weed treatment. By the end of the 11-month experiment, complete weed control (WF treatment) of largely woody competitors increased the basal diameter of E. globulus by 14%. As indicated by pre-dawn water potentials of > - 0.05 MPa, interspecies competition for water resources was minimal at this site. In contrast, competition for N appeared to be the major factor limiting growth. Estimations of total plot leaf N (g m(-2) ground) showed that competing vegetation accounted for up to 70% of the total leaf N at the start of the trial. This value fell to 15% by the end of the trial. Despite increased leaf N(area) in WF trees 5 months after imposition of weed control, the photosynthetic capacity (A(1500)) of E. globulus was unaffected by treatment suggesting that the growth gains from weed control were largely unrelated to changes in leaf-level photosynthesis. Increased nutrient availability brought about by weed control enabled trees to increase investment into leaf-area production. Estimates of whole-tree carbon budget based on direct measurements of dark respiration and A(1500) allowed us to clearly demonstrate the importance of leaf area driving greater productivity following early weed control in a nutrient-limited site.

The Maize MID-COMPLEMENTING ACTIVITY homolog CELL NUMBER REGULATOR13/NARROW ODD DWARF, coordinates organ growth and tissue patterning

USDA-ARS?s Scientific Manuscript database

Organogenesis occurs from cell division, expansion and differentiation. How these cellular processes are coordinated remains elusive. The maize leaf provides an excellent system to study cellular differentiation because it has several different tissues and cell types. The narrow odd dwarf (nod) mut...

What happens in the pith stays in the pith: tissue-localized defense responses facilitate chemical niche differentiation between two spatially separated herbivores.

PubMed

Lee, Gisuk; Joo, Youngsung; Kim, Sang-Gyu; Baldwin, Ian T

2017-11-01

Herbivore attack is known to elicit systemic defense responses that spread throughout the host plant and influence the performance of other herbivores. While these plant-mediated indirect competitive interactions are well described, and the co-existence of herbivores from different feeding guilds is common, the mechanisms of co-existence are poorly understood. In both field and glasshouse experiments with a native tobacco, Nicotiana attenuata, we found no evidence of negative interactions when plants were simultaneously attacked by two spatially separated herbivores: a leaf chewer Manduca sexta and a stem borer Trichobaris mucorea. T. mucorea attack elicited jasmonic acid (JA) and jasmonoyl-l-isoleucine bursts in the pith of attacked stems similar to those that occur in leaves when M. sexta attacks N. attenuata leaves. Pith chlorogenic acid (CGA) levels increased 1000-fold to levels 6-fold higher than leaf levels after T. mucorea attack; these increases in pith CGA levels, which did not occur in M. sexta-attacked leaves, required JA signaling. With plants silenced in CGA biosynthesis (irHQT plants), CGA, as well as other caffeic acid conjugates, was demonstrated in both glasshouse and field experiments to function as a direct defense protecting piths against T. mucorea attack, but not against leaf chewers or sucking insects. T. mucorea attack does not systemically activate JA signaling in leaves, while M. sexta leaf-attack transiently induces detectable but minor pith JA levels that are dwarfed by local responses. We conclude that tissue-localized defense responses allow tissue-specialized herbivores to share the same host and occupy different chemical defense niches in the same hostplant. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Evaluation of in vitro enzymatic and non-enzymatic antioxidant properites of leaf extract from Alpinia Purpurata (Vieill.) K. Schum.

PubMed

Raj, Chinthamony Arul; Ragavendran, Paramasivam; Sophia, Dominic; Starlin, Thangarajan; Rathi, Muthian Ahalliya; Gopalakrishnan, Velliyur Kanniappan

2016-09-01

To evaluate the enzymatic and non-enzymatic antioxidants of leaf extract from Alpinia purpurata. One gram of fresh leaf of Alpinia purpurata was grinded in 2 mL of 50% ethanol and centrifuged at 10,000×g at 4°C for 10 min. The supernatant obtained was used within 4 h for various enzymatic antioxidants assays like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), ascorbate oxidase, peroxidase, polyphenol oxidase (PPO) and non-enzymatic antioxidants such as vitamin C, total reduced glutathione (TRG) and lipid peroxidation (LPO). The leaf extract of Alpinia purpurata possess antioxidants like vitamin C 472.92±6.80 μg/mg protein, GST 372.11±5.70 μmol of 1-chloro 2,4 dinitrobenzene (CDNB)-reduced glutathione (GSH) conjugate formed/min/mg protein, GPx 281.69±6.43 μg of glutathione oxidized/min/mg protein, peroxidases 173.12±9.40 μmol/g tissue, TRG 75.27±3.55 μg/mg protein, SOD 58.03±2.11 U/mg protein, CAT 46.70±2.35 μmol of H2O2 consumed/min/mg protein in high amount whereas ascorbate oxidase 17.41±2.46 U/g tissue, LPO 2.71±0.14 nmol/L of malondialdehyde formed/min/mg protein and PPO 1.14±0.11 μmol/g tissue in moderate amount. Alpinia purpurata has the potential to scavenge the free radicals and protect against oxidative stress causing diseases. In future, Alpinia purpurata may serve as a good pharmacotherapeutic agent.

UPLC-QTOF-MS metabolomics analysis revealed the contributions of metabolites to the pathogenesis of Rhizoctonia solani strain AG-1-IA

PubMed Central

Hu, Wenjin; Pan, Xinli; Li, Fengfeng

2018-01-01

To explore the pathogenesis of Rhizoctonia solani and its phytotoxin phenylacetic acid (PAA) on maize leaves and sheaths, treated leaf and sheath tissues were analyzed and interpreted by ultra-performance liquid chromatography-mass spectrometry combined with chemometrics. The PAA treatment had similar effects to those of R. solani on maize leaves regarding the metabolism of traumatin, phytosphingosine, vitexin 2'' O-beta-D-glucoside, rutin and DIBOA-glucoside, which were up-regulated, while the synthesis of OPC-8:0 and 12-OPDA, precursors for the synthesis of jasmonic acid, a plant defense signaling molecule, was down-regulated under both treatments. However, there were also discrepancies in the influences exhibited by R. solani and PAA as the metabolic concentration of zeaxanthin diglucoside in the R. solani infected leaf group decreased. Conversely, in the PAA-treated leaf group, the synthesis of zeaxanthin diglucoside was enhanced. Moreover, although the synthesis of 12 metabolites were suppressed in both the R. solani- and PAA-treated leaf tissues, the inhibitory effect of R. solani was stronger than that of PAA. An increased expression of quercitrin and quercetin 3-O-glucoside was observed in maize sheaths treated by R. solani, while their concentrations were not changed significantly in the PAA-treated sheaths. Furthermore, a significant decrease in the concentration of L-Glutamate, which plays important roles in plant resistance to necrotrophic pathogens, only occurred in the R. solani-treated sheath tissues. The differentiated metabolite levels may be the partial reason of why maize sheaths were more susceptible to R. solani than leaves and may explain the underlying mechanisms of R. solani pathogenesis. PMID:29408919

UPLC-QTOF-MS metabolomics analysis revealed the contributions of metabolites to the pathogenesis of Rhizoctonia solani strain AG-1-IA.

PubMed

Hu, Wenjin; Pan, Xinli; Li, Fengfeng; Dong, Wubei

2018-01-01

To explore the pathogenesis of Rhizoctonia solani and its phytotoxin phenylacetic acid (PAA) on maize leaves and sheaths, treated leaf and sheath tissues were analyzed and interpreted by ultra-performance liquid chromatography-mass spectrometry combined with chemometrics. The PAA treatment had similar effects to those of R. solani on maize leaves regarding the metabolism of traumatin, phytosphingosine, vitexin 2'' O-beta-D-glucoside, rutin and DIBOA-glucoside, which were up-regulated, while the synthesis of OPC-8:0 and 12-OPDA, precursors for the synthesis of jasmonic acid, a plant defense signaling molecule, was down-regulated under both treatments. However, there were also discrepancies in the influences exhibited by R. solani and PAA as the metabolic concentration of zeaxanthin diglucoside in the R. solani infected leaf group decreased. Conversely, in the PAA-treated leaf group, the synthesis of zeaxanthin diglucoside was enhanced. Moreover, although the synthesis of 12 metabolites were suppressed in both the R. solani- and PAA-treated leaf tissues, the inhibitory effect of R. solani was stronger than that of PAA. An increased expression of quercitrin and quercetin 3-O-glucoside was observed in maize sheaths treated by R. solani, while their concentrations were not changed significantly in the PAA-treated sheaths. Furthermore, a significant decrease in the concentration of L-Glutamate, which plays important roles in plant resistance to necrotrophic pathogens, only occurred in the R. solani-treated sheath tissues. The differentiated metabolite levels may be the partial reason of why maize sheaths were more susceptible to R. solani than leaves and may explain the underlying mechanisms of R. solani pathogenesis.

Phytohormones and microRNAs as sensors and regulators of leaf senescence: assigning macro roles to small molecules.

PubMed

Sarwat, Maryam; Naqvi, Afsar Raza; Ahmad, Parvaiz; Ashraf, Muhammad; Akram, Nudrat Aisha

2013-12-01

Ageing or senescence is an intricate and highly synchronized developmental phase in the life of plant parts including leaf. Senescence not only means death of a plant part, but during this process, different macromolecules undergo degradation and the resulting components are transported to other parts of the plant. During the period from when a leaf is young and green to the stage when it senesces, a multitude of factors such as hormones, environmental factors and senescence associated genes (SAGs) are involved. Plant hormones including salicylic acid, abscisic acid, jasmonic acid and ethylene advance leaf senescence, whereas others like cytokinins, gibberellins, and auxins delay this process. The environmental factors which generally affect plant development and growth, can hasten senescence, the examples being nutrient dearth, water stress, pathogen attack, radiations, high temperature and light intensity, waterlogging, and air, water or soil contamination. Other important influences include carbohydrate accumulation and high carbon/nitrogen level. To date, although several genes involved in this complex process have been identified, still not much information exists in the literature on the signalling mechanism of leaf senescence. Now, the Arabidopsis mutants have paved our way and opened new vistas to elucidate the signalling mechanism of leaf senescence for which various mutants are being utilized. Recent studies demonstrating the role of microRNAs in leaf senescence have reinforced our knowledge of this intricate process. This review provides a comprehensive and critical analysis of the information gained particularly on the roles of several plant growth regulators and microRNAs in regulation of leaf senescence. Copyright © 2013 Elsevier Inc. All rights reserved.

Interpreting chlorophyll fluorescence signals: the effects of leaf age

NASA Astrophysics Data System (ADS)

Albert, L.; Vergeli, P.; Martins, G.; Saleska, S. R.; Huxman, T. E.

2015-12-01

Remote sensing of sun-induced chlorophyll fluorescence (SIF) promises robust estimation of carbon uptake across landscapes, as studies of plant physiology have shown that fluorescence emission is directly linked to photosynthesis at the leaf level. Yet most leaf-level studies demonstrating the link between chlorophyll fluorescence and photosynthesis have studied leaves in their prime: leaves that recently finished expansion and have yet to senesce. By contrast, remote sensing of landscapes involves observing leaves of different ages. For example, broadleaf deciduous forests and annual plant communities in temperate regions have leaves that develop and then senesce over the course of a growing season. In this experiment, we explored how leaf age and moisture availability affect steady-state fluoresence (Fs) at the leaf level. We simultaneously measured net photosynthesis (Anet) and Fs for leaves of known ages on greenhouse-grown dwarf Helianthus Annuus (sunflowers) from two watering treatments. To monitor plant water status, we measured pre-dawn water potential, and, for a subset of leaves, osmotic potential. Fully expanded or near-fully expanded leaves (~8 to ~23 days old) had higher Anet at saturating light than young, expanding leaves (less than 8 days old) or old leaves nearing senescence (>23 days old). We found a positive relationship between Fs and Anet, suggesting that the link between fluorescence emission and photosynthesis is robust across leaves of different ages. However, leaf age had marked effects on the light response curve of photosynthesis and fluorescence metrics. These results suggest that leaf age distribution, and changes in leaf age distribution due to phenology, should be considered when interpreting SIF at the landscape level.

Age dependence of dielectric properties of bovine brain and ocular tissues in the frequency range of 400 MHz to 18 GHz

NASA Astrophysics Data System (ADS)

Schmid, Gernot; Überbacher, Richard

2005-10-01

In order to identify possible age-dependent dielectric properties of brain and eye tissues in the frequency range of 400 MHz to 18 GHz, measurements on bovine grey and white matter as well as on cornea, lens (cortical) and the vitreous body were performed using a commercially available open-ended coaxial probe and a computer-controlled vector network analyser. Freshly excised tissues of 52 animals of two age groups (42 adult animals, i.e. 16-24 month old and 10 young animals, i.e. 4-6 month old calves) were examined within 8 min (brain tissue) and 15 min (eye tissue), respectively, of the animals' death. Tissue temperatures for the measurements were 32 ± 1 °C and 25 ± 1 °C for brain and eye tissues, respectively. Statistical analysis of the measured data revealed significant differences in the dielectric properties of white matter and cortical lens tissue between the adult and the young group. In the case of white matter the mean values of conductivity and permittivity of young tissue were 15%-22% and 12%-15%, respectively, higher compared to the adult tissue in the considered frequency range. Similarly, young cortical lens tissue was 25%-76% higher in conductivity and 27%-39% higher in permittivity than adult cortical lens tissue.

Leaf quality and insect herbivory in model tropical plant communities after long-term exposure to elevated atmospheric CO2.

PubMed

Arnone, J A; Zaller, J G; Körner, Ch; Ziegler, C; Zandt, H

1995-09-01

Results from laboratory feeding experiments have shown that elevated atmospheric carbon dioxide can affect interactions between plants and insect herbivores, primarily through changes in leaf nutritional quality occurring at elevated CO 2 . Very few data are available on insect herbivory in plant communities where insects can choose among species and positions in the canopy in which to feed. Our objectives were to determine the extent to which CO 2 -induced changes in plant communities and leaf nutritional quality may affect herbivory at the level of the entire canopy. We introduced equivalent populations of fourth instar Spodoptera eridania, a lepidopteran generalist, to complex model ecosystems containing seven species of moist tropical plants maintained under low mineral nutrient supply. Larvae were allowed to feed freely for 14 days, by which time they had reached the seventh instar. Prior to larval introductions, plant communities had been continuously exposed to either 340 μl CO 2 l -1 or to 610 μl CO 2 l -1 for 1.5 years. No major shifts in leaf nutritional quality [concentrations of N, total non-structural carbohydrates (TNC), sugar, and starch; ratios of: C/N, TNC/N, sugar/N, starch/N; leaf toughness] were observed between CO 2 treatments for any of the species. Furthermore, no correlations were observed between these measures of leaf quality and leaf biomass consumption. Total leaf area and biomass of all plant communities were similar when caterpillars were introduced. However, leaf biomass of some species was slightly greater-and for other species slightly less (e.g. Cecropia peltata)-in communities exposed to elevated CO 2 . Larvae showed the strongest preference for C. peltata leaves, the plant species that was least abundant in all communites, and fed relatively little on plants species which were more abundant. Thus, our results indicate that leaf tissue quality, as described by these parameters, is not necessarily affected by elevated CO 2 under relatively low nutrient conditions. Hence, the potential importance of CO 2 -induced shifts in leaf nutritional quality, as determinants of herbivory, may be overestimated for many plant communities growing on nutrient-poor sites if estimates are based on traditional laboratory feeding studies. Finally, slight shifts in the abundance of leaf tissue of various species occurring under elevated CO 2 will probably not significantly affect herbivory by generalist insects. However, generalist insect herbivores appear to become more dependent on less-preferred plant species in cases where elevated CO 2 results in reduced availability of leaves of a favoured plant species, and this greater dependency may eventually affect insect populations adversely.

Rhododendron oldhamii leaf extract improves fatty liver syndrome by increasing lipid oxidation and decreasing the lipogenesis pathway in mice.

PubMed

Liu, Ya-Ling; Lin, Lei-Chen; Tung, Yu-Tang; Ho, Shang-Tse; Chen, Yao-Li; Lin, Chi-Chen; Wu, Jyh-Horng

2017-01-01

Some members of Rhododendron genus are traditionally used as medicinal plants for arthritis, acute and chronic bronchitis, asthma, pain, inflammation, rheumatism, hypertension and metabolic diseases. To the best of our knowledge, there is no report on the protective effects of R. oldhamii leaf extract on non-alcoholic fatty liver disease (NAFLD) in vivo and in vitro . In this study, the effects of R. oldhamii leaf extract on inhibiting the free fatty acid (FFA)-induced accumulation of fat in HepG2 cells and on improving fatty liver syndrome in mice with high fat diet (HFD)-induced NAFLD were investigated. For the in vitro assay, HepG2 cells were treated with FFAs (oleate/palmitate = 2:1) with or without treatment with R. oldhamii leaf ethyl acetate (EtOAc) fraction to observe lipid accumulation using Nile red and oil red O stains. For the in vivo assay, C57BL/6 mice were randomly assigned to three groups ( n = 5), including the normal diet group, the HFD group and the HFD+EtOAc group. After 11 weeks, body weight, serum biochemical indices and the mRNA expressions of the liver tissue, as well as the outward appearance, weight and histopathological analysis of liver and adipose tissues were evaluated. Among the fractions derived from R. oldhamii leaf, the EtOAc fraction exhibited a strong fat-accumulation inhibitory activity. Following reverse-phase high-performance liquid chromatography (HPLC), four specific phytochemicals, including (2 R , 3 R )-astilbin (AS), hyposide (HY), guaijaverin (GU) and quercitrin (QU), were isolated and identified from the EtOAc fraction of R. oldhamii leaf extract. Among them, AS and HY showed excellent fat-accumulation inhibitory activity. Thus, the EtOAc fraction of R. oldhamii leaf and its derived phytochemicals have great potential in preventing FFA-induced fat accumulation. In addition, the EtOAc fraction of R. oldhamii leaf significantly improved fatty liver syndrome and reduced total cholesterol (TC) and triglyceride (TG) in HFD-induced NAFLD mice at a dosage of 200 mg/kg BW. These results demonstrated that the methanolic extracts from R. oldhamii leaf have excellent inhibitory activities against fat accumulation and anti-NAFLD activities and thus have great potential as a natural health product.

Ozone and Botrytis interactions in onion-leaf dieback: open-top chamber studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wukasch, R.T.; Hofstra, G.

1977-09-01

Paired open-top chambers were used to study interactions between Botrytis spp. and ozone in field-grown onions. Charcoal filters removed 35 to 65% of the ambient ozone, resulting in six-fold reduction of onion leaf dieback and a 28% increase in onion yield compared with unfiltered chambers. Symptoms of leaf injury appeared soon after ozone levels exceeded 294 ..mu..g/m/sup 3/ (0.15 ppm) for 4 hr. Lesions caused by Botrytis were few because no dew formed in the chambers. However, when leaves were wetted with foggers, inoculation with mycelial suspensions of B. sauamosa in late August produced significantly more lesions and leaf diebackmore » in the unfiltered chamber. Botrytis squamosa, B. cinerea, B. allii, and several genera of secondary fungi were isolated from these lesions. Botrytis squamosa was recovered from lesions only, whereas B. cinerea and B. allii were associated more generally with onion leaf tissue regardless of lesions. 25 references, 1 figure, 2 tables.« less

Try This: Plant Leaf Exploration

ERIC Educational Resources Information Center

Preston, Christine

2017-01-01

Plants are often overlooked in favour of animals when teaching about living things. Focusing on familiar animals that share human characteristics helps young children learn about similar features. Examining plants for their differences, though, helps foster wonder. In the author's experience, children find it intriguing that plants need…

Following Vegetative to Embryonic Cellular Changes in Leaves of Arabidopsis Overexpressing LEAFY COTYLEDON21[W][OPEN

PubMed Central

Feeney, Mistianne; Frigerio, Lorenzo; Cui, Yuhai; Menassa, Rima

2013-01-01

Embryogenesis in flowering plants is controlled by a complex interplay of genetic, biochemical, and physiological regulators. LEAFY COTYLEDON2 (LEC2) is among a small number of key transcriptional regulators that are known to play important roles in controlling major events during the maturation stage of embryogenesis, notably, the synthesis and accumulation of storage reserves. LEC2 overexpression causes vegetative tissues to change their developmental fate to an embryonic state; however, little information exists about the cellular changes that take place. We show that LEC2 alters leaf morphology and anatomy and causes embryogenic structures to form subcellularly in leaves of Arabidopsis (Arabidopsis thaliana). Chloroplasts accumulate more starch, the cytoplasm fills with oil bodies, and lytic vacuoles (LVs) appear smaller in size and accumulate protein deposits. Because LEC2 is responsible for activating the synthesis of seed storage proteins (SSPs) during seed development, SSP accumulation was investigated in leaves. The major Arabidopsis SSP families were shown to accumulate within small leaf vacuoles. By exploiting the developmental and tissue-specific localization of two tonoplast intrinsic protein isoforms, the small leaf vacuoles were identified as protein storage vacuoles (PSVs). Confocal analyses of leaf vacuoles expressing fluorescently labeled tonoplast intrinsic protein isoforms reveal an altered tonoplast morphology resembling an amalgamation of a LV and PSV. Results suggest that as the LV transitions to a PSV, the tonoplast remodels before the large vacuole lumen is replaced by smaller PSVs. Finally, using vegetative and seed markers to monitor the transition, we show that LEC2 induces a reprogramming of leaf development. PMID:23780897

The impact of canopy managements on grape and wine composition of cv. 'Istrian Malvasia' (Vitis vinifera L.).

PubMed

Rescic, Jan; Mikulic-Petkovsek, Maja; Rusjan, Denis

2016-11-01

The interest in producing wines preferred by consumers increases the need for improving practices to modify grape and wine composition. The aim of this study was to assess the impacts of three different canopy management measures, (1) early leaf removal in the cluster zone, (2) removal of young leaves above the second pair of wires and (3) Double Maturation Raisonnée, on the yield and chemical composition of 'Istrian Malvasia' grape and wine. Double Maturation Raisonnée had a significantly greater impact on phenolic compounds, while the highest soluble solids (24.3 and 23.5 °Brix) and titratable acidity (7.0 and 7.1 g L -1 ) were measured at early leaf removal. Leaf removal at véraison caused an unexpected augmentation of flavonols in the berry skin. Early leaf removal resulted in significantly lower extracts of wine. Nevertheless, they reached the highest mark (16.5 out of 20.0 points) in sensory evaluation compared with leaf removal at véraison and Double Maturation Raisonnée (15.0 points) and control (16.0 points). Leaf removal at véraison and Double Maturation Raisonnée improved the phenolic composition of wine, producing a full-bodied wine. On the other hand, early leaf removal significantly augmented the yield and titratable acidity, hydroxycinnamic acids and flavanols of wine, which might have led to a fresher but less-bodied wine. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Synthesis and assembly of Escherichia coli heat-labile enterotoxin B subunit in transgenic lettuce (Lactuca sativa).

PubMed

Kim, Tae-Geum; Kim, Mi-Young; Kim, Bang-Geul; Kang, Tae-Jin; Kim, Young-Sook; Jang, Yong-Suk; Arntzen, Charles J; Yang, Moon-Sik

2007-01-01

Escherichia coli heat-labile enterotoxin B subunit (LTB) strongly induces immune responses and can be used as an adjuvant for co-administered antigens. Synthetic LTB (sLTB) based on optimal codon usage by plants was introduced into lettuce cells (Lactuca sativa) by Agrobacterium tumefaciens-mediated transformation methods. The sLTB gene was detected in the genomic DNA of transgenic lettuce leaf cells by PCR DNA amplification. Synthesis and assembly of the sLTB protein into oligomeric structures of pentameric size was observed in transgenic plant extracts using Western blot analysis. The binding of sLTB pentamers to intestinal epithelial cell membrane glycolipid receptors was confirmed by G(M1)-ganglioside enzyme-linked immunosorbent assay (G(M1)-ELISA). Based on the results of ELISA, sLTB protein comprised approximately 1.0-2.0% of total soluble protein in transgenic lettuce leaf tissues. The synthesis and assembly of sLTB monomers into biologically active oligomers in transgenic lettuce leaf tissues demonstrates the feasibility of the use of edible plant-based vaccines consumed in the form of raw plant materials to induce mucosal immunity.

Effects of cadmium concentration on ozone-induced phytotoxicity in cress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czuba, M.; Ormrod, D.P.

1974-01-01

Cadmium solutions at concentrations of 0, 10, 40, 100, 500 or 1000 ppm were applied to the soil around cress (Lepidium sativum L. cv. Fine Curled) every 4th day for several weeks. Four week old plants were fumigated once at ozone levels of 0, 5, 10, 20, 25 or 30-35 pphm for 6 hours. Plants that had received higher concentrations of cadmium showed markedly increased sensitivity to ozone in terms of visible leaf damage after ozone treatment. Plants receiving cadmium solution alone or those receiving ozone treatment alone either did not show leaf damage or as much leaf damage asmore » plants which had received both treatments. Mineral analyses of plant tissues showed the relationship between tissue content of both essential and toxic cations and the sensitivity of the plant to various ozone levels. Pigment analyses showed changes in chlorophyll amounts and ratios between treatments. Statistical analyses of data for morphological parameters showed that there is an interaction between Cd and ozone treatments over a range of concentrations.« less

Aboveground Tree Growth Varies with Belowground Carbon Allocation in a Tropical Rainforest Environment

PubMed Central

Raich, James W.; Clark, Deborah A.; Schwendenmann, Luitgard; Wood, Tana E.

2014-01-01

Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the tree plantations, which had fully developed, closed canopies, allocated more carbon belowground - to their root systems - than did mature forest. This increase in belowground carbon allocation correlated significantly with aboveground tree growth but not with canopy production (i.e., leaf fall or fine litter production). In contrast, there were no correlations between canopy production and either tree growth or belowground carbon allocation. Enhanced allocation of carbon to root systems can enhance plant nutrient uptake, providing nutrients beyond those required for the production of short-lived tissues such as leaves and fine roots, and thus enabling biomass accumulation. Our analyses support this deduction at our site, showing that enhanced allocation of carbon to root systems can be an important mechanism promoting biomass accumulation during forest growth in the moist tropics. Identifying factors that control when, where and for how long this occurs would help us to improve models of forest growth and nutrient cycling, and to ascertain the role that young forests play in mitigating increased atmospheric carbon dioxide. PMID:24945351

Effects of artificial enclosure of young lettuce leaves on tipburn incidence and leaf calcium concentration

NASA Technical Reports Server (NTRS)

Barta, D. J.; Tibbitts, T. W.

1986-01-01

The young developing leaves of 20-day-old lettuce plants (Lactuca sativa L. 'Buttercrunch') were enclosed by aluminized polyethylene sheaths to decrease transpiration and reduce Ca transport. The plants were grown in recirculating solution culture system using a modified half-strength Hoagland's solution under cool-white fluorescent lamps with a photosynthetic photon flux of 350 micromoles s-1 m-2 in a 16:8-hr (light:dark) period. Air temperature and humidity were 20 degrees C and 65%, respectively. After 4 days of enclosure, 53% of the inner leavers (leaves one to 3 cm in length) were tipburned. After the same period, less than 1% of the inner leaves on control plants were tipburned. The concentration of Ca in enclosed inner leaves was 0.63 mg g-1 dry weight, compared to 1.48 mg g-1 dry weight in inner leaves that were not enclosed. The Ca concentration in transpiring outer leaves of all plants was 9.9 mg g-1 dry weight. The Mg concentration in enclosed inner leaves was 2.25 mg g-1 dry weight, compared to 2.34 mg g-1 dry weight in inner leaves that were not enclosed. This research documents that enclosures of leaves at the growing point, as would occur with normal head development, is sufficient to create a limiting concentration of Ca in the enclosed tissue and encourage tipburn development.

SEMI-ROLLED LEAF1 Encodes a Putative Glycosylphosphatidylinositol-Anchored Protein and Modulates Rice Leaf Rolling by Regulating the Formation of Bulliform Cells1[W][OA

PubMed Central

Xiang, Jing-Jing; Zhang, Guang-Heng; Qian, Qian; Xue, Hong-Wei

2012-01-01

Leaf rolling is an important agronomic trait in rice (Oryza sativa) breeding and moderate leaf rolling maintains the erectness of leaves and minimizes shadowing between leaves, leading to improved photosynthetic efficiency and grain yields. Although a few rolled-leaf mutants have been identified and some genes controlling leaf rolling have been isolated, the molecular mechanisms of leaf rolling still need to be elucidated. Here we report the isolation and characterization of SEMI-ROLLED LEAF1 (SRL1), a gene involved in the regulation of leaf rolling. Mutants srl1-1 (point mutation) and srl1-2 (transferred DNA insertion) exhibit adaxially rolled leaves due to the increased numbers of bulliform cells at the adaxial cell layers, which could be rescued by complementary expression of SRL1. SRL1 is expressed in various tissues and is expressed at low levels in bulliform cells. SRL1 protein is located at the plasma membrane and predicted to be a putative glycosylphosphatidylinositol-anchored protein. Moreover, analysis of the gene expression profile of cells that will become epidermal cells in wild type but probably bulliform cells in srl1-1 by laser-captured microdissection revealed that the expression of genes encoding vacuolar H+-ATPase (subunits A, B, C, and D) and H+-pyrophosphatase, which are increased during the formation of bulliform cells, were up-regulated in srl1-1. These results provide the transcript profile of rice leaf cells that will become bulliform cells and demonstrate that SRL1 regulates leaf rolling through inhibiting the formation of bulliform cells by negatively regulating the expression of genes encoding vacuolar H+-ATPase subunits and H+-pyrophosphatase, which will help to understand the mechanism regulating leaf rolling. PMID:22715111

18O Spatial Patterns of Vein Xylem Water, Leaf Water, and Dry Matter in Cotton Leaves

PubMed Central

Gan, Kim Suan; Wong, Suan Chin; Yong, Jean Wan Hong; Farquhar, Graham Douglas

2002-01-01

Three leaf water models (two-pool model, Péclet effect, and string-of-lakes) were assessed for their robustness in predicting leaf water enrichment and its spatial heterogeneity. This was achieved by studying the 18O spatial patterns of vein xylem water, leaf water, and dry matter in cotton (Gossypium hirsutum) leaves grown at different humidities using new experimental approaches. Vein xylem water was collected from intact transpiring cotton leaves by pressurizing the roots in a pressure chamber, whereas the isotopic content of leaf water was determined without extracting it from fresh leaves with the aid of a purpose-designed leaf punch. Our results indicate that veins have a significant degree of lateral exchange with highly enriched leaf water. Vein xylem water is thus slightly, but progressively enriched in the direction of water flow. Leaf water enrichment is dependent on the relative distances from major veins, with water from the marginal and intercostal regions more enriched and that next to veins and near the leaf base more depleted than the Craig-Gordon modeled enrichment of water at the sites of evaporation. The spatial pattern of leaf water enrichment varies with humidity, as expected from the string-of-lakes model. This pattern is also reflected in leaf dry matter. All three models are realistic, but none could fully account for all of the facets of leaf water enrichment. Our findings acknowledge the presence of capacitance in the ground tissues of vein ribs and highlight the essential need to incorporate Péclet effects into the string-of-lakes model when applying it to leaves. PMID:12376664

Use of electron microprobe x-ray analysis for determination of low calcium concentrations across leaves deficient in calcium

NASA Technical Reports Server (NTRS)

Barta, D. J.; Tibbitts, T. W.

1991-01-01

An electron microprobe with wavelength-dispersive x-ray spectrometry (WDS) was found to be useful for the determination of Ca concentrations in leaf tissue deficient in Ca. WDS effectively detected Ca concentrations as low as 0.2 mg/g dry wt in the presence of high levels of K and Mg (120 and 50 mg/g dry wt, respectively). Leaf specimens were prepared for analysis by quick-freezing in liquid nitrogen and freeze-drying at -20 degrees C to maintain elemental integrity within the tissue. Because dry material was analyzed, sample preparation was simple and samples could be stored for long periods before analysis. A large beam diameter of 50 gm was used to minimize tissue damage under the beam and analyze mineral concentrations within several cells at one time. Beam penetration was between 50 and 55 microns, approximately one-third of the thickness of the leaf. For analysis of concentrations in interveinal areas, analyses directed into the abaxial epidermis were found most useful. However, because of limited beam penetration, analyses of veinal areas would require use of cross sections [correction of crosssections]. Solid mineral standards were used for instrument standardization. To prevent measurement errors resulting from differences between the matrix of the mineral standards and the analyzed tissue, concentrations in leaves were corrected using gelatin standards prepared and analyzed under the same conditions. WDS was found to be useful for documenting that very low Ca levels occur in specific areas of lettuce leaves exhibiting the Ca deficiency injury termed tipburn.

Boron toxicity characteristics of four northern California endemic tree species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glaubig, B.A.; Bingham, F.T.

A greenhouse study was undertaken to determine the characteristics of soil B toxicity for four tree species endemic to The Geysers area in northern California: digger pine (Pinus sabiniana Dougl. ex D. Don), California laurel (or, California bay) (Umbellularia californica (Hoo. and Arn. Nutt.)), madrone (Arbutus menziesii Pursh), and bigleaf maple (Acer macrophyllum Pursh). Significant exponential relationships were found between soil B concentration and relative growth, and between tissue B concentration and relative growth for the four species. Significant linear relationships were found between both soil and tissue B concentration and foliar damage for the four species. Foliar damages overmore » 25% of the leaf or needle area on digger pine, California laurel, madrone, and bigleaf maple, respectively, occurred at saturated soil extract concentrations (mmol B/L) of 1.2, 0.4, 0.5, and 0.08. Twenty-five percent foliar damage was associated with leaf or needle tissue concentrations (mmol B/kg) of 115, 100, 50, and 30 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. Growth decrements of 25% occurred at saturated soil extract concentrations (mmol B/L) of 1.6, 0.3, 0.2, 0.5 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. Twenty-five percent growth decrements were associated with leaf or needle tissue concentrations (mmol B/kg) of 140, 100, 20, and 7 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. By comparison with two agronomic crops - cotton (Gossypium hirsutum L.) and cowpea (Vigna unguiculata L.) - the four tree species were placed into one of six B tolerance classes.« less

The modulatory effect of Moringa oleifera leaf extract on endogenous antioxidant systems and inflammatory markers in an acetaminophen-induced nephrotoxic mice model

PubMed Central

Karthivashan, Govindarajan; Kura, Aminu Umar; Arulselvan, Palanisamy; Md. Isa, Norhaszalina

2016-01-01

N-Acetyl-p-Aminophenol (APAP), also known as acetaminophen, is the most commonly used over-the counter analgesic and antipyretic medication. However, its overdose leads to both liver and kidney damage. APAP-induced toxicity is considered as one of the primary causes of acute liver failure; numerous scientific reports have focused majorly on APAP hepatotoxicity. Alternatively, not many works approach APAP nephrotoxicity focusing on both its mechanisms of action and therapeutic exploration. Moringa oleifera (MO) is pervasive in nature, is reported to possess a surplus amount of nutrients, and is enriched with several bioactive candidates including trace elements that act as curatives for various clinical conditions. In this study, we evaluated the nephro-protective potential of MO leaf extract against APAP nephrotoxicity in male Balb/c mice. A single-dose acute oral toxicity design was implemented in this study. Group 2, 3, 4 and 5 received a toxic dose of APAP (400 mg/kg of bw, i.p) and after an hour, these groups were administered with saline (10 mL/kg), silymarin—positive control (100 mg/kg of bw, i.p), MO leaf extract (100 mg/kg of bw, i.p), and MO leaf extract (200 mg/kg bw, i.p) respectively. Group 1 was administered saline (10 mL/kg) during both the sessions. APAP-treated mice exhibited a significant elevation of serum creatinine, blood urea nitrogen, sodium, potassium and chloride levels. A remarkable depletion of antioxidant enzymes such as SOD, CAT and GSH-Px with elevated MDA levels has been observed in APAP treated kidney tissues. They also exhibited a significant rise in pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and decreased anti-inflammatory (IL-10) cytokine level in the kidney tissues. Disorganized glomerulus and dilated tubules with inflammatory cell infiltration were clearly observed in the histology of APAP treated mice kidneys. All these pathological changes were reversed in a dose-dependent manner after MO leaf extract treatment. Therefore, MO leaf extract has demonstrated some therapeutic effectiveness against APAP-induced nephrotoxicity through enhancement of the endogenous antioxidant system and a modulatory effect on specific inflammatory cytokines in kidney tissues. PMID:27441110

The Arabidopsis BRAHMA Chromatin-Remodeling ATPase Is Involved in Repression of Seed Maturation Genes in Leaves1[W][OA

PubMed Central

Tang, Xurong; Hou, Anfu; Babu, Mohan; Nguyen, Vi; Hurtado, Lidia; Lu, Qing; Reyes, Jose C.; Wang, Aiming; Keller, Wilfred A.; Harada, John J.; Tsang, Edward W.T.; Cui, Yuhai

2008-01-01

Synthesis and accumulation of seed storage proteins (SSPs) is an important aspect of the seed maturation program. Genes encoding SSPs are specifically and highly expressed in the seed during maturation. However, the mechanisms that repress the expression of these genes in leaf tissue are not well understood. To gain insight into the repression mechanisms, we performed a genetic screen for mutants that express SSPs in leaves. Here, we show that mutations affecting BRAHMA (BRM), a SNF2 chromatin-remodeling ATPase, cause ectopic expression of a subset of SSPs and other embryogenesis-related genes in leaf tissue. Consistent with the notion that such SNF2-like ATPases form protein complexes in vivo, we observed similar phenotypes for mutations of AtSWI3C, a BRM-interacting partner, and BSH, a SNF5 homolog and essential SWI/SNF subunit. Chromatin immunoprecipitation experiments show that BRM is recruited to the promoters of a number of embryogenesis genes in wild-type leaves, including the 2S genes, expressed in brm leaves. Consistent with its role in nucleosome remodeling, BRM appears to affect the chromatin structure of the At2S2 promoter. Thus, the BRM-containing chromatin-remodeling ATPase complex involved in many aspects of plant development mediates the repression of SSPs in leaf tissue. PMID:18508955

Disruption of stomatal lineage signaling or transcriptional regulators has differential effects on mesophyll development, but maintains coordination of gas exchange.

PubMed

Dow, Graham J; Berry, Joseph A; Bergmann, Dominique C

2017-10-01

Stomata are simultaneously tasked with permitting the uptake of carbon dioxide for photosynthesis while limiting water loss from the plant. This process is mainly regulated by guard cell control of the stomatal aperture, but recent advancements have highlighted the importance of several genes that control stomatal development. Using targeted genetic manipulations of the stomatal lineage and a combination of gas exchange and microscopy techniques, we show that changes in stomatal development of the epidermal layer lead to coupled changes in the underlying mesophyll tissues. This coordinated response tends to match leaf photosynthetic potential (V cmax ) with gas-exchange capacity (g smax ), and hence the uptake of carbon dioxide for water lost. We found that different genetic regulators systematically altered tissue coordination in separate ways: the transcription factor SPEECHLESS (SPCH) primarily affected leaf size and thickness, whereas peptides in the EPIDERMAL PATTERNING FACTOR (EPF) family altered cell density in the mesophyll. It was also determined that interlayer coordination required the cell-surface receptor TOO MANY MOUTHS (TMM). These results demonstrate that stomata-specific regulators can alter mesophyll properties, which provides insight into how molecular pathways can organize leaf tissues to coordinate gas exchange and suggests new strategies for improving plant water-use efficiency. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The unique structural and biochemical development of single cell C4 photosynthesis along longitudinal leaf gradients in Bienertia sinuspersici and Suaeda aralocaspica (Chenopodiaceae)

PubMed Central

Koteyeva, Nuria K.; Voznesenskaya, Elena V.; Berry, James O.; Cousins, Asaph B.; Edwards, Gerald E.

2016-01-01

Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica. Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 photosynthesis. PMID:26957565

Tomato plant and leaf age effects on the probing and settling behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae).

PubMed

Joost, P Houston; Riley, David G

2008-02-01

The effect of tomato, Solanum lycopersicum L., plant and leaf age on the probing and settling behavior of Frankliniella fusca (Hinds) and F. occidentalis (Pergande) was studied using electrical penetration graph technique and whole plant bioassays. Male and female F. fusca probed and ingested more and for longer periods of time on 3- and 4-wk-old plants compared with 6- and 8-wk-old plants. Female F. fusca probed and ingested more frequently than males in the plant age experiment, but not in the leaf age experiment. F. fusca probed and ingested more frequently on 2- and 4-wk-old leaves compared with 1-wk-old leaves. Plant age did not affect the probing frequency or duration of F. occidentalis; however, males probed and ingested longer than females in the plant age experiment and on the oldest leaf in the leaf age experiment. Both thrips species preferred to settle on 3-wk-old plants. F. fusca preferred to settle on 4-wk-old leaves after settling randomly for an hour. F. occidentalis showed no settling preference relative to leaf age. The preference of F. fusca for young plants suggests that this species could attack tomato plants at a very early stage, which is important for understanding its role as a vector in the transmission of Tospovirus in the field.

Inoculum Density Relationships for Infection of Some Eastern US Forest Species by Phytophthora ramorum

Treesearch

Paul Tooley; Marsha Browning; Robert Leighty

2013-01-01

Our objectives were to establish inoculum density relationships between P. ramorum and selected hosts using detached leaf and whole-plant inoculations. Young plants and detached leaves of Quercus prinus (Chestnut oak), Q. rubra (Northern red oak), Acer rubrum (red maple), ...

NEGLECTED COMPONENTS OF BIODIVERSITY: SOIL ORIBATID MITES, COMMUNITY STRUCTURE AND SOIL RECOVERY

EPA Science Inventory

Oribatid mites are an abundant and diverse component of soils in regional pine forests, and are valuable in characterizing the biodiversity of these forested lands. We sampled oribatid mites using soil cores and leaf litterbags, in young aggrading forest stands. Comparing these...

Isolation of Mesophyll Cells and Bundle Sheath Cells from Digitaria sanguinalis (L.) Scop. Leaves and a Scanning Microscopy Study of the Internal Leaf Cell Morphology 1

PubMed Central

Edwards, Gerald E.; Black, Clanton C.

1971-01-01

A technique is described for the separation of mesophyll and bundle sheath cells from Digitaria sanguinalis leaves and evidence for separation is given with light and scanning electron micrographs. Gentle grinding of fully differentiated leaves in a mortar releases mesophyll cells which are isolated on nylon nets by filtration. More extensive grinding of the remaining tissue yields bundle sheath strands which are isolated by filtration with stainless steel sieves and nylon nets. Further grinding of bundle sheath strands in a tissue homogenizer releases bundle sheath cells which are collected on nylon nets. Percentage of purity derived from cell counts and yield data on a chlorophyll basis are given. The internal leaf cell morphology is presented in scanning electron micrographs and compared with light micrographs of fully-differentiated D. sanguinalis leaves. In leaves of plants which possess the C4-dicarboxylic acid cycle of photosynthesis, the relationship of leaf morphology to photosynthesis in mesophyll and bundle sheath cells is considered, and the hypothesis is presented that as atmospheric CO2 enters a leaf about 85% is fixed by the C4-dicarboxylic acid cycle in the mesophyll cells and 10 to 15% is fixed by the reductive pentose phosphate cycle in the bundle sheath cells. A technique also is given for the isolation of mesophyll cells from spinach leaves. Images PMID:16657571

Plasticity in leaf-level water relations of tropical rainforest trees in response to experimental drought.

PubMed

Binks, Oliver; Meir, Patrick; Rowland, Lucy; da Costa, Antonio Carlos Lola; Vasconcelos, Steel Silva; de Oliveira, Alex Antonio Ribeiro; Ferreira, Leandro; Christoffersen, Bradley; Nardini, Andrea; Mencuccini, Maurizio

2016-07-01

The tropics are predicted to become warmer and drier, and understanding the sensitivity of tree species to drought is important for characterizing the risk to forests of climate change. This study makes use of a long-term drought experiment in the Amazon rainforest to evaluate the role of leaf-level water relations, leaf anatomy and their plasticity in response to drought in six tree genera. The variables (osmotic potential at full turgor, turgor loss point, capacitance, elastic modulus, relative water content and saturated water content) were compared between seasons and between plots (control and through-fall exclusion) enabling a comparison between short- and long-term plasticity in traits. Leaf anatomical traits were correlated with water relation parameters to determine whether water relations differed among tissues. The key findings were: osmotic adjustment occurred in response to the long-term drought treatment; species resistant to drought stress showed less osmotic adjustment than drought-sensitive species; and water relation traits were correlated with tissue properties, especially the thickness of the abaxial epidermis and the spongy mesophyll. These findings demonstrate that cell-level water relation traits can acclimate to long-term water stress, and highlight the limitations of extrapolating the results of short-term studies to temporal scales associated with climate change. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Acid rain research program. Annual progress report, September 1975--June 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, L.S.; Raynor, G.S.

1976-09-01

The aims of the research program are: (a) to observe the minimum threshold dose of simulated acid rain to produce visual and histological effects on plant foliage, (b) approach threshold limits of simulated sulfate acid rain that affect plant growth and reproduction, and (c) to measure chemical and meteorological parameters of incident rain. Acute leaf injury to several plant species resulted from exposure of foliage to simulated sulfate acid rain of pH level 2.3 to 2.9. Only slight injury occurred at 3.1. Scanning electron micrographs showed that injury to upper leaf surfaces occurred mostly at the base of trichomes (leafmore » hairs) and near stomata. An association of lesion development near vascular tissue was also noted. Histologically, lesions are characterized by an initial collapse of the epidermis with eventual lysis and collapse of more internal leaf tissues on the upper leaf surface of pinto beans which complemented detailed descriptions of visual lesion development after daily exposures to simulated rain. Initial experiments with gametophytes of Pteridium aquilinum show that reproduction of this fern species is very sensitive to solutions of pH 5.2 while vegetative development is not affected at pH levels of 2.2. Initial rain samples from the sequential sampler have been obtained. Initial portions of rain events exhibit a pH near 3.0 in some cases. More complete chemical analyses are anticipated.« less

Isolation of Mesophyll Cells and Bundle Sheath Cells from Digitaria sanguinalis (L.) Scop. Leaves and a Scanning Microscopy Study of the Internal Leaf Cell Morphology.

PubMed

Edwards, G E; Black, C C

1971-01-01

A technique is described for the separation of mesophyll and bundle sheath cells from Digitaria sanguinalis leaves and evidence for separation is given with light and scanning electron micrographs. Gentle grinding of fully differentiated leaves in a mortar releases mesophyll cells which are isolated on nylon nets by filtration. More extensive grinding of the remaining tissue yields bundle sheath strands which are isolated by filtration with stainless steel sieves and nylon nets. Further grinding of bundle sheath strands in a tissue homogenizer releases bundle sheath cells which are collected on nylon nets. Percentage of purity derived from cell counts and yield data on a chlorophyll basis are given.The internal leaf cell morphology is presented in scanning electron micrographs and compared with light micrographs of fully-differentiated D. sanguinalis leaves. In leaves of plants which possess the C(4)-dicarboxylic acid cycle of photosynthesis, the relationship of leaf morphology to photosynthesis in mesophyll and bundle sheath cells is considered, and the hypothesis is presented that as atmospheric CO(2) enters a leaf about 85% is fixed by the C(4)-dicarboxylic acid cycle in the mesophyll cells and 10 to 15% is fixed by the reductive pentose phosphate cycle in the bundle sheath cells.A technique also is given for the isolation of mesophyll cells from spinach leaves.

Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves

PubMed Central

Niinemets, Ülo; Sun, Zhihong; Talts, Eero

2018-01-01

Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully-expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from postillumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP. The saturating light intensity (QI90) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modeling canopy isoprene emission. PMID:26037962

Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves.

PubMed

Niinemets, Ülo; Sun, Zhihong; Talts, Eero

2015-12-01

Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP ), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from post-illumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI ) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP . The saturating light intensity (QI90 ) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modelling canopy isoprene emission. © 2015 John Wiley & Sons Ltd.

Variability in mesophyll conductance between barley genotypes, and effects on transpiration efficiency and carbon isotope discrimination.

PubMed

Barbour, Margaret M; Warren, Charles R; Farquhar, Graham D; Forrester, Guy; Brown, Hamish

2010-07-01

Leaf internal, or mesophyll, conductance to CO(2) (g(m)) is a significant and variable limitation of photosynthesis that also affects leaf transpiration efficiency (TE). Genotypic variation in g(m) and the effect of g(m) on TE were assessed in six barley genotypes (four Hordeum vulgare and two H. bulbosum). Significant variation in g(m) was found between genotypes, and was correlated with photosynthetic rate. The genotype with the highest g(m) also had the highest TE and the lowest carbon isotope discrimination as recorded in leaf tissue (Delta(p)). These results suggest g(m) has unexplored potential to provide TE improvement within crop breeding programmes.

Herbivory alters plant carbon assimilation, patterns of biomass allocation and nitrogen use efficiency

NASA Astrophysics Data System (ADS)

Peschiutta, María Laura; Scholz, Fabián Gustavo; Goldstein, Guillermo; Bucci, Sandra Janet

2018-01-01

Herbivory can trigger physiological processes resulting in leaf and whole plant functional changes. The effects of chronic infestation by an insect on leaf traits related to carbon and nitrogen economy in three Prunus avium cultivars were assessed. Leaves from non-infested trees (control) and damaged leaves from infested trees were selected. The insect larvae produce skeletonization of the leaves leaving relatively intact the vein network of the eaten leaves and the abaxial epidermal tissue. At the leaf level, nitrogen content per mass (Nmass) and per area (Narea), net photosynthesis per mass (Amass) and per area (Aarea), photosynthetic nitrogen-use efficiency (PNUE), leaf mass per area (LMA) and total leaf phenols content were measured in the three cultivars. All cultivars responded to herbivory in a similar fashion. The Nmass, Amass, and PNUE decreased, while LMA and total content of phenols increased in partially damaged leaves. Increases in herbivore pressure resulted in lower leaf size and total leaf area per plant across cultivars. Despite this, stem cumulative growth tended to increase in infected plants suggesting a change in the patterns of biomass allocation and in resources sequestration elicited by herbivory. A larger N investment in defenses instead of photosynthetic structures may explain the lower PNUE and Amass observed in damaged leaves. Some physiological changes due to herbivory partially compensate for the cost of leaf removal buffering the carbon economy at the whole plant level.

Use of an inexpensive chlorophyll meter to predict Nitrogen levels in leaf tissues of water hyacinth (Eichhornia crassipes (Mart.) Solms

USDA-ARS?s Scientific Manuscript database

Tissue nitrogen is also an important indicator of plant health and can be a useful predictor of plant vigor and susceptibility to disease and pests. Hence, knowing nitrogen content may aid in determining establishment success of plants used in restoration programs, including those destined for aqua...

Sodium and chloride concentration in leaf, woody, and root tissue of Populus irrigated with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; A.H. Wiese; B. Sexton; R.B. Hall

2007-01-01

There are few reports in the literature about the response of different genomic groups and clones of Populus to elevated levels of sodium (Na+) and chloride (Cl-). In addition, there is an increasing need to understand the variation in salt tolerance and tissue composition of such genotypes over multiple...

Macro- and micro-nutrient concentration in leaf, woody, and root tissue of Populus irrigated with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart T. Sexton; Richard B. Hall

2007-01-01

Landfill leachate offers an opportunity to supply water and plant nutritional benefits at a lower cost than traditional sources. Information about nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps increase biomass production along with evaluating the impacts of leachate chemistry on tree health.

Assessment of biological leaf tissue using biospeckle laser imaging technique

NASA Astrophysics Data System (ADS)

Ansari, M. Z.; Mujeeb, A.; Nirala, A. K.

2018-06-01

We report on the application of an optical imaging technique, the biospeckle laser, as a potential tool to assess biological and medicinal plant leaves. The biospeckle laser technique is a non-invasive and non-destructive optical technique used to investigate biological objects. Just after their removal from plants, the torn leaves were used for biospeckle laser imaging. Quantitative evaluation of the biospeckle data using the inertia moment (IM) of the time history speckle pattern, showed that the IM can be utilized to provide a biospeckle signature to the plant leaves. It showed that leaves from different plants can have their own characteristic IM values. We further investigated the infected regions of the leaves that display a relatively lower biospeckle activity than the healthy tissue. It was easy to discriminate between the infected and healthy regions of the leaf tissue. The biospeckle technique can successfully be implemented as a potential tool for the taxonomy of quality leaves. Furthermore, the technique can help boost the quality of ayurvedic medicines.

Reduction of Health Risks Due to Chromium(VI)Using Mesquite: A Potential Cr Phytoremediator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardea-Torresdey, Jorge L.; Aldrich, Mary V.; Peralta-Videa, Jose R.

Chromium is a transition metal extensively used in industry. Cr mining and industrial operations account for chromium wastes at Superfund sites in the United States. A study was performed to investigate the possibility of using mesquite (Prosopis spp.), which is an indigenous desert plant species, to remove Cr from contaminated sites. In this study, mesquite plants were grown in an agar-based medium containing 75 mg L-1 and 125 mg L-1 of Cr(VI). The Cr content of leaf tissue (992 mg kg-1 of dry weight, from 125 mg L-1 of Cr(VI)) indicated that mesquite could be classified as a chromium hyperaccumulator.more » X-ray absorption spectroscopy (XAS) studies performed to experimental samples showed that mesquite roots absorbed some of the supplied Cr(VI). However, the data analyses of plant tissues demonstrated that the absorbed Cr(VI) was fully reduced to Cr(III) in the leaf tissue.« less

FOREST-BGC, A general model of forest ecosystem processes for regional applications. II. Dynamic carbon allocation and nitrogen budgets.

PubMed

Running, Steven W.; Gower, Stith T.

1991-01-01

A new version of the ecosystem process model FOREST-BGC is presented that uses stand water and nitrogen limitations to alter the leaf/root/stem carbon allocation fraction dynamically at each annual iteration. Water deficit is defined by integrating a daily soil water deficit fraction annually. Current nitrogen limitation is defined relative to a hypothetical optimum foliar N pool, computed as maximum leaf area index multiplied by maximum leaf nitrogen concentration. Decreasing availability of water or nitrogen, or both, reduces the leaf/root carbon partitioning ratio. Leaf and root N concentrations, and maximum leaf photosynthetic capacity are also redefined annually as functions of nitrogen availability. Test simulations for hypothetical coniferous forests were performed for Madison, WI and Missoula, MT, and showed simulated leaf area index ranging from 4.5 for a control stand at Missoula, to 11 for a fertilized stand at Madison, with Year 50 stem carbon biomasses of 31 and 128 Mg ha(-1), respectively. Total nitrogen incorporated into new tissue ranged from 34 kg ha(-1) year(-1) for the unfertilized Missoula stand, to 109 kg ha(-1) year(-1) for the fertilized Madison stand. The model successfully showed dynamic annual carbon partitioning controlled by water and nitrogen limitations.

Characterization and pathogenicity of Fusarium species associated with leaf spot of mango (Mangifera indica L.).

PubMed

Omar, Nurul Husna; Mohd, Masratulhawa; Mohamed Nor, Nik Mohd Izham; Zakaria, Latiffah

2018-01-01

Leaf spot diseases are mainly caused by fungi including Fusarium. In the present study several species of Fusarium were isolated from the leaf spot lesion of mango (Mangifera indica L.) Based on morphological characteristics, TEF-1α sequences and phylogenetic analysis, five species were identified as F. proliferatum, F. semitectum, F. mangiferae, F. solani and F. chlamydosporum. Pathogenicity test indicated that representative isolates of F. proliferatum, F. semitectum and F. chlamydosporum were pathogenic on mango leaves causing leaf spot with low to moderate virulence. Nevertheless, abundance of spots on the leaf can disrupt photosynthesis which in turn reduced growth, and lead to susceptibility to infection by opportunistic pathogens due to weakening of the plant. Fusarium solani and F. mangiferae were non-pathogenic and it is possible that both species are saprophyte which associated with nutrient availability on the surface of the leaf through decaying leave tissues. The occurrence of Fusarium spp. on the leaf spot lesion and the effect from the disease needs to be considered when developing disease management method of mango cultivation as numerous spot on the leaves could effect the photosynthesis process and finally giving low yield and less quality of mango. Copyright © 2017. Published by Elsevier Ltd.

Leaf expansion in Phaseolus: transient auxin-induced growth increase

PubMed Central

Keller, Christopher P.

2017-01-01

Control of leaf expansion by auxin is not well understood. Evidence from short term exogenous applications and from treatment of excised tissues suggests auxin positively influences growth. Manipulations of endogenous leaf auxin content, however, suggests that, long-term, auxin suppresses leaf expansion. This study attempts to clarify the growth effects of auxin on unifoliate (primary) leaves of the common bean (Phaseolus vulgaris) by reexamining the response to auxin treatment of both excised leaf strips and attached leaves. Leaf strips, incubated in culture conditions that promoted steady elongation for up to 48 h, treated with 10 μM NAA responded with an initial surge of elongation growth complete within 10 hours followed by insensitivity. A range of NAA concentrations from 0.1 μM to 300 μM induced increased strip elongation after 24 hours and 48 hours. Increased elongation and epinastic curvature of leaf strips was found specific to active auxins. Expanding attached unifoliates treated once with aqueous auxin α-naphthalene acetic acid (NAA) at 1.0 mM showed both an initial surge in growth lasting 4–6 hours followed by growth inhibition sustained at least as long as 24 hours post treatment. Auxin-induced inhibition of leaf expansion was associated with smaller epidermal cell area. Together the results suggest increasing leaf auxin first increases growth then slows growth through inhibition of cell expansion. Excised leaf strips, retain only the initial increased growth response to auxin and not the subsequent growth inhibition, either as a consequence of wounding or of isolation from the plant. PMID:29200506

Effects of mutations in the Arabidopsis Cold Shock Domain Protein 3 (AtCSP3) gene on leaf cell expansion.

PubMed

Yang, Yongil; Karlson, Dale

2012-08-01

The cold shock domain is among the most evolutionarily conserved nucleic acid binding domains from prokaryotes to higher eukaryotes, including plants. Although eukaryotic cold shock domain proteins have been extensively studied as transcriptional and post-transcriptional regulators during various developmental processes, their functional roles in plants remains poorly understood. In this study, AtCSP3 (At2g17870), which is one of four Arabidopsis thaliana c old s hock domain proteins (AtCSPs), was functionally characterized. Quantitative RT-PCR analysis confirmed high expression of AtCSP3 in reproductive and meristematic tissues. A homozygous atcsp3 loss-of-function mutant exhibits an overall reduced seedling size, stunted and orbicular rosette leaves, reduced petiole length, and curled leaf blades. Palisade mesophyll cells are smaller and more circular in atcsp3 leaves. Cell size analysis indicated that the reduced size of the circular mesophyll cells appears to be generated by a reduction of cell length along the leaf-length axis, resulting in an orbicular leaf shape. It was also determined that leaf cell expansion is impaired for lateral leaf development in the atcsp3 loss-of-function mutant, but leaf cell proliferation is not affected. AtCSP3 loss-of-function resulted in a dramatic reduction of LNG1 transcript, a gene that is involved in two-dimensional leaf polarity regulation. Transient subcellular localization of AtCSP3 in onion epidermal cells confirmed a nucleocytoplasmic localization pattern. Collectively, these data suggest that AtCSP3 is functionally linked to the regulation of leaf length by affecting LNG1 transcript accumulation during leaf development. A putative function of AtCSP3 as an RNA binding protein is also discussed in relation to leaf development.

Effects of inert dust on olive (Olea europaea L.) leaf physiological para.

PubMed

Nanos, George D; Ilias, Ilias F

2007-05-01

Cement factories are major pollutants for the surrounding areas. Inert dust deposition has been found to affect photosynthesis, stomatal functioning and productivity. Very few studies have been conducted on the effects of cement kiln dust on the physiology of perennial fruit crops. Our goal was to study some cement dust effects on olive leaf physiology.effects on olive leaf physiology. On Cement kiln dust has been applied periodically since April 2003 onto olive leaves. Cement dust accumulation and various leaf physiological parameters were evaluated early in July 2003. Measurements were also taken on olive trees close to the cement factory. Leaf dry matter content and specific leaf weight increased with leaf age and dust content. Cement dust decreased leaf total chlorophyll content and chlorophyll a/chlorophyll b ratio. As a result, photosynthetic rate and quantum yield decreased. In addition, transpiration rate slightly decreased, stomatal conductance to H2O and CO2 movement decreased, internal CO2 concentration remained constant and leaf temperature increased. The changes in chlorophyll are possibly due to shading and/or photosystem damage. The changes in stomatal functioning were possibly due to dust accumulation between the peltates or othe effects on stomata. Dust (in this case from a cement kiln) seems to cause substantial changes to leaf physiology, possibly leading to reduced olive productivity. Avoidance of air contamination from cement factories by using available technology should be examined together with any possible methodologies to reduce plant tissue contamination from cement dust. Longterm effects of dust (from cement kiln or other sources) on olive leaf, plant productivity and nutritional quality of edible parts could be studied for conclusive results on dust contamination effects to perennial crops.

Relationships between stem diameter, sapwood area, leaf area and transpiration in a young mountain ash forest.

PubMed

Vertessy, R A; Benyon, R G; O'Sullivan, S K; Gribben, P R

1995-09-01

We examined relationships between stem diameter, sapwood area, leaf area and transpiration in a 15-year-old mountain ash (Eucalyptus regnans F. Muell.) forest containing silver wattle (Acacia dealbata Link.) as a suppressed overstory species and mountain hickory (Acacia frigescens J.H. Willis) as an understory species. Stem diameter explained 93% of the variation in leaf area, 96% of the variation in sapwood area and 88% of the variation in mean daily spring transpiration in 19 mountain ash trees. In seven silver wattle trees, stem diameter explained 87% of the variation in sapwood area but was a poor predictor of the other variables. When transpiration measurements from individual trees were scaled up to a plot basis, using stem diameter values for 164 mountain ash trees and 124 silver wattle trees, mean daily spring transpiration rates of the two species were 2.3 and 0.6 mm day(-1), respectively. The leaf area index of the plot was estimated directly by destructive sampling, and indirectly with an LAI-2000 plant canopy analyzer and by hemispherical canopy photography. All three methods gave similar results.

Stimulated Leaf Dark Respiration in Tomato in an Elevated Carbon Dioxide Atmosphere

PubMed Central

Li, Xin; Zhang, Guanqun; Sun, Bo; Zhang, Shuai; Zhang, Yiqing; Liao, Yangwenke; Zhou, Yanhong; Xia, Xiaojian; Shi, Kai; Yu, Jingquan

2013-01-01

It is widely accepted that leaf dark respiration is a determining factor for the growth and maintenance of plant tissues and the carbon cycle. However, the underlying effect and mechanism of elevated CO2 concentrations ([CO2]) on dark respiration remain unclear. In this study, tomato plants grown at elevated [CO2] showed consistently higher leaf dark respiratory rate, as compared with ambient control plants. The increased respiratory capacity was driven by a greater abundance of proteins, carbohydrates, and transcripts involved in pathways of glycolysis carbohydrate metabolism, the tricarboxylic acid cycle, and mitochondrial electron transport energy metabolism. This study provides substantial evidence in support of the concept that leaf dark respiration is increased by elevated [CO2] in tomato plants and suggests that the increased availability of carbohydrates and the increased energy status are involved in the increased rate of dark respiration in response to elevated [CO2]. PMID:24305603

The content of phenolic compounds in leaf tissues of white (Aesculus hippocastanum L.) and red horse chestnut (Aesculus carea H.) colonized by the horse chestnut leaf miner (Cameraria ohridella Deschka & Dimić).

PubMed

Oszmiański, Jan; Kalisz, Stanisław; Aneta, Wojdyło

2014-09-15

Normally, plant phenolics are secondary metabolites involved in the defense mechanisms of plants against fungal pathogens. Therefore, in this study we attempted to quantify and characterize phenolic compounds in leaves of white and red horse chestnut with leaf miner larvae before and after Cameraria ohridella attack. A total of 17 phenolic compounds belonging to the hydroxycinnamic acid, flavan-3-ols and flavonol groups were identified and quantified in white and red horse chestnut leaf extracts. Significantly decreased concentrations of some phenolic compounds, especially of flavan-3-ols, were observed in infected leaves compared to the non-infected ones. Additionally, a higher content of polyphenolic compounds especially (-)-epicatechin and procyanidins in leaves of red-flowering than in white-flowering horse chestnut may explain their greater resistance to C. ohridella insects.

Enzyme-triggered self-assembly of a small molecule: a supramolecular hydrogel with leaf-like structures and an ultra-low minimum gelation concentration

NASA Astrophysics Data System (ADS)

Wang, Huaimin; Ren, Chunhua; Song, Zhijian; Wang, Ling; Chen, Xuemei; Yang, Zhimou

2010-06-01

We report on the use of a phosphatase to assist the formation of leaf-like structures and a supramolecular hydrogel with an ultra-low minimum gelation concentration. The compound can gel water at a minimum gelation concentration of 0.01 wt%, which is the lowest gelation concentration reported up to now. The images obtained by transmission electron microscopy (TEM) reveal the existence of leaf-like structures serving as the matrix of the hydrogels. The stability of the hydrogels was studied and emission spectra were used to get information about the molecular packing in the leaf-like structures. Since lowering the concentration of the gelator decreases the toxicity of the resulting hydrogels, ultra-low concentration gels have potential uses as biocompatible biomaterials for, e.g., cell cultures, tissue engineering, and drug delivery.

Refining the application of direct embryogenesis in sugarcane: Effect of the developmental phase of leaf disc explants and the timing of DNA transfer on transformation efficiency.

PubMed

Snyman, S J; Meyer, G M; Richards, J M; Haricharan, N; Ramgareeb, S; Huckett, B I

2006-10-01

A rapid in vitro protocol using direct somatic embryogenesis and microprojectile bombardment was investigated to establish the developmental phases most suitable for efficient sugarcane transformation. Immature leaf roll disc explants with and without pre-emergent inflorescence tissue were compared. It was shown that for effective transformation to occur, explants should be cultured for several days to allow initiation of embryo development prior to bombardment. Leaf roll discs with pre-emergent inflorescences showed a higher degree of embryogenic competence than non-flowering explants, and transformation efficiency was higher when explants containing floral initials were bombarded. Despite the occurrence of high numbers of phenotypically negative plants, combining the use of inflorescent leaf roll discs with direct embryogenic regeneration has the potential to improve the speed and efficiency of transgenesis in sugarcane.

Heavy metals in Franklin`s gull tissues: Age and tissue differences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, J.; Gochfeld, M.

1999-04-01

The authors examined the concentrations of lead, cadmium, chromium, mercury, manganese, and selenium in feathers, liver, kidney, heart, brain, and breast muscle of Franklin`s gulls (Larus pipixcan) nesting in northwestern Minnesota, USA, in 1994. Between 16% (chromium) and 71% (selenium, manganese) of the variation in metal concentrations was explained by tissue and age, except for selenium and arsenic, which were only explained by tissue. Of 35 possible differences (seven metals in five tissues), 24 significant age-related differences were found in Franklin`s gulls, with young generally having lower concentrations of metals in all of their tissues than adults. A notable exceptionmore » was the liver; young had significantly higher concentrations of selenium, chromium, manganese, and arsenic than did adults. Three notable findings were the following: young had significantly higher concentrations of selenium, chromium, manganese, and arsenic in their liver than did adults; young had 30 times as much chromium in the liver than adults; and adults had greatly elevated concentrations of cadmium in feathers, kidney, and liver.« less

Transcriptional transitions in Nicotiana benthamiana leaves upon induction of oil synthesis by WRINKLED1 homologs from diverse species and tissues.

PubMed

Grimberg, Åsa; Carlsson, Anders S; Marttila, Salla; Bhalerao, Rishikesh; Hofvander, Per

2015-08-08

Carbon accumulation and remobilization are essential mechanisms in plants to ensure energy transfer between plant tissues with different functions or metabolic needs and to support new generations. Knowledge about the regulation of carbon allocation into oil (triacylglycerol) in plant storage tissue can be of great economic and environmental importance for developing new high-yielding oil crops. Here, the effect on global gene expression as well as on physiological changes in leaves transiently expressing five homologs of the transcription factor WRINKLED1 (WRI1) originating from diverse species and tissues; Arabidopsis thaliana and potato (Solanum tuberosum) seed embryo, poplar (Populus trichocarpa) stem cambium, oat (Avena sativa) grain endosperm, and nutsedge (Cyperus esculentus) tuber parenchyma, were studied by agroinfiltration in Nicotiana benthamiana. All WRI1 homologs induced oil accumulation when expressed in leaf tissue. Transcriptome sequencing revealed that all homologs induced the same general patterns with a drastic shift in gene expression profiles of leaves from that of a typical source tissue to a source-limited sink-like tissue: Transcripts encoding enzymes for plastid uptake and metabolism of phosphoenolpyruvate, fatty acid and oil biosynthesis were up-regulated, as were also transcripts encoding starch degradation. Transcripts encoding enzymes in photosynthesis and starch synthesis were instead down-regulated. Moreover, transcripts representing fatty acid degradation were up-regulated indicating that fatty acids might be degraded to feed the increased need to channel carbons into fatty acid synthesis creating a futile cycle. RT-qPCR analysis of leaves expressing Arabidopsis WRI1 showed the temporal trends of transcripts selected as 'markers' for key metabolic pathways one to five days after agroinfiltration. Chlorophyll fluorescence measurements of leaves expressing Arabidopsis WRI1 showed a significant decrease in photosynthesis, even though effect on starch content could not be observed. This data gives for the first time a general view on the transcriptional transitions in leaf tissue upon induction of oil synthesis by WRI1. This yields important information about what effects WRI1 may exert on global gene expression during seed and embryo development. The results suggest why high oil content in leaf tissue cannot be achieved by solely transcriptional activation by WRI1, which can be essential knowledge in the development of new high-yielding oil crops.

Inducible repression of multiple expansin genes leads to growth suppression during leaf development.

PubMed

Goh, Hoe-Han; Sloan, Jennifer; Dorca-Fornell, Carmen; Fleming, Andrew

2012-08-01

Expansins are cell wall proteins implicated in the control of plant growth via loosening of the extracellular matrix. They are encoded by a large gene family, and data linked to loss of single gene function to support a role of expansins in leaf growth remain limited. Here, we provide a quantitative growth analysis of transgenics containing an inducible artificial microRNA construct designed to down-regulate the expression of a number of expansin genes that an expression analysis indicated are expressed during the development of Arabidopsis (Arabidopsis thaliana) leaf 6. The results support the hypothesis that expansins are required for leaf growth and show that decreased expansin gene expression leads to a more marked repression of growth during the later stage of leaf development. In addition, a histological analysis of leaves in which expansin gene expression was suppressed indicates that, despite smaller leaves, mean cell size was increased. These data provide functional evidence for a role of expansins in leaf growth, indicate the importance of tissue/organ developmental context for the outcome of altered expansin gene expression, and highlight the separation of the outcome of expansin gene expression at the cellular and organ levels.

Modulation of δ-Aminolevulinic Acid Dehydratase Activity by the Sorbitol-Induced Osmotic Stress in Maize Leaf Segments.

PubMed

Jain, M; Tiwary, S; Gadre, R

2018-01-01

Osmotic stress induced with 1 M sorbitol inhibited δ-aminolevulinic acid dehydratase (ALAD) and aminolevulinic acid (ALA) synthesizing activities in etiolated maize leaf segments during greening; the ALAD activity was inhibited to a greater extent than the ALA synthesis. When the leaves were exposed to light, the ALAD activity increased for the first 8 h, followed by a decrease observed at 16 and 24 h in both sorbitol-treated and untreated leaf tissues. The maximum inhibition of the enzyme activity was observed in the leaf segments incubated with sorbitol for 4 to 8 h. Glutamate increased the ALAD activity in the in vitro enzymatic preparations obtained from the sorbitol-treated leaf segments; sorbitol inhibited the ALAD activity in the preparations from both sorbitol-treated and untreated leaves. It was suggested that sorbitol-induced osmotic stress inhibits the enzyme activity by affecting the ALAD induction during greening and regulating the ALAD steady-state level of ALAD in leaf cells. The protective effect of glutamate on ALAD in the preparations from the sorbitol-treated leaves might be due to its stimulatory effect on the enzyme.

Electrotonic potentials in Aloe vera L.: Effects of intercellular and external electrodes arrangement.

PubMed

Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Scott, Jessenia M; Jackson, Mariah M Z; Greeman, Esther A; Greenidge, Ariane S; Cohen, Devin O; Volkova, Maia I; Shtessel, Yuri B

2017-02-01

Electrostimulation of plants can induce plant movements, activation of ion channels, ion transport, gene expression, enzymatic systems activation, electrical signaling, plant-cell damage, enhanced wound healing, and influence plant growth. Here we found that electrical networks in plant tissues have electrical differentiators. The amplitude of electrical responses decreases along a leaf and increases by decreasing the distance between polarizing Pt-electrodes. Intercellular Ag/AgCl electrodes inserted in a leaf and extracellular Ag/AgCl electrodes attached to the leaf surface were used to detect the electrotonic potential propagation along a leaf of Aloe vera. There is a difference in duration and amplitude of electrical potentials measured by electrodes inserted in a leaf and those attached to a leaf's surface. If the external reference electrode is located in the soil near the root, it changes the amplitude and duration of electrotonic potentials due to existence of additional resistance, capacitance, ion channels and ion pumps in the root. The information gained from this study can be used to elucidate extracellular and intercellular communication in the form of electrical signals within plants. Copyright © 2016 Elsevier B.V. All rights reserved.

Different mechanisms drive the performance of native and invasive woody species in response to leaf phosphorus supply during periods of drought stress and recovery.

PubMed

Oliveira, Marciel Teixeira; Medeiros, Camila Dias; Frosi, Gabriella; Santos, Mauro Guida

2014-09-01

The effects of drought stress and leaf phosphorus (Pi) supply on photosynthetic metabolism in woody tropical species are not known, and given the recent global environmental change models that forecast lower precipitation rates and periods of prolonged drought in tropical areas, this type of study is increasingly important. The effects of controlled drought stress and Pi supply on potted young plants of two woody species, Anadenanthera colubrina (native) and Prosopis juliflora (invasive), were determined by analyzing leaf photosynthetic metabolism, biochemical properties and water potential. In the maximum stress, both species showed higher leaf water potential (Ψl) in the treatment drought +Pi when compared with the respective control -Pi. The native species showed higher gas exchange under drought +Pi than under drought -Pi conditions, while the invasive species showed the same values between drought +Pi and -Pi. Drought affected the photochemical part of photosynthetic machinery more in the invasive species than in the native species. The invasive species showed higher leaf amino acid content and a lower leaf total protein content in both Pi treatments with drought. The two species showed different responses to the leaf Pi supply under water stress for several variables measured. In addition, the strong resilience of leaf gas exchange in the invasive species compared to the native species during the recovery period may be the result of higher efficiency of Pi use. The implications of this behavior for the success of this invasive species in semiarid environments are discussed. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Young Adult Reference Services in the Public Library.

ERIC Educational Resources Information Center

Boylan, Patricia

1984-01-01

Methods suggested for use by public libraries to stay on top of school assignments include a large, loose-leaf type binder entitled "School Assignments" to be kept at reference desk; assignment-related book lists; school assignment forms; and teacher notification forms to alert them if the library cannot fulfill their information…

Variation in species-level plant functional traits over wetland indicator status categories

USGS Publications Warehouse

McCoy-Sulentic, Miles E.; Kolb, Thomas E.; Merritt, David M.; Palmquist, Emily C.; Ralston, Barbara E.; Sarr, Daniel A.

2017-01-01

Wetland indicator status (WIS) describes the habitat affinity of plant species and is used in wetland delineations and resource inventories. Understanding how species-level functional traits vary across WIS categories may improve designations, elucidate mechanisms of adaptation, and explain habitat optima and niche. We investigated differences in species-level traits of riparian flora across WIS categories, extending their application to indicate hydrologic habitat. We measured or compiled data on specific leaf area (SLA), stem specific gravity (SSG), seed mass, and mature height of 110 plant species that occur along the Colorado River in Grand Canyon, Arizona. Additionally, we measured leaf δ13C, δ15N, % carbon, % nitrogen, and C/N ratio of 56 species with C3 photosynthesis. We asked the following: (i) How do species-level traits vary over WIS categories? (ii) Does the pattern differ between herbaceous and woody species? (iii) How well do multivariate traits define WIS categories? (iv) Which traits are correlated? The largest trait differences among WIS categories for herbaceous species occurred for SSG, seed mass, % leaf carbon and height, and for woody species occurred for height, SSG, and δ13C. SSG increased and height decreased with habitat aridity for both woody and herbaceous species. The δ13C and hence water use efficiency of woody species increased with habitat aridity. Water use efficiency of herbaceous species increased with habitat aridity via greater occurrence of C4 grasses. Multivariate trait assemblages differed among WIS categories. Over all species, SLA was correlated with height, δ13C, % leaf N, and C/N; height was correlated with SSG and % leaf C; SSG was correlated with % leaf C. Adaptations of both herbaceous and woody riparian species to wet, frequently inundated habitats include low-density stem tissue. Adaptations to drier habitats in the riparian zone include short, high-density cavitation-resistant stem tissue, and high water use efficiency. The results enhance understanding about using traits to describe plant habitat in riparian systems.

Ecophysiological response of Crambe maritima to airborne and soil-borne salinity

PubMed Central

de Vos, Arjen C.; Broekman, Rob; Groot, Maartje P.; Rozema, Jelte

2010-01-01

Background and Aims There is a need to evaluate the salt tolerance of plant species that can be cultivated as crops under saline conditions. Crambe maritima is a coastal plant, usually occurring on the driftline, with potential use as a vegetable crop. The aim of this experiment was to determine the growth response of Crambe maritima to various levels of airborne and soil-borne salinity and the ecophysiological mechanisms underlying these responses. Methods In the greenhouse, plants were exposed to salt spray (400 mm NaCl) as well as to various levels of root-zone salinity (RZS) of 0, 50, 100, 200 and 300 mm NaCl during 40 d. The salt tolerance of Crambe maritima was assessed by the relative growth rate (RGR) and its components. To study possible salinity effects on the tissue and cellular level, the leaf succulence, tissue Na+ concentrations, Na+ : K+ ratio, net K+/Na+ selectivity, N, P, K+, Ca2+, Mg2+, proline, soluble sugar concentrations, osmotic potential, total phenolics and antioxidant capacity were measured. Key Results Salt spray did not affect the RGR of Crambe maritima. However, leaf thickness and leaf succulence increased with salt spray. Root zone salinities up to 100 mm NaCl did not affect growth. However, at 200 mm NaCl RZS the RGR was reduced by 41 % compared with the control and by 56 % at 300 mm NaCl RZS. The reduced RGR with increasing RZS was largely due to the reduced specific leaf area, which was caused by increased leaf succulence as well as by increased leaf dry matter content. No changes in unit leaf rate were observed but increased RZS resulted in increased Na+ and proline concentrations, reduced K+, Ca2+ and Mg2+ concentrations, lower osmotic potential and increased antioxidant capacity. Proline concentrations of the leaves correlated strongly (r = 0·95) with RZS concentrations and not with plant growth. Conclusions Based on its growth response, Crambe maritima can be classified as a salt spray tolerant plant that is sensitive to root zone salinities exceeding 100 mm NaCl. PMID:20354071

Ultrastructural effects of AAL-toxin TA from the fungus Alternaria alternata on black nightshade (Solanum nigrum L.) leaf discs and correlation with biochemical measures of toxicity.

PubMed

Abbas, H K; Paul, R N; Riley, R T; Tanaka, T; Shier, W T

1998-12-01

Ultrastructural effects of AAL-toxin TA from Alternaria alternata on black nightshade (Solanum, nigrum L.) leaf discs and correlation with biochemical measures of toxicity. In black nightshade (Solanum nigrum L.) leaf discs floating in solutions of AAL-toxin TA (0.01-200 microM) under continuous light at 25 degrees C, electrolyte leakage, chlorophyll loss, autolysis, and photobleaching were observed within 24 h. Electrolyte leakage, measured by the conductivity increase in the culture medium, began after 12 h with 200 microM AAL-toxin T(A), but was observed after 24 h with 0.01 to 50 microM AAL-toxin T(A), when it ranged from 25%) to 63% of total releasable electrolytes, respectively. After 48 h incubation, leakage ranged from 39% to 79% of total for 0.01 to 200 microM AAL-toxin T(A), respectively, while chlorophyll loss ranged from 5% to 32% of total, respectively. Ultrastructural examination of black night-shade leaf discs floating in 10 microM AAL-toxin TA under continuous light at 25 degrees C revealed cytological damage beginning at 30 h, consistent with the time electrolyte leakage and chlorophyll reduction were observed. After 30 h incubation chloroplast starch grains were enlarged in control leaf discs, but not in AAL-toxin T(A)-treated discs, and the thylakoids of treated tissue contained structural abnormalities. After 36-48 h incubation with 10 microM AAL-toxin T(A), all tissues were destroyed with only cell walls, starch grains, and thylakoid fragments remaining. Toxicity was light-dependent, because leaf discs incubated with AAL-toxin T(A) in darkness for up to 72 h showed little phytotoxic damage. Within 6 h of exposure to > or =0.5 microM toxin, phytosphingosine and sphinganine in black nightshade leaf discs increased markedly, and continued to increase up to 24 h exposure. Thus, phy siological and ultrastructural changes occurred in parallel with disruption of sphingolipid synthesis, consistent with the hypothesis that AAL-toxin T(A) causes phytotoxicity by interrupting sphingolipid biosynthesis, thereby damaging cellular membranes.

Structure and vascular tissue expression of duplicated TERMINAL EAR1-like paralogues in poplar.

PubMed

Charon, Céline; Vivancos, Julien; Mazubert, Christelle; Paquet, Nicolas; Pilate, Gilles; Dron, Michel

2010-02-01

TERMINAL EAR1-like (TEL) genes encode putative RNA-binding proteins only found in land plants. Previous studies suggested that they may regulate tissue and organ initiation in Poaceae. Two TEL genes were identified in both Populus trichocarpa and the hybrid aspen Populus tremula x P. alba, named, respectively, PoptrTEL1-2 and PtaTEL1-2. The analysis of the organisation around the PoptrTEL genes in the P. trichocarpa genome and the estimation of the synonymous substitution rate for PtaTEL1-2 genes indicate that the paralogous link between these two Populus TEL genes probably results from the Salicoid large-scale gene-duplication event. Phylogenetic analyses confirmed their orthology link with the other TEL genes. The expression pattern of both PtaTEL genes appeared to be restricted to the mother cells of the plant body: leaf founder cells, leaf primordia, axillary buds and root differentiating tissues, as well as to mother cells of vascular tissues. Most interestingly, PtaTEL1-2 transcripts were found in differentiating cells of secondary xylem and phloem, but probably not in the cambium itself. Taken together, these results indicate specific expression of the TEL genes in differentiating cells controlling tissue and organ development in Populus (and other Angiosperm species).

The world's biomes and primary production as a triple tragedy of the commons foraging game played among plants

PubMed Central

Gonzalez-Meler, Miquel A.; Lynch, Douglas J.; Baltzer, Jennifer L.

2016-01-01

Plants appear to produce an excess of leaves, stems and roots beyond what would provide the most efficient harvest of available resources. One way to understand this overproduction of tissues is that excess tissue production provides a competitive advantage. Game theoretic models predict overproduction of all tissues compared with non-game theoretic models because they explicitly account for this indirect competitive benefit. Here, we present a simple game theoretic model of plants simultaneously competing to harvest carbon and nitrogen. In the model, a plant's fitness is influenced by its own leaf, stem and root production, and the tissue production of others, which produces a triple tragedy of the commons. Our model predicts (i) absolute net primary production when compared with two independent global datasets; (ii) the allocation relationships to leaf, stem and root tissues in one dataset; (iii) the global distribution of biome types and the plant functional types found within each biome; and (iv) ecosystem responses to nitrogen or carbon fertilization. Our game theoretic approach removes the need to define allocation or vegetation type a priori but instead lets these emerge from the model as evolutionarily stable strategies. We believe this to be the simplest possible model that can describe plant production. PMID:28120794

The world's biomes and primary production as a triple tragedy of the commons foraging game played among plants.

PubMed

McNickle, Gordon G; Gonzalez-Meler, Miquel A; Lynch, Douglas J; Baltzer, Jennifer L; Brown, Joel S

2016-11-16

Plants appear to produce an excess of leaves, stems and roots beyond what would provide the most efficient harvest of available resources. One way to understand this overproduction of tissues is that excess tissue production provides a competitive advantage. Game theoretic models predict overproduction of all tissues compared with non-game theoretic models because they explicitly account for this indirect competitive benefit. Here, we present a simple game theoretic model of plants simultaneously competing to harvest carbon and nitrogen. In the model, a plant's fitness is influenced by its own leaf, stem and root production, and the tissue production of others, which produces a triple tragedy of the commons. Our model predicts (i) absolute net primary production when compared with two independent global datasets; (ii) the allocation relationships to leaf, stem and root tissues in one dataset; (iii) the global distribution of biome types and the plant functional types found within each biome; and (iv) ecosystem responses to nitrogen or carbon fertilization. Our game theoretic approach removes the need to define allocation or vegetation type a priori but instead lets these emerge from the model as evolutionarily stable strategies. We believe this to be the simplest possible model that can describe plant production. © 2016 The Author(s).

Trade-offs between seed and leaf size (seed-phytomer-leaf theory): functional glue linking regenerative with life history strategies … and taxonomy with ecology?

PubMed

Hodgson, John G; Santini, Bianca A; Montserrat Marti, Gabriel; Royo Pla, Ferran; Jones, Glynis; Bogaard, Amy; Charles, Mike; Font, Xavier; Ater, Mohammed; Taleb, Abdelkader; Poschlod, Peter; Hmimsa, Younes; Palmer, Carol; Wilson, Peter J; Band, Stuart R; Styring, Amy; Diffey, Charlotte; Green, Laura; Nitsch, Erika; Stroud, Elizabeth; Romo-Díez, Angel; de Torres Espuny, Lluis; Warham, Gemma

2017-11-10

While the 'worldwide leaf economics spectrum' (Wright IJ, Reich PB, Westoby M, et al. 2004. The worldwide leaf economics spectrum. Nature : 821-827) defines mineral nutrient relationships in plants, no unifying functional consensus links size attributes. Here, the focus is upon leaf size, a much-studied plant trait that scales positively with habitat quality and components of plant size. The objective is to show that this wide range of relationships is explicable in terms of a seed-phytomer-leaf (SPL) theoretical model defining leaf size in terms of trade-offs involving the size, growth rate and number of the building blocks (phytomers) of which the young shoot is constructed. Functional data for 2400+ species and English and Spanish vegetation surveys were used to explore interrelationships between leaf area, leaf width, canopy height, seed mass and leaf dry matter content (LDMC). Leaf area was a consistent function of canopy height, LDMC and seed mass. Additionally, size traits are partially uncoupled. First, broad laminas help confer competitive exclusion while morphologically large leaves can, through dissection, be functionally small. Secondly, leaf size scales positively with plant size but many of the largest-leaved species are of medium height with basally supported leaves. Thirdly, photosynthetic stems may represent a functionally viable alternative to 'small seeds + large leaves' in disturbed, fertile habitats and 'large seeds + small leaves' in infertile ones. Although key elements defining the juvenile growth phase remain unmeasured, our results broadly support SPL theory in that phytometer and leaf size are a product of the size of the initial shoot meristem (≅ seed mass) and the duration and quality of juvenile growth. These allometrically constrained traits combine to confer ecological specialization on individual species. Equally, they appear conservatively expressed within major taxa. Thus, 'evolutionary canalization' sensu Stebbins (Stebbins GL. 1974. Flowering plants: evolution above the species level . Cambridge, MA: Belknap Press) is perhaps associated with both seed and leaf development, and major taxa appear routinely specialized with respect to ecologically important size-related traits. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

WHITE STRIPE LEAF4 Encodes a Novel P-Type PPR Protein Required for Chloroplast Biogenesis during Early Leaf Development

PubMed Central

Wang, Ying; Ren, Yulong; Zhou, Kunneng; Liu, Linglong; Wang, Jiulin; Xu, Yang; Zhang, Huan; Zhang, Long; Feng, Zhiming; Wang, Liwei; Ma, Weiwei; Wang, Yunlong; Guo, Xiuping; Zhang, Xin; Lei, Cailin; Cheng, Zhijun; Wan, Jianmin

2017-01-01

Pentatricopeptide repeat (PPR) proteins comprise a large family in higher plants and perform diverse functions in organellar RNA metabolism. Despite the rice genome encodes 477 PRR proteins, the regulatory effects of PRR proteins on chloroplast development remains unknown. In this study, we report the functional characterization of the rice white stripe leaf4 (wsl4) mutant. The wsl4 mutant develops white-striped leaves during early leaf development, characterized by decreased chlorophyll content and malformed chloroplasts. Positional cloning of the WSL4 gene, together with complementation and RNA-interference tests, reveal that it encodes a novel P-family PPR protein with 12 PPR motifs, and is localized to chloroplast nucleoids. Quantitative RT-PCR analyses demonstrate that WSL4 is a low temperature response gene abundantly expressed in young leaves. Further expression analyses show that many nuclear- and plastid-encoded genes in the wsl4 mutant are significantly affected at the RNA and protein levels. Notably, the wsl4 mutant causes defects in the splicing of atpF, ndhA, rpl2, and rps12. Our findings identify WSL4 as a novel P-family PPR protein essential for chloroplast RNA group II intron splicing during early leaf development in rice. PMID:28694820

Compound-Specific Radiocarbon Dating Reveals the Age Distribution of Plant-Wax Biomarkers Exported to the Bengal Fan

NASA Astrophysics Data System (ADS)

Galy, V.; French, K. L.; Hein, C. J.; Haghipour, N.; Wacker, L.; Kudrass, H.; Eglinton, T. I.

2017-12-01

The stable isotope composition of leaf-wax compounds preserved in lacustrine and marine sediments has been widely used to reconstruct terrestrial paleo-environments. However, the timescales of plant-wax storage in continental reservoirs before riverine export are not well known, representing a key uncertainty in paleo-environment studies. We couple numerical models with bulk and leaf-wax fatty acid organic 13C and 14C signatures hosted in a high-deposition-rate sediment core from the Bengal shelf canyon in order to estimate storage timescales within the Ganges-Brahmaputra catchment area. The fatty acid 14C record reveals a muted nuclear weapons bomb spike, requiring that the Ganges-Brahmaputra river system exports a mixture of young and old (pre-aged) leaf-wax compounds. According to numerical simulations, 79-83% of the leaf-wax fatty acids in this core are sourced from continental reservoirs that store organic carbon on an average of 1000-1200 calendar years, while the remainder has an average age of 15 years. These results demonstrate that a majority of the leaf-wax compounds produced in the Ganges-Brahmaputra river basin was stored in soils, floodplains, and wetlands prior to its export to the Bengal Fan. We will discuss the implications of these findings for plant-wax based paleoenvironmental records.

Autophagy Supports Biomass Production and Nitrogen Use Efficiency at the Vegetative Stage in Rice1[OPEN

PubMed Central

Hayashida, Yasukazu; Kurusu, Takamitsu; Kojima, Soichi; Makino, Amane

2015-01-01

Much of the nitrogen in leaves is distributed to chloroplasts, mainly in photosynthetic proteins. During leaf senescence, chloroplastic proteins, including Rubisco, are rapidly degraded, and the released nitrogen is remobilized and reused in newly developing tissues. Autophagy facilitates the degradation of intracellular components for nutrient recycling in all eukaryotes, and recent studies have revealed critical roles for autophagy in Rubisco degradation and nitrogen remobilization into seeds in Arabidopsis (Arabidopsis thaliana). Here, we examined the function of autophagy in vegetative growth and nitrogen usage in a cereal plant, rice (Oryza sativa). An autophagy-disrupted rice mutant, Osatg7-1, showed reduced biomass production and nitrogen use efficiency compared with the wild type. While Osatg7-1 showed early visible leaf senescence, the nitrogen concentration remained high in the senescent leaves. 15N pulse chase analysis revealed suppression of nitrogen remobilization during leaf senescence in Osatg7-1. Accordingly, the reduction of nitrogen available for newly developing tissues in Osatg7-1 likely led its reduced leaf area and tillers. The limited leaf growth in Osatg7-1 decreased the photosynthetic capacity of the plant. Much of the nitrogen remaining in senescent leaves of Osatg7-1 was in soluble proteins, and the Rubisco concentration in senescing leaves of Osatg7-1 was about 2.5 times higher than in the wild type. Transmission electron micrographs showed a cytosolic fraction rich with organelles in senescent leaves of Osatg7-1. Our results suggest that autophagy contributes to efficient nitrogen remobilization at the whole-plant level by facilitating protein degradation for nitrogen recycling in senescent leaves. PMID:25786829

[Cold resistance of four evergreen broad-leaved tree species].

PubMed

Wang, Na; Wang, Kui Ling; Liu, Qing Hua; Liu, Qing Chao

2016-10-01

The leaves of four evergreen plants, i.e., Fatsia japonica, Nerium indicum, Mahonia bealei and Acer cinnamomifolium were used as the experimental materials. By measuring the changes of in vitro leaf in soluble sugar, soluble protein, free proline, POD activity, chlorophyll content and relative electrolytic conductivity under aritificial simulated low temperature, combining the measurements of SPAD, leaf surface features and anatomical changes in organizational structure in the process of natural wintering, the cold resistance of four evergreen tree species was evaluated comprehensively. The results showed that in the process of artificial low temperature stress, the chlorophyll content of the leaves of four evergreen species decreased, the content of soluble protein pea-ked at -20 ℃, and the soluble sugar, free proline, POD activity and relative electrolytic conductivity showed an overall upward trend. The semilethal temperatures of four species were -8.0, -13.4, -19.4 and -14.8 ℃, respectively. During the winter, the leaf SPAD of the four species changed markedly, reflecting that the change of relative chlorophyll content was related to the change of temperature. Meanwhile, the leaf thickness, cutin layer thickness, stockade tissue thickness and tightness of four species increased and the plasmolysis occurred thereafter. Also the content of starch grains and calcium oxalate cluster crystal increased. The typical stomatal pits and the intensive non-glandular trichome within the pits of N. indicum and the sclerenchyma of M. Bealei could improve the cold resistance of plants to some extent. In addition, the phenomena like the breakage of wax layer in leaf surface, the fracture of epidermal hair and the deformation of palisade tissue indicated that plants were damaged to a certain extent by low temperature.