Rapid multiplication of Dalbergia sissoo Roxb.: a timber yielding tree legume through axillary shoot proliferation and ex vitro rooting.

PubMed

Vibha, J B; Shekhawat, N S; Mehandru, Pooja; Dinesh, Rachana

2014-01-01

An efficient and improved method for in vitro propagation of mature tree of Dalbergia sissoo, an ecologically and commercially important timber yielding species, has been developed through axillary shoot proliferation. Bud breaking occurred from nodal shoot segments derived from rejuvenated shoots produced during early spring from a 20-25-year-old lopped tree, on MS medium containing 8.88 μM benzylaminopurine (BAP). Multiple shoots differentiated (20-21shoots/node) on re-culture of explants on half-strength agar gelled amended MS medium with a combination of 2.22 μM of BAP and 0.002 μM of thidiazuron (TDZ) with 1.0 mM each of Ca(NO3)2, K2SO4, KCl, and NH4(SO4)2. The maximum shoot multiplication (29-30 shoots/node) was achieved on subculturing in the above mentioned but liquid medium. Furthermore, the problem of shoot tip necrosis and defoliation observed on solid medium were overcome by the use of liquid medium. Ex vitro rooting was achieved on soilrite after basal treatment of microshoots with 984 μM of indole-3-butyric acid (IBA) for 2 min. About 90 % microshoots were rooted on soilrite within 2-3 weeks under the greenhouse conditions. From 20 nodal shoot segments, about 435 hardened plants were acclimatized and transplanted. This is the first report for rapid in vitro propagation of mature trees of D. sissoo on liquid medium followed by ex vitro rooting.

76 FR 1339 - Pine Shoot Beetle; Additions to Quarantined Areas

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-10

..., a pest of pine trees, into noninfested areas of the United States. DATES: Effective on January 10... managed and natural stands of pine and especially affects weak and dying trees. The beetle has been found... distorted growth in host trees. Large infestations of PSB typically kill most of the lateral shoots near the...

Long-shoot/short-shoot phenomenon in woody plants

Treesearch

Ronald E. Sosebee

2001-01-01

Shoot growth in shrubs is often overlooked as an important component of phenological development in woody plants. However, shoot growth dictates the pattern of growth of deciduous trees or shrubs, especially following defoliation or canopy damage. In general, woody shoots are divided into short- and long-shoots. Short-shoots, sometimes called "spurs," are...

Enhanced Acquisition Rates of 'Candidatus Liberibacter asiaticus' by the Asian Citrus Psyllid (Hemiptera: Liviidae) in the Presence of Vegetative Flush Growth in Citrus.

PubMed

Sétamou, Mamoudou; Alabi, Olufemi J; Kunta, Madhurababu; Jifon, John L; da Graça, John V

2016-10-01

The Asian citrus psyllid preferentially feeds and exclusively reproduces on young, newly emerged flush shoots of citrus. Asian citrus psyllid nymphs feed and complete their life stages on these flush shoots. Recent studies conducted under greenhouse conditions have shown that the transmission rates of 'Candidatus Liberibacter asiaticus' (CLas), the putative causal agent of huanglongbing disease of citrus, are enhanced when flush shoots are present. However, it is unclear if CLas acquisition by migrant adult Asian citrus psyllids is similarly enhanced. To address this knowledge gap, cohorts of Asian citrus psyllid adults were allowed 1-wk acquisition access period (AAP) on flushing and nonflushing shoots of qPCR-tested symptomatic (CLas+) and asymptomatic (CLas-) 10-yr-old sweet orange trees under field conditions. After the AAP, they were tested for CLas by qPCR. Progeny Asian citrus psyllid adults that emerged 4 wk post-AAP were similarly retrieved and tested. Eighty percent of flushing and 30% of nonflushing CLas+ trees produced infective Asian citrus psyllid adults, indicating that flush shoots have greater potential to be inoculum sources for CLas acquisition. Concomitantly, 21.1% and 6.0% infective adults were retrieved, respectively, from flushing and nonflushing CLas+ trees, indicating that Asian citrus psyllid adults acquire CLas more efficiently from flush shoots relative to mature shoots. In addition, 12.1% of infective Asian citrus psyllid adult progeny were obtained from 70% of flushing CLas+ trees. Significantly lower mean Ct values were also obtained from infective adults retrieved from flushing relative to nonflushing trees. The results underscore the role of flush shoots in CLas acquisition and the need to protect citrus trees from Asian citrus psyllid infestations during flush cycles. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

How young trees cope with removal of whole or parts of shoots: an analysis of local and distant responses to pruning in 1-year-old apple (Malus xdomestica; Rosaceae) trees.

PubMed

Fumey, Damien; Lauri, Pierre-Éric; Guédon, Yann; Godin, Christophe; Costes, Evelyne

2011-11-01

Manipulation of tree architecture by pruning provides an experimental context to analyze architectural plasticity resulting from competition between developing organs. The objective of this study was to quantify the effects of the removal of all or part of shoots through pruning on the redistribution of growth and flowering at spatial and temporal levels. Two types of pruning cuts were applied: (1) heading cuts of either the main stem or laterals and (2) thinning cuts (i.e., complete removal) of laterals. These two types of cuts were applied in summer and winter on 1-yr-old cultivars of Fuji and Braeburn apple trees. Tree topology and geometry were described over 3 years, and responses were analyzed for both local and distant scales. Heading cuts induced quasi-deterministic local responses on pruned axes, whereas responses to thinning cuts were more variable. For the main stem and laterals, responses over greater spatial and temporal scales were highlighted with (1) stronger growth the year after summer pruning and (2) modification of branching and flowering along the unpruned parts after winter pruning. Pruning typically induced growth redistribution toward traumatic reiterations and enhanced growth of the remaining unpruned axes with a concomitant decrease of flowering and cambial growth. Although results could be interpreted in relation to the root-shoot balance, tree responses appeared highly cultivar-specific.

Loss of a highly conserved sterile alpha motif domain gene (WEEP) results in pendulous branch growth in peach trees.

PubMed

Hollender, Courtney A; Pascal, Thierry; Tabb, Amy; Hadiarto, Toto; Srinivasan, Chinnathambi; Wang, Wanpeng; Liu, Zhongchi; Scorza, Ralph; Dardick, Chris

2018-05-15

Plant shoots typically grow upward in opposition to the pull of gravity. However, exceptions exist throughout the plant kingdom. Most conspicuous are trees with weeping or pendulous branches. While such trees have long been cultivated and appreciated for their ornamental value, the molecular basis behind the weeping habit is not known. Here, we characterized a weeping tree phenotype in Prunus persica (peach) and identified the underlying genetic mutation using a genomic sequencing approach. Weeping peach tree shoots exhibited a downward elliptical growth pattern and did not exhibit an upward bending in response to 90° reorientation. The causative allele was found to be an uncharacterized gene, Ppa013325 , having a 1.8-Kb deletion spanning the 5' end. This gene, dubbed WEEP , was predominantly expressed in phloem tissues and encodes a highly conserved 129-amino acid protein containing a sterile alpha motif (SAM) domain. Silencing WEEP in the related tree species Prunus domestica (plum) resulted in more outward, downward, and wandering shoot orientations compared to standard trees, supporting a role for WEEP in directing lateral shoot growth in trees. This previously unknown regulator of branch orientation, which may also be a regulator of gravity perception or response, provides insights into our understanding of how tree branches grow in opposition to gravity and could serve as a critical target for manipulating tree architecture for improved tree shape in agricultural and horticulture applications. Copyright © 2018 the Author(s). Published by PNAS.

Effect of adenine sulphate interaction on growth and development of shoot regeneration and inhibition of shoot tip necrosis under in vitro condition in adult Syzygium cumini L.--a multipurpose tree.

PubMed

Naaz, Afshan; Shahzad, Anwar; Anis, Mohammad

2014-05-01

An efficient method for cloning Syzygium cumini (above 40 years old) through mature nodal segments has been successfully developed and that could be exploited for large-scale production of this valuable multipurpose tree. Nodal segments from mature tree were taken as explants and cultured on MS basal medium with different cytokinins (BA, Kin, AdS). The application of BA proved to be the best responsive cytokinin for the induction of shoot buds and shoots, but the proliferated shoots exhibited slower and stunted growth accompanied with abscission of leaves and shoot tip necrosis (STN). The problem of leaf abscission and STN was considerably reduced by the application of an adjuvant, adenine sulphate (AdS) in the optimal medium which led to the production of a maximum of 14 shoots. Further improvement in shoot bud regeneration and improved growth pattern of the regenerating tissue was obtained on the media comprised of MS + BA (10 μM) + GA3 (2.5 μM). A total number of 15 shoots with mean shoot length of 5.9 cm was obtained. The healthy elongated shoots were then rooted on MS basal augmented with NAA (5 μM). The plantlets obtained were healthy and were successfully acclimatized and transferred under field condition with 70 % survival rate.

Tomicus piniperda (Coleoptera: Scolytidae) Shoot-Feding Characteristics and Overwintering Behavior in Scotch Pine Christmas Trees

Treesearch

Robert A. Haack; Robert K. Lawrence; George C. Heaton

2001-01-01

Overwintering behavior of Tomicus piniperda (L.) was studied in a Scotch pine (Pinus sylvestris L.) Christmas tree plantation in Indiana (1992-1994) and a plantation in Michigan (1994). In general, adults feed inside shoots during summer, then move to overwintering sites at the base of trees in autumn. In early autumn, adults were...

Genomewide analysis of ABCBs with a focus on ABCB1 and ABCB19 in Malus domestica.

PubMed

Ma, Juan Juan; Han, Mingyu

2016-03-01

The B subfamily of ATP-binding cassette (ABC) proteins (ABCB) plays a vital role in auxin efflux. However, no systematic study has been done in apple. In this study, we performed genomewide identification and expression analyses of the ABCB family in Malus domestica for the first time. We identified a total of 25 apple ABCBs that were divided into three clusters based on the phylogenetic analysis. Most ABCBs within the same cluster demonstrated a similar exon-intron organization. Additionally, the digital expression profiles of ABCB genes shed light on their functional divergence. ABCB1 and ABCB19 are two well-studied auxin efflux carrier genes, and we found that their expression levels are higher in young shoots of M106 than in young shoots ofM9. Since young shoots are the main source of auxin synthesis and auxin efflux involves in tree height control. This suggests that ABCB1 and ABCB19 may also take a part in the auxin efflux and tree height control in apple.

Shoot bending promotes flower bud formation by miRNA-mediated regulation in apple (Malus domestica Borkh.).

PubMed

Xing, Libo; Zhang, Dong; Zhao, Caiping; Li, Youmei; Ma, Juanjuan; An, Na; Han, Mingyu

2016-02-01

Flower induction in apple (Malus domestica Borkh.) trees plays an important life cycle role, but young trees produce fewer and inferior quality flower buds. Therefore, shoot bending has become an important cultural practice, significantly promoting the capacity to develop more flower buds during the growing seasons. Additionally, microRNAs (miRNAs) play essential roles in plant growth, flower induction and stress responses. In this study, we identified miRNAs potentially involved in the regulation of bud growth, and flower induction and development, as well as in the response to shoot bending. Of the 195 miRNAs identified, 137 were novel miRNAs. The miRNA expression profiles revealed that the expression levels of 68 and 27 known miRNAs were down-regulated and up-regulated, respectively, in response to shoot bending, and that the 31 differentially expressed novel miRNAs between them formed five major clusters. Additionally, a complex regulatory network associated with auxin, cytokinin, abscisic acid (ABA) and gibberellic acid (GA) plays important roles in cell division, bud growth and flower induction, in which related miRNAs and targets mediated regulation. Among them, miR396, 160, 393, and their targets associated with AUX, miR159, 319, 164, and their targets associated with ABA and GA, and flowering-related miRNAs and genes, regulate bud growth and flower bud formation in response to shoot bending. Meanwhile, the flowering genes had significantly higher expression levels during shoot bending, suggesting that they are involved in this regulatory process. This study provides a framework for the future analysis of miRNAs associated with multiple hormones and their roles in the regulation of bud growth, and flower induction and formation in response to shoot bending in apple trees. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Leaf flush in black walnut at several midwest locations

Treesearch

Calvin F. Bey

1972-01-01

Late spring frosts damage the tender new growth of black walnut trees, and the earliest trees to break dormancy are vulnerable for the longest period. Walnut trees growing in coves and low spots (frost pockets) are most vulnerable. If the terminal shoot is killed, one or more lateral buds at the base of the newly killed shoot commonly develop; generally, the result is...

Branch age and light conditions determine leaf-area-specific conductivity in current shoots of Scots pine.

PubMed

Grönlund, Leila; Hölttä, Teemu; Mäkelä, Annikki

2016-08-01

Shoot size and other shoot properties more or less follow the availability of light, but there is also evidence that the topological position in a tree crown has an influence on shoot development. Whether the hydraulic properties of new shoots are more regulated by the light or the position affects the shoot acclimation to changing light conditions and thereby to changing evaporative demand. We investigated the leaf-area-specific conductivity (and its components sapwood-specific conductivity and Huber value) of the current-year shoots of Scots pine (Pinus sylvestris L.) in relation to light environment and topological position in three different tree classes. The light environment was quantified in terms of simulated transpiration and the topological position was quantified by parent branch age. Sample shoot measurements included length, basal and tip diameter, hydraulic conductivity of the shoot, tracheid area and density, and specific leaf area. In our results, the leaf-area-specific conductivity of new shoots declined with parent branch age and increased with simulated transpiration rate of the shoot. The relation to transpiration demand seemed more decisive, since it gave higher R(2) values than branch age and explained the differences between the tree classes. The trend of leaf-area-specific conductivity with simulated transpiration was closely related to Huber value, whereas the trend of leaf-area-specific conductivity with parent branch age was related to a similar trend in sapwood-specific conductivity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

XEROMORPHY INCREASES IN SHOOTS OF PSEUDOTSUGA MENZIESII (MIRB.) FRANCO SEEDLINGS WITH EXPOSURE TO ELEVATED TEMPERATURE BUT NOT ELEVATED CO2

EPA Science Inventory

Seedling structure influences tree structure and function, ultimately determining the potential productivity of trees and their competitiveness for resources. We investigated changes in shoot organ structure, as indicated by biomass allocation, allometry and anatomy in response ...

Effects of excluding goat herbivory on Acacia tortilis woodland around pastoralist settlements in northwest Kenya

NASA Astrophysics Data System (ADS)

Oba, Gufu

1998-08-01

Browsing by goats is considered to cause poor tree regeneration and reduced tree growth around settlements throughout the arid zones of sub-Saharan Africa. This study investigated whether excluding goats from Acacia tortilis woodlands increased tree regeneration, current season's shoot growth rates and browse production over a period of 52 months between 1986 and 1990. The study also investigated the effects of climatic variability on tree growth and browse production. Excluding goat herbivory provided no advantage over continuous browsing for juvenile A. tortilis. Trees on the unbrowsed and on browsed transects increased by 22.2 (standard error [SE] ± 0.53) cm·yr -1 and 25.0 (SE ± 0.58) cm·yr -1, respectively. Fewer but longer shoots were produced by trees on the unbrowsed transects, while trees on the browsed transects invested more in shorter shoots. Net total browse production was lower on unbrowsed (1.73 [standard deviation (SD) ± 4.3] t·ha -1·yr -1) than on the browsed (3.03 [SD ± 3.6] t·ha -1 ·yr -1) transects. Biomass production on unbrowsed and browsed transects was closely correlated with rainfall and presumably soil moisture during wet seasons. Relative growth rates (RGR) of current season's shoots in the two treatments did not differ, implying goat herbivory at moderate stocking density (i.e. 13.0 tropical livestock units [TLU]·km -2) stimulated shoot growth. RGR remained positive except on the browsed transects during 1990, a dry year. Goat browsing pressure was moderate. Total biomass loss on unbrowsed transects was 15.5 %·yr -1 compared with 27.7 %·yr -1 on the browsed transects. These findings do not support the notion that goats always destroy young trees around settlements. Goat herbivory at moderate intensity stimulated shoot productivity. However, the results should not be used to generalize all conditions throughout sub-Saharan Africa, let alone the arid zones of northern Kenya. Rather, there is a need to emphasize individual case studies that ultimately can be used for managing degraded woodlands near pastoralist settlements.

Root-zone temperatures affect phenology of bud break, flower cluster development, shoot extension growth and gas exchange of 'Braeburn' (Malus domestica) apple trees.

PubMed

Greer, Dennis H; Wünsche, Jens N; Norling, Cara L; Wiggins, Harry N

2006-01-01

We investigated the effects of root-zone temperature on bud break, flowering, shoot growth and gas exchange of potted mature apple (Malus domestica (Borkh.)) trees with undisturbed roots. Soil respiration was also determined. Potted 'Braeburn' apple trees on M.9 rootstock were grown for 70 days in a constant day/night temperature regime (25/18 degrees C) and one of three constant root-zone temperatures (7, 15 and 25 degrees C). Both the proportion and timing of bud break were significantly enhanced as root-zone temperature increased. Rate of floral cluster opening was also markedly increased with increasing root-zone temperature. Shoot length increased but shoot girth growth declined as root-zone temperatures increased. Soil respiration and leaf photosynthesis generally increased as root-zone temperatures increased. Results indicate that apple trees growing in regions where root zone temperatures are < or = 15 degrees C have delayed bud break and up to 20% fewer clusters than apple trees exposed to root zone temperatures of > or = 15 degrees C. The effect of root-zone temperature on shoot performance may be mediated through the mobilization of root reserves, although the role of phytohormones cannot be discounted. Variation in leaf photosynthesis across the temperature treatments was inadequately explained by stomatal conductance. Given that root growth increases with increasing temperature, changes in sink activity induced by the root-zone temperature treatments provide a possible explanation for the non-stomatal effect on photosynthesis. Irrespective of underlying mechanisms, root-zone temperatures influence bud break and flowering in apple trees.

Shoot water relations of mature black spruce families displaying a genotype x environment interaction in growth rate. I. Family and site effects over three growing seasons

Treesearch

Kurt H. Johnsen; John E Major

1999-01-01

Pressure-volume curves were determined for black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families. During the first two years, trees were measured from a plantation on a dry site. In the third year, trees were sampled from the dry site and a wet site. Diurnal measurements of shoot water potential allowed in situ ...

An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

PubMed Central

Rodríguez-Gamir, Juan; Primo-Millo, Eduardo; Forner-Giner, María Ángeles

2016-01-01

Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L.) Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.). The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy. PMID:27223695

Histology and cell wall biochemistry of stone cells in the physical defence of conifers against insects.

PubMed

Whitehill, Justin G A; Henderson, Hannah; Schuetz, Mathias; Skyba, Oleksandr; Yuen, Macaire Man Saint; King, John; Samuels, A Lacey; Mansfield, Shawn D; Bohlmann, Jörg

2016-08-01

Conifers possess an array of physical and chemical defences against stem-boring insects. Stone cells provide a physical defence associated with resistance against bark beetles and weevils. In Sitka spruce (Picea sitchensis), abundance of stone cells in the cortex of apical shoots is positively correlated with resistance to white pine weevil (Pissodes strobi). We identified histological, biochemical and molecular differences in the stone cell phenotype of weevil resistant (R) or susceptible (S) Sitka spruce genotypes. R trees displayed significantly higher quantities of cortical stone cells near the apical shoot node, the primary site for weevil feeding. Lignin, cellulose, xylan and mannan were the most abundant components of stone cell secondary walls, respectively. Lignin composition of stone cells isolated from R trees contained a higher percentage of G-lignin compared with S trees. Transcript profiling revealed higher transcript abundance in the R genotype of coumarate 3-hydroxylase, a key monolignol biosynthetic gene. Developing stone cells in current year apical shoots incorporated fluorescent-tagged monolignol into the secondary cell wall, while mature stone cells of previous year apical shoots did not. Stone cell development is an ephemeral process, and fortification of shoot tips in R trees is an effective strategy against insect feeding. © 2015 John Wiley & Sons Ltd.

A study of crown development mechanisms using a shoot-based tree model and segmented terrestrial laser scanning data.

PubMed

Sievänen, Risto; Raumonen, Pasi; Perttunen, Jari; Nikinmaa, Eero; Kaitaniemi, Pekka

2018-05-24

Functional-structural plant models (FSPMs) allow simulation of tree crown development as the sum of modular (e.g. shoot-level) responses triggered by the local environmental conditions. The actual process of space filling by the crowns can be studied. Although the FSPM simulations are at organ scale, the data for their validation have usually been at more aggregated levels (whole-crown or whole-tree). Measurements made by terrestrial laser scanning (TLS) that have been segmented into elementary units (internodes) offer a phenotyping tool to validate the FSPM predictions at levels comparable with their detail. We demonstrate the testing of different formulations of crown development of Scots pine trees in the LIGNUM model using segmented TLS data. We made TLS measurements from four sample trees growing in a forest on a relatively poor soil from sapling size to mature stage. The TLS data were segmented into internodes. The segmentation also produced information on whether needles were present in the internode. We applied different formulations of crown development (flushing of buds and length of growth of new internodes) in LIGNUM. We optimized the parameter values of each formulation using genetic algorithms to observe the best fit of LIGNUM simulations to the measured trees. The fitness function in the estimation combined both tree-level characteristics (e.g. tree height and crown length) and measures of crown shape (e.g. spatial distribution of needle area). Comparison of different formulations against the data indicates that the Extended Borchert-Honda model for shoot elongation works best within LIGNUM. Control of growth by local density in the crown was important for all shoot elongation formulations. Modifying the number of lateral buds as a function of local density in the crown was the best way to accomplish density control. It was demonstrated how segmented TLS data can be used in the context of a shoot-based model to select model components.

In vitro propagation, ex vitro rooting and leaf micromorphology of Bauhinia racemosa Lam.: a leguminous tree with medicinal values.

PubMed

Sharma, Udit; Kataria, Vinod; Shekhawat, N S

2017-10-01

A micropropagation system for Bauhinia racemosa Lam. was developed involving axillary shoot proliferation and ex vitro rooting using nodal explants obtained from mature tree. MS medium with 3.0 mg l -1 BA (6-benzyladenine) was optimum for shoot bud induction. For shoot multiplication, mother explants were transferred repeatedly on medium containing low concentration of BA (0.75 mg l -1 ). Number of shoots was increased up to two passages and decreased thereafter. Shoot multiplication was further enhanced on MS medium containing 0.25 mg l -1 each of BA and Kin (Kinetin) with 0.1 mg l -1 of NAA (α-naphthalene acetic acid). Addition of 0.004 mg l -1 TDZ (thidiazuron) increased the rate of shoot multiplication and 21.81 ± 1.26 shoots per culture vessel were obtained. In vitro regenerated shoots were rooted under ex vitro conditions treated with 400 mg l -1 IBA (indole-3-butyric acid) for 7 min on sterile soilrite. After successful hardening in greenhouse, ex vitro rooted plants were transferred to the field conditions with ≈85% of survival rate. Micromorphological changes were observed on leaf surface i.e. development of vein density and trichomes and stomatal appearance, when plants were subjected to environmental conditions. This is the first report on in vitro regeneration of B. racemosa from mature tree.

Eastern Pine Shoot Borer

Treesearch

Louis F. Wilson

1978-01-01

The eastern pineshoot borer Eucosma gloriola Heinrich 2, also known as the white pine tip moth, American pine shoot moth, white pine shoot borer, and Tordeuse americaine, du pin, injures young conifers in Northeastern North America. Because it infests the new shoots of sapling conifers, this insect is particularly destructive on planted trees destined for the Christmas...

Influence of the variation of geometrical and topological traits on light interception efficiency of apple trees: sensitivity analysis and metamodelling for ideotype definition

PubMed Central

Da Silva, David; Han, Liqi; Faivre, Robert; Costes, Evelyne

2014-01-01

Background and Aims The impact of a fruit tree's architecture on its performance is still under debate, especially with regard to the definition of varietal ideotypes and the selection of architectural traits in breeding programmes. This study aimed at providing proof that a modelling approach can contribute to this debate, by using in silico exploration of different combinations of traits and their consequences on light interception, here considered as one of the key parameters to optimize fruit tree production. Methods The variability of organ geometrical traits, previously described in a bi-parental population, was used to simulate 1- to 5-year-old apple trees (Malus × domestica). Branching sequences along trunks observed during the first year of growth of the same hybrid trees were used to initiate the simulations, and hidden semi-Markov chains previously parameterized were used in subsequent years. Tree total leaf area (TLA) and silhouette to total area ratio (STAR) values were estimated, and a sensitivity analysis was performed, based on a metamodelling approach and a generalized additive model (GAM), to analyse the relative impact of organ geometry and lateral shoot types on STAR. Key Results A larger increase over years in TLA mean and variance was generated by varying branching along trunks than by varying organ geometry, whereas the inverse was observed for STAR, where mean values stabilized from year 3 to year 5. The internode length and leaf area had the highest impact on STAR, whereas long sylleptic shoots had a more significant effect than proleptic shoots. Although the GAM did not account for interactions, the additive effects of the geometrical factors explained >90% of STAR variation, but much less in the case of branching factors. Conclusions This study demonstrates that the proposed modelling approach could contribute to screening architectural traits and their relative impact on tree performance, here viewed through light interception. Even though trait combinations and antagonism will need further investigation, the approach opens up new perspectives for breeding and genetic selection to be assisted by varietal ideotype definition. PMID:24723446

Bur and nut production on three chestnut cultivars

Treesearch

Michele Warmund; Darin J. Enderton; J.W. Van Sambeek

2010-01-01

Studies were conducted to characterize bur and nut development on shoots of young chestnut (Castanea sp.) trees over a two year period and to determine the effect of secondary (2°) bur removal on subsequent bur and nut production. Terminal shoots of 'Peach' trees with primary (1°) and 2° burs (PS) grew longer and...

Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus.

PubMed

Sétamou, Mamoudou; Flores, Daniel; French, J Victor; Hall, David G

2008-08-01

The abundance and spatial dispersion of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) were studied in 34 grapefruit (Citrus paradisi Macfad.) and six sweet orange [Citrus sinensis (L.) Osbeck] orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot infestation levels did not vary with host plant species, densities of D. citri eggs, nymphs, and adults were significantly higher on sweet orange than on grapefruit. D. citri immatures also were found in significantly higher numbers in the southeastern quadrant of trees than other parts of the canopy. The spatial distribution of D. citri nymphs and adults was analyzed using Iowa's patchiness regression and Taylor's power law. Taylor's power law fitted the data better than Iowa's model. Based on both regression models, the field dispersion patterns of D. citri nymphs and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly >1. For the average density of each life stage obtained during our surveys, the minimum number of flush shoots per tree needed to estimate D. citri densities varied from eight for eggs to four flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and eight flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions. A presence-absence sampling plan with a fixed precision level was developed and can be used to provide a quick estimation of D. citri populations in citrus orchards.

Effects of disbudding on shoot mortality and stem deformity in black cherry

Treesearch

Charles O. Rexrode

1979-01-01

Insect damage was simulated by the removal of buds from black cherry trees to determine the effects on stem mortality and tree form. Black cherry was very sensitive to disbudding. All degrees of disbudding caused terminal deformities and stem deformity nearly always occurred after the terminal bud was destroyed. Shoot mortality usually occurred after half or more of...

Variation of maximum tree height and annual shoot growth of Smith fir at various elevations in the Sygera Mountains, southeastern Tibetan Plateau.

PubMed

Wang, Yafeng; Čufar, Katarina; Eckstein, Dieter; Liang, Eryuan

2012-01-01

Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height increment of Smith fir (Abies georgei var. smithii) in seven forest plots (30 m×40 m) along two altitudinal transects between 3,800 m and 4,200/4,390 m above sea level (a.s.l.) in the Sygera Mountains, southeastern Tibetan Plateau. Four plots were located on north-facing slopes and three plots on southeast-facing slopes. At each site, annual shoot growth was obtained by measuring the distance between successive terminal bud scars along the main stem of 25 trees that were between 2 and 4 m high. Maximum/mean tree height and mean annual height increment of Smith fir decreased with increasing altitude up to the tree line, indicative of a stress gradient (the dominant temperature gradient) along the altitudinal transect. Above-average mean minimum summer (particularly July) temperatures affected height increment positively, whereas precipitation had no significant effect on shoot growth. The time series of annual height increments of Smith fir can be used for the reconstruction of past climate on the southeastern Tibetan Plateau. In addition, it can be expected that the rising summer temperatures observed in the recent past and anticipated for the future will enhance Smith fir's growth throughout its altitudinal distribution range.

Micropropagation of Crataeva adansonii D.C. Prodr: an ornamental avenue tree.

PubMed

Tyagi, Purnima; Sharma, P K; Kothari, S L

2010-01-01

In this chapter, we describe multiplication of the superior and elite tree of Crataeva adansonii using plant tissue culture techniques. An ornamental and avenue tree, it is not available in abundance because of poor seed germination and seedling establishment. It reproduces in nature by root suckers, but that restricts its distribution to very limited areas. Efficient procedures are outlined for plant regeneration through direct shoot bud formation, indirect organogenesis, and somatic embryogenesis through callus formation. Different explants were utilized for separate pathways of regeneration. Murashige and Skoog's (MS) medium containing 3 mg/L BA and 0.05-0.1 mg/L NAA is most effective in direct induction of axillary buds from nodal explants and shoot tips. Adventitious shoots developed from leaves on MS medium containing 3 mg/L BA and 0.1 mg/L NAA. De novo shoots were obtained from the anthers on MS medium supplemented with 3 mg/L BA. Somatic embryos developed on half strength MS medium containing 0.1 mg/L 2, 4-D. Roots were induced at the cut ends of shoots on MS basal medium devoid of growth regulators. The plantlets were then transferred to pots.

Host physiological condition regulates parasitic plant performance: Arceuthobium vaginatum subsp. cryptopodum on Pinus ponderosa.

PubMed

Bickford, Christopher P; Kolb, Thomas E; Geils, Brian W

2005-12-01

Much research has focused on effects of plant parasites on host-plant physiology and growth, but little is known about effects of host physiological condition on parasite growth. Using the parasitic dwarf mistletoe Arceuthobium vaginatum subsp. cryptopodum (Viscaceae) and its host Pinus ponderosa, we investigated whether changes in host physiological condition influenced mistletoe shoot development in northern Arizona forests. We conducted two studies in two consecutive years and used forest thinning (i.e., competitive release) to manipulate host physiological condition. We removed dwarf mistletoe shoots in April, before the onset of the growing season, and measured the amount of regrowth in the first season after forest thinning (Study I: n=38 trees; Study II: n=35 trees). Thinning increased tree uptake of water and carbon in both studies, but had no effect on leaf N concentration or delta13C. Mistletoe shoot growth was greater on trees with high uptake of water and carbon in thinned stands than trees with low uptake in unthinned stands. These findings show that increased resource uptake by host trees increases resources to these heterotrophic dwarf mistletoes, and links mistletoe performance to changes in host physiological condition.

Sphaeropsis Shoot Blight

Treesearch

Jill Pokorny

1998-01-01

Sphaeropsis shoot blight, formerly called Diplodia shoot blight, is worldwide in distribution and can infect many conifer hosts. Although many pine species are reported hosts, this disease causes severe damage only to trees that are predisposed by unfavorable environmental conditions. Non-native, exotic pine species growing outside their natural range are especially...

Winning by a neck: tall giraffes avoid competing with shorter browsers.

PubMed

Cameron, Elissa Z; du Toit, Johan T

2007-01-01

With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild.

The variation of methane flux rates from boreal tree species at the beginning of the growing season

NASA Astrophysics Data System (ADS)

Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

2016-04-01

Boreal forests are considered as net sink for atmospheric methane (CH4) because of the CH4 oxidizing bacteria in the aerobic soil layer. However, within the last decades it has become more evident that trees play an important role in the global CH4 budget by offering pathways for anaerobically produced CH4 from deeper soil layers to the atmosphere. Furthermore, trees may also act as independent sources of CH4. To confirm magnitude, variability and the origin of the tree mediated CH4 emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured tree stem and shoot CH4 exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in southern Finland (61° 51'N, 24° 17'E, 181 asl). The fluxes were measured from silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation and forest structure by using the static chamber technique. Scaffold towers were used for measurements at multiple stem heights and shoots. The aim was to study the vertical profile of CH4 fluxes at stem and shoot level and compare these fluxes among the studied species, and to observe temporal changes in CH4 flux over the beginning of the growing season. We found that all the trees emitted CH4 from their stems and shoots. Overall, the birches showed higher emissions compared to the spruces. The emission rates were considerably larger in the lower parts of the birch stems than upper parts, and these emissions increased during the growing season. The spruces had more variation in the stem CH4 flux, but the emission rates of the upper parts of the stem exceeded the birch emissions at the same height. The shoot fluxes of all the studied trees indicated variable CH4 emissions without a clear pattern regarding the vertical profile and progress of the growing season.

Shoot size significantly affects rooting response of sugar maple softwood cuttings

Treesearch

John R. Donnelly

1974-01-01

Three hundred softwood cuttings were collected from each of three mature sugar maple trees to test the effect of shoot size on adventitious root formation. One of the trees was a good rooter (61 percent rooted); one was a poor rooter (19 percent rooted); and the third was a non-rooter (1 percent rooted). There was an insufficient number of rooted cuttings from the...

Relationship of shoot dieback in pecan to fungi and fruiting stress

USDA-ARS?s Scientific Manuscript database

Two shoot dieback maladies (SDM) of pecan [Carya illinoinensis (Wangenh.) C. Koch] are of unknown cause and can adversely affect tree canopy health. They occur during either early spring (SpSDM) or early summer (SuSDM). Field studies found that both maladies predominately occur on shoots retaining...

Variation in crown light utilization characteristics among tropical canopy trees.

PubMed

Kitajima, Kaoru; Mulkey, Stephen S; Wright, S Joseph

2005-02-01

Light extinction through crowns of canopy trees determines light availability at lower levels within forests. The goal of this paper is the exploration of foliage distribution and light extinction in crowns of five canopy tree species in relation to their shoot architecture, leaf traits (mean leaf angle, life span, photosynthetic characteristics) and successional status (from pioneers to persistent). Light extinction was examined at three hierarchical levels of foliage organization, the whole crown, the outermost canopy and the individual shoots, in a tropical moist forest with direct canopy access with a tower crane. Photon flux density and cumulative leaf area index (LAI) were measured at intervals of 0.25-1 m along multiple vertical transects through three to five mature tree crowns of each species to estimate light extinction coefficients (K). Cecropia longipes, a pioneer species with the shortest leaf life span, had crown LAI <0.5. Among the remaining four species, crown LAI ranged from 2 to 8, and species with orthotropic terminal shoots exhibited lower light extinction coefficients (0.35) than those with plagiotropic shoots (0.53-0.80). Within each type, later successional species exhibited greater maximum LAI and total light extinction. A dense layer of leaves at the outermost crown of a late successional species resulted in an average light extinction of 61% within 0.5 m from the surface. In late successional species, leaf position within individual shoots does not predict the light availability at the individual leaf surface, which may explain their slow decline of photosynthetic capacity with leaf age and weak differentiation of sun and shade leaves. Later-successional tree crowns, especially those with orthotropic branches, exhibit lower light extinction coefficients, but greater total LAI and total light extinction, which contribute to their efficient use of light and competitive dominance.

Carbon dioxide exchange of buds and developing shoots of boreal Norway spruce exposed to elevated or ambient CO2 concentration and temperature in whole-tree chambers.

PubMed

Hall, Marianne; Räntfors, Mats; Slaney, Michelle; Linder, Sune; Wallin, Göran

2009-04-01

Effects of ambient and elevated temperature and atmospheric carbon dioxide concentration ([CO2]) on CO2 assimilation rate and the structural and phenological development of shoots during their first growing season were studied in 45-year-old Norway spruce trees (Picea abies (L.) Karst.) enclosed in whole-tree chambers. Continuous measurements of net assimilation rate (NAR) in individual buds and shoots were made from early bud development to late August in two consecutive years. The largest effect of elevated temperature (TE) was manifest early in the season as an earlier start and completion of shoot length development, and a 1-3-week earlier shift from negative to positive NAR compared with the ambient temperature (TA) treatments. The largest effect of elevated [CO2] (CE) was found later in the season, with a 30% increase in maximum NAR compared with trees in the ambient [CO2] treatments (CA), and shoots assimilating their own mass in terms of carbon earlier in the CE treatments than in the CA treatments. Once the net carbon assimilation compensation point (NACP) had been reached, TE had little or no effect on the development of NAR performance, whereas CE had little effect before the NACP. No interactive effects of TE and CE on NAR were found. We conclude that in a climate predicted for northern Sweden in 2100, current-year shoots of P. abies will assimilate their own mass in terms of carbon 20-30 days earlier compared with the current climate, and thereby significantly contribute to canopy assimilation during their first year.

Estimation of the number of aphids carrying Citrus tristeza virus that visit adult citrus trees.

PubMed

Marroquín, Carlos; Olmos, Antonio; Teresa Gorris, María; Bertolini, Edson; Carmen Martínez, M; Carbonell, Emilio A; Hermoso de Mendoza, Alfonso; Cambra, Mariano

2004-03-01

Aphid species were counted on citrus trees in orchards in Valencia, Spain, in the spring and autumn of 1997, 1998 and 1999. Moericke yellow water traps, the 'sticky shoot' method and counts of established colonies were used in extensive surveys in which 29,502 aphids were recorded and identified. Aphis spiraecola and Aphis gossypii were the most abundant aphid species. The numbers of aphid species landing on mature trees of grapefruit, sweet orange, lemon and clementine and satsuma mandarins, were estimated by counting the numbers of young shoots/tree and aphids trapped on sticky shoots. The proportions of the different aphid species captured were: A. gossypii (53%), A. spiraecola (32%), Toxoptera aurantii (11%), Myzus persicae (1%), Aphis craccivora (1%) and other species (2%). Clementine was the most visited species with 266,700 aphids landing/tree in spring 2000, followed by lemon (147,000), sweet orange (129,150), grapefruit (103,200), and satsuma (92,400). The numbers and relative percentages of aphids carrying Citrus tristeza virus (CTV) were assessed by nested RT-PCR in single closed tubes and analysed by extraction of RNA-CTV targets from trapped aphids. An average of 37,190 CTV-carrying aphids visited each tree in spring 2000 (29 per shoot). The percentage detection of viral RNA in the aphid species that landed were 27% for A. gossypii, 23% for A. spiraecola and 19% for T. aurantii. This high incidence of aphids carrying CTV is consistent with the high prevalence and rapid spread of CTV in sweet orange, clementine, and satsuma mandarins in recent years in the region. The infection rate was proportional to the number of aphids landing/tree.

Growth and branching habit of rooted cuttings collected from epicormic shoots of Betula pendula Roth.

PubMed

Cameron, A D; Sani, H

1994-04-01

Patterns of shoot growth and branching were studied over two growing seasons in rooted cuttings collected from both epicormic shoots and seedlings of Betula pendula Roth. Epicormic shoots were induced to sprout on stumps and small logs of 5-, 10- and 30-year-old trees. The use of epicormic shoots enhanced the rooting capacity of stem cuttings collected from these shoots but did not appear to reverse the process of maturation. In this study, maturation was based on characteristics typical of mature trees but not necessarily those of the mother plant, because it was not possible to root cuttings, for comparison, from 5-, 10- and 30-year-old ortets, other than from epicormic shoots. There was evidence of the persistence of mature characteristics through an increase in shoot plagiotropism with increasing ortet age. Rooted cuttings from both seedlings and epicormic shoots, however, assumed an increasingly orthotropic habit with a smaller shoot angle at the end of the first growing season than at the beginning and this continued into the second growing season. Other indications of maturation, such as delayed bud flushing and the incidence of flowering with increasing ortet age, were also evident in rooted cuttings from epicormic shoots. There was a clear difference in branching habit depending on cutting source. Rooted cuttings derived from epicormic shoots produced nearly twice as many lateral branches compared with rooted cuttings collected from seedlings, but this was not an effect of maturation. There was some evidence that rooted cuttings derived from seedlings grew taller than rooted cuttings from epicormic shoots.

Influence of Pre- and Postharvest Summer Pruning on the Growth, Yield, Fruit Quality, and Carbohydrate Content of Early Season Peach Cultivars

PubMed Central

Ikinci, Ali

2014-01-01

Winter and summer pruning are widely applied processes in all fruit trees, including in peach orchard management. This study was conducted to determine the effects of summer prunings (SP), as compared to winter pruning (WP), on shoot length, shoot diameter, trunk cross sectional area (TCSA) increment, fruit yield, fruit quality, and carbohydrate content of two early ripening peach cultivars (“Early Red” and “Maycrest”) of six years of age, grown in semiarid climate conditions, in 2008 to 2010. The trees were grafted on GF 677 rootstocks, trained with a central leader system, and spaced 5 × 5 m apart. The SP carried out after harvesting in July and August decreased the shoot length significantly; however, it increased its diameter. Compared to 2009, this effect was more marked in year 2010. In general, control and winter pruned trees of both cultivars had the highest TCSA increment and yield efficiency. The SP increased the average fruit weight and soluble solids contents (SSC) more than both control and WP. The titratable acidity showed no consistent response to pruning time. The carbohydrate accumulation in shoot was higher in WP and in control than in SP trees. SP significantly affected carbohydrate accumulation; postharvest pruning showed higher carbohydrate content than preharvest pruning. PMID:24737954

Branch architecture in Ginkgo biloba: wood anatomy and long shoot-short shoot interactions.

PubMed

Little, Stefan A; Jacobs, Brooke; McKechnie, Steven J; Cooper, Ranessa L; Christianson, Michael L; Jernstedt, Judith A

2013-10-01

Ginkgo, centrally placed in seed plant phylogeny, is considered important in many phylogenetic and evolutionary studies. Shoot dimorphism of Ginkgo has been long noted, but no work has yet been done to evaluate the relationships between overall branch architecture and wood ring characters, shoot growth, and environmental conditions. • Branches, sampled from similar canopy heights, were mapped with the age of each long shoot segment determined by counting annual leaf-scar series on its short shoots. Transverse sections were made for each long shoot segment and an adjacent short shoot; wood ring thickness, number of rings, and number of tracheids/ring were determined. Using branch maps, we identified wood rings for each long shoot segment to year and developmental context of each year (distal short shoot growth only vs. at least one distal long shoot). Climate data were also analyzed in conjunction with developmental context. • Significantly thicker wood rings occur in years with distal long shoot development. The likelihood that a branch produced long shoots in a given year was lower with higher maximum annual temperature. Annual maximum temperature was negatively correlated with ring thickness in microsporangiate trees only. Annual minimum temperatures were correlated differently with ring thickness of megasporangiate and microsporangiate trees, depending on the developmental context. There were no significant effects associated with precipitation. • Overall, developmental context alone predicts wood ring thickness about as well as models that include temperature. This suggests that although climatic factors may be strongly correlated with wood ring data among many gymnosperm taxa, at least for Ginkgo, correlations with climate data are primarily due to changes in proportions of shoot developmental types (LS vs. SS) across branches.

Seasonal Shoot-Feeding By Tomicus Piniperda (Coleoptera: Scolytidae) In Michigan

Treesearch

Robert A. Haack; Robert K. Lawrence; George C. Heaton

2000-01-01

Seasonal shoot-feeding by Tomicus piniperda (L.) was monitored at 2-week intervals on 15 Scotch pine, Pinus sylvestris L., trees from 8 April through 16 November 1994 in southern Michigan. All shoots that showed evidence of T. piniperda attack were removed every two weeks. In 1994, initial spring flight of

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.

Shoot water relations of mature black spruce families displaying a genotype x environment interaction in growth rate. II. Temporal trends and response to varying soil water conditions

Treesearch

John E. Major; Kurt H. Johnsen

1999-01-01

Pressure-volume curves and shoot water potentials were determined for black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families at the Petawawa Research Forest, Ontario, Canada. Trees were sampled from a dry site in 1992 and from the dry site and a wet site in 1993. Modulus of elasticity (e ), osmotic potential at...

Apical bud toughness tests and tree sway movements to examine crown abrasion: preliminary results

Treesearch

Tyler Brannon; Wayne Clatterbuck

2012-01-01

Apical bud toughness differences were examined for several species to determine if crown abrasion affects shoot growth of determinate and indeterminate species during stand development. Determinate buds will set and harden after initial shoot elongation in the spring, while the indeterminate shoots form leaves from the apical meristem continuously based on the...

Shoot Growth Patterns of Young Loblolly Pine

Treesearch

William D. Boyer

1970-01-01

Most shoot elongation on Pinus taeda L. seedlings and saplings near Durham. North Carolina. was supplied by the lirst growth Ilush, which began about April 1 and ended in mid-May 1967. New growth per shoot declined with distance from the tree top. All leaders had three flushes and half had four. Variation in internode growth was dependent upon...

Soil processes and tree growth at shooting ranges in a boreal forest reflect contamination history and lead-induced changes in soil food webs.

PubMed

Selonen, Salla; Setälä, Heikki

2015-06-15

The effects of shooting-derived lead (Pb) on the structure and functioning of a forest ecosystem, and the recovery of the ecosystem after range abandonment were studied at an active shotgun shooting range, an abandoned shooting range where shooting ceased 20 years earlier and an uncontaminated control site. Despite numerous lead-induced changes in the soil food web, soil processes were only weakly related to soil food web composition. However, decomposition of Scots pine (Pinus sylvestris) needle litter was retarded at the active shooting range, and microbial activity, microbial biomass and the rate of decomposition of Pb-contaminated grass litter decreased with increasing soil Pb concentrations. Tree (P. sylvestris) radial growth was suppressed at the active shooting range right after shooting activities started. In contrast, the growth of pines improved at the abandoned shooting range after the cessation of shooting, despite reduced nitrogen and phosphorus contents of the needles. Higher litter degradation rates and lower Pb concentrations in the topmost soil layer at the abandoned shooting range suggest gradual recovery after range abandonment. Our findings suggest that functions in lead-contaminated coniferous forest ecosystems depend on the successional stage of the forest as well as the time since the contamination source has been eliminated, which affects, e.g., the vertical distribution of the contaminant in the soil. However, despite multiple lead-induced changes throughout the ecosystem, the effects were rather weak, indicating high resistance of coniferous forest ecosystems to this type of stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of dormancy progression and low-temperature response on changes in the sorbitol concentration in xylem sap of Japanese pear during winter season.

PubMed

Ito, Akiko; Sugiura, Toshihiko; Sakamoto, Daisuke; Moriguchi, Takaya

2013-04-01

In order to elucidate which physiological event(s) are involved in the seasonal changes of carbohydrate dynamics during winter, we examined the effects of different low temperatures on the carbohydrate concentrations of Japanese pear (Pyrus pyrifolia (Burm.) Nakai). For four winter seasons, large increases in the sorbitol concentration of shoot xylem sap occurred during mid- to late December, possibly due to the endodormancy completion and low-temperature responses. When trees were kept at 15 °C from 3 November to 3 December in order to postpone the initiation and completion of chilling accumulation that would break endodormancy, sorbitol accumulation in xylem sap was always higher from trees with sufficient chilling accumulation than from trees that received insufficient chilling. However, an additional increase in xylem sap sorbitol occurred around late December in trees regardless of whether their chilling accumulation naturally progressed or was postponed. To examine different temperature effects more closely, we compared the carbohydrate concentrations of trees subjected to either 6 or 0 °C treatment. The sorbitol concentration in xylem sap tremendously increased at 0 °C treatment compared with 6 °C treatment. However, an additional increase in xylem sap sorbitol occurred at both the temperatures when sufficient chilling accumulated with a peak coinciding with the peak expression in shoots of the sorbitol transporter gene (PpSOT2). Interestingly, the total carbohydrate concentration of shoots tremendously increased with exposure to 0 °C compared with exposure to 6 °C, but was not affected by the amount of accumulated chilling. Instead, as chilling accumulated the ratio of sorbitol to total soluble sugars in shoots increased. We presumed that carbohydrates in the shoot tissues may be converted to sorbitol and loaded into the xylem sap so that the sorbitol accumulation patterns were synchronized with the progression of dormancy, whereas the total carbohydrate transported into shoots from other storage organs may be related to freezing tolerance acquisition independent of dormancy progression. We thus propose that there are different effects of dormancy progression and low-temperature responses on carbohydrate dynamics in Japanese pear.

Gnomonia canker, shoot blight, and leaf spot of yellow birch.

Treesearch

Kenneth J. Jr. Kessler

1978-01-01

Describes a canker, shoot blight, and leaf spot disease of yellow birch seedlings in the northern Great Lakes region and tells how and when trees become infected by the fungal causal agent, Gnomonia setacea.

Insights into secondary growth in perennial plants: its unequal spatial and temporal dynamics in the apple (Malus domestica) is driven by architectural position and fruit load

PubMed Central

Lauri, P. É.; Kelner, J. J.; Trottier, C.; Costes, E.

2010-01-01

Background and Aims Secondary growth is a main physiological sink. However, the hierarchy between the processes which compete with secondary growth is still a matter of debate, especially on fruit trees where fruit weight dramatically increases with time. It was hypothesized that tree architecture, here mediated by branch age, is likely to have a major effect on the dynamics of secondary growth within a growing season. Methods Three variables were monitored on 6-year-old ‘Golden Delicious’ apple trees from flowering time to harvest: primary shoot growth, fruit volume, and cross-section area of branch portions of consecutive ages. Analyses were done through an ANOVA-type analysis in a linear mixed model framework. Key Results Secondary growth exhibited three consecutive phases characterized by unequal relative area increment over the season. The age of the branch had the strongest effect, with the highest and lowest relative area increment for the current-year shoots and the trunk, respectively. The growth phase had a lower effect, with a shift of secondary growth through the season from leafy shoots towards older branch portions. Eventually, fruit load had an effect on secondary growth mainly after primary growth had ceased. Conclusions The results support the idea that relationships between production of photosynthates and allocation depend on both primary growth and branch architectural position. Fruit load mainly interacted with secondary growth later in the season, especially on old branch portions. PMID:20228088

Insights into secondary growth in perennial plants: its unequal spatial and temporal dynamics in the apple (Malus domestica) is driven by architectural position and fruit load.

PubMed

Lauri, P E; Kelner, J J; Trottier, C; Costes, E

2010-04-01

Secondary growth is a main physiological sink. However, the hierarchy between the processes which compete with secondary growth is still a matter of debate, especially on fruit trees where fruit weight dramatically increases with time. It was hypothesized that tree architecture, here mediated by branch age, is likely to have a major effect on the dynamics of secondary growth within a growing season. Three variables were monitored on 6-year-old 'Golden Delicious' apple trees from flowering time to harvest: primary shoot growth, fruit volume, and cross-section area of branch portions of consecutive ages. Analyses were done through an ANOVA-type analysis in a linear mixed model framework. Secondary growth exhibited three consecutive phases characterized by unequal relative area increment over the season. The age of the branch had the strongest effect, with the highest and lowest relative area increment for the current-year shoots and the trunk, respectively. The growth phase had a lower effect, with a shift of secondary growth through the season from leafy shoots towards older branch portions. Eventually, fruit load had an effect on secondary growth mainly after primary growth had ceased. The results support the idea that relationships between production of photosynthates and allocation depend on both primary growth and branch architectural position. Fruit load mainly interacted with secondary growth later in the season, especially on old branch portions.

Trait-specific responses of Scots pine to irrigation on a short vs long time scale.

PubMed

Feichtinger, Linda M; Eilmann, Britta; Buchmann, Nina; Rigling, Andreas

2015-02-01

In xeric environments, an increase in drought is related to reduced forest productivity and to enhanced mortality. However, predictions of future forest development remain difficult as the mechanisms underlying the responses of mature trees to long-term variations in water availability are not well understood. Here, we aimed to compare the adjustments in radial growth and morphological needle and shoot traits of mature Scots pine (Pinus sylvestris L.) growing along open water channels with those of control trees growing under naturally dry conditions at three sites in Valais, an inner-Alpine dry valley of Switzerland. The trees growing along two channels had been irrigated since germination (>70 years), whereas those along another previously drained channel had been irrigated only from 2010 to 2012, when the channel was re-established, and could thus be used to quantify the short-term effects of re-irrigation. Linear mixed models revealed that needle and shoot lengths as well as early- and late-wood basal area increments (BAIs) were most responsive to short-term and long-term irrigation. However, the magnitude of the response to the short-term irrigation exceeded that of the long-term irrigation. An extreme drought during the first half of 2011 led to an immediate decrease in the needle length, needle width, and early- and late-wood BAIs of the control trees, whereas the shoot length and needle numbers of control trees reacted with a 1-year delay to the extreme drought, as the shoots were responding to water availability of previous year's summer. Such negative responses to dry climatic conditions were even found in irrigated trees at one of our sites, which might be linked to tree growth becoming more sensitive to drought with increasing tree height and leaf area. In order to improve predictions of future forest development, long-term studies are necessary that consider lagged responses and adjustment processes of trees to changes in water availability. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

An efficient in vitro shoot regeneration from leaf petiolar explants and ex vitro rooting of Bixa orellana L.- A dye yielding plant.

PubMed

Mohammed, Arifullah; Chiruvella, Kishore K; Namsa, Nima D; Ghanta, Rama Gopal

2015-07-01

Bixa orellana L. (Bixaceae) is a multipurpose tree grown for the production of commercially important dyes. In the present study, an efficient, reproducible protocol was developed for direct plant regeneration from in vitro derived petiole explants of Bixa orellana L. Murashige and Skoog medium (MS) supplemented with 2-isopentenyl adenine (9.8 μM) and naphthalene acetic acid (10.7 μM) was found to be optimum for production of high frequency of shoot organogenesis. Subculturing of the shoots onto the fresh MS medium containing similar concentrations of 2-iP (9.8 μM) and NAA (10.7 μM) produced elongated shoots. Elongated shoots when placed onto MS medium supplemented with 1.7 μM indole-3-acetic acid and 14.7 μM 2-iP produced optimal rooting. Rooted plantlets were acclimatized and transplanted to the field successfully. Histological investigation revealed the origin of shoot primordia, from sub-epidermal cells of petiole explants. The regeneration protocol developed in this study can be useful for mass in vitro propagation and effective genetic transformation of commercially important edible dye yielding tree species.

Molecular basis of angiosperm tree architecture

USDA-ARS?s Scientific Manuscript database

The shoot architecture of trees greatly impacts orchard and forest management methods. Amassing greater knowledge of the molecular genetics behind tree form can benefit these industries as well as contribute to basic knowledge of plant developmental biology. This review covers basic components of ...

Effects of elevated CO(2) concentration and nutrition on net photosynthesis, stomatal conductance and needle respiration of field-grown Norway spruce trees.

PubMed

Roberntz, Peter; Stockfors, Jan

1998-04-01

To study the effects of elevated CO(2) on gas exchange, nonstructural carbohydrate and nutrient concentrations in current-year foliage of 30-year-old Norway spruce (Picea abies (L.) Karst.) trees, branches were enclosed in ventilated, transparent plastic bags and flushed with ambient air (mean 370 &mgr;mol CO(2) mol(-1); control) or ambient air + 340 &mgr;mol CO(2) mol(-1) (elevated CO(2)) during two growing seasons. One branch bag was installed on each of 24 selected trees from control and fertilized plots. To reduce the effect of variation among trees, results from each treated branch were compared with those from a control branch on the same whorl of the same tree. Elevated CO(2) increased rates of light-saturated photosynthesis on average by 55% when measured at the treatment CO(2) concentration. The increase was larger in shoots with high needle nitrogen concentrations than in shoots with low needle nitrogen concentrations. However, shoots grown in elevated CO(2) showed a decrease in photosynthetic capacity compared with shoots grown in ambient CO(2). When measured at the internal CO(2) concentration of 200 &mgr;mol CO(2) mol(-1), photosynthetic rates of branches in the elevated CO(2) treatments were reduced by 8 to 32%. The elevated CO(2) treatment caused a 9 to 20% reduction in carboxylation efficiency and an 18% increase in respiration rates. In response to elevated CO(2), starch, fructose and glucose concentrations in the needles increased on average 33%, whereas concentrations of potassium, nitrogen, phosphorus, magnesium and boron decreased. Needle nitrogen concentrations explained 50-60% of the variation in photosynthesis and CO(2) acclimation was greater at low nitrogen concentrations than at high nitrogen concentrations. We conclude that the enhanced photosynthetic rates found in shoots exposed to elevated CO(2) increased carbohydrate concentrations, which may have a negative feedback on the photosynthetic apparatus and stimulate cyanide-resistant respiration. We also infer that the decrease in nutrient concentrations of needles exposed to elevated CO(2) was the result of retranslocation of nutrients to other parts of the branch or tree.

Red Pine Shoot Moth

Treesearch

John Hainze; David Hall

The red pine shoot moth recently caused significant damage to red pine plantations in Minnesota, Wisconsin and Michigan. Trees of all ages have been attacked, but the most severe damage has occurred in 20-40 year old plantations growing on sandy soils.

Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree ring C and O stable isotopes

EPA Science Inventory

• Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually induce tree death. • To investigate long-term impacts of dwarf mistletoe...

Shoot growth orientation in trees is influenced by gravitropic control via a signaling pathway that includes TAC1 and LAZY1

USDA-ARS?s Scientific Manuscript database

Understanding the molecular basis behind tree architecture could have significant impacts in tree crop agriculture and forestry. The ability to manipulate tree branch growth and patterning could lead to significant productivity improvements through reduced pesticide use, reduced labor for harvestin...

Geographic variation in ponderosa pine leader growth

Treesearch

James W. Hanover

1963-01-01

Growth of the shoot apices of 91 trees in a 45-year-old Pinus ponderosa Laws. provenance test was measured periodically with a transit. Analysis of the measurements led to the following conclusions: (1) 19 races of ponderosa pine planted near Priest River, Idaho, showed phenological, morphological, or physiological variation in six characters: date of beginning growth...

Buds enable pitch and shortleaf pines to recover from injury

Treesearch

S. Little; H. A. Somes

1956-01-01

Pitch and shortleaf pines often survive severe damage by fires, cutting, rabbits, or deer. Deer may take all but 2 inches of the 6- to 8-inch shoots of seedlings, and still these seedlings may live and develop new shoots. Fires may kill all the foliage and terminal shoots on sapling or pole-size stems, but still these trees may green up and develop new leaders. Many of...

Effect of shading intensity on morphological and color traits, and chemical components of new tea (Camellia sinensis L.) shoots under direct covering cultivation.

PubMed

Sano, Tomohito; Horie, Hideki; Matsunaga, Akiko; Hirono, Yuhei

2018-05-02

Use of covering cultivation to shade tea (Camellia sinensis L.) trees to produce high-quality, high-priced green tea has recently increased in Japan. Knowledge of shading effects on morphological and color traits, and chemical components of new tea shoots is important for product quality and productivity. We assessed these traits of tea shoots and their relationships under covering cultivation of various radiation intensities. Leaf thickness, LMA (leaf mass per area), and leaf density of new tea leaves were smaller under covering culture than under open-field culture. SPAD values and chlorophyll contents were larger under covering culture than under open culture. The derived exponential equation for estimating chlorophyll contents from SPAD values was improved by considering leaf thickness. Covering culture decreased EC (epicatechin) and EGC (epigallocatechin) contents, and increased theanine and caffeine contents. Principal component analysis on shoot and leaf traits indicated that LMA, and chlorophyll, EC, and EGC contents were strongly associated with shading effects. Morphological and color traits, and chemical components of new tea shoots and leaves varied depending on radiation intensity, shoot growth, and cropping season. These findings are useful for covering cultivation with high quality and high productivity in tea gardens. This article is protected by copyright. All rights reserved.

Study of the Light Received Characteristics of a Plant-Shoot-Light-Condensing System with Simple Leaves or Lobed Leaves

NASA Astrophysics Data System (ADS)

Obara, Shin'ya

Plant shoot configurations evolve so that maximum sunlight may be obtained. The objective of this study is to develop a compact light-condensing system mimicking a plant shoot configuration that is applicable to a light source from a large area. In this paper, the relationship between the position of a light source (the sun) and the rate at which light is absorbed by each leaf was investigated in detail for plant shoot models of a dogwood (simple leaf) and a ginkgo tree (lobed leaf). The rate of light quantum received in each leaf model is reported to an analysis program that uses cross entropy (CE). The analyses showed that the peak amount of light received in the plant-shoot-light-condensing system was during February (vernal equinox) and October (autumnal equinox). Similarly, the rate of light quantum received in each leaf was measured with the CE. The results found that the plant-shoot-light-condensing system that maximizes the amount of light received has differences in the light received in each leaf. Furthermore, the light-condensing characteristics of the ginkgo biloba model are better than the dogwood model. The light-condensing characteristics of a leaf are influenced by the size, a lobe, shape, and the length of the branch.

Root-shoot allometry of tropical forest trees determined in a large-scale aeroponic system.

PubMed

Eshel, Amram; Grünzweig, José M

2013-07-01

This study is a first step in a multi-stage project aimed at determining allometric relationships among the tropical tree organs, and carbon fluxes between the various tree parts and their environment. Information on canopy-root interrelationships is needed to improve understanding of above- and below-ground processes and for modelling of the regional and global carbon cycle. Allometric relationships between the sizes of different plant parts will be determined. Two tropical forest species were used in this study: Ceiba pentandra (kapok), a fast-growing tree native to South and Central America and to Western Africa, and Khaya anthotheca (African mahogany), a slower-growing tree native to Central and Eastern Africa. Growth and allometric parameters of 12-month-old saplings grown in a large-scale aeroponic system and in 50-L soil containers were compared. The main advantage of growing plants in aeroponics is that their root systems are fully accessible throughout the plant life, and can be fully recovered for harvesting. The expected differences in shoot and root size between the fast-growing C. pentandra and the slower-growing K. anthotheca were evident in both growth systems. Roots were recovered from the aeroponically grown saplings only, and their distribution among various diameter classes followed the patterns expected from the literature. Stem, branch and leaf allometric parameters were similar for saplings of each species grown in the two systems. The aeroponic tree growth system can be utilized for determining the basic allometric relationships between root and shoot components of these trees, and hence can be used to study carbon allocation and fluxes of whole above- and below-ground tree parts.

Conservation and multiplication of encapsulated micro shoots of Rauvolfia vomitoria--an endangered medicinal tree: ISSR and RAPD based evaluation of genetic fidelity of converted plantlets.

PubMed

Mehrotra, Shakti; Rahman, Liaq Ur; Mishra, Jahnvi; Kukreja, Arun K

2012-12-01

The in vitro grown axillary micro shoots of Rauvolfia vomitoria were encapsulated in alginate beads. Following 6 months of normal storage at 25 +/- 2 degrees C the regrowth of encapsulated micro shoots, reached 95.2% within 40 days of incubation on MS medium containing 1.0 mg/L BAP and 0.1 mg/L NAA. Among the responding encapsulated explants 69.6% showed emergence of multiple shoots. The developing shoots showed rhizogenesis in two weeks following their transfer to rooting medium. Healthy plants were established in a glass house with 95% survival. Of the 50 RAPD primers tested, 10 produced 23 clear and reproducible amplicons, with an average of 2.3 bands per primer. Eleven ISSR primers produced a total of 42 bands, with a size range of 0.1-1.9 kb. The number of scorable bands for each primer varied from 2 to 6, with an average of 3.81. The similarity matrix, calculated individually from the results obtained from ISSR and RAPD analysis, showed similarity coefficients ranging from 1.0 for RAPD and 0.85 to 1.0 for ISSR.

Identification of two new phylogenetically distant phytoplasmas from Senna surattensis plants exhibiting stem fasciation and shoot proliferation symptoms

USDA-ARS?s Scientific Manuscript database

Sunshine trees (Senna surattensis Burm.) exhibiting unusual stem fasciation symptoms were observed in Yunnan, China. Morphological abnormalities of the affected plants included enlargement and flattening of stems and excessive proliferation of shoots. An electron microscopic investigation revealed...

In vitro propagation, encapsulation, and genetic fidelity analysis of Terminalia arjuna: a cardioprotective medicinal tree.

PubMed

Gupta, Amit K; Harish; Rai, Manoj K; Phulwaria, Mahendra; Agarwal, Tanvi; Shekhawat, N S

2014-07-01

The present study described an improved and reproducible in vitro regeneration system for Terminalia arjuna using nodal segment explants obtained from a mature plant. Shoot tips excised from in vitro proliferated shoots were encapsulated in 3 % sodium alginate and 100 mM CaCl2[Symbol: see text]2H2O for the development of synthetic seeds which may be applicable in short-term storage and germplasm exchange of elite genotype. Shoot multiplication was significantly influenced by a number of factors, namely types and concentrations of plant growth regulators, medium composition, repeated transfer of mother explants, subculturing of in vitro regenerated shoot clumps, agar concentrations, and temperature. Maximum numbers of shoots (16.50 ± 3.67) were observed on modified Murashige and Skoog (MMS) medium containing 0.5 mg l(-1) of benzylaminopurine (BAP) and 0.1 mg l(-1) of naphthalene acetic acid (NAA). To shortening the regeneration pathway, rooting of micropropagated shoots under in vitro condition was excluded and an experiment on ex vitro rooting was conducted and it was observed that the highest percentage of shoots rooted ex vitro when treated with indole-3-butyric acid (IBA, 250 mg l(-1)) + 2-naphthoxy acetic acid (NOA, 250 mg l(-1)) for 5 min. The well-developed ex vitro rooted shoots were acclimatized successfully in soilrite under greenhouse conditions with 80 % survival of plants. Randomly amplified polymorphic DNA (RAPD) analysis confirmed that all the regenerated plants were genetically identical to the mother plant, suggesting the absence of detectable genetic variation in the regenerated plantlets. To the best of our knowledge, this is the first report on synthetic seed production as well as ex vitro rooting and genetic fidelity assessment of micropropagated shoots of T. arjuna.

In vitro propagation, micromorphological studies and ex vitro rooting of cannon ball tree (Couroupita guianensis aubl.): a multipurpose threatened species.

PubMed

Shekhawat, Mahipal S; Manokari, M

2016-01-01

In vitro propagation methods using seeds and nodal segments of a 21-year old Couroupita guianensis - a medicinally important but threatened tree have been developed. Hundred percent of the seeds germinated on half strength Murashige and Skoog (MS) medium with 2.0 mg l(-1) indole-3 butyric acid (IBA). Nodal segments were found most suitable for the establishment of cultures. About 90 % explants responded and 4.1 ± 0.23 shoots per node were induced after five weeks of inoculation on MS medium +4.0 mg l(-1) 6-benzylaminopurine (BAP). Further shoot multiplication was achieved by repeated transfer of mother explants and subculturing of in vitro produced shoots on fresh medium. Maximum number (8.2 ± 0.17) of shoots were regenerated on MS medium with 1.0 mg l(-1) each of BAP and Kinetin (Kin) + 0.5 mg l(-1) α-naphthalene acetic acid (NAA) with additives (50 mg l(-1) of ascorbic acid and 25 mg l(-1) each of adenine sulphate, L-arginine and citric acid). The multiplied shoots rooted (4.3 ± 0.26 roots/shoot) on half strength MS medium with 2.5 mg l(-1) IBA. All the shoots were rooted ex vitro when pulse treated with 400 mg l(-1) of IBA for five min with an average of 7.3 ± 0.23 roots per shoot. Nearly 86 % of these plantlets were acclimatized within 7-8 weeks and successfully transferred in the field. Biologically significant developmental changes were observed during acclimation particularly in leaf micromorphology in terms of changes in stomata, veins and vein-islets, and trichomes. This study helps in understanding the response by the plants towards outer environmental conditions during acclimatization. This is the first report on micropropagation of C. guianensis, which could be used for the large-scale multiplication, restoration and conservation of germplasm of this threatened and medicinally important tree.

Micropropagation of annatto (Bixa orellana L.) from mature tree and assessment of genetic fidelity of micropropagated plants with RAPD markers.

PubMed

Siril, E A; Joseph, Nisha

2013-01-01

An in vitro propagation technique based on axillary bud proliferation was developed for the first time to mature annatto (Bixa orellana L.) tree. Nodal segments cultured on Murashige and Skoog (MS) medium supplemented with 1.0 μM benzyl adenine (BA) and tender coconut water (10 %) showed significantly high (P < 0.05) explant response (67.0 %), development of elongated shoots (3.36), shoot buds (8.9) and shoot elongation (3.53 cm). Cytokinins like zeatin, isopentenyl adenine (2-iP), kinetin, or thidiazuron (TDZ) were inferior to BA to induce multiple shoots. Seasonal variations significantly affected the in vitro response of nodal explants. In vitro rooting experiments have showed 55.6 % rooting on MS medium containing 15 μM indole-3-butyric acid (IBA). Alternatively, in vitro raised shoots were rooted (61.1 %) ex vitro, by 10 mM indole-3-butyric acid (IBA) for 30 s. The results of the RAPD marker system revealed the genetic stability among the micropropagated plants. The present protocol in brief, can be used for the clonal propagation of the superior genotype and preservation of germplasm.

Forest fire in the central Himalaya: climate and recovery of trees

NASA Astrophysics Data System (ADS)

Sharma, Subrat; Rikhari, H. C.

A forest fire event is influenced by climatic conditions and is supported by accumulation of fuel on forest floor. After forest fire, photosynthetically active solar radiation was reduced due to accumulation of ash and dust particles in atmosphere. Post-fire impacts on Quercus leucotrichophora, Rhododendron arboreum and Lyonia ovalifolia in a broadleaf forest were analysed after a wild fire. Bark depth damage was greatest for L. ovalifolia and least for Q. leucotrichophora. Regeneration of saplings was observed for all the tree species through sprouting. Epicormic recovery was observed for the trees of all the species. Young trees of Q. leucotrichophora (<40 cm circumference at breast height) were susceptible to fire as evident by the lack of sprouting. Under-canopy tree species have a high potential for recovery as evident by greater length and diameter of shoots and numbers of buds and leaves per shoot than canopy species. Leaf area, leaf moisture and specific leaf area were greater in the deciduous species, with few exceptions, than in evergreen species.

Developmental decline in height growth in Douglas-fir.

Treesearch

Barbara J. Bond; Nicole M. Czarnomski; Clifton Cooper; Michael E. Day; Michael S. Greenwood

2007-01-01

The characteristic decline in height growth that occurs over a tree's lifespan is often called "age-related decline." But is the reduction in height growth in aging trees a function of age or of size? We grafted shoot tips across different ages and sizes of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees to determine whether...

The genetic architecture of shoot-root covariation during seedling emergence of a desert tree, Populus euphratica.

PubMed

Zhang, Miaomiao; Bo, Wenhao; Xu, Fang; Li, Huan; Ye, Meixia; Jiang, Libo; Shi, Chaozhong; Fu, Yaru; Zhao, Guomiao; Huang, Yuejiao; Gosik, Kirk; Liang, Dan; Wu, Rongling

2017-06-01

The coordination of shoots and roots is critical for plants to adapt to changing environments by fine-tuning energy production in leaves and the availability of water and nutrients from roots. To understand the genetic architecture of how these two organs covary during developmental ontogeny, we conducted a mapping experiment using Euphrates poplar (Populus euphratica), a so-called hero tree able to grow in the desert. We geminated intraspecific F 1 seeds of Euphrates Poplar individually in a tube to obtain a total of 370 seedlings, whose shoot and taproot lengths were measured repeatedly during the early stage of growth. By fitting a growth equation, we estimated asymptotic growth, relative growth rate, the timing of inflection point and duration of linear growth for both shoot and taproot growth. Treating these heterochronic parameters as phenotypes, a univariate mapping model detected 19 heterochronic quantitative trait loci (hQTLs), of which 15 mediate the forms of shoot growth and four mediate taproot growth. A bivariate mapping model identified 11 pleiotropic hQTLs that determine the covariation of shoot and taproot growth. Most QTLs detected reside within the region of candidate genes with various functions, thus confirming their roles in the biochemical processes underlying plant growth. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Microbial control of wood-boring insects attacking forest and shade trees

Treesearch

Ann E. Hajek; Leah S. Bauer

2007-01-01

Wood-boring insect pests that feed on the bark, phloem, or xylem (wood) of living trees pose unique management challenges because their immature stages live in cryptic, often inaccessible, habitats within host trees. The eggs of wood borers are laid in or on tree trunks, branches, terminal shoots, or roots. After the eggs hatch, neonates tunnel in and feed on internal...

Increased production of azadirachtin from an improved method of androgenic cultures of a medicinal tree Azadirachta indica A. Juss.

PubMed

Srivastava, Priyanka; Chaturvedi, Rakhi

2011-07-01

Present report is the first direct evidence of azadirachtin production in androgenic haploid cultures of Azadirachta indica, a woody medicinal tree. Anther cultures at early-late-uninucleate stage of microspores were established on MS medium with BAP (5 μM), 2,4-D (1 μM) and NAA (1 μM) containing 12% sucrose. The calli, induced, were further multiplied on 2,4-D and Kinetin media. Shoots, differentiated on BAP (2.2 μM) + NAA (0.05 μM) medium, were elongated on MS + BAP (0.5 μM) and multiplied on MS + BAP (1 μM) + CH (250 mg/l). Thereafter, the shoots were rooted on ¼ MS + IBA (0.5 μM). Cytological analysis of the calli and regenerants have confirmed their haploid status with the chromosome number as 2n = x = 12. The haploid cell lines and leaves from in vitro grown plantlets were analyzed for azadirachtin by RP-HPLC and mass spectroscopy. Maximum azadirachtin (728.41 μg/g DW) was detected in calli supporting best shoot proliferation while least (49 μg/g DW) was observed in an undifferentiated line from maintenance medium. This study has brought us a step closer to develop genetically pure lines that could serve as new and attractive alternative ways of homogeneous controlled production of high value compounds, round the year, independent of geographical and climatic barrier.

Increased production of azadirachtin from an improved method of androgenic cultures of a medicinal tree Azadirachta indica A. Juss

PubMed Central

Srivastava, Priyanka

2011-01-01

Present report is the first direct evidence of azadirachtin production in androgenic haploid cultures of Azadirachta indica, a woody medicinal tree. Anther cultures at early-late-uninucleate stage of microspores were established on MS medium with BAP (5 µM), 2,4-D (1 µM) and NAA (1 µM) containing 12% sucrose. The calli, induced, were further multiplied on 2,4-D and Kinetin media. Shoots, differentiated on BAP (2.2 µM) + NAA (0.05 µM) medium, were elongated on MS + BAP (0.5 µM) and multiplied on MS + BAP (1 µM) + CH (250 mg/l). Thereafter, the shoots were rooted on ¼ MS + IBA (0.5 µM). Cytological analysis of the calli and regenerants have confirmed their haploid status with the chromosome number as 2n = x = 12. The haploid cell lines and leaves from in vitro grown plantlets were analyzed for azadirachtin by RP-HPLC and mass spectroscopy. Maximum azadirachtin (728.41 µg/g DW) was detected in calli supporting best shoot proliferation while least (49 µg/g DW) was observed in an undifferentiated line from maintenance medium. This study has brought us a step closer to develop genetically pure lines that could serve as new and attractive alternative ways of homogeneous controlled production of high value compounds, round the year, independent of geographical and climatic barrier. PMID:21701249

Adventitious shoot regeneration from in vitro leaf explants of Fraxinus nigra

Treesearch

Jun Hyung Lee; Paula M. Pijut

2017-01-01

Black ash (Fraxinus nigra) is an endangered hardwood tree species under threat of extirpation by the emerald ash borer (EAB), an aggressive exotic phloemfeeding beetle. We have developed an efficient regeneration system through adventitious shoot organogenesis in F. nigra using in vitro-derived leaf explants. Two types of leaf...

Micropropagation of Capparis decidua (Forsk.) Edgew. - a tree of arid horticulture.

PubMed

Deora, N S; Shekhawat, N S

1995-12-01

A method for micropropagation of mature trees of Capparis decidua was developed. Multiple shoots were obtained from nodal explants on Murashige and Skoog's (1962) medium+0.1mgl(-1) NAA+5.0mgl(-1)BAP+additives (50mgl(-1) ascorbic acid and25 mgl(-1) each of adenine sulphate, L-arginine and citric acid) at 28 ± 2°C, 12 h/dphotoperiod and 35-40 μmol m(-2)s(-1) photon flux density. The shoots were multiplied by (i) subculture of nodal shoot segments onto MS +0.1 mgl(--1) IAA+1.0mgl(-1) BAPH+additives, and (ii) repeated transfer of original explant onto MS+ 0.1mgl(-1) IAA+mg l(-1) BAP+additives, at intervals of 3 weeks. Sixty to 70% of the shoots rooted when pulse treated with 100 mg l(-1) IBA in half strength MS liquid medium for 4h, and then transferred onto hormone-free half-strength agar-gelled MS basal saltmedium. Incubation in dark at 33 ± 2°C for 6d favoured root induction. In vitro hardened plants were transferred to pots.

Potential link between biotic defense activation and recalcitrance to induction of somatic embryogenesis in shoot primordia from adult trees of white spruce (Picea glauca)

PubMed Central

2013-01-01

Background Among the many commercial opportunities afforded by somatic embryogenesis (SE), it is the ability to clonally propagate individual plants with rare or elite traits that has some of the most significant implications. This is particularly true for many long-lived species, such as conifers, but whose long generation times pose substantive challenges, including increased recalcitrance for SE as plants age. Identification of a clonal line of somatic embryo-derived trees whose shoot primordia have remained responsive to SE induction for over a decade, provided a unique opportunity to examine the molecular aspects underpinning SE within shoot tissues of adult white spruce trees. Results Microarray analysis was used to conduct transcriptome-wide expression profiling of shoot explants taken from this responsive genotype following one week of SE induction, which when compared with that of a nonresponsive genotype, led to the identification of four of the most differentially expressed genes within each genotype. Using absolute qPCR to expand the analysis to three weeks of induction revealed that differential expression of all eight candidate genes was maintained to the end of the induction treatment, albeit to differing degrees. Most striking was that both the magnitude and duration of candidate gene expression within the nonresponsive genotype was indicative of an intense physiological response. Examining their putative identities further revealed that all four encoded for proteins with similarity to angiosperm proteins known to play prominent roles in biotic defense, and that their high-level induction over an extended period is consistent with activation of a biotic defense response. In contrast, the more temperate response within the responsive genotype, including induction of a conifer-specific dehydrin, is more consistent with elicitation of an adaptive stress response. Conclusions While additional evidence is required to definitively establish an association between SE responsiveness and a specific physiological response, these results suggest that biotic defense activation may be antagonistic, likely related to the massive transcriptional and metabolic reprogramming that it elicits. A major issue for future work will be to determine how and if suppressing biotic defense activation could be used to promote a physiological state more conducive to SE induction. PMID:23937238

Tomicus piniperda (Coleaoptera: Scolytidae) Within and Between Tree Movement When Migrating to Overwintering Sites

Treesearch

Ye Hui; Robert A. Haack; Toby R. Petrice

2002-01-01

Tomicus piniperda (L.) (Coleoptera: Scolytidae) is a univoltine bark beetle that conducts maturation feeding inside shoots of pine (Pinus) trees during summer and fall. In the northern portion of its range, where freezing winter temperatures occur, adults overwinter in the outer bark at the base of live pine trees. In the present...

Tomicus Piniperda (Coleoptera: Scolytidae) Reproduction and Behavior on Scotch Pine Christmas Trees taken Indoors

Treesearch

Robert A. Haack; Robert K. Lawrence

1997-01-01

Tomicus piniperda, the pine shoot beetle, is an exotic insect that was first found in North America in 1992. A federal quarantine currently restricts movement of pine products, including Christmas trees, from infested to uninfested counties. We conducted a study to determine if T. piniperda would reproduce in Christmas trees that...

Scab severity in relation to hedge pruning pecan trees in the Southeastern USA

USDA-ARS?s Scientific Manuscript database

Scab is the most damaging disease of pecan in the Southeastern USA. Pecan trees are tall (up to 30+ m), and managing disease in the upper canopy is problematic. Hedge pruning trees to ~12 m is being explored to facilitate efficacy of ground-based fungicide sprays, but resulting vigorous shoot growth...

Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree-ring C and O stable isotopes

Treesearch

D. E. Marias; F. C. Meinzer; D. R. Woodruff; D. C. Shaw; S. L. Voelker; Steven W. Oak; William J. Otrosina; William D. Smith; Kamal J.K. Gandhi

2014-01-01

Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture and photosynthetic gas exchange and can eventually induce tree death. To investigate the long-term (1886–2010) impacts of dwarf mistletoe on the growth and gas exchange characteristics of host western hemlock, we...

Induction of somatic embryogenesis in explants of shoot cultures established from adult Eucalyptus globulus and E. saligna × E. maidenii trees.

PubMed

Corredoira, E; Ballester, A; Ibarra, M; Vieitez, A M

2015-06-01

A reproducible procedure for induction of somatic embryogenesis (SE) from adult trees of Eucalyptus globulus Labill. and the hybrid E. saligna Smith × E. maidenii has been developed for the first time. Somatic embryos were obtained from both shoot apex and leaf explants of all three genotypes evaluated, although embryogenic frequencies were significantly influenced by the species/genotype, auxin and explant type. Picloram was more efficient for somatic embryo induction than naphthaleneacetic acid (NAA), with the highest frequency of induction being obtained in Murashige and Skoog medium containing 40 µM picloram and 40 mg l(-1) gum Arabic, in which 64% of the shoot apex explants and 68.8% of the leaf explants yielded somatic embryos. The embryogenic response of the hybrid was higher than that of the E. globulus, especially when NAA was used. The cultures initiated on picloram-containing medium consisted of nodular embryogenic structures surrounded by a mucilaginous coating layer that emerged from a watery callus developed from the initial explants. Cotyledonary somatic embryos were differentiated after subculture of these nodular embryogenic structures on a medium lacking plant growth regulators. Histological analysis confirmed the bipolar organization of the somatic embryos, with shoot and root meristems and closed procambial tissue that bifurcated into small cotyledons. The root pole was more differentiated than the shoot pole, which appeared to be formed by a few meristematic layers. Maintenance of the embryogenic lines by secondary SE was attained by subculturing individual cotyledonary embryos or small clusters of globular and torpedo embryos on medium with 16.11 µM NAA at 4- to 5-week intervals. Somatic embryos converted into plantlets after being transferred to liquid germination medium although plant regeneration remained poor. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Micropropagation of Pithecellobium dulce (Roxb.) Benth-a multipurpose leguminous tree and assessment of genetic fidelity of micropropagated plants using molecular markers.

PubMed

Goyal, Pooja; Kachhwaha, Sumita; Kothari, S L

2012-04-01

An efficient and reproducible protocol has been developed for in vitro propagation of Pithecellobium dulce (Roxb.) Benth (a multipurpose leguminous tree) from field grown nodal segments (axillary bud). Shoot bud induction occurred from nodal explants of 15-years-old tree on Murashige and Skoog (MS) basal medium supplemented with 4.4 μM 6-benzyladenine (BA) and multiplication was achieved on MS medium supplemented with 4.4 μM BA + 0.73 μM phenylacetic acid (PAA) i.e. up to 7 shoot buds in the period of 5-6 weeks. Addition of adenine sulphate (AdS) to this medium further enhanced the number of shoot buds up to 10. Proliferating shoot cultures were established by repeatedly subculturing primary culture on fresh medium (MS + 4.4 μM BA + 0.73 μM PAA) after every 25 days. In vitro rooting was achieved on MS medium supplemented with 2.46 μM Indole-3-butyric acid (IBA) + 41.63 μM activated charcoal (AC). The micropropagated shoots with well developed roots were acclimatized in green house in pots containing sand, soil and manure (1:1:1). Genetic stability of micropropagated clones was evaluated using Random amplified polymorphic DNA (RAPD) and Inter simple sequence repeat (ISSR) markers. The amplification products were monomorphic in micropropagated plants and similar to those of mother plant. No polymorphism was detected revealing the genetic uniformity of micropropagated plants. This is the first report of an efficient protocol for regeneration of P. dulce through organogenesis, which can be used for further genetic transformation and pharmaceutical purposes.

The yeast flora of the coast redwood, Sequoia sempervirens.

PubMed

Middelhoven, W J

2003-01-01

Only four yeast species could be isolated from young and perannual shoots of the coast redwood tree, Sequoia sempervirens, and from soil beneath the trees, viz. both varieties of Debaryomyces hansenii, Trichosporon pullulans, T. porosum and an unidentified red basidiomycetous yeast.

Adventitious shoot regeneration and rooting of Fraxinus americana

Treesearch

Kaitlin J. Palla; Paula M. Pijut

2010-01-01

White ash (Fraxinus americana) trees provide both ecological and economic benefits. Loss of this North American endemic would disturb the environment. The urban ash tree industry in the United States would also suffer, as would manufacturers of baseball bats, furniture, and cabinets.

A dark incubation period is important for Agrobacterium-mediated transformation of mature internode explants of sweet orange, grapefruit, citron, and a citrange rootstock.

PubMed

Marutani-Hert, Mizuri; Bowman, Kim D; McCollum, Greg T; Mirkov, T Erik; Evens, Terence J; Niedz, Randall P

2012-01-01

Citrus has an extended juvenile phase and trees can take 2-20 years to transition to the adult reproductive phase and produce fruit. For citrus variety development this substantially prolongs the time before adult traits, such as fruit yield and quality, can be evaluated. Methods to transform tissue from mature citrus trees would shorten the evaluation period via the direct production of adult phase transgenic citrus trees. Factors important for promoting shoot regeneration from internode explants from adult phase citrus trees were identified and included a dark incubation period and the use of the cytokinin zeatin riboside. Transgenic trees were produced from four citrus types including sweet orange, citron, grapefruit, and a trifoliate hybrid using the identified factors and factor settings. The critical importance of a dark incubation period for shoot regeneration was established. These results confirm previous reports on the feasibility of transforming mature tissue from sweet orange and are the first to document the transformation of mature tissue from grapefruit, citron, and a trifoliate hybrid.

A Dark Incubation Period Is Important for Agrobacterium-Mediated Transformation of Mature Internode Explants of Sweet Orange, Grapefruit, Citron, and a Citrange Rootstock

PubMed Central

Marutani-Hert, Mizuri; Bowman, Kim D.; McCollum, Greg T.; Mirkov, T. Erik; Evens, Terence J.; Niedz, Randall P.

2012-01-01

Background Citrus has an extended juvenile phase and trees can take 2–20 years to transition to the adult reproductive phase and produce fruit. For citrus variety development this substantially prolongs the time before adult traits, such as fruit yield and quality, can be evaluated. Methods to transform tissue from mature citrus trees would shorten the evaluation period via the direct production of adult phase transgenic citrus trees. Methodology/Principal Findings Factors important for promoting shoot regeneration from internode explants from adult phase citrus trees were identified and included a dark incubation period and the use of the cytokinin zeatin riboside. Transgenic trees were produced from four citrus types including sweet orange, citron, grapefruit, and a trifoliate hybrid using the identified factors and factor settings. Significance The critical importance of a dark incubation period for shoot regeneration was established. These results confirm previous reports on the feasibility of transforming mature tissue from sweet orange and are the first to document the transformation of mature tissue from grapefruit, citron, and a trifoliate hybrid. PMID:23082165

Carbon Allocation into Different Fine-Root Classes of Young Abies alba Trees Is Affected More by Phenology than by Simulated Browsing

PubMed Central

Endrulat, Tina; Buchmann, Nina; Brunner, Ivano

2016-01-01

Abies alba (European silver fir) was used to investigate possible effects of simulated browsing on C allocation belowground by 13CO2 pulse-labelling at spring, summer or autumn, and by harvesting the trees at the same time point of the labelling or at a later season for biomass and for 13C-allocation into the fine-root system. Before budburst in spring, the leader shoots and 50% of all lateral shoots of half of the investigated 5-year old Abies alba saplings were clipped to simulate browsing. At harvest, different fine-root classes were separated, and starch as an important storage compartment was analysed for concentrations. The phenology had a strong effect on the allocation of the 13C-label from shoots to roots. In spring, shoots did not supply the fine-roots with high amounts of the 13C-label, because the fine-roots contained less than 1% of the applied 13C. In summer and autumn, however, shoots allocated relatively high amounts of the 13C-label to the fine roots. The incorporation of the 13C-label as structural C or as starch into the roots is strongly dependent on the root type and the root diameter. In newly formed fine roots, 3–5% of the applied 13C was incorporated, whereas 1–3% in the ≤0.5 mm root class and 1–1.5% in the >0.5–1.0 mm root class were recorded. Highest 13C-enrichment in the starch was recorded in the newly formed fine roots in autumn. The clipping treatment had a significant positive effect on the amount of allocated 13C-label to the fine roots after the spring labelling, with high relative 13C-contents observed in the ≤0.5 mm and the >0.5–1.0 mm fine-root classes of clipped trees. No effects of the clipping were observed after summer and autumn labelling in the 13C-allocation patterns. Overall, our data imply that the season of C assimilation and, thus, the phenology of trees is the main determinant of the C allocation from shoots to roots and is clearly more important than browsing. PMID:27123860

Carbon Allocation into Different Fine-Root Classes of Young Abies alba Trees Is Affected More by Phenology than by Simulated Browsing.

PubMed

Endrulat, Tina; Buchmann, Nina; Brunner, Ivano

2016-01-01

Abies alba (European silver fir) was used to investigate possible effects of simulated browsing on C allocation belowground by 13CO2 pulse-labelling at spring, summer or autumn, and by harvesting the trees at the same time point of the labelling or at a later season for biomass and for 13C-allocation into the fine-root system. Before budburst in spring, the leader shoots and 50% of all lateral shoots of half of the investigated 5-year old Abies alba saplings were clipped to simulate browsing. At harvest, different fine-root classes were separated, and starch as an important storage compartment was analysed for concentrations. The phenology had a strong effect on the allocation of the 13C-label from shoots to roots. In spring, shoots did not supply the fine-roots with high amounts of the 13C-label, because the fine-roots contained less than 1% of the applied 13C. In summer and autumn, however, shoots allocated relatively high amounts of the 13C-label to the fine roots. The incorporation of the 13C-label as structural C or as starch into the roots is strongly dependent on the root type and the root diameter. In newly formed fine roots, 3-5% of the applied 13C was incorporated, whereas 1-3% in the ≤0.5 mm root class and 1-1.5% in the >0.5-1.0 mm root class were recorded. Highest 13C-enrichment in the starch was recorded in the newly formed fine roots in autumn. The clipping treatment had a significant positive effect on the amount of allocated 13C-label to the fine roots after the spring labelling, with high relative 13C-contents observed in the ≤0.5 mm and the >0.5-1.0 mm fine-root classes of clipped trees. No effects of the clipping were observed after summer and autumn labelling in the 13C-allocation patterns. Overall, our data imply that the season of C assimilation and, thus, the phenology of trees is the main determinant of the C allocation from shoots to roots and is clearly more important than browsing.

Tomicus piniperda (Coleoptera: Scolytidae) Emergence in Relation to Burial Depth of Brood Logs

Treesearch

Robert A. Haack; Toby R. Petrice; Therese M. Poland

2000-01-01

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest of pines, Pinus spp., that was first found in the United States in 1992. A federal quarantine currently regulates movement of pine Christmas trees and pine nursery stock from infested to uninfested counties. The current national Pine Shoot Beetle Compliance Management...

European Pine Shoot Moth

Treesearch

William E. Miller; Arthur R. Hastings; John F. Wootten

1961-01-01

In the United States, the European pine shoot moth has caused much damage in young, plantations of red pine. It has been responsible for reduced planting of red pine in many areas. Although attacked trees rarely if ever die, their growth is inhibited and many are, deformed. Scotch pine and Austrian pine (Pinus nigra Arnold) are usually not so badly damaged. Swiss...

Eradicating European pine shoot moth in commercial nurseries with methyl bromide.

Treesearch

V.M. Carolin; W.K. Coulter

1963-01-01

This is the third in a series of reports on experimental fumigation of the European pine shoot moth in residential areas and nurseries. Methods and techniques derived in previous studies on single ornamentals were adapted to fumigation of a commercial nursery. An elongate cubical chamber was built for treatment of trees in rows. Fumigation of an...

Effects of nitrogen and phosphorus fertilizers on deer browsing and growth of young Douglas-fir.

Treesearch

Glenn L. Crouch; M.A. Radwan

1981-01-01

Nitrogen and phosphorus were applied to young Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees to determine their effects on deer browsing and tree growth. Nitrogen (N) proauced measurable responses in browsing of terminal shoots and growth of trees the first year, but effects were mostly negligible 2 years after treatments. No responses to...

Removal of chromium by some multipurpose tree seedlings of Indian thar desert.

PubMed

Mathur, Nishi; Singh, Joginder; Bohra, Sachendra; Bohra, Avinash; Vyas, Anil

2010-01-01

An experiment was conducted to study the potential of chromium (Cr) phytoaccumulatory capabilities of four tree species viz., Anogeissus latifolia, Terminalia arjuna, Tecomella undulata, and Salvadora persica Possibility of enhancement of Cr uptake by citric acid and vesicular arbuscular mycorrhizal fungi (VAM) amendments were also tried. Cr is a major pollutant of the environment. Chromium can exist in oxidation states from III to VI, but the most stable and common forms of Cr are trivalent and hexavalent species. Cr(VI) was more toxic to the tree growth in terms of collar diameter (CD) increment in all the tree species than Cr(lll). Roots accumulated more Cr than shoots in all the tree species. There was more than 10 fold increase in root Cr content in comparison with shoot Cr content in all the trees at all the concentration of Cr and all sources of Cr. Citric acid significantly increased the Cr content in the tissues of roots in all the species under both speciation of Cr. The highest increase in Cr content brought by 20 mM citric acid addition was in A. latifolia Results suggest that Anogeissus latifolia is a potential Cr accumulator with citric acid as soil amendment.

Effects of increasing root carbon investment on the mortality and resprouting of Haloxylon ammodendron seedlings under drought.

PubMed

Zhang, Y; Xie, J-B; Li, Y

2017-03-01

Tree mortality induced by drought is one of the most complex processes in ecology. Although two mechanisms associated with water and carbon balance are proposed to explain tree mortality, outstanding problems still exist. Here, in order to test how the root system benefits survival and resprouting of Haloxylon ammodendron seedlings, we examined the various water- and carbon-related physiological indicators (shoot water potential, photosynthesis, dark respiration, hydraulic conductance and non-structural carbohydrates [NSC]) of H. ammodendron seedlings, which were grown in drought and control conditions throughout a grow season in greenhouse. The survival time of the seedling root system (died 70 days after drought) doubled the survival time of the shoot (died at 35 days). Difference in survival time between shoot and root resulted from sustained root respiration supported by increased NSC in roots under drought. Furthermore, investment into the root contributed to resprouting following drought. Based on these results, a death criterion is proposed for this species. The time sequence of major events indicated that drought shifted carbon allocation between shoot and root and altered the flux among different sinks (growth, respiration or storage). The interaction of water and carbon processes determined death or survival of droughted H. ammodendron seedlings. These findings revealed that the 'root protection' strategy is critical in determining survival and resprouting of this species, and provided insights into the effects of carbon and water dynamics on tree mortality. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Phytoaccumulation of heavy metals in natural plants thriving on wastewater effluent at Hattar industrial estate, Pakistan.

PubMed

Irshad, Muhammad; Ahmad, Sajjad; Pervez, Arshid; Inoue, Mitsuhiro

2015-01-01

The objective of this research was to compare the potential of native plants for the phytoaccumulation of heavy metals (HM). Thirteen predominant plant species (including trees, bushes and grasses) namely Ricinus communis, Ipomoea carnea, Cannabis sativa, Parthenium hysterophorus, Acacia nilotica, Dalbergia sissoo, Acacia modesta, Solanum nigrum, Xanthium stromarium, Chenopodium album, Cynodon dactylon, Eleusine indica, and Dactyloctenium aegyptium were collected from the wastewater originated from Hattar industrial estate of Pakistan, Plants shoots and roots were analyzed for heavy metals/metalloid: Pb, Cr, Cd, Zn, Fe, Ni, and As. Among plant species, the accumulation potential for HM varied depending on the type of element. Regardless of the plant species, HM concentrations varied in the order of Fe>Zn>Cr>Pb>Ni>Cd>As. Tree species of R. communis, A. nilotica, A. modesta, and D. sissoo exhibited an enhanced concentrations of metals. Accumulation pattern of Fe, Pb, Cd, and As in plants could be related to the HM composition of soil and wastewater. Most of the species exhibited higher HM composition in the root as compared to shoot. The species that found with greater ability to absorb HM in the root, got higher HM concentrations in its shoot. Shoot tissue concentrations of HM were attained by the species as D. sissoo>A. modesta>A. nilotica>R. communis>I. carnea>C. album>E. indica>P. hysterophorus>S. nigrum>C. sativa>D. aegyptium>X. strumarium>C. dactylon. Based on results, tree plants were noticed as higher accumulators of HM in polluted soils.

Photosynthetic, hydraulic and biomechanical responses of Juglans californica shoots to wildfire.

PubMed

Utsumi, Yasuhiro; Bobich, Edward G; Ewers, Frank W

2010-10-01

Leaf gas exchange and stem xylem hydraulic and mechanical properties were studied for unburned adults and resprouting burned Juglans californica (southern California black walnut) trees 1 year after a fire to explore possible trade-offs between mechanical and hydraulic properties of plants. The CO(2) uptake rates and stomatal conductance were 2-3 times greater for resprouting trees than for unburned adults. Both predawn and midday water potentials were more negative for unburned adult trees, indicating that the stems were experiencing greater water stress than the stems of resprouting trees. In addition, the xylem specific conductivity was similar in the two growth forms, even though the stems of resprouting trees were less vulnerable to water-stress-induced embolism than similar diameter, but older, stems of adult trees. The reduced vulnerability may have been due to less cavitation fatigue in stems of resprouts. The modulus of elasticity, modulus of rupture and xylem density were all greater for resprouts, indicating that resprouts have greater mechanical strength than do adult trees. The data suggest that there is no trade-off between stem mechanical strength and shoot hydraulic and photosynthetic efficiency in resprouts, which may have implications for the success of this species in the fire-prone plant communities of southern California.

Identification and characterization of microRNAs from in vitro-grown pear shoots infected with Apple stem grooving virus in response to high temperature using small RNA sequencing.

PubMed

Liu, Juan; Zhang, XueJiao; Zhang, FangPeng; Hong, Ni; Wang, GuoPing; Wang, Aiming; Wang, LiPing

2015-11-16

MicroRNAs (miRNAs) have functions in diverse biological processes such as growth, signal transduction, disease resistance, and stress responses in plants. Thermotherapy is an effective approach for elimination of viruses from fruit trees. However, the role of miRNAs in this process remains elusive. Previously, we showed that high temperature treatment reduces the titers of Apple stem grooving virus (ASGV) from the tips of in vitro-grown Pyrus pyrifolia plants. In this study, we identified high temperature-altered pear miRNAs using the next generation sequencing technology, and futher molecularly characterized miRNA-mediated regulaton of target gene expression in the meristem tip and base tissues of in vitro-grown, ASGV-infected pear shoots under different temperatures. Using in vitro-grown P. pyrifolia shoot meristem tips infected with ASGV, a total of 22,592,997 and 20,411,254 clean reads were obtained from Illumina high-throughput sequencing of small RNA libraries at 24 °C and 37 °C, respectively. We identified 149 conserved and 141 novel miRNAs. Seven conserved miRNAs and 77 novel miRNAs were differentially expressed at different temperatures. Target genes for differentially expressed known and novel miRNAs were predicted and functionally annotated. Gene Ontology (GO) analysis showed that high-ranking miRNA target genes were involved in metabolic processes, responses to stress, and signaling, indicating that these high temperature-responsive miRNAs have functions in diverse gene regulatory networks. Spatial expression patterns of the miRNAs and their target genes were found to be expressed in shoot tip and base tissues by qRT-PCR. In addition, high temperature reduced viral titers in the shoot meristem tip, while negatively regulated miRNA-mediated target genes related to resistance disease defense and hormone signal transduction pathway were up-regulated in the P. pyrifolia shoot tip in response to high temperature. These results suggested that miRNAs may have important functions in the high temperature-dependent decrease of ASGV titer in in vitro-grown pear shoots. This is the first report of miRNAs differentially expressed at 24 °C and 37 °C in the meristem tip of pear shoots infected with ASGV. The results of this study provide valuable information for further exploration of the function of high temperature-altered miRNAs in suppressing viral infections in pear and other fruit trees.

Rejuvenation of Sequoia sempervirens by Repeated Grafting of Shoot Tips onto Juvenile Rootstocks in Vitro 1

PubMed Central

Huang, Li-Chun; Lius, Suwenza; Huang, Bau-Lian; Murashige, Toshio; Mahdi, El Fatih M.; Van Gundy, Richard

1992-01-01

Repeated grafting of 1.5-centimeter long shoot tips from an adult Sequoia sempervirens tree onto fresh, rooted juvenile stem cuttings in vitro resulted in progressive restoration of juvenile traits. After four successive grafts, stem cuttings of previously adult shoots rooted as well, branched as profusely, and grew with as much or more vigor as those of seedling shoots. Reassays disclosed retention for 3 years of rooting competence at similar levels as originally restored. Adventitious shoot formation was remanifested and callus development was depressed in stem segments from the repeatedly grafted adult. The reversion was associated with appearance and disappearance of distinctive leaf proteins. Neither gibberellic acid nor N6-beneyladenine as nutrient supplements duplicated the graft effects. ImagesFigure 2Figure 5Figure 8 PMID:16668609

Eradicating European pine shoot moth on ornamental pines with methyl bromide.

Treesearch

V.M. Carolin; W.H. Klein; R.M. Thompson

1962-01-01

The recent introduction of the European pine shoot moth into this region poses a serious threat to natural pine stands. To combat this threat, quarantines were invoked and eradication programs undertaken. Destruction of infested trees has been used tentatively as an eradication technique. In the meantime, fumigation with methyl bromide was tested over the period of a...

Plant genetics and interspecific competitive interactions determine ectomycorrhizal fungal community responses to climate change.

PubMed

Gehring, Catherine; Flores-Rentería, Dulce; Sthultz, Christopher M; Leonard, Tierra M; Flores-Rentería, Lluvia; Whipple, Amy V; Whitham, Thomas G

2014-03-01

Although the importance of plant-associated microbes is increasingly recognized, little is known about the biotic and abiotic factors that determine the composition of that microbiome. We examined the influence of plant genetic variation, and two stressors, one biotic and one abiotic, on the ectomycorrhizal (EM) fungal community of a dominant tree species, Pinus edulis. During three periods across 16 years that varied in drought severity, we sampled the EM fungal communities of a wild stand of P. edulis in which genetically based resistance and susceptibility to insect herbivory was linked with drought tolerance and the abundance of competing shrubs. We found that the EM fungal communities of insect-susceptible trees remained relatively constant as climate dried, while those of insect-resistant trees shifted significantly, providing evidence of a genotype by environment interaction. Shrub removal altered the EM fungal communities of insect-resistant trees, but not insect-susceptible trees, also a genotype by environment interaction. The change in the EM fungal community of insect-resistant trees following shrub removal was associated with greater shoot growth, evidence of competitive release. However, shrub removal had a 7-fold greater positive effect on the shoot growth of insect-susceptible trees than insect-resistant trees when shrub density was taken into account. Insect-susceptible trees had higher growth than insect-resistant trees, consistent with the hypothesis that the EM fungi associated with susceptible trees were superior mutualists. These complex, genetic-based interactions among species (tree-shrub-herbivore-fungus) argue that the ultimate impacts of climate change are both ecological and evolutionary. © 2013 John Wiley & Sons Ltd.

Networks of highly branched stigmarian rootlets developed on the first giant trees

PubMed Central

Hetherington, Alexander J.; Berry, Christopher M.; Dolan, Liam

2016-01-01

Lycophyte trees, up to 50 m in height, were the tallest in the Carboniferous coal swamp forests. The similarity in their shoot and root morphology led to the hypothesis that their rooting (stigmarian) systems were modified leafy shoot systems, distinct from the roots of all other plants. Each consists of a branching main axis covered on all sides by lateral structures in a phyllotactic arrangement; unbranched microphylls developed from shoot axes, and largely unbranched stigmarian rootlets developed from rhizomorphs axes. Here, we reexamined the morphology of extinct stigmarian systems preserved as compression fossils and in coal balls from the Carboniferous period. Contrary to the long-standing view of stigmarian systems, where shoot-like rhizomorph axes developed largely unbranched, root-hairless rootlets, here we report that stigmarian rootlets were highly branched, developed at a density of ∼25,600 terminal rootlets per meter of rhizomorph, and were covered in root hairs. Furthermore, we show that this architecture is conserved among their only extant relatives, herbaceous plants in the Isoetes genus. Therefore, despite the difference in stature and the time that has elapsed, we conclude that both extant and extinct rhizomorphic lycopsids have the same rootlet system architecture. PMID:27226309

[Effects of bryophytes in dark coniferous forest of Changbai Mountains on three conifers seed germination and seedling growth].

PubMed

Lin, Fei; Hao, Zhanqing; Ye, Ji; Jiang, Ping

2006-08-01

This paper studied the effects of Hylocomium splendens and Rhytidiadelphus triquetrus, the main bryophytes in dark coniferous forests of Changbai Mountains, on the seed germination and seedling growth of Pinus koraiensis, Picea koraiensis and Larix olgensis. The results indicated that at definite concentrations, the water extract of H. splendens inhibited Picea koraiensis seed germination, while that of R. triquetrus promoted it. Although the water extracts of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, they expedited the occurrence of the tree species' daily germination peak. The water extracts of test bryophytes inhibited the seedling growth of P. koraiensis and Picea koraiensis, but promoted that of Larix olgensis. The living shoots of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, but delayed the daily germination peak of Picea koraiensis while promoted that of Larix olgensis, andthe killed shoots inhibited the seed germination of all test tree species. Living shoots in larger amounts promoted the seedling growth of Picea koraiensis and Larix olgensis, but killed shoots were inadverse.

BOREAS TE-12 SSA Shoot Geometry Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Walter-Shea, Elizabeth A.; Mesarch, Mark A.; Cheng, L.; Yang, Litao

2000-01-01

The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-12 (Terrestrial Ecology) team collected shoot geometry data in 1993 and 1994 from aspen, jack pine, and black spruce trees. Collections were made at the Southern Study Area Nipawin Fen Site (SSA FEN), Young Jack Pine (YJP), Old Jack Pine (OJP), Old Aspen (OA), Young Aspen (YA), Mixed Site (MIX), and Old Black Spruce (OBS) sites. A caliper was used to measure shoot and needle lengths and widths. A volume displacement procedure was used to measure the weight of the shoot or twig submerged in water. 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).

7 CFR 301.50-10 - Treatments and management method.

Code of Federal Regulations, 2013 CFR

2013-01-01

... chapter to neutralize the pine shoot beetle. (b) Management method for pine bark products. The following... pine (P. sylvestris), red pine (P. resinosa), and jack pine (P. banksiana) trees. Pine bark products... following procedures are followed: (1) For pine bark products produced from trees felled during the period...

7 CFR 301.50-10 - Treatments and management method.

Code of Federal Regulations, 2014 CFR

2014-01-01

... chapter to neutralize the pine shoot beetle. (b) Management method for pine bark products. The following... pine (P. sylvestris), red pine (P. resinosa), and jack pine (P. banksiana) trees. Pine bark products... following procedures are followed: (1) For pine bark products produced from trees felled during the period...

7 CFR 301.50-10 - Treatments and management method.

Code of Federal Regulations, 2011 CFR

2011-01-01

... chapter to neutralize the pine shoot beetle. (b) Management method for pine bark products. The following... pine (P. sylvestris), red pine (P. resinosa), and jack pine (P. banksiana) trees. Pine bark products... following procedures are followed: (1) For pine bark products produced from trees felled during the period...

7 CFR 301.50-10 - Treatments and management method.

Code of Federal Regulations, 2012 CFR

2012-01-01

... chapter to neutralize the pine shoot beetle. (b) Management method for pine bark products. The following... pine (P. sylvestris), red pine (P. resinosa), and jack pine (P. banksiana) trees. Pine bark products... following procedures are followed: (1) For pine bark products produced from trees felled during the period...

The hydraulic architecture of Juniperus communis L. ssp. communis: shrubs and trees compared.

PubMed

Beikircher, Barbara; Mayr, Stefan

2008-11-01

Juniperus communis ssp. communis can grow like a shrub or it can develop a tree-like habit. In this study, the hydraulic architecture of these contrasting growth forms was compared. We analysed the hydraulic efficiency (leaf-specific conductivity, k(l); specific conductivity, k(s); Huber value, HV) and the vulnerability to cavitation (the water potential corresponding to a 50% loss of conductivity, Psi(50)), as well as anatomical parameters [mean tracheid diameter, d; mean hydraulic diameter, d(h); cell wall reinforcement (t/b)(h)(2)] of shrub shoots, tree stems and tree branches. Shrub shoots were similar to tree branches (especially to lower branches) in growth form and conductivity (k(l) = 1.93 +/- 0.11 m(2) s(-1) MPa(-1) 10(-7), k(s) = 5.71 +/- 0.19 m(2) s(-1) MPa(-1) 10(-4)), but were similar to tree stems in their vulnerability to cavitation (Psi(50) = -5.81 +/- 0.08 MPa). Tree stems showed extraordinarily high k(l) and k(s) values, and HV increased from the base up. Stem xylem was more vulnerable to cavitation than branch xylem, where Psi(50) increased from lower (Psi(50) = -6.44 +/- 0.19 MPa) to upper branches (Psi(50) = -5.98 +/- 0.13 MPa). Conduit diameters were correlated with k(l) and k(s). Data indicate that differences in hydraulic architecture correspond to changes in growth form. In some aspects, the xylem hydraulics of tree-like Juniperus communis differs from that of other coniferous tree species.

Increased Needle Nitrogen Contents Did Not Improve Shoot Photosynthetic Performance of Mature Nitrogen-Poor Scots Pine Trees.

PubMed

Tarvainen, Lasse; Lutz, Martina; Räntfors, Mats; Näsholm, Torgny; Wallin, Göran

2016-01-01

Numerous studies have shown that temperate and boreal forests are limited by nitrogen (N) availability. However, few studies have provided a detailed account of how carbon (C) acquisition of such forests reacts to increasing N supply. We combined measurements of needle-scale biochemical photosynthetic capacities and continuous observations of shoot-scale photosynthetic performance from several canopy positions with simple mechanistic modeling to evaluate the photosynthetic responses of mature N-poor boreal Pinus sylvestris to N fertilization. The measurements were carried out in August 2013 on 90-year-old pine trees growing at Rosinedalsheden research site in northern Sweden. In spite of a nearly doubling of needle N content in response to the fertilization, no effect on the long-term shoot-scale C uptake was recorded. This lack of N-effect was due to strong light limitation of photosynthesis in all investigated canopy positions. The effect of greater N availability on needle photosynthetic capacities was also constrained by development of foliar phosphorus (P) deficiency following N addition. Thus, P deficiency and accumulation of N in arginine appeared to contribute toward lower shoot-scale nitrogen-use efficiency in the fertilized trees, thereby additionally constraining tree-scale responses to increasing N availability. On the whole our study suggests that the C uptake response of the studied N-poor boreal P. sylvestris stand to enhanced N availability is constrained by the efficiency with which the additional N is utilized. This efficiency, in turn, depends on the ability of the trees to use the greater N availability for additional light capture. For stands that have not reached canopy closure, increase in leaf area following N fertilization would be the most effective way for improving light capture and C uptake while for mature stands an increased leaf area may have a rather limited effect on light capture owing to increased self-shading. This raises the question if N limitation in boreal forests acts primarily by constraining growth of young stands while the commonly recorded increase in stem growth of mature stands following N addition is primarily the result of altered allocation and only to a limited extent the result of increased stand C-capture.

Below-ground interspecific competition for water in a rubber agroforestry system may enhance water utilization in plants

PubMed Central

Wu, Junen; Liu, Wenjie; Chen, Chunfeng

2016-01-01

Rubber-based (Hevea brasiliensis) agroforestry systems are regarded as the best way to improve the sustainability of rubber monocultures, but few reports have examined water use in such systems. Accordingly, we tested whether interplanting facilitates water utilization of rubber trees using stable isotope (δD, δ18O, and δ13C) methods and by measuring soil water content (SWC), shoot potential, and leaf C and N concentrations in a Hevea-Flemingia agroforestry system in Xishuangbanna, southwestern China. We detected a big difference in the utilization of different soil layer water between both species in this agroforestry system, as evidenced by the opposite seasonal fluctuations in both δD and δ18O in stem water. However, similar predawn shoot potential of rubber trees at both sites demonstrating that the interplanted species did not affect the water requirements of rubber trees greatly. Rubber trees with higher δ13C and more stable physiological indexes in this agroforestry system showed higher water use efficiency (WUE) and tolerance ability, and the SWC results suggested this agroforestry is conductive to water conservation. Our results clearly indicated that intercropping legume plants with rubber trees can benefit rubber trees own higher N supply, increase their WUE and better utilize soil water of each soil layer. PMID:26781071

Below-ground interspecific competition for water in a rubber agroforestry system may enhance water utilization in plants.

PubMed

Wu, Junen; Liu, Wenjie; Chen, Chunfeng

2016-01-19

Rubber-based (Hevea brasiliensis) agroforestry systems are regarded as the best way to improve the sustainability of rubber monocultures, but few reports have examined water use in such systems. Accordingly, we tested whether interplanting facilitates water utilization of rubber trees using stable isotope (δD, δ(18)O, and δ(13)C) methods and by measuring soil water content (SWC), shoot potential, and leaf C and N concentrations in a Hevea-Flemingia agroforestry system in Xishuangbanna, southwestern China. We detected a big difference in the utilization of different soil layer water between both species in this agroforestry system, as evidenced by the opposite seasonal fluctuations in both δD and δ(18)O in stem water. However, similar predawn shoot potential of rubber trees at both sites demonstrating that the interplanted species did not affect the water requirements of rubber trees greatly. Rubber trees with higher δ(13)C and more stable physiological indexes in this agroforestry system showed higher water use efficiency (WUE) and tolerance ability, and the SWC results suggested this agroforestry is conductive to water conservation. Our results clearly indicated that intercropping legume plants with rubber trees can benefit rubber trees own higher N supply, increase their WUE and better utilize soil water of each soil layer.

Forcing Epicormic Sprouts on Branch Segments of Adult Hardwoods for Softwood Cuttings

Treesearch

J. W. Van Sambeek; John E. Preece; Mark V. Coggeshall

2003-01-01

Branch segments cut from basal limbs of transitional or adult hardwood trees were forced in the greenhouse to initiate shoot growth from latent buds for the production of softwood cuttings. Forcing in February, March, and April produced 10 to 15 visible buds or elongating shoots per meter of branch wood, which was more than twice the number during any other month. On...

Experimental drought and heat can delay phenological development and reduce foliar and shoot growth in semiarid trees

DOE PAGES

Adams, Henry D.; Collins, Adam D.; Briggs, Samuel P.; ...

2015-09-22

Higher temperatures associated with climate change are anticipated to trigger an earlier start to the growing season, which could increase the terrestrial C sink strength. Greater variability in the amount and timing of precipitation is also expected with higher temperatures, bringing increased drought stress to many ecosystems. We experimentally assessed the effects of higher temperature and drought on the foliar phenology and shoot growth of mature trees of two semiarid conifer species. We exposed field-grown trees to a ~45% reduction in precipitation with a rain-out structure (‘drought’), a ~4.8 °C temperature increase with open-top chambers (‘heat’), and a combination ofmore » both simultaneously (‘drought + heat’). Over the 2013 growing season, drought, heat, and drought + heat treatments reduced shoot and needle growth in piñon pine ( Pinus edulis) by ≥39%, while juniper ( Juniperus monosperma) had low growth and little response to these treatments. Needle emergence on primary axis branches of piñon pine was delayed in heat, drought, and drought + heat treatments by 19–57 days, while secondary axis branches were less likely to produce needles in the heat treatment, and produced no needles at all in the drought + heat treatment. Growth of shoots and needles, and the timing of needle emergence correlated inversely with xylem water tension and positively with nonstructural carbohydrate concentrations. Our findings demonstrate the potential for delayed phenological development and reduced growth with higher temperatures and drought in tree species that are vulnerable to drought and reveal potential mechanistic links to physiological stress responses. Furthermore, climate change projections of an earlier and longer growing season with higher temperatures, and consequent increases in terrestrial C sink strength, may be incorrect for regions where plants will face increased drought stress with climate change.« less

Experimental drought and heat can delay phenological development and reduce foliar and shoot growth in semiarid trees.

PubMed

Adams, Henry D; Collins, Adam D; Briggs, Samuel P; Vennetier, Michel; Dickman, L Turin; Sevanto, Sanna A; Garcia-Forner, Núria; Powers, Heath H; McDowell, Nate G

2015-11-01

Higher temperatures associated with climate change are anticipated to trigger an earlier start to the growing season, which could increase the terrestrial C sink strength. Greater variability in the amount and timing of precipitation is also expected with higher temperatures, bringing increased drought stress to many ecosystems. We experimentally assessed the effects of higher temperature and drought on the foliar phenology and shoot growth of mature trees of two semiarid conifer species. We exposed field-grown trees to a ~45% reduction in precipitation with a rain-out structure ('drought'), a ~4.8 °C temperature increase with open-top chambers ('heat'), and a combination of both simultaneously ('drought + heat'). Over the 2013 growing season, drought, heat, and drought + heat treatments reduced shoot and needle growth in piñon pine (Pinus edulis) by ≥39%, while juniper (Juniperus monosperma) had low growth and little response to these treatments. Needle emergence on primary axis branches of piñon pine was delayed in heat, drought, and drought + heat treatments by 19-57 days, while secondary axis branches were less likely to produce needles in the heat treatment, and produced no needles at all in the drought + heat treatment. Growth of shoots and needles, and the timing of needle emergence correlated inversely with xylem water tension and positively with nonstructural carbohydrate concentrations. Our findings demonstrate the potential for delayed phenological development and reduced growth with higher temperatures and drought in tree species that are vulnerable to drought and reveal potential mechanistic links to physiological stress responses. Climate change projections of an earlier and longer growing season with higher temperatures, and consequent increases in terrestrial C sink strength, may be incorrect for regions where plants will face increased drought stress with climate change. © 2015 John Wiley & Sons Ltd.

Experimental drought and heat can delay phenological development and reduce foliar and shoot growth in semiarid trees

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

Adams, Henry D.; Collins, Adam D.; Briggs, Samuel P.

Higher temperatures associated with climate change are anticipated to trigger an earlier start to the growing season, which could increase the terrestrial C sink strength. Greater variability in the amount and timing of precipitation is also expected with higher temperatures, bringing increased drought stress to many ecosystems. We experimentally assessed the effects of higher temperature and drought on the foliar phenology and shoot growth of mature trees of two semiarid conifer species. We exposed field-grown trees to a ~45% reduction in precipitation with a rain-out structure (‘drought’), a ~4.8 °C temperature increase with open-top chambers (‘heat’), and a combination ofmore » both simultaneously (‘drought + heat’). Over the 2013 growing season, drought, heat, and drought + heat treatments reduced shoot and needle growth in piñon pine ( Pinus edulis) by ≥39%, while juniper ( Juniperus monosperma) had low growth and little response to these treatments. Needle emergence on primary axis branches of piñon pine was delayed in heat, drought, and drought + heat treatments by 19–57 days, while secondary axis branches were less likely to produce needles in the heat treatment, and produced no needles at all in the drought + heat treatment. Growth of shoots and needles, and the timing of needle emergence correlated inversely with xylem water tension and positively with nonstructural carbohydrate concentrations. Our findings demonstrate the potential for delayed phenological development and reduced growth with higher temperatures and drought in tree species that are vulnerable to drought and reveal potential mechanistic links to physiological stress responses. Furthermore, climate change projections of an earlier and longer growing season with higher temperatures, and consequent increases in terrestrial C sink strength, may be incorrect for regions where plants will face increased drought stress with climate change.« less

Physical and chemical characterization of biochars produced from coppiced wood of thirteen tree species for use in horticultural substrates

USDA-ARS?s Scientific Manuscript database

Seven-year-old coppiced shoots from thirteen species of native and non-native trees and shrubs were harvested, dried, and were pyrolyzed to produce biochars for potential use in horticultural substrates. Several chemical and physical characteristics of the biochars were determined. There were slight...

The effect of Phytophthora ramorum on the physiology and xylem function of young tanoak trees

Treesearch

Elizabeth Stamm; Jennifer Parke

2013-01-01

Tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, C.H. Cannon & S. H. Oh) is highly susceptible to Phytophthora ramorum. Symptoms include stem cankers, shoot dieback, and foliar blight. The mechanism by which P. ramorum kills the trees is not known, however. In this study we aimed to...

76 FR 50451 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-15

... practical utility; (b) the accuracy of the agency's estimate of burden including the validity of the... the United States from Canada. Pine shoot beetle (PSB) is a pest of pine trees. It can cause damage in weak and dying trees where reproductive and immature stages of PSB occur, and in the new growth of...

Melatonin enhances the recovery of cryopreserved shoot tips of American elm (Ulmus Americana L.)

USDA-ARS?s Scientific Manuscript database

Climate change and the global migrations of people and goods have exposed trees to new diseases and abiotic challenges that threaten the survival of species. In vitro germplasm storage via cryopreservation is an effective tool to ensure conservation of tree species, but plant cells and tissues are e...

Partial shoot reiteration in Wollemia nobilis (Araucariaceae) does not arise from ‘axillary meristems’

PubMed Central

Tomlinson, P. B.; Huggett, Brett A.

2011-01-01

Background and Aims Conifers are characterized by the paucity of axillary buds which in dicotyledonous trees usually occur at every node. To compensate, conifers also produce ‘axillary meristems’, which may be stimulated to late development. In juvenile material of Wollemia nobilis (Araucariaceae: Massart's model) first-order (plagiotropic) branches lack both axillary buds and, seemingly, axillary meristems. This contrasts with orthotropic (trunk) axes, which produce branches, either within the terminal bud or as reiterated orthotropic axes originating from axillary meristems. However, plagiotropic axes do produce branches if they are decapitated. This study investigated how this can occur if axillary meristems are not the source. Methods The terminal buds of a series of plagiotropic branches on juvenile trees were decapitated in order to generate axillary shoots. Shoots were culled at about weekly intervals to obtain stages in lateral shoot development. Serial sections were cut with a sliding microtome from the distal end of each sample and scanned sequentially for evidence of axillary meristems and early bud development. Key Results Anatomical search produced no clear evidence of pre-existing axillary meristems but did reveal stages of bud initiation. Buds were initiated in a group of small starch-rich cortical cells. Further development involved de-differentiation of these small cells and the development of contrasting outer and inner regions. The outer part becomes meristematic and organizes the apex of the new branch. The inner part develops a callus-like tissue of vacuolated cells within which vascular cambia are developed. This kind of insertion of a branch on the parent axis seems not to have been described before. Conclusions Axillary meristems in Wollemia characterize the leaf axils of trunk axes so that the origin of reiterated shoots is clear. Plagiotropic axes seemingly lack axillary meristems but still produce axillary branches by distinctive developmental processes. These observations demonstrate limited understanding of branch initiation in trees generally. PMID:21335327

Drought stress release increased growth rate but did not affect levels of storage carbohydrates in Scots pine trees

NASA Astrophysics Data System (ADS)

Schönbeck, Leonie; Gessler, Arthur; Rigling, Andreas; Schaub, Marcus; Li, Mai-He

2017-04-01

For trees, energy storage in the form of non-structural carbohydrates (NSCs) plays an important role for survival and growth, especially during stress events such as drought. It is hypothesized, that tree individuals that experience long-term drought stress use up larger amounts of NSCs than trees that do not experience drought. Consequently, such drought-induced depletion might lead to a decrease in tree vigor and carbon starvation, a mechanism that is subject of intensive debates in recent literature. Hence, if carbon starvation is occurring during drought, drought stress release should again increase NSC concentrations. A long-term (13 years) irrigation experiment is being conducted in the Pfyn forest, the largest Pinus sylvestris dominated forest in Switzerland, located in the dry inner-Alpine Swiss Rhone valley (average precipitation 600 mm/year, with frequent dry spells). Water addition ( 600 mm/year) is executed every year during the growing season between April and October. Tree height, stem diameter and crown transparency are being measured since 2003. In February, July and October 2015, roots, stem sapwood and needles were harvested from 30 irrigated and 30 control trees and 5 different crown transparency classes. Shoot length, needle morphology, soluble sugars, starch concentrations, needle δ13C and δ15N were measured. Shoot and stem growth were higher in irrigated trees than in control trees. Growth decreased with increasing crown transparency in both treatments. Only in July, needle starch levels were higher in irrigated trees than in control trees but there was no treatment effect for wood and root starch concentrations. Tissue starch and sugar levels were negatively correlated with crown transparency, particularly in the roots (p<0.001), independent of the treatment. Needle δ13C values were higher in the control trees than in the irrigated trees, where needle δ13C values were positively correlated with increasing transparency (p<0.01). Annual shoot growth was positively correlated with starch levels in the roots. The results show that 13 years of irrigation did lead to increased growth but not to increased NSC levels hence not confirming our initial hypothesis. δ13C levels indicate that control trees experienced more drought stress than irrigated trees. However, we found irrigated trees from high crown transparency classes with similar δ13C levels as for non-irrigated control trees. The release of drought stress has benefited the initially vital trees, whereas the initially inferior trees still show signs of drought stress. The results point to a 'winner takes it all principle', where differences between individuals increase when environment conditions improve. This caused the irrigation treatment not being effective in generally releasing drought stress and NSC depletion in all trees. As increasing crown transparency over both treatments is correlated with decreasing growth and decreasing NSC levels, there are still indications that reduced NSC is related to reduced tree vigor under drought.

Environmental Impact Research Program. Restoration of Problem Soil Materials at Corps of Engineers Construction Sites.

DTIC Science & Technology

1985-05-01

the total weight of a given population of organisms. Browse: Twigs or shoots, with or without attached leaves, of shrubs , trees, or woody vines ...volunteer woody plants, or the fsuccessful establishment, later on, of planted shrubs , trees, and ground covers. 184. Some problem soils absolutely...properly prepared seedbed. Woody plants, such as shrubs and trees, are established by seedling transplants. However, some woody species can be seeded

EARLY BUD-BREAK 1 (EBB1) is a regulator of release from seasonal dormancy in poplar trees

PubMed Central

Yordanov, Yordan S.; Ma, Cathleen; Strauss, Steven H.; Busov, Victor B.

2014-01-01

Trees from temperate latitudes transition between growth and dormancy to survive dehydration and freezing stress during winter months. We used activation tagging to isolate a dominant mutation affecting release from dormancy and identified the corresponding gene EARLY BUD-BREAK 1 (EBB1). We demonstrate through positioning of the tag, expression analysis, and retransformation experiments that EBB1 encodes a putative APETALA2/Ethylene responsive factor transcription factor. Transgenic up-regulation of the gene caused early bud-flush, whereas down-regulation delayed bud-break. Native EBB1 expression was highest in actively growing apices, undetectable during the dormancy period, but rapidly increased before bud-break. The EBB1 transcript was localized in the L1/L2 layers of the shoot meristem and leaf primordia. EBB1-overexpressing transgenic plants displayed enlarged shoot meristems, open and poorly differentiated buds, and a higher rate of cell division in the apex. Transcriptome analyses of the EBB1 transgenics identified 971 differentially expressed genes whose expression correlated with the EBB1 expression changes in the transgenic plants. Promoter analysis among the differentially expressed genes for the presence of a canonical EBB1-binding site identified 65 putative target genes, indicative of a broad regulatory context of EBB1 function. Our results suggest that EBB1 has a major and integrative role in reactivation of meristem activity after winter dormancy. PMID:24951507

Variation in light-intercepting area and photosynthetic rate of sun and shade shoots of two Picea species in relation to the angle of incoming light.

PubMed

Ishii, Hiroaki; Hamada, Yoko; Utsugi, Hajime

2012-10-01

We investigated the effects of sun- and shade-shoot architecture on the photosynthetic rates of two Picea species by applying light from various angles in the laboratory. Compared with sun shoots, shade shoots were characterized by lower mass allocation per light-intercepting area, less leaf mass per shoot mass, less mutual shading among leaves and more efficient allocation of chlorophyll to photosynthesis. The shoot silhouette to total leaf area ratio (STAR(ϕ)) decreased with increasing shoot inclination angle (ϕ, the shoot axis angle relative to the projection plane) and was consistently higher for the shade shoots. Morphological and physiological characteristics of the shade shoots resulted in maximum rates of net photosynthesis at ϕ = 0° (P(max,0)) similar to that of the sun shoots when expressed on a leaf mass, total leaf area and chlorophyll basis. When the angle of incoming light was varied, P(max,ϕ) per total leaf area (P(max,ϕ )/A(T)) of the shade shoots increased linearly with increasing STAR(ϕ), while P(max,ϕ) per shoot silhouette area did not change. In contrast, the response of the sun shoots was non-linear, and an optimum angle of incoming light was determined. Our results suggest that shade-shoot morphology is adaptive for utilizing diffuse light incoming from various angles, while sun-shoot morphology is adaptive for avoiding the negative effects of strong direct radiation and for enhancing light diffusion into the canopy. We propose that the angle of incoming light should be taken into account when estimating photosynthetic rates of sun shoots of conifer trees in the field.

Using SRμCT to define water transport capacity in Picea abies

NASA Astrophysics Data System (ADS)

Lautner, Silke; Lenz, Claudia; Hammel, Jörg; Moosmann, Julian; Kühn, Michael; Caselle, Michele; Vogelgesang, Matthias; Kopmann, Andreas; Beckmann, Felix

2017-10-01

Water transport from roots to shoots is a vital necessity in trees in order to sustain their photosynthetic activity and, hence, their physiological activity. The vascular tissue in charge is the woody body of root, stem and branches. In gymnosperm trees, like spruce trees (Picea abies (L.) Karst.), vascular tissue consists of tracheids: elongated, protoplast- free cells with a rigid cell wall that allow for axial water transport via their lumina. In order to analyze the over-all water transport capacity within one growth ring, time-consuming light microscopy analysis of the woody sample still is the conventional approach for calculating tracheid lumen area. In our investigations at the Imaging Beamline (IBL) operated by the Helmholtz-Zentrum Geesthacht (HZG) at PETRA III storage ring of the Deutsches Elektronen-Synchrotron DESY, Hamburg, we applied SRμCT on small wood samples of spruce trees in order to visualize and analyze size and formation of xylem elements and their respective lumina. The selected high-resolution phase-contrast technique makes full use of the novel 20 MPixel CMOS area detector developed within the cooperation of HZG and the Karlsruhe data by light microscopy analysis and, hence, prove, that μCT is a most appropriate method to gain valid information on xylem cell structure and tree water transport capacity.

Digital gene expression analysis of male and female bud transition in Metasequoia reveals high activity of MADS-box transcription factors and hormone-mediated sugar pathways.

PubMed

Zhao, Ying; Liang, Haiying; Li, Lan; Tang, Sha; Han, Xiao; Wang, Congpeng; Xia, Xinli; Yin, Weilun

2015-01-01

Metasequoia glyptostroboides is a famous redwood tree of ecological and economic importance, and requires more than 20 years of juvenile-to-adult transition before producing female and male cones. Previously, we induced reproductive buds using a hormone solution in juvenile Metasequoia trees as young as 5-to-7 years old. In the current study, hormone-treated shoots found in female and male buds were used to identify candidate genes involved in reproductive bud transition in Metasequoia. Samples from hormone-treated cone reproductive shoots and naturally occurring non-cone setting shoots were analyzed using 24 digital gene expression (DGE) tag profiles using Illumina, generating a total of 69,520 putative transcripts. Next, 32 differentially and specifically expressed transcripts were determined using quantitative real-time polymerase chain reaction, including the upregulation of MADS-box transcription factors involved in male bud transition and flowering time control proteins involved in female bud transition. These differentially expressed transcripts were associated with 243 KEGG pathways. Among the significantly changed pathways, sugar pathways were mediated by hormone signals during the vegetative-to-reproductive phase transition, including glycolysis/gluconeogenesis and sucrose and starch metabolism pathways. Key enzymes were identified in these pathways, including alcohol dehydrogenase (NAD) and glutathione dehydrogenase for the glycolysis/gluconeogenesis pathway, and glucanphosphorylase for sucrose and starch metabolism pathways. Our results increase our understanding of the reproductive bud transition in gymnosperms. In addition, these studies on hormone-mediated sugar pathways increase our understanding of the relationship between sugar and hormone signaling during female and male bud initiation in Metasequoia.

Micropropagation of juvenile and mature american beech

Treesearch

Melanie J. Barker; Paula M. Pijut; Michael E. Ostry; David R. Houston

1997-01-01

The purpose of this study was to micropropagate juvenile and mature American beech (Fagus grandifolia Ehrh.) resistant to beech bark disease. Shoot tips (from juvenile seedlings and root sprouts of mature trees) and buds from branches of mature trees, were cultured and multiplied on aspen culture medium supplemented with 0.89 ?M 6-benzyladenine, 0.27 ?M a-...

Reliability assessment of selected indicators of tree health

Treesearch

Pawel M. Lech

2000-01-01

The measurements of electrical resistance of near-cambium tissues, selected biometric features of needles and shoots, and the annual radial increment as well as visual estimates of crown defoliation were performed on about 100 Norway spruce trees in three 60- to 70-year-old stands located in the Western Sudety Mountains. The defoliation, electrical resistance, and...

Tree seedling response to LED spectra: Implications for forest restoration

Treesearch

Antonio Montagnoli; R. Kasten Dumroese; Mattia Terzaghi; Jeremiah R. Pinto; Nicoletta Fulgaro; Gabriella Stefania Scippa; Donato Chiatante

2018-01-01

We found that different spectra, provided by light-emitting diodes or a fluorescent lamp, caused different photomorphological responses depending on tree seedling type (coniferous or broad-leaved), species, seedling development stage, and seedling fraction (shoot or root). For two conifers (Picea abies and Pinus sylvestris) soon after germination (≤40 days), more...

Recent advances in the cryopreservation of shoot-derived germplasm of economically important fruit trees of Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis.

PubMed

Benelli, Carla; De Carlo, Anna; Engelmann, Florent

2013-01-01

This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at -5 °C, and then cooled slowly to -30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation-dehydration, vitrification, encapsulation-vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants. Copyright © 2012 Elsevier Inc. All rights reserved.

Effect of extending the photoperiod with low-intensity red or far-red light on the timing of shoot elongation and flower-bud formation of 1-year-old Japanese pear (Pyrus pyrifolia).

PubMed

Ito, Akiko; Saito, Takanori; Nishijima, Takaaki; Moriguchi, Takaya

2014-05-01

To investigate the effects of light quality (wavelength) on shoot elongation and flower-bud formation in Japanese pear (Pyrus pyrifolia (Burm. f.) Nakai), we treated 1-year-old trees with the following: (i) 8 h sunlight + 16 h dark (SD); (ii) 8 h sunlight + 16 h red light (LD(SD + R)); or (iii) 8 h sunlight + 16 h far-red (FR) light (LD(SD + FR)) daily for 4 months from early April (before the spring flush) until early August in 2009 and 2010. In both years, shoot elongation stopped earlier in the LD(SD + FR) treatment than in the SD and LD(SD + R) treatments. After 4 months of treatments, 21% (2009) or 40% (2010) of LD(SD + FR)-treated trees formed flower buds in the shoot apices, whereas all the shoot apices from SD or LD(SD + R)-treated plants remained vegetative. With an additional experiment conducted in 2012, we confirmed that FR light at 730 nm was the most efficacious wavelength to induce flower-bud formation. Reverse transcription-quantitative polymerase chain reaction revealed that the expression of two floral meristem identity gene orthologues, LEAFY (PpLFY2a) and APETALA1 (PpMADS2-1a), were up-regulated in the shoot apex of LD(SD + FR). In contrast, the expression of a flowering repressor gene, TERMINAL FLOWER 1 (PpTFL1-1a, PpTFL1-2a), was down-regulated. In addition, expression of an orthologue of the flower-promoting gene FLOWERING LOCUS T (PpFT1a) was positively correlated with flower-bud formation, although the expression of another orthologue, PpFT2a, was negatively correlated with shoot growth. Biologically active cytokinin and gibberellic acid concentrations in shoot apices were reduced with LD(SD + FR) treatment. Taken together, our results indicate that pear plants are able to regulate flowering in response to the R : FR ratio. Furthermore, LD(SD + FR) treatment terminated shoot elongation and subsequent flower-bud formation in the shoot apex at an earlier time, possibly by influencing the expression of flowering-related genes and modifying plant hormone concentrations. © The Author 2014. Published by Oxford University Press. All rights reserved.

Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus.

PubMed

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

2014-03-01

Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females.

Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus

PubMed Central

Munné-Bosch, Sergi

2014-01-01

Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females. PMID:24378602

Triazole induced drought tolerance in horse chestnut (Aesculus hippocastanum).

PubMed

Percival, Glynn C; Noviss, Kelly

2008-11-01

We determined the influence of the triazole derivatives paclobutrazol, penconazole, epixiconazole, propiconazole and myclobutanil on the drought tolerance and post drought recovery of container-grown horse chestnut (Aesculus hippocastanum L.) saplings. Myclobutanil neither conferred drought resistance, as assessed by its effects on a number of physiological and biochemical parameters, nor affected growth parameters measured after recovery from drought. Chlorophyll fluorescence (F(v)/F(m)), photosynthetic rates, total foliar chlorophyll and carotenoid concentrations, foliar proline concentration and superoxide dismutase and catalase activities were consistently higher and leaf necrosis and cellular electrolyte leakage was lower at the end of a 3-week drought in trees treated with paclobutrazol, penconazole, epixiconazole or propiconazole than in control trees. Twelve weeks after drought treatment, leaf area and shoot, root and total plant dry masses were greater in triazole-treated trees than in control trees with the exception of those treated with myclobutanil. In a separate study, trees were subjected to a 2-week drought and then sprayed with paclobutrazol, penconazole, epixiconazole, propiconazole or myclobutanil. Chlorophyll fluorescence, photosynthetic rate, foliar chlorophyll concentration and catalase activity over the following 12 weeks were 20 to 50% higher in triazole-treated trees than in control trees. At the end of the 12-week recovery period, leaf area and shoot, root and total plant dry masses were higher in triazole-treated trees than in control trees, with the exception of trees treated with myclobutanil. Application of triazole derivatives, with the exception of myclobutanil, enhanced tolerance to prolonged drought and, when applied after a 2-week drought, hastened recovery from drought. The magnitude of treatment effects was in the order epixiconazole approximately propiconazole > penconazole > paclobutrazol > myclobutanil.

Suitability of Some Southern and Western Pines as Hosts for the Pine Shoot Beetle, Tomicus piniperda (Coleoptera: Scolytidae)

Treesearch

T. A. Eager; C. W. Berisford; M. J. Dalusky; D. G. Nielsen; J. W. Brewer; S. J. Hilty; R. A. Haack

2004-01-01

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that has become established in North America. Discovered in Ohio in 1992, it has since been found in at least 13 states and parts of Canada. The beetle can cause signiÞcant growth loss in pines, and it represents a potential threat to trees in areas where it has not yet become...

The sentinel tree nursery as an early warning system for pathway risk assessment: Fungal pathogens associated with Chinese woody plants commonly shipped to Europe

PubMed Central

Vettraino, Anna Maria; Li, Hong-Mei; Eschen, Rene; Morales-Rodriguez, Carmen

2017-01-01

Introduction of and invasion by alien plant pathogens represents the main cause of emerging infectious diseases affecting domesticated and wild plant species worldwide. The trade in living plants is the most common pathway of introduction. Many of the alien tree pathogens recently introduced into Europe were not previously included on any quarantine lists. To help determine the potential risk of pest introduction through trading of ornamental plants, a sentinel nursery was established in Beijing, China in 2008. The sentinel nursery planting included four of the most common ornamental woody species shipped to Europe including Ilex cornuta var. fortunae, Zelkova schneideriana, Fraxinus chinensis and Buxus microphylla. Symptoms developing on these species within the sentinel nursery were detected in 2013 and consisted of necrotic spots on leaves, canker and stem necrosis, shoot blight and shoot necrosis. Fungi associated with the trees and their symptoms included Alternaria alternata detected from all hosts; Diaporthe liquidambaris and Diaporthe capsici from bark and leaf necrosis of Zelkova schneideriana; Botryosphaeria dothidea and Nothophoma quercina from stem cankers on Fraxinus chinensis and leaf necrosis on Ilex cornuta; and Pseudonectria foliicola from leaf necrosis on Buxus microphylla. Next generation sequencing analysis from asymptomatic tissues detected eighteen OTU’s at species level among which some taxa had not been previously recorded in Europe. These results clearly demonstrate that looking at trees of internationally traded species in the region of origin can reveal the presence of potentially harmful organisms of major forestry, landscape or crop trees. Results of this study also provide an indication as to how some disease agents can be introduced using pathways other than the co-generic hosts. Hence, sentinel nurseries represent one potential mechanism to address the current lack of knowledge about pests in the countries from where live plants are shipped and the threats they represent to native flora and crops in importing countries. PMID:29186190

The sentinel tree nursery as an early warning system for pathway risk assessment: Fungal pathogens associated with Chinese woody plants commonly shipped to Europe.

PubMed

Vettraino, Anna Maria; Li, Hong-Mei; Eschen, Rene; Morales-Rodriguez, Carmen; Vannini, Andrea

2017-01-01

Introduction of and invasion by alien plant pathogens represents the main cause of emerging infectious diseases affecting domesticated and wild plant species worldwide. The trade in living plants is the most common pathway of introduction. Many of the alien tree pathogens recently introduced into Europe were not previously included on any quarantine lists. To help determine the potential risk of pest introduction through trading of ornamental plants, a sentinel nursery was established in Beijing, China in 2008. The sentinel nursery planting included four of the most common ornamental woody species shipped to Europe including Ilex cornuta var. fortunae, Zelkova schneideriana, Fraxinus chinensis and Buxus microphylla. Symptoms developing on these species within the sentinel nursery were detected in 2013 and consisted of necrotic spots on leaves, canker and stem necrosis, shoot blight and shoot necrosis. Fungi associated with the trees and their symptoms included Alternaria alternata detected from all hosts; Diaporthe liquidambaris and Diaporthe capsici from bark and leaf necrosis of Zelkova schneideriana; Botryosphaeria dothidea and Nothophoma quercina from stem cankers on Fraxinus chinensis and leaf necrosis on Ilex cornuta; and Pseudonectria foliicola from leaf necrosis on Buxus microphylla. Next generation sequencing analysis from asymptomatic tissues detected eighteen OTU's at species level among which some taxa had not been previously recorded in Europe. These results clearly demonstrate that looking at trees of internationally traded species in the region of origin can reveal the presence of potentially harmful organisms of major forestry, landscape or crop trees. Results of this study also provide an indication as to how some disease agents can be introduced using pathways other than the co-generic hosts. Hence, sentinel nurseries represent one potential mechanism to address the current lack of knowledge about pests in the countries from where live plants are shipped and the threats they represent to native flora and crops in importing countries.

Increased Needle Nitrogen Contents Did Not Improve Shoot Photosynthetic Performance of Mature Nitrogen-Poor Scots Pine Trees

PubMed Central

Tarvainen, Lasse; Lutz, Martina; Räntfors, Mats; Näsholm, Torgny; Wallin, Göran

2016-01-01

Numerous studies have shown that temperate and boreal forests are limited by nitrogen (N) availability. However, few studies have provided a detailed account of how carbon (C) acquisition of such forests reacts to increasing N supply. We combined measurements of needle-scale biochemical photosynthetic capacities and continuous observations of shoot-scale photosynthetic performance from several canopy positions with simple mechanistic modeling to evaluate the photosynthetic responses of mature N-poor boreal Pinus sylvestris to N fertilization. The measurements were carried out in August 2013 on 90-year-old pine trees growing at Rosinedalsheden research site in northern Sweden. In spite of a nearly doubling of needle N content in response to the fertilization, no effect on the long-term shoot-scale C uptake was recorded. This lack of N-effect was due to strong light limitation of photosynthesis in all investigated canopy positions. The effect of greater N availability on needle photosynthetic capacities was also constrained by development of foliar phosphorus (P) deficiency following N addition. Thus, P deficiency and accumulation of N in arginine appeared to contribute toward lower shoot-scale nitrogen-use efficiency in the fertilized trees, thereby additionally constraining tree-scale responses to increasing N availability. On the whole our study suggests that the C uptake response of the studied N-poor boreal P. sylvestris stand to enhanced N availability is constrained by the efficiency with which the additional N is utilized. This efficiency, in turn, depends on the ability of the trees to use the greater N availability for additional light capture. For stands that have not reached canopy closure, increase in leaf area following N fertilization would be the most effective way for improving light capture and C uptake while for mature stands an increased leaf area may have a rather limited effect on light capture owing to increased self-shading. This raises the question if N limitation in boreal forests acts primarily by constraining growth of young stands while the commonly recorded increase in stem growth of mature stands following N addition is primarily the result of altered allocation and only to a limited extent the result of increased stand C-capture. PMID:27489553

Endogenous rhythmic growth in oak trees is regulated by internal clocks rather than resource availability

PubMed Central

Herrmann, S.; Recht, S.; Boenn, M.; Feldhahn, L.; Angay, O.; Fleischmann, F.; Tarkka, M T.; Grams, T.E.E.; Buscot, F.

2015-01-01

Common oak trees display endogenous rhythmic growth with alternating shoot and root flushes. To explore the mechanisms involved, microcuttings of the Quercus robur L. clone DF159 were used for 13C/15N labelling in combination with RNA sequencing (RNASeq) transcript profiling of shoots and roots. The effect of plant internal resource availability on the rhythmic growth of the cuttings was tested through inoculation with the ectomycorrhizal fungus Piloderma croceum. Shoot and root flushes were related to parallel shifts in above- and below-ground C and, to a lesser extent, N allocation. Increased plant internal resource availability by P. croceum inoculation with enhanced plant growth affected neither the rhythmic growth nor the associated resource allocation patterns. Two shifts in transcript abundance were identified during root and shoot growth cessation, and most concerned genes were down-regulated. Inoculation with P. croceum suppressed these transcript shifts in roots, but not in shoots. To identify core processes governing the rhythmic growth, functions [Gene Ontology (GO) terms] of the genes differentially expressed during the growth cessation in both leaves and roots of non-inoculated plants and leaves of P. croceum-inoculated plants were examined. Besides genes related to resource acquisition and cell development, which might reflect rather than trigger rhythmic growth, genes involved in signalling and/or regulated by the circadian clock were identified. The results indicate that rhythmic growth involves dramatic oscillations in plant metabolism and gene regulation between below- and above-ground parts. Ectomycorrhizal symbiosis may play a previously unsuspected role in smoothing these oscillations without modifying the rhythmic growth pattern. PMID:26320242

Tree planters` notes, Volume 46, Number 2, Spring 1995. Quarterly report

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

Nisley, R.

1995-12-31

;Contents: Certified Seed and Artificial Forest Regeneration; Missoula Technology and Development Center`s 1995 Nursery and Reforestation Programs; Trees Grow Better With Water; Botrytis cinerea Carried by Adult Fungus Gnats (Diptera: Sciaridae) in Container Nurseries; Oak Seedling Root and Shoot Growth on Restored Topsoil; Improved Vegetative Propagation of Scouler Willow; Estimating Poller Yield From Western White Pine: Preliminary Studies.

Shoot water relations of mature black spruce families displaying a genotype × environment interaction in growth rate. III. Diurnal patterns as influenced by vapor pressure deficit and internal water status

Treesearch

John E. Major; Kurt H. Johnsen

2001-01-01

Pressure­volume curves were constructed and shoot water potentials measured for +20-year-old black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families growing on a moist site and a dry site at the Petawawa Research Forest, Ontario, to determine whether differences in diurnal water relations traits were related to productivity. To...

[Occurrence of Solenopsis saevissima F Smith (Hymenoptera: Formicidae) damaging Schizolobium amazonicum].

PubMed

Lunz, Alexandre M; Harada, Ana Y; Aguiar, Tanice da S; Cardoso, Andreza S

2009-01-01

Injuries by Solenopsis saevissima F Smith in paricá (Schizolobium amazonicum) trees are described for the first time in Dom Eliseu County, Pará State, Brazil. This ant damages leaves and the shaft where holes and galleries are opened up to the plant shoot. Terminal and new shoots are attacked and destroyed, harming the development of upright and uniform trunks for commercialization. Arboreal nests constructed by this ant were also observed in some plants.

Clonal variation in heavy metal accumulation and biomass production in a poplar coppice culture. II. Vertical distribution and phytoextraction potential.

PubMed

Laureysens, I; De Temmerman, L; Hastir, T; Van Gysel, M; Ceulemans, R

2005-02-01

Short rotation coppice cultures (SRC) are intensively managed, high-density plantations of multi-shoot trees. In April 1996, an SRC field trial with 17 different poplar clones was established in Boom (Belgium) on a former waste disposal site. In December 1996 and January 2001, all shoots were cut back to a height of 5 cm to create a coppice culture. For six clones, wood and bark were sampled at the bottom, middle and top of a shoot in August and November 2002. No significant height effect of metal concentration was found, but for wood, metal concentrations generally increased toward the top of the shoot in August, and decreased toward the top of the shoot in November. Phytoextraction potential of a clone was primarily determined by metal concentration and by biomass production. Shoot size and number of shoots per stool were less important, as a high biomass production could be achieved by producing a few large shoots or many smaller shoots. Clone Fritzi Pauley accumulated 1.4 kg ha(-1) of Al over two years; Wolterson and Balsam Spire showed a relatively high accumulation of Cd and Zn, i.e. averaging, respectively 47 and 57 g ha(-1) for Cd and 2.4 and 2.0 kg ha(-1) for Zn over two years.

Three decades of research at Flakaliden advancing whole-tree physiology, forest ecosystem and global change research.

PubMed

Ryan, Michael G

2013-11-01

Nutrient supply often limits growth in forest ecosystems and may limit the response of growth to an increase in other resources, or to more favorable environmental factors such as temperature and soil water. To explore the consequences and mechanisms of optimum nutrient supply for forest growth, the Flakaliden research site was established in 1986 on a young Norway spruce site with nutrient-poor soil. This special section on research at Flakaliden presents five papers that explore different facets of nutrition, atmospheric CO2 concentration, [CO2], and increased temperature treatments, using the original experiment as a base. Research at Flakaliden shows the dominant role of nutrition in controlling the response of growth to the increased photosynthesis promoted by elevated [CO2] and temperature. Experiments with whole-tree chambers showed that all treatments (air temperature warming, elevated [CO2] and optimum nutrition) increased shoot photosynthesis by 30-50%, but growth only increased with [CO2] when combined with the optimum nutrition treatment. Elevated [CO2] and temperature increased shoot photosynthesis by increasing the slope between light-saturated photosynthesis and foliar nitrogen by 122%, the initial slope of the light response curve by 52% and apparent quantum yield by 10%. Optimum nutrition also decreased photosynthetic capacity by 17%, but increased it by 62% in elevated [CO2], as estimated from wood δ(13)C. Elevated air temperature advanced spring recovery of photosynthesis by 37%, but spring frost events remained the controlling factor for photosynthetic recovery, and elevated [CO2] did not affect this. Increased nutrient availability increased wood growth primarily through a 50% increase in tracheid formation, mostly during the peak growth season. Other notable contributions of research at Flakaliden include exploring the role of optimal nutrition in large-scale field trials with foliar analysis, using an ecosystem approach for multifactor experiments, development of whole-tree chambers allowing inexpensive environmental manipulations, long-term deployment of shoot chambers for continuous measurements of gas exchange and exploring the ecosystem response to soil and aboveground tree warming. The enduring legacy of Flakaliden will be the rich data set of long-term, multifactor experiments that has been and will continue to be used in many modeling and cross-site comparison studies.

Biomass expansion factor and root-to-shoot ratio for Pinus in Brazil.

PubMed

Sanquetta, Carlos R; Corte, Ana Pd; da Silva, Fernando

2011-09-24

The Biomass Expansion Factor (BEF) and the Root-to-Shoot Ratio (R) are variables used to quantify carbon stock in forests. They are often considered as constant or species/area specific values in most studies. This study aimed at showing tree size and age dependence upon BEF and R and proposed equations to improve forest biomass and carbon stock. Data from 70 sample Pinus spp. grown in southern Brazil trees in different diameter classes and ages were used to demonstrate the correlation between BEF and R, and forest inventory data, such as DBH, tree height and age. Total dry biomass, carbon stock and CO2 equivalent were simulated using the IPCC default values of BEF and R, corresponding average calculated from data used in this study, as well as the values estimated by regression equations. The mean values of BEF and R calculated in this study were 1.47 and 0.17, respectively. The relationship between BEF and R and the tree measurement variables were inversely related with negative exponential behavior. Simulations indicated that use of fixed values of BEF and R, either IPCC default or current average data, may lead to unreliable estimates of carbon stock inventories and CDM projects. It was concluded that accounting for the variations in BEF and R and using regression equations to relate them to DBH, tree height and age, is fundamental in obtaining reliable estimates of forest tree biomass, carbon sink and CO2 equivalent.

Digital gene expression analysis of male and female bud transition in Metasequoia reveals high activity of MADS-box transcription factors and hormone-mediated sugar pathways

PubMed Central

Zhao, Ying; Liang, Haiying; Li, Lan; Tang, Sha; Han, Xiao; Wang, Congpeng; Xia, Xinli; Yin, Weilun

2015-01-01

Metasequoia glyptostroboides is a famous redwood tree of ecological and economic importance, and requires more than 20 years of juvenile-to-adult transition before producing female and male cones. Previously, we induced reproductive buds using a hormone solution in juvenile Metasequoia trees as young as 5-to-7 years old. In the current study, hormone-treated shoots found in female and male buds were used to identify candidate genes involved in reproductive bud transition in Metasequoia. Samples from hormone-treated cone reproductive shoots and naturally occurring non-cone setting shoots were analyzed using 24 digital gene expression (DGE) tag profiles using Illumina, generating a total of 69,520 putative transcripts. Next, 32 differentially and specifically expressed transcripts were determined using quantitative real-time polymerase chain reaction, including the upregulation of MADS-box transcription factors involved in male bud transition and flowering time control proteins involved in female bud transition. These differentially expressed transcripts were associated with 243 KEGG pathways. Among the significantly changed pathways, sugar pathways were mediated by hormone signals during the vegetative-to-reproductive phase transition, including glycolysis/gluconeogenesis and sucrose and starch metabolism pathways. Key enzymes were identified in these pathways, including alcohol dehydrogenase (NAD) and glutathione dehydrogenase for the glycolysis/gluconeogenesis pathway, and glucanphosphorylase for sucrose and starch metabolism pathways. Our results increase our understanding of the reproductive bud transition in gymnosperms. In addition, these studies on hormone-mediated sugar pathways increase our understanding of the relationship between sugar and hormone signaling during female and male bud initiation in Metasequoia. PMID:26157452

Factors influencing axillary shoot proliferation and adventitious budding in cedar.

PubMed

Renau-Morata, Begoña; Ollero, Javier; Arrillaga, Isabel; Segura, Juan

2005-04-01

We developed procedures for in vitro cloning of Cedrus atlantica Manetti and C. libani A. Rich explants from juvenile and mature plants. Explant size was one determinant of the frequency of axillary bud break in both species. Shoot tips and nodal explants mainly developed calli, whereas bud sprouting occurred in defoliated microcuttings cultured on a modified Murashige and Skoog medium without growth regulators. Isolation and continuous subculture of sprouted buds on the same medium allowed cloning of microcuttings from C. atlantica and C. libani seedlings and bicentennial C. libani trees, thus providing a desirable alternative for multiplying mature trees that have demonstrated superior characteristics. We also report adventitious bud differentiation from isolated embryos of C. atlantica. Neither auxin treatments nor other methods tested, including infection with Agrobacterium rhizogenes, were effective in inducing root initiation.

Hydrostatic constraints on morphological exploitation of light in tall Sequoia sempervirens trees.

PubMed

Ishii, Hiroaki T; Jennings, Gregory M; Sillett, Stephen C; Koch, George W

2008-07-01

We studied changes in morphological and physiological characteristics of leaves and shoots along a height gradient in Sequoia sempervirens, the tallest tree species on Earth, to investigate whether morphological and physiological acclimation to the vertical light gradient was constrained by hydrostatic limitation in the upper crown. Bulk leaf water potential (Psi) decreased linearly and light availability increased exponentially with increasing height in the crown. During the wet season, Psi was lower in the outer than inner crown. C isotope composition of leaves (delta(13)C) increased with increasing height indicating greater photosynthetic water use efficiency in the upper crown. Leaf and shoot morphology changed continuously with height. In contrast, their relationships with light availability were discontinuous: morphological characteristics did not correspond to increasing light availability above 55-85 m. Mass-based chlorophyll concentration (chl) decreased with increasing height and increasing light availability. In contrast, area-based chl remained constant or increased with increasing height. Mass-based maximum rate of net photosynthesis (P (max)) decreased with increasing height, whereas area-based P (max) reached maximum at 78.4 m and decreased with increasing height thereafter. Mass-based P (max) increased with increasing shoot mass per area (SMA), whereas area-based P (max) was not correlated with SMA in the upper crown. Our results suggest that hydrostatic limitation of morphological development constrains exploitation of light in the upper crown and contributes to reduced photosynthetic rates and, ultimately, reduced height growth at the tops of tall S. sempervirens trees.

Carbohydrate metabolism changes in Prunus persica gummosis infected with Lasiodiplodia theobromae.

PubMed

Li, Z; Gao, L; Wang, Y T; Zhu, W; Ye, J L; Li, G H

2014-05-01

Peach gummosis represents a significant global disease of stone fruit trees and a major disease in the south peach production area of the Yangtze River of China. In this study, the carbohydrate composition of peach shoots during infection by Lasiodiplodia theobromae was examined. The expression of genes related to metabolic enzymes was also investigated. Control wounded and noninoculated tissue, lesion tissue, and wounded and inoculated surrounding lesion tissue of peach shoots were analyzed. Soluble sugars, glucose, mannose, arabinose, and xylose significantly increased in inoculated tissues of peach shoots compared with control tissues at different times after inoculation. Accumulation of polysaccharides was also observed by section observation and periodic acid Schiff's reagent staining during infection. Analysis using quantitative reverse-transcription polymerase chain reaction revealed that the abundance of key transcripts on the synthesis pathway of uridine diphosphate (UDP)-D-glucuronate, UDP-D-galactose, and UDP-D-arabinose increased but the synthesis of L-galactose and guanosine diphosphate-L-galactose were inhibited. After inoculation, the transcript levels of sugar transport-related genes (namely, SUT, SOT, GMT, and UGT) was induced. These changes in sugar content and gene expression were directly associated with peach gum polysaccharide formation and may be responsible for the symptoms of peach gummosis.

The first report of detection of a phytoplasma in olive trees in a botanic collection in Iran.

PubMed

Ahangaran, A; Khezri, S; Habibi, M Koohi; Alizadeh, A; Mohammadi, Gh Mosahebi

2006-01-01

In a survey in 2005 some symptoms were observed on three olive trees in a collection of different olive cultivars in one of the central provinces in Iran (Yazd Province). Affected trees exhibited a variable range of symptoms: dwarfing, shoot proliferation, internode shortening, small leaves, leaf rolling, abortive buds, appearance of very small shoots, hypertrophied, and die- back. The possibility of association of a phytoplasma with the disease was evaluated using polymerase chain reaction (PCR). Total DNA was extracted from midribs of symptomatic and healthy olive plants using phytoplasma enriched procedure and tested for the presence of phytoplasma by nested-PCR using phytoplasmal- universal primers R16F2/R16R2, followed by primers fU5/rU3 which amplify 1200 and 880bp DNA fragments of 16SrDNA, respectively. PCR resulted in amplification of expected DNA fragments in symptomatic but not in healthy olive by both primer pairs. On the basis of symptoms and positive reaction in PCR, these plants can be infected with a phytoplasma. This is the first report of olive trees phytoplasmal disease in Iran. Identification of the agent and its comparison with other phytoplasmal isolates reported from other plants (hosts) in Iran are being studied. Based on the quarantine requirements, one of these trees was eradicated and two of them were transplanted in an isolated green house for further studies.

Endogenous rhythmic growth in oak trees is regulated by internal clocks rather than resource availability.

PubMed

Herrmann, S; Recht, S; Boenn, M; Feldhahn, L; Angay, O; Fleischmann, F; Tarkka, M T; Grams, T E E; Buscot, F

2015-12-01

Common oak trees display endogenous rhythmic growth with alternating shoot and root flushes. To explore the mechanisms involved, microcuttings of the Quercus robur L. clone DF159 were used for (13)C/(15)N labelling in combination with RNA sequencing (RNASeq) transcript profiling of shoots and roots. The effect of plant internal resource availability on the rhythmic growth of the cuttings was tested through inoculation with the ectomycorrhizal fungus Piloderma croceum. Shoot and root flushes were related to parallel shifts in above- and below-ground C and, to a lesser extent, N allocation. Increased plant internal resource availability by P. croceum inoculation with enhanced plant growth affected neither the rhythmic growth nor the associated resource allocation patterns. Two shifts in transcript abundance were identified during root and shoot growth cessation, and most concerned genes were down-regulated. Inoculation with P. croceum suppressed these transcript shifts in roots, but not in shoots. To identify core processes governing the rhythmic growth, functions [Gene Ontology (GO) terms] of the genes differentially expressed during the growth cessation in both leaves and roots of non-inoculated plants and leaves of P. croceum-inoculated plants were examined. Besides genes related to resource acquisition and cell development, which might reflect rather than trigger rhythmic growth, genes involved in signalling and/or regulated by the circadian clock were identified. The results indicate that rhythmic growth involves dramatic oscillations in plant metabolism and gene regulation between below- and above-ground parts. Ectomycorrhizal symbiosis may play a previously unsuspected role in smoothing these oscillations without modifying the rhythmic growth pattern. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Water stress, shoot growth and storage of non-structural carbohydrates along a tree height gradient in a tall conifer

Treesearch

David R. Woodruff; Frederick C. Meinzer

2011-01-01

We analyzed concentrations of starch, sucrose, glucose and fructose in upper branch wood, foliage and trunk sapwood of Douglas-fir trees in height classes ranging from ~2 to ~57 m. Mean concentrations of non-structural carbohydrates (NSC) for all tissues were highest in the tallest height class and lowest in the lowest height class, and height-related trends in NSC...

Early results from genetic trials on the growth of Spanish cedar and itssusceptibility to the shoot borer moth in the Yucatan Peninsula, Mexico.

Treesearch

Sheila E. Ward; Kevyn E. Wightman; Bartolo Rodriguez Santiago

2008-01-01

Cedrela odorata (Spanish cedar) is a neotropical broadleaf tree species that is in high demand for furniture and interior fittings. In 1998, seed collections were made from Spanish cedar in the Yucatan Peninsula, Mexico, for genetic conservation and tree improvement projects. Progeny from these collections were established in genetic trials at Bacalar, Noh Bec, and Zoh...

Height-related trends in leaf xylem anatomy and shoot hydraulic characteristics in a tall conifer: safety versus efficiency in water transport

Treesearch

D.R. Woodruff; F.C. Meinzer; B. Lachenbruch

2008-01-01

Growth and aboveground biomass accumulation follow a common pattern as tree size increases, with productivity peaking when leaf area reaches its maximum and then declining as tree age and size increase. Age- and size-related declines in forest productivity are major considerations in setting the rotational age of commercial forests, and relate to issues of carbon...

Pinus sylvestris as a missing source of nitrous oxide and methane in boreal forest.

PubMed

Machacova, Katerina; Bäck, Jaana; Vanhatalo, Anni; Halmeenmäki, Elisa; Kolari, Pasi; Mammarella, Ivan; Pumpanen, Jukka; Acosta, Manuel; Urban, Otmar; Pihlatie, Mari

2016-03-21

Boreal forests comprise 73% of the world's coniferous forests. Based on forest floor measurements, they have been considered a significant natural sink of methane (CH4) and a natural source of nitrous oxide (N2O), both of which are important greenhouse gases. However, the role of trees, especially conifers, in ecosystem N2O and CH4 exchange is only poorly understood. We show for the first time that mature Scots pine (Pinus sylvestris L.) trees consistently emit N2O and CH4 from both stems and shoots. The shoot fluxes of N2O and CH4 exceeded the stem flux rates by 16 and 41 times, respectively. Moreover, higher stem N2O and CH4 fluxes were observed from wet than from dry areas of the forest. The N2O release from boreal pine forests may thus be underestimated and the uptake of CH4 may be overestimated when ecosystem flux calculations are based solely on forest floor measurements. The contribution of pine trees to the N2O and CH4 exchange of the boreal pine forest seems to increase considerably under high soil water content, thus highlighting the urgent need to include tree-emissions in greenhouse gas emission inventories.

Tree water relations can trigger monoterpene emissions from Scots pine stems during spring recovery

NASA Astrophysics Data System (ADS)

Vanhatalo, A.; Chan, T.; Aalto, J.; Korhonen, J. F.; Kolari, P.; Hölttä, T.; Nikinmaa, E.; Bäck, J.

2015-09-01

Tree canopies are known to emit large amounts of VOCs (volatile organic compounds) such as monoterpenes into the surrounding air. High VOC emission rates from boreal forests have been observed during the transition from winter to summer activity. The most important sources of these are considered to be the green foliage, understory vegetation and soil organisms, but emissions from the living stand woody compartments have so far not been quantified. We analyzed whether the non-foliar components could partially explain the springtime high emission rates. We measured the monoterpene emissions from Scots pine (Pinus sylvestris L.) stem and shoots during the dehardening phase of trees in field conditions in two consecutive springs. We observed a large, transient monoterpene burst from the stem, while the shoot monoterpene emissions remained low. The burst lasted about 12 h. Simultaneously, an unusual nighttime sap flow and a non-systematic diurnal pattern of tree diameter were detected. Hence, we suggest that the monoterpene burst was a consequence of the recovery of the stem from wintertime, and likely related to the refilling of embolized tracheids and/or phenological changes in the living cells of the stem. This indicates that the dominant processes and environmental drivers triggering the monoterpene emissions are different between the stem and the foliage.

Analysis of transcripts differentially expressed between fruited and deflowered 'Gala' adult trees: a contribution to biennial bearing understanding in apple.

PubMed

Guitton, B; Kelner, J J; Celton, J M; Sabau, X; Renou, J P; Chagné, D; Costes, E

2016-02-29

The transition from vegetative to floral state in shoot apical meristems (SAM) is a key event in plant development and is of crucial importance for reproductive success. In perennial plants, this event is recurrent during tree life and subject to both within-tree and between-years heterogeneity. In the present study, our goal was to identify candidate processes involved in the repression or induction of flowering in apical buds of adult apple trees. Genes differentially expressed (GDE) were examined between trees artificially set in either 'ON' or 'OFF' situation, and in which floral induction (FI) was shown to be inhibited or induced in most buds, respectively, using qRT-PCR and microarray analysis. From the period of FI through to flower differentiation, GDE belonged to four main biological processes (i) response to stimuli, including response to oxidative stress; (ii) cellular processes, (iii) cell wall biogenesis, and (iv) metabolic processes including carbohydrate biosynthesis and lipid metabolic process. Several key regulator genes, especially TEMPRANILLO (TEM), FLORAL TRANSITION AT MERISTEM (FTM1) and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) were found differentially expressed. Moreover, homologs of SPL and Leucine-Rich Repeat proteins were present under QTL zones previously detected for biennial bearing. This data set suggests that apical buds of 'ON' and 'OFF' trees were in different physiological states, resulting from different metabolic, hormonal and redox status which are likely to contribute to FI control in adult apple trees. Investigations on carbohydrate and hormonal fluxes from sources to SAM and on cell detoxification process are expected to further contribute to the identification of the underlying physiological mechanisms of FI in adult apple trees.

Internal development of vegetative buds of Norway spruce trees in relation to accumulated chilling and forcing temperatures.

PubMed

Viherä-Aarnio, Anneli; Sutinen, Sirkka; Partanen, Jouni; Häkkinen, Risto

2014-05-01

The timing of budburst of temperate trees is known to be controlled by complicated interactions of temperature and photoperiod. To improve the phenological models of budburst, better knowledge of the internal bud development preceding budburst in relation to environmental cues is needed. We studied the effect of accumulated chilling and forcing temperatures on the internal development of vegetative buds preceding budburst in Norway spruce [Picea abies (L.) Karst.]. Branches from 17-year-old trees of southern Finnish origin were transferred eight times at 1- to 2-week intervals from October to December 2007 from the field at Punkaharju (61°48'N, 29°20'E) to the greenhouse with forcing conditions (day length 12 h, +20 °C). After seven different durations of forcing, the developmental phase and primordial shoot growth of the buds were analysed at the stereomicroscopic level. Air temperature was recorded hourly throughout the study period. The accumulated chilling unit sum had a significant effect on the temperature sum that was required to attain a certain developmental phase; a higher amount of chilling required a lower amount of forcing. The variation in the rate of development of different buds within each sample branch in relation to the chilling unit and forcing temperature sum was low. Regarding primordial shoot growth, there was also an inverse relation between accumulated chilling and forcing, i.e., a higher accumulated chilling unit sum before forcing required a lower temperature sum to initiate primordial shoot growth and resulted in a stronger effect of accumulated forcing. A second-order regression model with an interaction of chilling and forcing explained the variation of primordial shoot growth with high precision (R(2) = 0.88). However, further studies are required to determine the final parameter values to be used in phenological modelling. © The Author 2014. Published by Oxford University Press. All rights reserved.

Cadmium tolerance and phytoremediation potential of acacia (Acacia nilotica L.) under salinity stress.

PubMed

Shabir, Rahat; Abbas, Ghulam; Saqib, Muhammad; Shahid, Muhammad; Shah, Ghulam Mustafa; Akram, Muhammad; Niazi, Nabeel Khan; Naeem, Muhammad Asif; Hussain, Munawar; Ashraf, Farah

2018-06-07

In this study, we explored the effect of salinity on cadmium (Cd) tolerance and phytoremediation potential of Acacia nilotica. Two-month-old uniform plants of A. nilotica were grown in pots contaminated with various levels of Cd (0, 5, 10, and 15 mg kg -1 ), NaCl (0%, 0.5%, 1.0% (hereafter referred as salinity), and all possible combinations of Cd + salinity for a period of six months. Results showed that shoot and root growth, biomass, tissue water content and chlorophyll (chl a, chl b, and total chl a+b) contents decreased more in response to salinity and combination of Cd + salinity compared to Cd alone. Shoot and root K concentrations significantly decreased with increasing soil Cd levels, whereas Na and Cl concentrations were not affected significantly. Shoot and root Cd concentrations, bioconcentration factor (BCF) and translocation factor (TF) increased with increasing soil Cd and Cd + salinity levels. At low level of salinity (0.5%), shoot and root Cd uptake enhanced, while it decreased at high level of salinity (1.0%). Due to Cd tolerance, high shoot biomass and shoot Cd uptake, this tree species has some potential for phytoremediation of Cd from the metal contaminated saline and nonsaline soils.

Effects of drought and irrigation on ecosystem functioning in a mature Scots pine forest

NASA Astrophysics Data System (ADS)

Dobbertin, Matthias; Brunner, Ivano; Egli, Simon; Eilmann, Britta; Graf Pannatier, Eisabeth; Schleppi, Patrick; Zingg, Andreas; Rigling, Andreas

2010-05-01

Climate change is expected to increase temperature and reduce summer precipitation in Switzerland. To study the expected effects of increased drought in mature forests two different approaches are in general possible: water can be partially or completely removed from the ecosystems via above- or below-canopy roofs or water can be added to already drought-prone ecosystems. Both methods have advantages and disadvantages. In our study water was added to a mature 90-year old Scots pine (Pinus sylvestris L.) forest with a few singe pubescent oaks (Quercus pubescens Willd.), located in the valley bottom of the driest region of Switzerland (Valais). In Valais, Scots pines are declining, usually with increased mortality rates following drought years. It was therefore of special interest to study here how water addition is changing forest ecosystem functioning. The irrigation experiment started in the summer of 2003. Out of eight 0.1 ha experimental plots, four were randomly selected for irrigation, the other four left as a control. Irrigation occurred during rainless nights between April and October, doubling the annual rainfall amount from 650 to 1300 mm. Irrigation water, taken from a near-by irrigation channel, added some nutrients to the plots, but nutrients which were deficient on the site, e.g. nitrogen and phosphorus, were not altered. Tree diameter, tree height and crown width were assessed before the start of the irrigation in winter 2002/2003 and after 7 years of the experiment in 2009/2010. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Additionally, tree mortality was annually evaluated. Mycorrhizal fruit bodies were identified and counted at weekly intervals from 2003 until 2007. Root samples were taken in 2004 and 2005. In 2004 and 2005 wood formation of thirteen trees was analysed in weekly or biweekly intervals using the pinning method. These trees were felled in 2006 for stem, shoot and needle growth analysis. Soil water content was significantly reduced during irrigation periods. Irrigation doubled tree stem growth, increased shoot growth and thus increased volume growth and crown dimensions. Annual tree mortality rates were reduced by 50% in irrigated plots. The growing period for stem growth was extended in pines as a result of irrigation. Altogether, increased growth and reduced mortality significantly increased tree stem basal area at breast height per ha. As irrigation also increased needle length, estimated mean foliage amount per tree and stand leaf area index significantly increased. However, the number of needle generations was not altered or even reduced due to irrigation. Root growth, was less affected by irrigation and only resulted in increased fine root length. Species richness and fruit body numbers of mycorrhizal fungi were several times higher on the irrigated plots. Overall, it can be concluded that water availability was the main ecosystem limiting factor and that any changes in water availability will result in changes in ecosystem functioning. References Brunner I, Graf-Pannatier E, Frey B, Rigling A, Landolt W, Dobbertin M (2009) Morphological and physiological responses of Scots pine fine roots to water supply in a climatic dry area in Switzerland. Tree Physiology 29:541-550. Dobbertin M, Eilmann B, Bleuler P, Giuggiola A, Graf Pannatier E, Landolt W, Schleppi P, Rigling A (2010) Effect of irrigation on needle, shoot and stem growth in natural drought-exposed Pinus sylvestris forests, Tree Physiology, doi:10.1093/treephys/tpp123. Eilmann B, Zweifel R, Buchmann N, Fonti P, Rigling A (2009) Drought induced adaptation of the xylem in Pinus sylvestris and Quercus pubescens. Tree Physiology 29:1011-1020.

Revealing critical mechanisms of BR-mediated apple nursery tree growth using iTRAQ-based proteomic analysis.

PubMed

Zheng, Liwei; Ma, Juanjuan; Zhang, Lizhi; Gao, Cai; Zhang, Dong; Zhao, Caiping; Han, Mingyu

2018-02-20

Brassinosteroid is identified as an important hormone. However, information about brassinosteroid has not been fully elucidated, and few studies concerned its role in apple. The aim of this work was to study the role of brassinosteroid for apple tree growth. In our study, the effect of brassinosteroid on apple nursery tree was analyzed. The biomass, cell size and xylem content of apple nursery tree were obviously evaluated by brassinosteroid treatment; mineral elements contents, photosynthesis indexes, carbohydrate level and hormone contents were significantly high in brassinosteroid treated trees. To explore the molecular mechanisms of these phenotypic differences, iTRAQ-based quantitative proteomics were used to identify the expression profiles of proteins in apple nursery tree shoot tips in response to brassinosteroid at a key period (14days after brassinosteroid treatment). A total of 175 differentially expressed proteins were identified. They were mainly involved in chlorophyII biosynthesis, photosynthesis, carbohydrate metabolism, glycolysis, citric acid cycle, respiratory action, hormone signal, cell growth and ligin metabolism. The findings in this study indicate that brassinosteroid mediating apple nursery tree growth may be mainly through energy metabolism. Important biological processes identified here can be useful theoretical basis and provide new insights into the molecular mechanisms of brassinosteroid. Brassinosteroid is very important for plant growth and development. However, the molecular mechanism of brassinosteroid mediating growth process is not perfectly clear in plant, especially in apple nursery tree. We used a combination of physiological and bioinformatics analysis to investigate the effects of brassinosteroid on apple nursery tree growth and development. The data reported here demonstrated that brassinosteroid regulates apple nursery tree growth mainly through energy metabolism. Therefore it can provide a theoretical basis from energy points for developing dwarfed or compact apple trees. This will benefit for low orchard management cost as well as early bearing, and high fruit yield as well as quality. Copyright © 2017 Elsevier B.V. All rights reserved.

SUMO Leaf Water Potential

DOE Data Explorer

Sevanto, Sanna [Los Alamos National Laboratory; Dickman, Turin L. [Los Alamos National Laboratory; Collins, Adam [Los Alamos National Laboratory; Grossiord, Charlotte [Swiss Federal Institute for Forest Snow and Landscape Research; Adams, Henry [Oklahoma State University; Borrego, Isaac [USGS Southwest Biological Science Center; McDowell, Nate [Pacific Northwest National Laboratory (PNNL)

2018-01-01

The Los Alamos Survival–Mortality experiment (SUMO) is located on Frijoles Mesa near Los Alamos, New Mexico, USA, at an elevation of 2150 m. This was a tree manipulation study that investigated the relative impacts of drought and warming on plant function and reveals how trees adapt to drought and heat in semi-arid regions. The study factored the role of tree hydraulic acclimation to both precipitation and temperature and separated their effects.The experiment is located in a pinon-juniper woodland near the ponderosa pine (Pinus ponderosa) forest ecotone. Monthly pre-dawn and midday shoot water potentials for each target tree. See SUMO Target Tree Information data package (doi:10.15485/1440544) for additional information. Data released by Los Alamos National Lab for public use under LA-UR-18-23656.

Machine vision system for measuring conifer seedling morphology

NASA Astrophysics Data System (ADS)

Rigney, Michael P.; Kranzler, Glenn A.

1995-01-01

A PC-based machine vision system providing rapid measurement of bare-root tree seedling morphological features has been designed. The system uses backlighting and a 2048-pixel line- scan camera to acquire images with transverse resolutions as high as 0.05 mm for precise measurement of stem diameter. Individual seedlings are manually loaded on a conveyor belt and inspected by the vision system in less than 0.25 seconds. Designed for quality control and morphological data acquisition by nursery personnel, the system provides a user-friendly, menu-driven graphical interface. The system automatically locates the seedling root collar and measures stem diameter, shoot height, sturdiness ratio, root mass length, projected shoot and root area, shoot-root area ratio, and percent fine roots. Sample statistics are computed for each measured feature. Measurements for each seedling may be stored for later analysis. Feature measurements may be compared with multi-class quality criteria to determine sample quality or to perform multi-class sorting. Statistical summary and classification reports may be printed to facilitate the communication of quality concerns with grading personnel. Tests were conducted at a commercial forest nursery to evaluate measurement precision. Four quality control personnel measured root collar diameter, stem height, and root mass length on each of 200 conifer seedlings. The same seedlings were inspected four times by the machine vision system. Machine stem diameter measurement precision was four times greater than that of manual measurements. Machine and manual measurements had comparable precision for shoot height and root mass length.

Green revolution trees: semidwarfism transgenes modify gibberellins, promote root growth, enhance morphological diversity, and reduce competitiveness in hybrid poplar.

PubMed

Elias, Ani A; Busov, Victor B; Kosola, Kevin R; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W; Rood, Stewart B; Strauss, Steven H

2012-10-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA(20) and GA(8), in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations.

Green Revolution Trees: Semidwarfism Transgenes Modify Gibberellins, Promote Root Growth, Enhance Morphological Diversity, and Reduce Competitiveness in Hybrid Poplar1[C][W][OA

PubMed Central

Elias, Ani A.; Busov, Victor B.; Kosola, Kevin R.; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W.; Rood, Stewart B.; Strauss, Steven H.

2012-01-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA20 and GA8, in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations. PMID:22904164

Suitability of multipurpose trees, shrubs and grasses to rehabilitate gullies in the sub-humid tropics

NASA Astrophysics Data System (ADS)

Talema, Ayalew; Muys, Bart; Poesen, Jean; Padro, Roc; Dibaba, Hirko; Diels, Jan

2017-04-01

Vegetation plays a vital role for sustainable rehabilitation of degraded lands. However, the selection of suitable and effective plant species remains a long-lasting challenge in most parts of the sub-humid tropics. To address this challenge 18 multipurpose plant species (6 trees, 3 shrubs and 9 grasses), preselected from the regional species pool in Southwest Ethiopia were planted in severely degraded gullies and monitored from July 2011 to June 2014. The experiment had a split-plot design with farmyard manure (FYM) application, as main plot and plant species as sub-plot factors repeated in three blocks. The study revealed that grasses were the most successful to rehabilitate the gully within the monitoring period, compared to trees and shrubs. The survival rate of the four most successful grass species, Chrysopogon zizanioides, Pennisetum macrourum, Pennisetum polystachion and Pennisetum purpureum ranged from 61 to 90% with FYM application and from 20 to 85% without FYM, while most of the well-known indigenous and exotic trees and shrubs failed to survive. For the grass Pennisetum purpureum, shoot height, shoot and root dry biomass increased by 300%, 342% and 578% respectively due to FYM application, with a remarkably higher response to FYM compared to all the other studied species. The overall results demonstrate that severely degraded lands can be effectively restored by using early successional species such as locally adapted and selected grasses before the plantation of trees and shrubs.

7 CFR 319.40-5 - Importation and entry requirements for specified articles.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Christmas trees have been treated with methyl bromide to kill the pine shoot beetle; or, alternatively, in... certificate must indicate that the regulated articles have been treated with methyl bromide to kill the pine...

7 CFR 319.40-5 - Importation and entry requirements for specified articles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Christmas trees have been treated with methyl bromide to kill the pine shoot beetle; or, alternatively, in... certificate must indicate that the regulated articles have been treated with methyl bromide to kill the pine...

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

Popenoe, J.

Long sylleptic shoots produced on apple trees in the nursery result in increased early yields once the trees are planted in the orchard. Spur-type Delicious trees do not naturally produce branches in the nursery. To achieve branched spur-type Delicious trees, applications of combinations of growth regulators benzyladenine (BA) and gibberellic acid 4 + 7 (GA) and leaf removal (LR) techniques were tested. Spacings of 15, 25, 35, and 45 cm and MM.106, M.7, M.26 and seedling rootstocks were tested for their effects on branching. Carbon partitioning changes caused by these treatments were evaluated by dry weight analysis and for benzyladenine,more » leaf removal and tipping treatments by {sup 14}C-photoassimilate labelling. Possible involvement of roots produced cytokinins was examined by {sup 14}C-benzyladenine labeling through the xylem and by analyzing relationships between root mass and branching characteristics. Although partitioning of {sup 14}C-photoassimilate was increased to the top of the plant by BA sprays, and to the bottom of the plant by LR and tipping for up to six days after treatment, final plant weights were not different. No relationship between branching and root mass or {sup 14}C-benzyladenine mobilization was found. This evidence indicates branched trees possessed no greater dry weight than unbranched trees, only a redistribution of the dry weight into a form more suited to early fruit production in high density planting systems.« less

Predicting Flowering Behavior and Exploring Its Genetic Determinism in an Apple Multi-family Population Based on Statistical Indices and Simplified Phenotyping.

PubMed

Durand, Jean-Baptiste; Allard, Alix; Guitton, Baptiste; van de Weg, Eric; Bink, Marco C A M; Costes, Evelyne

2017-01-01

Irregular flowering over years is commonly observed in fruit trees. The early prediction of tree behavior is highly desirable in breeding programmes. This study aims at performing such predictions, combining simplified phenotyping and statistics methods. Sequences of vegetative vs. floral annual shoots (AS) were observed along axes in trees belonging to five apple related full-sib families. Sequences were analyzed using Markovian and linear mixed models including year and site effects. Indices of flowering irregularity, periodicity and synchronicity were estimated, at tree and axis scales. They were used to predict tree behavior and detect QTL with a Bayesian pedigree-based analysis, using an integrated genetic map containing 6,849 SNPs. The combination of a Biennial Bearing Index (BBI) with an autoregressive coefficient (γ g ) efficiently predicted and classified the genotype behaviors, despite few misclassifications. Four QTLs common to BBIs and γ g and one for synchronicity were highlighted and revealed the complex genetic architecture of the traits. Irregularity resulted from high AS synchronism, whereas regularity resulted from either asynchronous locally alternating or continual regular AS flowering. A relevant and time-saving method, based on a posteriori sampling of axes and statistical indices is proposed, which is efficient to evaluate the tree breeding values for flowering regularity and could be transferred to other species.

A Phenological Timetable of Oak Growth under Experimental Drought and Air Warming

PubMed Central

Kuster, Thomas M.; Dobbertin, Matthias; Günthardt-Goerg, Madeleine S.; Schaub, Marcus; Arend, Matthias

2014-01-01

Climate change is expected to increase temperature and decrease summer precipitation in Central Europe. Little is known about how warming and drought will affect phenological patterns of oaks, which are considered to possess excellent adaptability to these climatic changes. Here, we investigated bud burst and intra-annual shoot growth of Quercus robur, Q. petraea and Q. pubescens grown on two different forest soils and exposed to air warming and drought. Phenological development was assessed over the course of three growing seasons. Warming advanced bud burst by 1–3 days °C−1 and led to an earlier start of intra-annual shoot growth. Despite this phenological shift, total time span of annual growth and shoot biomass were not affected. Drought changed the frequency and intensity of intra-annual shoot growth and advanced bud burst in the subsequent spring of a severe summer drought by 1–2 days. After re-wetting, shoot growth recovered within a few days, demonstrating the superior drought tolerance of this tree genus. Our findings show that phenological patterns of oaks are modified by warming and drought but also suggest that ontogenetic factors and/or limitations of water and nutrients counteract warming effects on the biomass and the entire span of annual shoot growth. PMID:24586988

Gibberellin Promotes Shoot Branching in the Perennial Woody Plant Jatropha curcas

PubMed Central

Ni, Jun; Gao, Congcong; Chen, Mao-Sheng; Pan, Bang-Zhen; Ye, Kaiqin; Xu, Zeng-Fu

2015-01-01

Strigolactone (SL), auxin and cytokinin (CK) interact to regulate shoot branching. CK has long been considered to be the only key phytohormone to promote lateral bud outgrowth. Here we report that gibberellin also acts as a positive regulator in the control of shoot branching in the woody plant Jatropha curcas. We show that gibberellin and CK synergistically promote lateral bud outgrowth, and that both hormones influence the expression of putative branching regulators, J. curcas BRANCHED1 and BRANCHED2, which are key transcription factors maintaining bud dormancy. Moreover, treatment with paclobutrazol, an inhibitor of de novo gibberellin biosynthesis, significantly reduced the promotion of bud outgrowth by CK, suggesting that gibberellin is required for CK-mediated axillary bud outgrowth. In addition, SL, a plant hormone involved in the repression of shoot branching, acted antagonistically to both gibberellin and CK in the control of lateral bud outgrowth. Consistent with this, the expression of JcMAX2, a J. curcas homolog of Arabidopsis MORE AXILLARY GROWTH 2 encoding an F-box protein in the SL signaling pathway, was repressed by gibberellin and CK treatment. We also provide physiological evidence that gibberellin also induces shoot branching in many other trees, such as papaya, indicating that a more complicated regulatory network occurs in the control of shoot branching in some perennial woody plants. PMID:26076970

Weaver ant role in cashew orchards in Vietnam.

PubMed

Peng, Renkang; Lan, La Pham; Christian, Keith

2014-08-01

Cashew (Anacardium occidentale L.) is a very important source of income for more than 200,000 farmer households in Vietnam. The present cashew productivity in Vietnam is low and unstable, and pest damage is partly responsible for this. Cashew farmers rely on pesticides to minimize the damage, resulting in adverse impacts on farm environment and farmers' health. Weaver ants (Oecophylla spp) are effective biocontrol agents of a range of cashew insect pests in several cashew-growing countries, and these ants are widely distributed in Vietnam. The aim of this study is to evaluate the potential of weaver ants in cashew orchards in Vietnam. Field surveys and field experiment were conducted in five cashew orchards from July 2006 to January 2008 in Binh Phuoc, Dong Nai, and Ba Ria Vung Tau provinces, Vietnam. Based on the field surveys, the most important pests that damage flushing foliar and floral shoots and young cashew fruits and nuts were mosquito bugs, brown shoot borers, blue shoot borers, and fruit-nut borers. The damage caused by each of these pests was significantly lower on trees with weaver ants compared with trees without the ants, showing that the ants were able to keep these pest damages under the control threshold. Regular monitoring of the field experiment showed that weaver ants were similar to insecticides for controlling mosquito bugs, blue shoot borers, fruit-nut borers, leaf rollers, and leaf miners. Aphids did not become major pests in plot with weaver ants. To manage insect pest assemblage in cashew orchards, an integrated pest management using weaver ants as a major component is discussed.

Elimination of PPV and PNRSV through thermotherapy and meristem-tip culture in nectarine.

PubMed

Manganaris, G A; Economou, A S; Boubourakas, I N; Katis, N I

2003-10-01

The plum pox virus (PPV) and prunus necrotic ringspot virus (PNRSV) cause serious disease problems in stone-fruit trees. In this work, the possibility of obtaining plant material free from these viruses through thermotherapy and meristem-tip culture from infected nectarine shoots (Prunus persica var. nectarina Max, cv. 'Arm King') was studied. In addition, the detection of these viruses in in vitro cultures and young acclimatized plantlets with double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) and multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) was studied. Meristem-tip explants (0.8-1.3 mm) derived from sprouted buds of winter wood and spring shoots from field grown plants had a 2-5% regeneration response. However, application of thermotherapy to potted nectarine trees (3 weeks at a maximum temperature of 35 degrees C) facilitated excision of longer meristem tips (1.3-2.0 mm) that resulted in a significantly higher regeneration response (38%) in woody plant medium (WPM) without plant growth regulators. Such explants formed multiple shoots with the addition of 8 microM benzylaminopurine and 0.8 microM indoleacetic acid. When they were tested for the presence of PPV and PNRSV, 86% and 81% were found to be virus-free as detected by DAS-ELISA and multiplex RT-PCR, respectively. Individual shoots excised from virus-free cultures readily rooted in vitro (half-strength WPM plus 2 microM indolebutyric acid) and grew to plantlets. The combination of an efficient protocol for virus elimination and the establishment of highly sensitive diagnostics resulted in the production of nectarine plants free from PPV and PNRSV.

Seasonal variation of degree-day accumulation in relation to phenology of western spruce budworm, Douglas-fir tussock moth, and host trees in northeastern Oregon.

Treesearch

Boyd E. Wickman

1988-01-01

The annual variation of degree-days and early summer phenology of Douglas-fir tussock moth, western spruce budworm, and their host trees was monitored over five to six seasons at two locations in the Blue Mountains. Accumulated degree-days and the phenology of bud burst and larval development were consistent and comparable at the two sites. Either degree-days or shoot...

Natural radionuclides in trees grown on a uranium mill tailings waste pile.

PubMed

Strok, Marko; Smodiš, Borut; Eler, Klemen

2011-06-01

The purpose of the study was to investigate natural radionuclide uptake and allocation by trees. Samples from six Scots pines (P. sylvestris), six Norway spruces (Picea abies) and one sycamore maple (Acer pseudoplatanus) tree, growing on the Boršt uranium mill tailings waste pile in Slovenia were collected. (238)U, (230)Th, (226)Ra and (210)Pb activity concentrations in wood, shoots and 1-year-old needles or leaves were determined. Particular radionuclides were separated from the samples by appropriate radiochemical procedures and their activity concentrations measured with an alpha spectrometry system. In addition, concentration ratios for different plant parts were calculated. Results showed that for all radionuclides, the highest activity concentrations were found in foliage, followed by shoots and wood. The activity concentrations in trees were from 0.01 to 5.4 Bq kg(-1) for (238)U, 0.03-11.3 Bq kg(-1) for (230)Th, 2.7-2,728 Bq kg(-1) for (226)Ra and 5.1-321 Bq kg(-1) for (210)Pb. All activity concentrations were calculated on dry weight basis. The calculated concentration ratios were from 1.05E-5 to 5.39E-3 for (238)U, 7.65E-6-2.88E-3 for (230)Th, 3.10E-4-3.16E-1 for (226)Ra and 6.70E-4-4.22E-2 for (210)Pb.

Which are the most important parameters for modelling carbon assimilation in boreal Norway spruce under elevated [CO(2)] and temperature conditions?

PubMed

Hall, Marianne; Medlyn, Belinda E; Abramowitz, Gab; Franklin, Oskar; Räntfors, Mats; Linder, Sune; Wallin, Göran

2013-11-01

Photosynthesis is highly responsive to environmental and physiological variables, including phenology, foliage nitrogen (N) content, atmospheric CO2 concentration ([CO2]), irradiation (Q), air temperature (T) and vapour pressure deficit (D). Each of these responses is likely to be modified by long-term changes in climatic conditions such as rising air temperature and [CO2]. When modelling photosynthesis under climatic changes, which parameters are then most important to calibrate for future conditions? To assess this, we used measurements of shoot carbon assimilation rates and microclimate conditions collected at Flakaliden, northern Sweden. Twelve 40-year-old Norway spruce trees were enclosed in whole-tree chambers and exposed to elevated [CO2] and elevated air temperature, separately and in combination. The treatments imposed were elevated temperature, +2.8 °C in July/August and +5.6 °C in December above ambient, and [CO2] (ambient CO2 ∼370 μ mol mol(-1), elevated CO2 ∼700 μ mol mol(-1)). The relative importance of parameterization of Q, T and D responses for effects on the photosynthetic rate, expressed on a projected needle area, and the annual shoot carbon uptake was quantified using an empirical shoot photosynthesis model, which was developed and fitted to the measurements. The functional form of the response curves was established using an artificial neural network. The [CO2] treatment increased annual shoot carbon (C) uptake by 50%. Most important was effects on the light response curve, with a 67% increase in light-saturated photosynthetic rate, and a 52% increase in the initial slope of the light response curve. An interactive effect of light saturated photosynthetic rate was found with foliage N status, but no interactive effect for high temperature and high CO2. The air temperature treatment increased the annual shoot C uptake by 44%. The most important parameter was the seasonality, with an elongation of the growing season by almost 4 weeks. The temperature response curve was almost flat over much of the temperature range. A shift in temperature optimum had thus an insignificant effect on modelled annual shoot C uptake. The combined temperature and [CO2] treatment resulted in a 74% increase in annual shoot C uptake compared with ambient conditions, with no clear interactive effects on parameter values.

Leafhopper control in filed-grown red maples with systemic insecticides

USDA-ARS?s Scientific Manuscript database

Red maple, a popular landscape tree, can be susceptible to foliar damage caused by potato leafhopper feeding. Typical potato leafhopper injury includes distorted leaf tissue and reduced shoot growth. This research identified systemic neonicotinoid insecticides, Allectus and Discus, which controlled...

Ectopic expression of class 1 KNOX genes induce adventitious shoot regeneration and alter growth and development of tobacco (Nicotiana tabacum L) and European plum (Prunus domestica L).

PubMed

Srinivasan, C; Liu, Zongrang; Scorza, Ralph

2011-04-01

Transgenic plants of tobacco (Nicotiana tabacum L) and European plum (Prunus domestica L) were produced by transforming with the apple class 1 KNOX genes (MdKN1 and MdKN2) or corn KNOX1 gene. Transgenic tobacco plants were regenerated in vitro from transformed leaf discs cultured in a medium lacking cytokinin. Ectopic expression of KNOX genes retarded shoot growth by suppressing elongation of internodes in transgenic tobacco plants. Expression of each of the three KNOX1 genes induced malformation and extensive lobbing in tobacco leaves. In situ regeneration of adventitious shoots was observed from leaves and roots of transgenic tobacco plants expressing each of the three KNOX genes. In vitro culture of leaf explants and internode sections excised from in vitro grown MdKN1 expressing tobacco shoots regenerated adventitious shoots on MS (Murashige and Skoog 1962) basal medium in the absence of exogenous cytokinin. Transgenic plum plants that expressed the MdKN2 or corn KNOX1 gene grew normally but MdKN1 caused a significant reduction in plant height, leaf shape and size and produced malformed curly leaves. A high frequency of adventitious shoot regeneration (96%) was observed in cultures of leaf explants excised from corn KNOX1-expressing transgenic plum shoots. In contrast to KNOX1-expressing tobacco, leaf and internode explants of corn KNOX1-expressing plum required synthetic cytokinin (thidiazuron) in the culture medium to induce adventitious shoot regeneration. The induction of high-frequency regeneration of adventitious shoots in vitro from leaves and stem internodal sections of plum through the ectopic expression of a KNOX1 gene is the first such report for a woody perennial fruit trees.

High-Frequency Measurements of Tree Methane Fluxes Indicate a Primary Souce Inside Tree Tissue

NASA Astrophysics Data System (ADS)

Brewer, P.; Megonigal, P.

2017-12-01

Methane emissions from the boles and shoots of living upland trees is a recent discovery with significant implications for methane budgets. Forest soil methane uptake is the greatest terrestrial methane sink, but studies have shown this may be partially for fully offset by tree methane sources. However, our ability to quantify the tree source has been hampered because the ultimate biological source(s) of methane is unclear. We measured methane fluxes from two species of living tree boles in an Eastern North American deciduous forest over 100 consecutive days. Our two hour sampling intervals allowed us to characterize diurnal patterns and seasonal dynamics. We observed wide intraspecific differences in average flux rates and diurnal dynamics, even between adjacent individuals. This and other properties of the fluxes indicates the primary methane source is likely within the tree tissues, not in soil or groundwater. Emissions of methane from trees offset approximately 10% of soil uptake on average, but at times tree fluxes were much higher. Preliminary analyses indicate the highest rates are related to tree life history, tree growth, temperature, ground-water depth, and soil moisture.

Morphological defects in native Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant

PubMed Central

Watanabe, Yoshito; Ichikawa, San’ei; Kubota, Masahide; Hoshino, Junko; Kubota, Yoshihisa; Maruyama, Kouichi; Fuma, Shoichi; Kawaguchi, Isao; Yoschenko, Vasyl I.; Yoshida, Satoshi

2015-01-01

After the accident at the Fukushima Daiichi Nuclear Power Plant (F1NPP) in March 2011, much attention has been paid to the biological consequences of the released radionuclides into the surrounding area. We investigated the morphological changes in Japanese fir, a Japanese endemic native conifer, at locations near the F1NPP. Japanese fir populations near the F1NPP showed a significantly increased number of morphological defects, involving deletions of leader shoots of the main axis, compared to a control population far from the F1NPP. The frequency of the defects corresponded to the radioactive contamination levels of the observation sites. A significant increase in deletions of the leader shoots became apparent in those that elongated after the spring of 2012, a year after the accident. These results suggest possibility that the contamination by radionuclides contributed to the morphological defects in Japanese fir trees in the area near the F1NPP. PMID:26314382

Transcriptome Analysis of the Signalling Networks in Coronatine-Induced Secondary Laticifer Differentiation from Vascular Cambia in Rubber Trees

PubMed Central

Wu, Shaohua; Zhang, Shixin; Chao, Jinquan; Deng, Xiaomin; Chen, Yueyi; Shi, Minjing; Tian, Wei-Min

2016-01-01

The secondary laticifer in rubber tree (Hevea brasiliensis Muell. Arg.) is a specific tissue within the secondary phloem. This tissue differentiates from the vascular cambia, and its function is natural rubber biosynthesis and storage. Given that jasmonates play a pivotal role in secondary laticifer differentiation, we established an experimental system with jasmonate (JA) mimic coronatine (COR) for studying the secondary laticifer differentiation: in this system, differentiation occurs within five days of the treatment of epicormic shoots with COR. In the present study, the experimental system was used to perform transcriptome sequencing and gene expression analysis. A total of 67,873 unigenes were assembled, and 50,548 unigenes were mapped at least in one public database. Of these being annotated unigenes, 15,780 unigenes were differentially expressed early after COR treatment, and 19,824 unigenes were differentially expressed late after COR treatment. At the early stage, 8,646 unigenes were up-regulated, while 7,134 unigenes were down-regulated. At the late stage, the numbers of up- and down-regulated unigenes were 7,711 and 12,113, respectively. The annotation data and gene expression analysis of the differentially expressed unigenes suggest that JA-mediated signalling, Ca2+ signal transduction and the CLAVATA-MAPK-WOX signalling pathway may be involved in regulating secondary laticifer differentiation in rubber trees. PMID:27808245

Increased growth of young citrus trees under reduced radiation load in a semi-arid climate.

PubMed

Raveh, E; Cohen, S; Raz, T; Yakir, D; Grava, A; Goldschmidt, E E

2003-01-01

This study investigated the effects of radiation heat-load reduction by shading on the growth and development of citrus trees in a warm subtropical region. The experiment was conducted from mid-June until late October when daily maximal air temperature averaged 29.3 degrees C. Two-year-old de-fruited Murcott tangor (Citrus reticulata BlancoxCitrus sinensis (L.) Osb.) trees were grown under 30% or 60% shade tunnels, or 60% flat shade (providing midday shade only), using highly reflective aluminized nets. Non-shaded trees were used as the control. Shading reduced direct more than diffuse radiation. Daily radiation was reduced by 35% for the 30% Tunnel and 60% Flat treatments, and by 55% for the 60% Tunnel. Two days of intensive measurement showed that shading increased average sunlit leaf conductance by 44% and photosynthesis by 29%. Shading did not significantly influence root and stem dry weight growth, but it increased the increment in leaf dry weight during the three month period by an average of 28% relative to the control, while final tree height in the 30% Tunnel treatment exceeded the control by 35%. Shoot to root and shoot mass ratios increased and root mass ratio decreased due to shading because of the increase in leaf dry weight. Shading increased starch concentration in leaves while the shadiest treatment, 60% Tunnel, decreased starch concentration in the roots. Carbon isotope ratio (delta(13)C) of exposed leaves that developed under shading was significantly reduced by 1.9 per thousand in the 60% Tunnel, indicating that shading increased CO(2) concentrations at the chloroplasts (C(c)), as would be expected from increased conductance. Substomatal CO(2) concentrations, C(i), computed from leaf net CO(2) assimilation rate and conductance values, also indicate that shading increases internal CO(2) concentrations. Based on tree dry mass, tree height, and total carbohydrates fractions, the 30% Tunnel and the 60% Flat were the optimal shade treatments.

Gibberellin Promotes Shoot Branching in the Perennial Woody Plant Jatropha curcas.

PubMed

Ni, Jun; Gao, Congcong; Chen, Mao-Sheng; Pan, Bang-Zhen; Ye, Kaiqin; Xu, Zeng-Fu

2015-08-01

Strigolactone (SL), auxin and cytokinin (CK) interact to regulate shoot branching. CK has long been considered to be the only key phytohormone to promote lateral bud outgrowth. Here we report that gibberellin also acts as a positive regulator in the control of shoot branching in the woody plant Jatropha curcas. We show that gibberellin and CK synergistically promote lateral bud outgrowth, and that both hormones influence the expression of putative branching regulators, J. curcas BRANCHED1 and BRANCHED2, which are key transcription factors maintaining bud dormancy. Moreover, treatment with paclobutrazol, an inhibitor of de novo gibberellin biosynthesis, significantly reduced the promotion of bud outgrowth by CK, suggesting that gibberellin is required for CK-mediated axillary bud outgrowth. In addition, SL, a plant hormone involved in the repression of shoot branching, acted antagonistically to both gibberellin and CK in the control of lateral bud outgrowth. Consistent with this, the expression of JcMAX2, a J. curcas homolog of Arabidopsis MORE AXILLARY GROWTH 2 encoding an F-box protein in the SL signaling pathway, was repressed by gibberellin and CK treatment. We also provide physiological evidence that gibberellin also induces shoot branching in many other trees, such as papaya, indicating that a more complicated regulatory network occurs in the control of shoot branching in some perennial woody plants. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Tree and forest water use under elevated CO2 and temperature in Scandinavian boreal forest

NASA Astrophysics Data System (ADS)

Berg Hasper, Thomas; Wallin, Göran; Lamba, Shubhangi; Sigurdsson, Bjarni D.; Laudon, Hjalmar; Medhurst, Jane L.; Räntfors, Mats; Linder, Sune; Uddling, Johan

2014-05-01

According to experimental studies and models, rising atmospheric carbon dioxide concentration ([CO2]) and temperature have the potential to affect stomatal conductance and, consequently, tree and forest transpiration. This effect has in turn the capacity to influence the terrestrial energy and water balance, including affecting of the magnitude of river runoff. Furthermore, forest productivity is currently water-limited in southern Scandinavia and in a near future, under the projected climatic change, this limitation may become a reality in the central and northern parts of Scandinavia. In this study we examine the water-use responses in 12 40-year old native boreal Norway spruce (Picea abies (L.) Karst.) trees exposed to a factorial combination of two levels of [CO2] (ambient and doubled) and temperature (ambient and +2.8 °C in summer / +5.6 °C in winter), as well as of entire boreal forests to temporal variation in [CO2], temperature and precipitation over the past 50 years in central and northern Sweden. The controlled factorial CO2 and temperature whole-tree chamber experiment at Flakaliden study site demonstrated that Norway spruce trees lacked elevated [CO2]-induced water savings at guard cell, shoot, and tree levels in the years of measurements. Experimentally, elevated temperature did not result in increased shoot or tree water use as stomatal closure fully cancelled the effect of higher vapour pressure deficit in warmed air environment. Consistent with these results, large scale river runoff data and evapotranspiration estimates from large forested watersheds in central Sweden supported lack of elevated CO2-mediated water savings, and rather suggested that the increasing evapotranspiration trend found in this study was primarily linked to increasing precipitation, rising temperature and more efficient forest management. The results from the whole-tree chamber experiment and boreal forested watersheds have important implications for more accurate predictions of boreal atmosphere-biosphere interactions, indicating that tree responses to precipitation and temperature are more important than responses to elevated [CO2] in determining the future forest water-use and hydrology of Scandinavian boreal ecosystems.

In vitro propagation of olive (Olea europaea L.) by nodal segmentation of elongated shoots.

PubMed

Lambardi, Maurizio; Ozudogru, Elif Aylin; Roncasaglia, Romano

2013-01-01

Olive (Olea europaea L.), long-living, ever-green fruit tree of the Old World, has been part of a traditional landscape in the Mediterranean area for centuries. Both the fruits consumed after processing and the oil extracted from the fruits are among the main components of the Mediterranean diet, widely used for salads and cooking, as well as for preserving other food. Documentations show that the ancient use of this beautiful tree also includes lamp fuel production, wool treatment, soap production, medicine, and cosmetics. However, unlike the majority of the fruit species, olive propagation is still a laborious practice. As regards traditional propagation, rooting of cuttings and grafting stem segments onto rootstocks are possible, former being achieved only when the cuttings are collected in specific periods (spring or beginning of autumn), and latter only when skilled grafters are available. In both the cases, performance of the cultivars varies considerably. The regeneration of whole plants from ovules, on the other hand, is used only occasionally. Micropropagation of olive is not easy mainly due to explant oxidation, difficulties in explant disinfection, and labor-oriented establishment of in vitro shoot cultures. However today, the progress in micropropagation technology has made available the complete protocols for several Mediterranean cultivars. This chapter describes a micropropagation protocol based on the segmentation of nodal segments obtained from elongated shoots.

Agrobacterium-medicated transformation of mature Prunus serotina (black cherry) and regeneration of trangenic shoots

Treesearch

Xiaomei Liu; Paula Pijut

2010-01-01

A protocol for Agrobacterium-mediated transformation was developed for in vitro leaf explants of an elite, mature Prunus serotina tree. Agrobacterium tumefaciens strain EHA105 harboring an RNAi plasmid with the black cherry AGAMOUS (AG) gene was used. Bacteria were induced...

Introduction of a citrus blight-associated gene into Carrizo citrange [Citrus sinensis (L.) Osbc. x Poncirus trifoliata (L.) Raf.] by Agrobacterium-mediated transformation.

PubMed

Kayim, M; Ceccardi, T L; Berretta, M J G; Barthe, G A; Derrick, K S

2004-11-01

The protein p12 accumulates in leaves of trees with citrus blight (CB), a serious decline of unknown cause. The function of p12 is not known, but sequence analysis indicates it may be related to expansins. In studies to determine the function of p12, sense and antisense constructs were used to make transgenic Carrizo citrange using an Agrobacterium-mediated transformation system. Homogeneous beta-glucuronidase+ (GUS+) sense and antisense transgenic shoots were regenerated using kanamycin as a selective agent. Twenty-five sense and 45 antisense transgenic shoots were in vivo grafted onto Carrizo citrange for further analyses. In addition, 20 sense and 18 antisense shoots were rooted. The homogeneous GUS+ plants contained either the p12 sense or antisense gene (without the intron associated with the gene in untransformed citrus) as shown by PCR and Southern blotting. Northern blots showed the expected RNA in the sense and antisense plants. A protein of identical size and immunoreactivity was observed in seven of nine sense plants but not in nine antisense or non-transgenic plants. At the current stage of growth, there are no visual phenotypic differences between the transgenic and non-transgenic plants. Selected plants will be budded with sweet orange for field evaluation for resistance or susceptibility to CB and general rootstock performance.

Patterns of diversity in leaves from canopies of Ginkgo biloba are revealed using Specific Leaf Area as a morphological character.

PubMed

Christianson, Michael L; Niklas, Karl J

2011-07-01

The difference reported in the literature for the Specific Leaf Area (SLA, cm(2)/g) of leaves on short- and long-shoots of Acer rubrum could mean that SLA can serve as a quantitative morphological trait. Our survey of SLA in canopies of Ginkgo biloba sampled a different clade of seed plants to investigate this morphological phenomenon. Such a survey in this dioecious taxon, and one in which a single canopy may have juvenile and reproductive portions, as well as one where canopies bear leaves of several shapes, examine these additional morphological factors as well as any long-shoot short-shoot differences. We measured SLA for a set of 642 dried leaves, a sampling across all morphological levels in canopies of large landscape specimens. The tabulated values were analyzed as distributions. Populations of leaves of G. biloba, sorted by morphological features of canopy structure, differ between long- and short-shoots (175%), on the two genders of tree (131%), in the juvenile and reproductive portions of a canopy (183%), and with the presence or absence of seed on short-shoots in the reproductive portion of megasporangiate canopies (114%). Basipetal leaves of long-shoots and leaves of short-shoots have similar values of SLA. With the exception of the acropetal decrease in SLA along long-shoots, the differences among the several classes of leaf seem to reflect local sink strength, even though the sink itself develops after leaves mature. The large overall range in the values of SLA in Ginkgo underscores the relevance of the details of canopy structure to parsing ecological phenomena.

Stem girdling indicates prioritized carbon allocation to the root system at the expense of radial stem growth in Norway spruce under drought conditions

PubMed Central

Oberhuber, Walter; Gruber, Andreas; Lethaus, Gina; Winkler, Andrea; Wieser, Gerhard

2017-01-01

The early culmination of maximum radial growth (RG) in late spring has been found in several coniferous species in a dry inner Alpine environment. We hypothesized that an early decrease in RG is an adaptation to cope with drought stress, which might require an early switch of carbon (C) allocation to belowground organs. To test this hypothesis, we experimentally subjected six-year-old Norway spruce saplings (tree height: 1.35 m; n = 80 trees) to two levels of soil water availability (watered versus drought conditions) and manipulated tree C status by physically blocking phloem transport at three girdling dates (GD). The influence of C availability and drought on tree growth (radial and shoot growth; root biomass) in response to girdling was analyzed in both treatments. Non-structural carbohydrates (NSCs, soluble sugars and starch) were measured in the stem, root and current leader to evaluate changes in tree C status due to girdling. The main finding was a significant increase in RG of the girdled trees compared to the controls above the girdling zone (UZ). At all girdling dates the RG increase was significantly more intense in the drought-stressed compared with watered trees (c. 3.3 and 1.9-fold higher compared with controls in the drought-stressed and watered trees, respectively), most likely indicating that an early switch of C allocation to belowground occurs as an adaptation to maintain tree water status under drought conditions. Reactivation of the cambium after the cessation of its regular activity was detected in UZ in drought-stressed trees, while below the girdling zone no xylem formation was found and the NSC content was strikingly reduced. Irrespective of water availability, girdling before growth onset significantly reduced the progression of bud break (P < 0.05) and the length of the current leader shoot by −47% (P < 0.01) indicating a reduction in xylem hydraulic conductance, which was corroborated by significantly reduced xylem sap flow (P < 0.001). Based on our findings, we conclude that during the growing season drought stress prioritizes an early switch of C allocation to the root system as an adaptation to maintain adequate tree water status in drought-prone environments. PMID:28392608

Southwestern Pine Tip Moth

Treesearch

Daniel T. Jennings; Robert E. Stevens

1982-01-01

The southwestern pine tip moth, Rhyacionia neomexicana (Dyar), injures young ponderosa pines (Pinus ponderosa Dougl. ex Laws) in the Southwest, central Rockies, and midwestern plains. Larvae feed on and destroy new, expanding shoots, often seriously reducing terminal growth of both naturally regenerated and planted pines. The tip moth is especially damaging to trees on...

EFFECTS OF CARBON DIOXIDE AND OZONE ON GROWTH AND BIOMASS ALLOCATION IN PINUS PONDEROSA

EPA Science Inventory

The future productivity of forests will be affected by combinations of elevated atmospheric CO2 and O3. Because productivity of forests will, in part, be determined by growth of young trees, we evaluated shoot growth and biomass responses of Pinus ponderosa seedlings exposed to ...

Characterizing the walnut genome through analyses of BAC end sequences

USDA-ARS?s Scientific Manuscript database

Persian walnut (Juglans regia L.) is an economically important tree for its nut crop and timber. To gain insight into the structure and evolution of the walnut genome, we constructed two bacterial artificial chromosome (BAC) libraries, containing a total of 129,024 clones, from in vitro-grown shoots...

Evaluation of twig pre-harvest temperature for effective cryopreservation of Vaccinium dormant buds

USDA-ARS?s Scientific Manuscript database

Cryopreservation of plant material by dormant buds is less expensive than using shoot tips; however currently, dormant buds are used only for preservation of selected temperate tree and shrub species. Using dormant buds could be an efficient strategy for long-term preservation of blueberry (Vacciniu...

Sporulation of Phytophthora ramorum and P. kernoviae on asymptomatic foliage and fruit

Treesearch

S. Denman; E. Moralejo; S.A. Kirk; E. Orton; A. Whybrow

2008-01-01

Phytophthora ramorum and P. kernoviae are newly discovered invasive Phytophthoras causing leaf necrosis, shoot tip dieback (mostly on ornamental and forest understorey host species) and bleeding cankers on tree trunks of a wide range of plant species. Both pathogens are now present in south-west England....

Late winter availablility of surose to buds of shoots affects flowering and crop load

USDA-ARS?s Scientific Manuscript database

Alternate bearing by individual pecan [Carya illinoinensis (Wangenh.) K. Koch] trees is problematic for nut producers and processors. There are many unknowns regarding alternate bearing physiology, such as the relationship between leaf area and production of high quality pecan kernels. This experime...

Screening larch in vitro for resistance to Mycosphaerella laricina

Treesearch

M.E. Ostry; Paula M. Pijut; D.D. Skilling

1991-01-01

Needle blight of larch caused by Mycosphaerella laricina seriously limits the productivity of susceptible trees in the north central and northeastern United States. Adventitious shoots, derived from cotyledon tissue culture, of selected European larch (Larix decidua) and a hybrid larch were inoculated in vitro with three isolates...

A comparative analysis of genetic variation in rootstocks and scions of old olive trees - a window into the history of olive cultivation practices and past genetic variation.

PubMed

Barazani, Oz; Westberg, Erik; Hanin, Nir; Dag, Arnon; Kerem, Zohar; Tugendhaft, Yizhar; Hmidat, Mohammed; Hijawi, Thameen; Kadereit, Joachim W

2014-05-28

Past clonal propagation of olive trees is intimately linked to grafting. However, evidence on grafting in ancient trees is scarce, and not much is known about the source of plant material used for rootstocks. Here, the Simple Sequence Repeat (SSR) marker technique was used to study genetic diversity of rootstocks and scions in ancient olive trees from the Levant and its implications for past cultivation of olives. Leaf samples were collected from tree canopies (scions) and shoots growing from the trunk base (suckers). A total of 310 trees were sampled in 32 groves and analyzed with 14 SSR markers. In 82.7% of the trees in which both scion and suckers could be genotyped, these were genetically different, and thus suckers were interpreted to represent the rootstock of grafted trees. Genetic diversity values were much higher among suckers than among scions, and 194 and 87 multi-locus genotypes (MLGs) were found in the two sample groups, respectively. Only five private alleles were found among scions, but 125 among suckers. A frequency analysis revealed a bimodal distribution of genetic distance among MLGs, indicating the presence of somatic mutations within clones. When assuming that MLGs differing by one mutation are identical, scion and sucker MLGs were grouped in 20 and 147 multi-locus lineages (MLLs). The majority of scions (90.0%) belonged to a single common MLL, whereas 50.5% of the suckers were single-sample MLLs. However, one MLL was specific to suckers and found in 63 (22.6%) of the samples. Our results provide strong evidence that the majority of olive trees in the study are grafted, that the large majority of scions belong to a single ancient cultivar containing somatic mutations, and that the widespread occurrence of one sucker genotype may imply rootstock selection. For the majority of grafted trees it seems likely that saplings were used as rootstocks; their genetic diversity probably is best explained as the result of a long history of sexual reproduction involving cultivated, feral and wild genotypes.

A comparative analysis of genetic variation in rootstocks and scions of old olive trees – a window into the history of olive cultivation practices and past genetic variation

PubMed Central

2014-01-01

Background Past clonal propagation of olive trees is intimately linked to grafting. However, evidence on grafting in ancient trees is scarce, and not much is known about the source of plant material used for rootstocks. Here, the Simple Sequence Repeat (SSR) marker technique was used to study genetic diversity of rootstocks and scions in ancient olive trees from the Levant and its implications for past cultivation of olives. Leaf samples were collected from tree canopies (scions) and shoots growing from the trunk base (suckers). A total of 310 trees were sampled in 32 groves and analyzed with 14 SSR markers. Results In 82.7% of the trees in which both scion and suckers could be genotyped, these were genetically different, and thus suckers were interpreted to represent the rootstock of grafted trees. Genetic diversity values were much higher among suckers than among scions, and 194 and 87 multi-locus genotypes (MLGs) were found in the two sample groups, respectively. Only five private alleles were found among scions, but 125 among suckers. A frequency analysis revealed a bimodal distribution of genetic distance among MLGs, indicating the presence of somatic mutations within clones. When assuming that MLGs differing by one mutation are identical, scion and sucker MLGs were grouped in 20 and 147 multi-locus lineages (MLLs). The majority of scions (90.0%) belonged to a single common MLL, whereas 50.5% of the suckers were single-sample MLLs. However, one MLL was specific to suckers and found in 63 (22.6%) of the samples. Conclusions Our results provide strong evidence that the majority of olive trees in the study are grafted, that the large majority of scions belong to a single ancient cultivar containing somatic mutations, and that the widespread occurrence of one sucker genotype may imply rootstock selection. For the majority of grafted trees it seems likely that saplings were used as rootstocks; their genetic diversity probably is best explained as the result of a long history of sexual reproduction involving cultivated, feral and wild genotypes. PMID:24886387

Coping with gravity: the foliar water relations of giant sequoia.

PubMed

Williams, Cameron B; Reese Næsborg, Rikke; Dawson, Todd E

2017-10-01

In tall trees, the mechanisms by which foliage maintains sufficient turgor pressure and water content against height-related constraints remain poorly understood. Pressure-volume curves generated from leafy shoots collected crown-wide from 12 large Sequoiadendron giganteum (Lindley) J. Buchholz (giant sequoia) trees provided mechanistic insights into how the components of water potential vary with height in tree and over time. The turgor loss point (TLP) decreased with height at a rate indistinguishable from the gravitational potential gradient and was controlled by changes in tissue osmotica. For all measured shoots, total relative water content at the TLP remained above 75%. This high value has been suggested to help leaves avoid precipitous declines in leaf-level physiological function, and in giant sequoia was controlled by both tissue elasticity and the balance of water between apoplasm and symplasm. Hydraulic capacitance decreased only slightly with height, but importantly this parameter was nearly double in value to that reported for other tree species. Total water storage capacity also decreased with height, but this trend essentially disappeared when considering only water available within the typical range of water potentials experienced by giant sequoia. From summer to fall measurement periods we did not observe osmotic adjustment that would depress the TLP. Instead we observed a proportional shift of water into less mobile apoplastic compartments leading to a reduction in hydraulic capacitance. This collection of foliar traits allows giant sequoia to routinely, but safely, operate close to its TLP, and suggests that gravity plays a major role in the water relations of Earth's largest tree species. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Bud development and shoot morphology in relation to crown location

PubMed Central

Kukk, Maarja; Sõber, Anu

2015-01-01

Plant architecture is shaped by endogenous growth processes interacting with the local environment. The current study investigated crown development in young black alder trees, assessing the effects of local light conditions and branch height on individual bud mass and contents. In addition, we examined the characteristics of parent shoots [the cross-sectional area (CSA) of stem and total leaf area, shoot length, the number of nodes, the number and total mass of buds per shoot] and leaf–stem as well as bud–stem allometry, as several recent studies link bud development to hydraulic architecture. We sampled shoots from top branches and two lower-crown locations: one subjected to deep shade and the other resembling the upper branches in light availability. Sampling was carried out three times between mid-July and late October, spanning from the early stages of bud growth to dormancy. Individual bud mass and shoot characteristics varied in response to light conditions, whereas leaf–stem allometry depended on branch height, most likely compensating for the increasing length of hydraulic pathways. Despite the differences in individual bud mass, the number of preformed leaves varied little across the crown, indicating that the plasticity in shoot characteristics was mainly achieved by neoformation. The relationship between total bud mass and stem CSA scaled similarly across crown locations. However, scaling slopes gradually decreased throughout the sampling period, driven by bud rather than by stem growth. This suggests that the allometry of total bud mass and CSA of stem is regulated locally, instead of resulting from crown-level processes. PMID:26187607

Data for developing allometric models and evaluating carbon stocks of the Zambezi Teak Forests in Zambia.

PubMed

Ngoma, Justine; Moors, Eddy; Kruijt, Bart; Speer, James H; Vinya, Royd; Chidumayo, Emmanuel N; Leemans, Rik

2018-04-01

This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (< 5 cm DBH) trees. We further presented Root-to-Shoot Ratios of uprooted trees. Data on the importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection on applying this data.

Micropropagation and non-steroidal anti-inflammatory and anti-arthritic agent boswellic acid production in callus cultures of Boswellia serrata Roxb.

PubMed

Nikam, Tukaram D; Ghorpade, Ravi P; Nitnaware, Kirti M; Ahire, Mahendra L; Lokhande, Vinayak H; Chopra, Arvind

2013-01-01

Micropropagation through cotyledonary and leaf node and boswellic acid production in stem callus of a woody medicinal endangered tree species Boswellia serrata Roxb. is reported. The response for shoots, roots and callus formation were varied in cotyledonary and leafy nodal explants from in vitro germinated seeds, if inoculated on Murshige and Skoog's (MS) medium fortified with cytokinins and auxins alone or together. A maximum of 8.0 ± 0.1 shoots/cotyledonary node explant and 6.9 ± 0.1 shoots/leafy node explants were produced in 91 and 88 % cultures respectively on medium with 2.5 μM 6-benzyladenine (BA) and 200 mg l(-1) polyvinylpyrrolidone (PVP). Shoots treated with 2.5 μM IBA showed the highest average root number (4.5) and the highest percentage of rooting (89 %). Well rooted plantlets were acclimatized and 76.5 % of the plantlets showed survival upon transfer to field conditions. Randomly amplified polymorphic DNA (RAPD) analysis of the micropropagated plants compared with mother plant revealed true-to-type nature. The four major boswellic acid components in calluses raised from root, stem, cotyledon and leaf explants were analyzed using HPLC. The total content of four boswellic acid components was higher in stem callus obtained on MS with 15.0 μM IAA, 5.0 μM BA and 200 mg l(-1) PVP. The protocol reported can be used for conservation and exploitation of in vitro production of medicinally important non-steroidal anti-inflammatory metabolites of B. serrata.

Height-related trends in leaf xylem anatomy and shoot hydraulic characteristics in a tall conifer: safety versus efficiency in water transport.

PubMed

Woodruff, D R; Meinzer, F C; Lachenbruch, B

2008-01-01

Hydraulic vulnerability of Douglas-fir (Pseudotsuga menziesii) branchlets decreases with height, allowing shoots at greater height to maintain hydraulic conductance (K shoot) at more negative leaf water potentials (Psi l). To determine the basis for this trend shoot hydraulic and tracheid anatomical properties of foliage from the tops of Douglas-fir trees were analysed along a height gradient from 5 to 55 m. Values of Psi l at which K shoot was substantially reduced, declined with height by 0.012 Mpa m(-1). Maximum K shoot was reduced by 0.082 mmol m(-2) MPa(-1) s(-1) for every 1 m increase in height. Total tracheid lumen area per needle cross-section, hydraulic mean diameter of leaf tracheid lumens, total number of tracheids per needle cross-section and leaf tracheid length decreased with height by 18.4 microm(2) m(-1), 0.029 microm m(-1), 0.42 m(-1) and 5.3 microm m(-1), respectively. Tracheid thickness-to-span ratio (tw/b)2 increased with height by 1.04 x 10(-3) m(-1) and pit number per tracheid decreased with height by 0.07 m(-1). Leaf anatomical adjustments that enhanced the ability to cope with vertical gradients of increasing xylem tension were attained at the expense of reduced water transport capacity and efficiency, possibly contributing to height-related decline in growth of Douglas fir.

Dendrometric measurements reveal stages leading to tree mortality in a semiarid pine forest

NASA Astrophysics Data System (ADS)

Tatarinov, Fyodor; Preisler, Yakir; Klein, Tamir; Rotenberg, Eyal; Yakir, Dan

2017-04-01

Increasing frequency and intensity of climatic extreme events, such as droughts may lead to increasing vulnerability of forests, especially in semi-arid regions. In the spring of 2016 mortality was observed among trees used for sap flow (SF) and dendrometry measurements in the semi-arid Fluxnet pine forest site of Yatir in Israel (280mm annual mean precipitation). This was accompanied by bark-beetle attack, and with visual drying of needles starting in April 2016. Comparative analysis of dendrometry and sap flux (SF) measurements in 31 trees of which 7 died and 24 survived permitted identification of the stages leading to tree mortality. Distinction between dying and surviving trees was identified in the dendrometric measurements from Nov. 2015, about five months before visual mortality signs: First, clear decline in diameter (DBH) was observed in all dying trees, whereas DBH of living trees remained constant until the first rain in January 2016 followed by growth. Second, the diurnal patterns in DBH showed a gradual shift of the diurnal DBH maximum from noon-time to early morning from the summer of 2015 to the spring of 2016 in surviving trees, whereas in dying trees it remained stable around noontime. Third, the diurnal swelling/shrinkage dynamics, assumed to reflect water use and storage dynamics, showed clear decline in magnitude, down to near zero, in the dying trees while regular daily cycle continued in the surviving trees. In September 2015 Shoot measurements showed midnight minimum of leaf water potential, lower than in living trees (-4.5 vs. -3.6 MPa respectively). Sap flow measurements were not sufficiently sensitive during the non-active season (fall and early winter) and indicated changes only after the first rain in January 2016. At this time, SF showed dramatic increase in SF with typical midday maximum in the surviving trees, whereas in dying trees SF remained low and irregular. The results show that indicators of mortality can be detected at least 5 months before visual signs are observed, and demonstrate the interacting effects of carbon economy (growth) and tree water management (radial water movement and storage) on the development of mortality in Aleppo pine trees.

Tree stem diameter variations and transpiration in Scots pine: an analysis using a dynamic sap flow model.

PubMed

Perämäki, M; Nikinmaa, E; Sevanto, S; Ilvesniemi, H; Siivola, E; Hari, P; Vesala, T

2001-08-01

A dynamic model for simulating water flow in a Scots pine (Pinus sylvestris L.) tree was developed. The model is based on the cohesion theory and the assumption that fluctuating water tension driven by transpiration, together with the elasticity of wood tissue, causes variations in the diameter of a tree stem and branches. The change in xylem diameter can be linked to water tension in accordance with Hookeâ s law. The model was tested against field measurements of the diurnal xylem diameter change at different heights in a 37-year-old Scots pine at Hyytiälä, southern Finland (61 degrees 51' N, 24 degrees 17' E, 181 m a.s.l.). Shoot transpiration and soil water potential were input data for the model. The biomechanical and hydraulic properties of wood and fine root hydraulic conductance were estimated from simulated and measured stem diameter changes during the course of 1 day. The estimated parameters attained values similar to literature values. The ratios of estimated parameters to literature values ranged from 0.5 to 0.9. The model predictions (stem diameters at several heights) were in close agreement with the measurements for a period of 6 days. The time lag between changes in transpiration rate and in sap flow rate at the base of the tree was about half an hour. The analysis showed that 40% of the resistance between the soil and the top of the tree was located in the rhizosphere. Modeling the water tension gradient and consequent woody diameter changes offer a convenient means of studying the link between wood hydraulic conductivity and control of transpiration.

Survival strategies in semi-arid climate for isohydric and anisohydric species

NASA Astrophysics Data System (ADS)

Guerin, M. F.; Gentine, P.; Uriarte, M.

2013-12-01

The understanding of survival strategies in dry land remains a challenging problem aiming at the interrelationship between local hydrology, plant physiology and climate. Carbon starvation and hydraulic failure are thought to be the two main factors leading to drought-induced mortality beside biotic perturbation. In order to better comprehend mortality the understanding of abiotic mechanisms triggering mortality is being studied in a tractable model for soil-plant-atmosphere continuum emphasizing the role of soil hydraulic properties, photosynthesis, embolism, leaf-gas exchange and climate. In particular the role of the frequency vs. the intensity of droughts is highlighted within such model. The analysis of the model included a differentiation between isohydric and anisohydric tree regulation and is supported by an extensive dataset of Pinion and Juniper growing in a semi-arid ecosystem. An objective of reduced number of parameters was approached with allometric equations to characterize tree's main traits and their hydraulic controls. Leaf area, sapwood area and tree's height are used to derive capacitance, conductance and photosynthetic abilities of the plant. A parameter sensitivity is performed highlighting the role of root:shoot ratio, rooting depth, photosynthetic capacity, quantum efficiency, and most importantly water use efficiency. Analytic development emphasizes two regimes of transpiration/photosynthesis denoted as stage-I (no embolism) and stage-II (embolism dominated) in analogy with stage I-stage II treminology for evaporation (Phillip,1957). Anisohydric species tend to remain in stage-I during which they still can assimilate carbon at full potential thus avoiding carbon starvation. Isohydric species tend to remain longer in stage-II. The effects of drought intensity/frequency on those 2 stages are described. Figure: sensitivity of Piñons stage 1 (top left), stage 2 (top right), and total cavitation duration (sum of stage 1 and stage 2 - bottom left) and time to carbon starvation (defined as 0-crossover of NSC content - bottom right) to Leaf Area Index (LAI) and root:shoot area.

Nitrous oxide fluxes from forest floor, tree stems and canopies of boreal tree species during spring

NASA Astrophysics Data System (ADS)

Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

2017-04-01

Boreal forests are considered as small sources of atmospheric nitrous oxide (N2O) due to microbial N2O production in the soils. Recent evidence shows that trees may play an important role in N2O exchange of forest ecosystems by offering pathways for soil produced N2O to the atmosphere. To confirm magnitude, variability and the origin of the tree mediated N2O emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured forest floor, tree stem and shoot N2O exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in Southern Finland (61˚ 51´N, 24˚ 17´E, 181 a.s.l.). The fluxes were measured in silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation cover and forest structure. The aim was to study the vertical profile of N2O fluxes at stem level and to observe temporal changes in N2O fluxes over the beginning of the growing season. The N2O exchange was determined using the static chamber technique and gas chromatographic analyses. Scaffold towers were used for measurements at multiple stem heights and at the canopy level. Overall, the N2O fluxes from the forest floor and trees at both sites were very small and close to the detection limit. The measured trees mainly emitted N2O from their stems and shoots, while the forest floor acted as a sink of N2O at the paludified site and as a small source of N2O at the mineral soil site. Stem emissions from all the trees at both sites were on average below 0.5 μg N2O m-2 of stem area h-1, and the shoot emissions varied between 0.2 and 0.5 ng N2O m-2 g-1 dry biomass. When the N2O fluxes were scaled up to the whole forest ecosystem, based on the tree biomass and stand density, the N2O emissions from birch and spruce trees at the paludified site were 1.4 and 2.2 mg N2O ha-1 h-1, respectively, while the forest floor was a sink of -6.1 mg N2O ha-1 h-1. At the mineral soil site the upscaled N2O emissions from birch trees and forest floor were 3.6 and 8.9 mg N2O ha-1 h-1, respectively, indicating that the emissions from trees significantly contribute to the N2O emissions from boreal forests. The results also indicate that tree canopies contributed up to 89% of the whole-tree N2O emissions. Our findings demonstrate that we urgently need more studies focusing on leaf-level N2O exchange in forest ecosystems. Acknowledgement This research was financially supported by the National Programme for Sustainability I (LO1415), Czech Science Foundation (17-18112Y), ENVIMET (CZ.1.07/2.3.00/20.0246) , Emil Aaltonen Foundation, Academy of Finland Research Fellow projects (292699, 263858, 288494), The Academy of Finland Centre of Excellence (projects 1118615, 272041), and ICOS-Finland (281255). We thank Hyytiälä SMEAR II station staff and Marek Jakubik for technical support.

Precipitation, not air temperature, drives functional responses of trees in semi-arid ecosystems

DOE PAGES

Grossiord, Charlotte; Sevanto, Sanna; Adams, Henry D.; ...

2016-09-14

Model scenarios of climate change predict that warming and drought will occur simultaneously in the future in many regions. The capacity of woody species to modify their physiology and morphology in response to environmental conditions is widely recognized, but little is known about the responses of trees to reduced precipitation and increased temperature acting simultaneously. In a semi-arid woodland, we assessed in this paper the responses in physiological (needle emergence, maximum photosynthesis, stomatal conductance, water use efficiency (WUE) and shoot elongation) and morphological (needle length and thickness, and leaf mass per area (LMA)) foliar traits of piñon pine (Pinus edulis)more » in response to three years of a 45% reduction in precipitation, a 4.8 °C increase in air temperature and their simultaneous effects. A strong change in physiological and morphological traits in response to reduced precipitation was observed. Precipitation reduction delayed needle emergence, decreased photosynthesis and stomatal conductance, increased WUE, decreased shoot elongation and induced shorter needles with a higher LMA. Trees subjected to simultaneous reductions in precipitation and warming demonstrated a similar response. However, atmospheric warming did not induce a response in any of the measured traits. Physiological and morphological traits of trees in this semi-arid climate were more responsive to changes in soil moisture than air temperature. Long-term exposure to seasonal drought stress in arid sites may have resulted in strong plastic responses to this first stressor. However, atmospheric warming probably was not experienced as a stress for trees in this warm and dry climate. Finally and overall, our results indicate that in semi-arid ecosystems where tree functioning is already highly limited by soil water availability, atmospheric warming as anticipated with climate change may have less impact on foliar trait responses than previously thought.« less

Precipitation, not air temperature, drives functional responses of trees in semi-arid ecosystems

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

Grossiord, Charlotte; Sevanto, Sanna; Adams, Henry D.

Model scenarios of climate change predict that warming and drought will occur simultaneously in the future in many regions. The capacity of woody species to modify their physiology and morphology in response to environmental conditions is widely recognized, but little is known about the responses of trees to reduced precipitation and increased temperature acting simultaneously. In a semi-arid woodland, we assessed in this paper the responses in physiological (needle emergence, maximum photosynthesis, stomatal conductance, water use efficiency (WUE) and shoot elongation) and morphological (needle length and thickness, and leaf mass per area (LMA)) foliar traits of piñon pine (Pinus edulis)more » in response to three years of a 45% reduction in precipitation, a 4.8 °C increase in air temperature and their simultaneous effects. A strong change in physiological and morphological traits in response to reduced precipitation was observed. Precipitation reduction delayed needle emergence, decreased photosynthesis and stomatal conductance, increased WUE, decreased shoot elongation and induced shorter needles with a higher LMA. Trees subjected to simultaneous reductions in precipitation and warming demonstrated a similar response. However, atmospheric warming did not induce a response in any of the measured traits. Physiological and morphological traits of trees in this semi-arid climate were more responsive to changes in soil moisture than air temperature. Long-term exposure to seasonal drought stress in arid sites may have resulted in strong plastic responses to this first stressor. However, atmospheric warming probably was not experienced as a stress for trees in this warm and dry climate. Finally and overall, our results indicate that in semi-arid ecosystems where tree functioning is already highly limited by soil water availability, atmospheric warming as anticipated with climate change may have less impact on foliar trait responses than previously thought.« less

Investigation of plant hormone level changes in shoot tips of longan (Dimocarpus longan Lour.) treated with potassium chlorate by liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Susawaengsup, Chanthana; Rayanakorn, Mongkon; Wongpornchai, Sugunya; Wangkarn, Sunanta

2011-08-15

The endogenous levels of indole-3-acetic acid (IAA), gibberellins (GAs), abscisic acid (ABA) and cytokinins (CKs) and their changes were investigated in shoot tips of ten longan (Dimocarpus longan Lour.) trees for off-season flowering until 60 days after potassium chlorate treatment in comparison with those of ten control (untreated) longan trees. These analytes were extracted and interfering matrices removed with a single mixed-mode solid phase extraction under optimum conditions. The recoveries at three levels of concentration were in the range of 72-112%. The endogenous plant hormones were separated and quantified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Detection limits based on the signal-to-noise ratio ranged from 10 ng mL(-1) for gibberellin A4 (GA4) to 200 ng mL(-1) for IAA. Within the first week after potassium chlorate treatment, dry weight (DW) amounts in the treated longan shoot tips of four gibberellins, namely: gibberellin A1(GA1), gibberellic acid (GA3), gibberellin A19 (GA19) and gibberellin A20 (GA20), were found to increase to approximately 25, 50, 20 and 60 ng g(-1) respectively, all of which were significantly higher than those of the controls. In contrast, gibberellin A8 (GA8) obtained from the treated longan was found to decrease to approximately 20 ng g(-1)DW while that of the control increased to around 80 ng g(-1)DW. Certain CKs which play a role in leaf bud induction, particularly isopentenyl adenine (iP), isopentenyl adenosine (iPR) and dihydrozeatin riboside (DHZR), were found to be present in amounts of approximately 20, 50 and 60 ng g(-1)DW in the shoot tips of the control longan. The analytical results obtained from the two-month off-season longan flowering period indicate that high GA1, GA3, GA19 and GA20 levels in the longan shoot tips contribute to flower bud induction while high levels of CKs, IAA and ABA in the control longan contribute more to the vegetative development. Copyright © 2011 Elsevier B.V. All rights reserved.

Crown development in a pioneer tree, Rhus trichocarpa, in relation to the structure and growth of individual branches.

PubMed

Osada, Noriyuki

2006-01-01

Based on an allometric reconstruction, the structure and biomass-allocation patterns of branches and current-year shoots were investigated in branches of various heights in the pioneer tree Rhus trichocarpa, to evaluate how crown development is achieved and limited in association with height. Path analysis was conducted to explore the effects of light availability, basal height and size of individual branches on branch structure and growth. Branch angle was affected by basal height, whereas branch mass was influenced primarily by light availability. This result suggests that branch structure is strongly constrained by basal height, and that trees mediate such constraints under different light environments. Previous-year leaf area and light availability showed positive effects on current-year stem mass. In contrast, branch basal height and mass negatively affected current-year stem mass. Moreover, the length of stems of a given diameter decreased with increasing branch height. Therefore the cost of biomass investment for a unit growth in length is greater for branches of larger size and at upper positions. Vertical growth rate in length decreased with increasing height. Height-dependent changes in stem allometry and angle influenced the reduction in vertical growth rate to a similar degree.

Ultrastructure of integument wax and wax-producing structures in the melaleuca psyllid Boreioglycaspis melaleucae (Hemiptera: Psyllidae)

USDA-ARS?s Scientific Manuscript database

The melaleuca psyllid has been introduced to Florida as a biological control agent against Melaleuca quinquenervia, an invasive evergreen tree that has invaded large areas of Florida wetland since its introduction earlier from Australia as an ornamental plant. Colonies of the psyllid on young shoots...

76 FR 13968 - Notice of Request for Extension of Approval of an Information Collection; Pine Shoot Beetle; Host...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

... the introduction of plant pests. Subpart--Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant..., plant parts, and seeds for propagation; and Subpart-- Logs, Lumber, and Other Unmanufactured Wood... per response. Respondents: Christmas tree and nursery industry. Estimated annual number of respondents...

Pinus ponderosa: geographic races and subspecies based on morphological variation

Treesearch

Robert Z. Callaham

2013-01-01

Morphological variation of ponderosa pine (Pinus ponderosa Dougl. ex Laws.), growing north of Mexico, is described. A map shows distributions of five putative races that are analyzed and discussed. Characteristics of branches, shoots, and needles were measured for 10 or fewer trees growing on 147 plots located at 1,500-ft elevational intervals...

Water relations and photosynthetic performance in Larix sibirica growing in the forest-steppe ecotone of northern Mongolia.

PubMed

Dulamsuren, Choimaa; Hauck, Markus; Bader, Martin; Osokhjargal, Dalaikhuu; Oyungerel, Shagjjav; Nyambayar, Suran; Runge, Michael; Leuschner, Christoph

2009-01-01

Shoot water relations were studied in Siberian larch (Larix sibirica Ledeb.) trees growing at the borderline between taiga and steppe in northern Mongolia. Larix sibirica is the main tree species in these forests covering 80% of Mongolia's forested area. Minimum shoot water potentials (Psi(m)) close to the point of zero turgor (Psi(0)) repeatedly recorded throughout the growing season suggest that the water relations in L. sibirica were often critical. The Psi(m) varied in close relation to the atmospheric vapor pressure deficit, whereas Psi(0) was correlated with monthly precipitation. Young larch trees growing at the forest line to the steppe were more susceptible to drought than mature trees at the same sites. Furthermore, isolated trees growing on the steppe exhibited lower Psi(m) and recovered to a lower degree from drought overnight than the trees at the forest line. Indications of drought stress in L. sibirica were obtained in two study areas in Mongolia's forest-steppe ecotone: one in the mountain taiga of the western Khentey in northernmost Mongolia, the other in the forest-steppe at the southern distribution limit of L. sibirica on Mt. Bogd Uul, southern Khentey. Larix sibirica growing in riverine taiga with contact to the groundwater table was better water-supplied than the larch trees growing at the forest line to the steppe. Larch trees from the interior of light taiga forests on north-facing slopes, however, exhibited more critical water relations than the trees at the forest line. Frequent drought stress in mature trees and even more in young larch trees at the forest-steppe borderline suggests that L. sibirica does not have the potential to encroach on the steppe under the present climate, except in a sequence of exceptionally moist and cool years. A regression of the present borderline between forest and steppe is likely to occur, as average temperatures are increasing everywhere and precipitation is decreasing regionally in Mongolia's taiga forest region. Higher stomatal conductance concomitant to lower Psi(m) in trees of northern-slope forests compared to trees from the forest line to the steppe may be the result of a recent increase in drought intensity that affects better drought-adapted trees at the forest edge less than the trees in the forest interior. We conclude that drought is a key factor explaining the forest-steppe borderline in northern Mongolia. The proportion of forests within the present vegetation pattern of forests on north-facing slopes and the grasslands on south-facing slopes in Mongolia's forest-steppe ecotone is not likely to increase under the present climate, but may decrease with increasing aridity due to global warming.

Characterization of cytokinin signaling and homeostasis gene families in two hardwood tree species: Populus trichocarpa and Prunus persica.

PubMed

Immanen, Juha; Nieminen, Kaisa; Duchens Silva, Héctor; Rodríguez Rojas, Fernanda; Meisel, Lee A; Silva, Herman; Albert, Victor A; Hvidsten, Torgeir R; Helariutta, Ykä

2013-12-16

Through the diversity of cytokinin regulated processes, this phytohormone has a profound impact on plant growth and development. Cytokinin signaling is involved in the control of apical and lateral meristem activity, branching pattern of the shoot, and leaf senescence. These processes influence several traits, including the stem diameter, shoot architecture, and perennial life cycle, which define the development of woody plants. To facilitate research about the role of cytokinin in regulation of woody plant development, we have identified genes associated with cytokinin signaling and homeostasis pathways from two hardwood tree species. Taking advantage of the sequenced black cottonwood (Populus trichocarpa) and peach (Prunus persica) genomes, we have compiled a comprehensive list of genes involved in these pathways. We identified genes belonging to the six families of cytokinin oxidases (CKXs), isopentenyl transferases (IPTs), LONELY GUY genes (LOGs), two-component receptors, histidine containing phosphotransmitters (HPts), and response regulators (RRs). All together 85 Populus and 45 Prunus genes were identified, and compared to their Arabidopsis orthologs through phylogenetic analyses. In general, when compared to Arabidopsis, differences in gene family structure were often seen in only one of the two tree species. However, one class of genes associated with cytokinin signal transduction, the CKI1-like family of two-component histidine kinases, was larger in both Populus and Prunus than in Arabidopsis.

Characterization of cytokinin signaling and homeostasis gene families in two hardwood tree species: Populus trichocarpa and Prunus persica

PubMed Central

2013-01-01

Background Through the diversity of cytokinin regulated processes, this phytohormone has a profound impact on plant growth and development. Cytokinin signaling is involved in the control of apical and lateral meristem activity, branching pattern of the shoot, and leaf senescence. These processes influence several traits, including the stem diameter, shoot architecture, and perennial life cycle, which define the development of woody plants. To facilitate research about the role of cytokinin in regulation of woody plant development, we have identified genes associated with cytokinin signaling and homeostasis pathways from two hardwood tree species. Results Taking advantage of the sequenced black cottonwood (Populus trichocarpa) and peach (Prunus persica) genomes, we have compiled a comprehensive list of genes involved in these pathways. We identified genes belonging to the six families of cytokinin oxidases (CKXs), isopentenyl transferases (IPTs), LONELY GUY genes (LOGs), two-component receptors, histidine containing phosphotransmitters (HPts), and response regulators (RRs). All together 85 Populus and 45 Prunus genes were identified, and compared to their Arabidopsis orthologs through phylogenetic analyses. Conclusions In general, when compared to Arabidopsis, differences in gene family structure were often seen in only one of the two tree species. However, one class of genes associated with cytokinin signal transduction, the CKI1-like family of two-component histidine kinases, was larger in both Populus and Prunus than in Arabidopsis. PMID:24341635

Soil fluoride spiking effects on olive trees (Olea europaea L. cv. Chemlali).

PubMed

Zouari, M; Ben Ahmed, C; Fourati, R; Delmail, D; Ben Rouina, B; Labrousse, P; Ben Abdallah, F

2014-10-01

A pot experiment under open air conditions was carried out to investigate the uptake, accumulation and toxicity effects of fluoride in olive trees (Olea europaea L.) grown in a soil spiked with inorganic sodium fluoride (NaF). Six different levels (0, 20, 40, 60, 80 and 100mM NaF) of soil spiking were applied through NaF to irrigation water. At the end of the experiment, total fluoride content in soil was 20 and 1770mgFkg(-1) soil in control and 100mM NaF treatments, respectively. The comparative distribution of fluoride partitioning among the different olive tree parts showed that the roots accumulated the most fluoride and olive fruits were minimally affected by soil NaF spiking as they had the lowest fluoride content. In fact, total fluoride concentration varied between 12 and 1070µgFg(-1) in roots, between 9 and 570µgFg(-1) in shoots, between 12 and 290µgFg(-1) in leaves, and between 10 and 29µgFg(-1) in fruits, respectively for control and 100mM NaF treatments. Indeed, the fluoride accumulation pattern showed the following distribution: roots>shoots>leaves>fruits. On the other hand, fluoride toxicity symptoms such as leaf necrosis and leaf drop appeared only in highly spiked soils (60, 80 and 100mM NaF). Copyright © 2014 Elsevier Inc. All rights reserved.

Does structural parasitism by epiphytes exist? A case study between Tillandsia recurvata and Parkinsonia praecox.

PubMed

Flores-Palacios, A

2016-05-01

The effects that epiphytes have on their hosts have been poorly explored in an experimentally. Correlational evidence suggests that epiphytes may be either mutualists or structural parasites, as has been proposed for Tillandsia recurvata on Parkinsonia praecox. To test the effect of T. recurvata upon P. praecox, the epiphyte load on branches of P. praecox was measured and two 1-year experiments were performed to detect the effect of transplantation/removal of epiphytes and shade (0%, 35%. 50% and 80%) on shoot dynamics. If T. recurvata represents a selective pressure for P. praecox, then the frequency of branches carrying large epiphyte loads will be high, and host shoot survival will decrease in the presence of T. recurvata and with increased shade. A weak inverse relationship between epiphyte load and percentage of dead shoots in the host was detected. Shoot survival was independent of epiphyte presence. Shade decreased shoot survival by 35-72%. Results suggest that at the study site, T. recurvata is a commensalist of P. praecox. An alternative hypothesis to explain the correlation between high epiphyte load and branch/tree decay is that older branches carry more epiphytes, receive more shade from neighbouring branches and could be undergoing a natural decline process. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Comparative evaluation of total RNA extraction methods in Theobroma cacao using shoot apical meristems.

PubMed

Silva, D V; Branco, S M J; Holanda, I S A; Royaert, S; Motamayor, J C; Marelli, J P; Corrêa, R X

2016-03-04

Theobroma cacao is a species of great economic importance with its beans used for chocolate production. The tree has been a target of various molecular studies. It contains many polyphenols, which complicate the extraction of nucleic acids with the extraction protocols requiring a large amount of plant material. These issues, therefore, necessitate the optimization of the protocols. The aim of the present study was to evaluate different methods for extraction of total RNA from shoot apical meristems of T. cacao 'CCN 51' and to assess the influence of storage conditions for the meristems on the extraction. The study also aimed to identify the most efficient protocol for RNA extraction using a small amount of plant material. Four different protocols were evaluated for RNA extraction using one shoot apical meristem per sample. Among these protocols, one that was more efficient was then tested to extract RNA using four different numbers of shoot apical meristems, subjected to three different storage conditions. The best protocol was tested for cDNA amplification using reverse transcription-polymerase chain reaction; the cDNA quality was determined to be satisfactory for molecular analyses. The study revealed that with the best RNA extraction protocol, one shoot apical meristem was sufficient for extraction of high-quality total RNA. The results obtained might enable advances in genetic analyses and molecular studies using reduced amount of plant material.

Relationship between leaf functional traits and productivity in Aquilaria crassna (Thymelaeaceae) plantations: a tool to aid in the early selection of high-yielding trees.

PubMed

López-Sampson, Arlene; Cernusak, Lucas A; Page, Tony

2017-05-01

Physiological traits are frequently used as indicators of tree productivity. Aquilaria species growing in a research planting were studied to investigate relationships between leaf-productivity traits and tree growth. Twenty-eight trees were selected to measure isotopic composition of carbon (δ13C) and nitrogen (δ15N) and monitor six leaf attributes. Trees were sampled randomly within each of four diametric classes (at 150 mm above ground level) ensuring the variability in growth of the whole population was represented. A model averaging technique based on the Akaike's information criterion was computed to identify whether leaf traits could assist in diameter prediction. Regression analysis was performed to test for relationships between carbon isotope values and diameter and leaf traits. Approximately one new leaf per week was produced by a shoot. The rate of leaf expansion was estimated as 1.45 mm day-1. The range of δ13C values in leaves of Aquilaria species was from -25.5‰ to -31‰, with an average of -28.4 ‰ (±1.5‰ SD). A moderate negative correlation (R2 = 0.357) between diameter and δ13C in leaf dry matter indicated that individuals with high intercellular CO2 concentrations (low δ13C) and associated low water-use efficiency sustained rapid growth. Analysis of the 95% confidence of best-ranked regression models indicated that the predictors that could best explain growth in Aquilaria species were δ13C, δ15N, petiole length, number of new leaves produced per week and specific leaf area. The model constructed with these variables explained 55% (R2 = 0.55) of the variability in stem diameter. This demonstrates that leaf traits can assist in the early selection of high-productivity trees in Aquilaria species. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Heavy metal stress in alders: Tolerance and vulnerability of the actinorhizal symbiosis.

PubMed

Bélanger, Pier-Anne; Bellenger, Jean-Philippe; Roy, Sébastien

2015-11-01

Alders have already demonstrated their potential for the revegetation of both mining and industrial sites. These actinorhizal trees and shrubs and the actinobacteria Frankia associate in a nitrogen-fixing symbiosis which could however be negatively affected by the presence of heavy metals, and accumulate them. In our hydroponic assay with black alders, quantification of the roots and shoots metal concentrations showed that, in the absence of stress, symbiosis increases Mo and Ni root content and simultaneously decreases Mo shoot content. Interestingly, the Mo shoot content also decreases in the presence of Ni, Cu, Pb, Zn and Cd for symbiotic alders. In symbiotic alders, Pb shoot translocation was promoted in presence of Pb. On the other hand, Cd exclusion in symbiotic root tissues was observed with Pb and Cd. In the presence of symbiosis, only Cd and Pb showed translocation into aerial tissues when present in the nutrient solution. Moreover, the translocation of Ni to shoot was prevented by symbiosis in the presence of Cd, Ni and Pb. The hydroponic experiment demonstrated that alders benefit from the symbiosis, producing more biomass (total, root and shoot) than non nodulated alders in control condition, and in the presence of metals (Cu, Ni, Zn, Pb and Cd). Heavy metals did not reduce the nodule numbers (SNN), but the presence of Zn or Cd did reduce nodule allocation. Our study suggests that the Frankia-alder symbiosis is a promising (and a compatible) plant-microorganism association for the revegetation of contaminated sites, with minimal risk of metal dispersion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distribution of Xylella fastidiosa in Sycamore associated with low temperature and host resistance

Treesearch

T.S.M. Henneberger; K.L. Stevenson; C.J. Chang

2004-01-01

Experiments were conducted in the field and laboratory to determine effects of low temperatures 4% on Xylella fastidiosa populations in American sycamore. Roots and shoots from naturally infected trees at two locations were collected monthly. Sap extracted from the samples was tested by enzyme-linked immunosorbent assay for presence of X...

Stem Deformity in Black Cherry

Treesearch

Charles O. Rexrode

1978-01-01

A 2-year study of stem deformity in black cherry on the Allegheny and Monongahela National Forests revealed that insects, disease, frost, and browsing by deer were the major sources of injury to the terminal shoots of seedlings and saplings. Twenty-seven species of insects from 19 families and 5 orders were associated with young black cherry trees. Of these species,...

Height and seasonal growth pattern of jack pine full-sib families

Treesearch

Don E. Riemenschneider

1981-01-01

Total tree height, seasonal shoot elongation, dates of growth initiation and cessation, and mean daily growth rate were measured and analyzed for a population of jack pine full-sib families derived from inter-provenance crosses. Parental provenance had no effect on these variables although this may have been due to small sample size. Progenies differed significantly...

SEASONAL CHANGES IN ROOT AND SOIL RESPIRATION OF OZONE-EXPOSED PONDEROSA PINE (PINUS PONDEROSA) GROWN IN DIFFERENT SUBSTRATES

EPA Science Inventory

Exposure to(ozone 0-3)has been shown to decrease the allocation of carbon to tree roots. Decreased allocation of carbon to roots might disrupt root metabolism and rhizosphere organisms. The effects of soil type and shoot 0, exposure on below-ground respiration and soil microbial ...

Whole genome sequence analyses revealed that strains of “Candidatus Liberibacter asiaticus” recently found in two California locations were different

USDA-ARS?s Scientific Manuscript database

‘Candidatus Liberibacter asiaticus’ (CLas), an a-proteobacterium, is associated with citrus Huanglongbing (HLB; yellow shoot disease). In California, CLas was first detected in residential neighborhoods of Hacienda Heights (HH) in 2012 and San Gabriel (SG) in 2015. Although all infected trees were d...

Carbohydrate levels in current-year shoots of sugar maple

Treesearch

John R. Donnelly

1976-01-01

Diurnal changes in carbohydrate concentrations in leaves and current-year stems of a mature sugar maple tree were studied in June and September. In leaves, alcohol-soluble sugar concentration was highest in the morning and lowest in late afternoon or early evening; diurnal changes in starch lagged about 5 hours behind changes in sugar. Carbohydrate concentrations in...

Rhus copallinum L.

Treesearch

K.F Connor

2004-01-01

Shining sumac is an upright, deciduous, clonal shrub or (rarely) small tree from 3 to 6 m tall. Bark ranges in color from light brown to gray to reddish-brown. Shoots and twigs are hairy and reddish in color. Twigs have conspicuous lenticels. The sparsely branched, flat crown is composed of alternate, pinnately compound leaves approximately 15 to 30 cm long, with wings...

Morphology and accumulation of epicuticular wax on needles of Douglas-fir (Pseudotsuga menziesii var. menziesii)

Treesearch

Constance A. Harrington; William C. Carlson

2015-01-01

Past studies have documented differences in epicuticular wax among several tree species but little attention has been paid to changes in accumulation of foliar wax that can occur during the year. We sampled current-year needles from the terminal shoots of Douglas-fir (Pseudotsuga menziesii var. menziesii) in late June/early...

Internode or stem unit: a problem of terminology

Treesearch

William B. Critchfield

1985-01-01

In recent years the term stem unit (SU) has increasingly supplanted internode in the literature of conifer shoot growth, especially since the adoption of SU in a collection of papers titled "Tree Physiology and Yield Improvement" (Cannell and Last 1976). In standard botanical terminology, a node is the point on a stem where one or more lateral appendages (...

Diplodia Blight of Pines

Treesearch

Glenn W. Peterson

1981-01-01

The fungus Diplodia pinea (Desm.) Kickx is most damaging to plantings of both exotic and native pine species in the United States. The fungus is seldom found in natural pine stands. Diplodia pinea kills current-year shoots, major branches, and ultimately entire trees. The effects of this disease are most severe in landscape, windbreak, and park plantings in the Central...

The Temporal and Spatial Distribution of Filbert Weevil Infested Acorns in an Oak Woodland in Marin County, California

Treesearch

Vernard R. Lewis

1991-01-01

Two-hundred shoots contained within randomly selected locations from each of thirty-six coast live oak, Quercus agrifolia, trees were sampled to determine the abundance and spatial distribution of acorns infested by the filbert weevil, Curculio occidentis in northern California during 1989. The seasonal abundance of infested acorns...

Green foliage losses from ponderosa pines induced by Abert squirrels and snowstorms: A comparison. [Sciurus aberti; Pinus pondersosa

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

Allred, W.S.; Gaud, W.S.

1993-01-01

Abert squirrels (Sciurus aberti) are obligate herbivores on ponderosa pine (Pinus ponderosa). The inner bark of pine shoots is considered one of the predominant food resources obtained by foraging squirrels. As squirrels forage for this resource they induce green needle losses from chosen feed trees. Amounts of induced green needle losses appear to vary according to the availability of alternative foods and squirrel population densities. Weather also induces green needle losses to ponderosa pines. Results of this study indicate that, at least in some years, heavy snowstorms can induce greater amounts of green needle losses than squirrels. Squirrel herbivory wasmore » not indicated as a factor in any tree mortality. However, losses due to snowstorms are more severe since they may cause the actual depletion of trees in the forest because of the tree mortality they inflict.« less

Growth enhancement of Quercus alba saplings by CO[sub 2] enrichment under field conditions

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

Norby, R.J.; O'Neill, E.G.; Wullschleger, S.D.

1993-06-01

White oak (Quercus alba L.) trees were grown in soil under field conditions for four growing seasons in open-top chambers containing ambient air continuously enriched with 0, 150, or 300 [mu]mol/mol CO[sub 2]. The trees were significantly larger in elevated CO[sub 2]: whole-tree mass (including woody roots) was 36% greater in +150 and 140% greater in +300 compared to ambient-grown trees. There were no significant effects of CO[sub 2] concentration on root-to-shoot or leaf area ratios. The stimulatory effect of CO[sub 2] occurred during seedling establishment, and there was no effect of CO[sub 2] on relative growth rate after themore » first field season. However, photosynthesis remained consistently higher in elevated CO[sub 2], foliar respiration was reduced, and fine root density and CO[sub 2] efflux from the soil were higher, as previously reported with yellow- poplar trees.« less

Suberin-derived aliphatic monomers as biomarkers for SOM affected by root litter contribution

NASA Astrophysics Data System (ADS)

Kogel-Knabner, I.; Spielvogel, S.-; Prietzel, J.-

2012-12-01

The patchy distribution of trees and ground vegetation may have major impact on SOC variability and stability at the small scale. Knowledge about correlations between the pattern of tree and ground vegetation, SOC stocks in different soil depths and the contribution of root- vs. shoot-derived carbon to different SOC fractions is scarce. We have tested analysis of hydrolysable aliphatic monomers derived from the biopolyesters cutin- and suberin to investigate whether their composition can be traced back after decay and transformation into soil organic matter (SOM) to study SOM source, degradation, and stand history. The main objective of this study was to elucidate the relative abundance of cutin and suberin in different particle size and density fractions of a Norway spruce and a European beech site with increasing distance to stems. Soil samples, root, bark and needle/leave samples were analyzed for their cutin and/or suberin signature. Previous to isolation of bound lipids, sequential solvent extraction was used to remove free lipids and other solvent extractable compounds. Cutin- and suberin-derived monomers were extracted from the samples using base hydrolysis. Before analysis by Gas Chromatography/Mass Spectrometry (GC/MS), extracts were derivatized to convert compounds to trimethylsilyl derivatives. Statistical analysis identified four variables which as combined factors discriminated significantly between cutin and suberin based on their structural units. We found a relative enrichment of cutin and suberin contents in the occluded fraction at both sites that decreased with increasing distance to the trees. We conclude from our results that (i) patchy above- and belowground carbon input caused by heterogeneous distribution of trees and ground vegetation has major impact on SOC variability and stability at the small scale, (ii) tree species is an important factor influencing SOC heterogeneity at the stand scale due to pronounced differences in above- and belowground carbon input among the tree species and that (iii) forest conversion may substantially alter SOC stocks and spatial distribution. Suberin biomarkers can thus be used as indicators for the presence of root influence on SOM composition and for identifying root-affected soil compartments.

Expression Profiling of FLOWERING LOCUS T-Like Gene in Alternate Bearing ‘Hass' Avocado Trees Suggests a Role for PaFT in Avocado Flower Induction

PubMed Central

Ziv, Dafna; Zviran, Tali; Zezak, Oshrat; Samach, Alon; Irihimovitch, Vered

2014-01-01

In many perennials, heavy fruit load on a shoot decreases the ability of the plant to undergo floral induction in the following spring, resulting in a pattern of crop production known as alternate bearing. Here, we studied the effects of fruit load on floral determination in ‘Hass' avocado (Persea americana). De-fruiting experiments initially confirmed the negative effects of fruit load on return to flowering. Next, we isolated a FLOWERING LOCUS T-like gene, PaFT, hypothesized to act as a phloem-mobile florigen signal and examined its expression profile in shoot tissues of on (fully loaded) and off (fruit-lacking) trees. Expression analyses revealed a strong peak in PaFT transcript levels in leaves of off trees from the end of October through November, followed by a return to starting levels. Moreover and concomitant with inflorescence development, only off buds displayed up-regulation of the floral identity transcripts PaAP1 and PaLFY, with significant variation being detected from October and November, respectively. Furthermore, a parallel microscopic study of off apical buds revealed the presence of secondary inflorescence axis structures that only appeared towards the end of November. Finally, ectopic expression of PaFT in Arabidopsis resulted in early flowering transition. Together, our data suggests a link between increased PaFT expression observed during late autumn and avocado flower induction. Furthermore, our results also imply that, as in the case of other crop trees, fruit-load might affect flowering by repressing the expression of PaFT in the leaves. Possible mechanism(s) by which fruit crop might repress PaFT expression, are discussed. PMID:25330324

Expression profiling of FLOWERING LOCUS T-like gene in alternate bearing 'Hass' avocado trees suggests a role for PaFT in avocado flower induction.

PubMed

Ziv, Dafna; Zviran, Tali; Zezak, Oshrat; Samach, Alon; Irihimovitch, Vered

2014-01-01

In many perennials, heavy fruit load on a shoot decreases the ability of the plant to undergo floral induction in the following spring, resulting in a pattern of crop production known as alternate bearing. Here, we studied the effects of fruit load on floral determination in 'Hass' avocado (Persea americana). De-fruiting experiments initially confirmed the negative effects of fruit load on return to flowering. Next, we isolated a FLOWERING LOCUS T-like gene, PaFT, hypothesized to act as a phloem-mobile florigen signal and examined its expression profile in shoot tissues of on (fully loaded) and off (fruit-lacking) trees. Expression analyses revealed a strong peak in PaFT transcript levels in leaves of off trees from the end of October through November, followed by a return to starting levels. Moreover and concomitant with inflorescence development, only off buds displayed up-regulation of the floral identity transcripts PaAP1 and PaLFY, with significant variation being detected from October and November, respectively. Furthermore, a parallel microscopic study of off apical buds revealed the presence of secondary inflorescence axis structures that only appeared towards the end of November. Finally, ectopic expression of PaFT in Arabidopsis resulted in early flowering transition. Together, our data suggests a link between increased PaFT expression observed during late autumn and avocado flower induction. Furthermore, our results also imply that, as in the case of other crop trees, fruit-load might affect flowering by repressing the expression of PaFT in the leaves. Possible mechanism(s) by which fruit crop might repress PaFT expression, are discussed.

PpeTAC1 promotes the horizontal growth of branches in peach trees and is a member of a functionally conserved gene family found in diverse plants species.

PubMed

Dardick, Chris; Callahan, Ann; Horn, Renate; Ruiz, Karina B; Zhebentyayeva, Tetyana; Hollender, Courtney; Whitaker, Michael; Abbott, Albert; Scorza, Ralph

2013-08-01

Trees are capable of tremendous architectural plasticity, allowing them to maximize their light exposure under highly competitive environments. One key component of tree architecture is the branch angle, yet little is known about the molecular basis for the spatial patterning of branches in trees. Here, we report the identification of a candidate gene for the br mutation in Prunus persica (peach) associated with vertically oriented growth of branches, referred to as 'pillar' or 'broomy'. Ppa010082, annotated as hypothetical protein in the peach genome sequence, was identified as a candidate gene for br using a next generation sequence-based mapping approach. Sequence similarity searches identified rice TAC1 (tiller angle control 1) as a putative ortholog, and we thus named it PpeTAC1. In monocots, TAC1 is known to lead to less compact growth by increasing the tiller angle. In Arabidopsis, an attac1 mutant showed more vertical branch growth angles, suggesting that the gene functions universally to promote the horizontal growth of branches. TAC1 genes belong to a gene family (here named IGT for a shared conserved motif) found in all plant genomes, consisting of two clades: one containing TAC1-like genes; the other containing LAZY1, which contains an EAR motif, and promotes vertical shoot growth in Oryza sativa (rice) and Arabidopsis through influencing polar auxin transport. The data suggest that IGT genes are ancient, and play conserved roles in determining shoot growth angles in plants. Understanding how IGT genes modulate branch angles will provide insights into how different architectural growth habits evolved in terrestrial plants. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Control of fire blight (Erwinia amylovora) on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

PubMed Central

Aćimović, Srđan G.; Zeng, Quan; McGhee, Gayle C.; Sundin, George W.; Wise, John C.

2015-01-01

Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1–2 apple tree injections of either streptomycin, potassium phosphites (PH), or acibenzolar-S-methyl (ASM), significant reduction of blossom and shoot blight symptoms was observed compared to water injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2, and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR) under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control. PMID:25717330

Growth, shoot phenology and physiology of diverse seed sources of black spruce: II 23-year-old field trees

Treesearch

Kurt H. Johnsen; John R. Seiler; John E. Major

1996-01-01

Four sources of 23-year-old black spruce (Picea mariana (Mill.) B.S.P.) from a provenance test at the Petawawa National Forestry Institute (46° N, 77°30¢ W) were assessed for height growth, shoot phenology and seasonal gas exchange. The provenances were designated 7000 (Yukon, 63°34¢ N, 135°55¢ W), 6979 (Alberta 52°22¢ N, 115°15¢ W), 6908 (Ontario, 48°59¢ N, 80°38¢ W)...

Juggling carbon: allocation patterns of a dominant tree in a fire-prone savanna.

PubMed

Schutz, Alexander Ernest Noel; Bond, William J; Cramer, Michael D

2009-05-01

In frequently burnt mesic savannas, trees can get trapped into a cycle of surviving fire-induced stem death (i.e. topkill) by resprouting, only to be topkilled again a year or two later. The ability of savanna saplings to resprout repeatedly after fire is a key component of recent models of tree-grass coexistence in savannas. This study investigated the carbon allocation and biomass partitioning patterns that enable a dominant savanna tree, Acacia karroo, to survive frequent and repeated topkill. Root starch depletion and replenishment, foliage recovery and photosynthesis of burnt and unburnt plants were compared over the first year after a burn. The concentration of starch in the roots of the burnt plants (0.08 +/- 0.01 g g(-1)) was half that of the unburnt plant (0.16 +/- 0.01 g g(-1)) at the end of the first growing season after topkill. However, root starch reserves of the burnt plants were replenished over the dry season and matched that of unburnt plants within 1 year after topkill. The leaf area of resprouting plants recovered to match that of unburnt plants within 4-5 months after topkill. Shoot growth of resprouting plants was restricted to the first few months of the wet season, whereas photosynthetic rates remained high into the dry season, allowing replenishment of root starch reserves. (14)C labeling showed that reserves were initially utilized for shoot growth after topkill. The rapid foliage recovery and the replenishment of reserves within a single year after topkill implies that A. karroo is well adapted to survive recurrent topkill and is poised to take advantage of unusually long fire-free intervals to grow into adults. This paper provides some of the first empirical evidence to explain how savanna trees in frequently burnt savannas are able to withstand frequent burning as juveniles and survive to become adults.

Seasonal carbohydrate storage and mobilization in bearing and non-bearing pistachio (Pistacia vera) trees.

PubMed

Spann, Timothy M; Beede, Robert H; Dejong, Theodore M

2008-02-01

We analyzed annual carbohydrate storage and mobilization of bearing ("on") and non-bearing ("off") 'Kerman' pistachio (Pistacia vera L.) trees growing on three different rootstocks. On all rootstocks, carbohydrate storage in shoots and branches of "on" and "off" trees was lowest following the spring growth flush. In "off" trees, stored carbohydrates increased and remained high after the initial growth flush. In "on" trees, stem carbohydrates increased temporarily in early summer, but were mobilized in mid-season during kernel fill, and then increased again after nut harvest. During the dormant season, the only substantial differences in carbohydrate storage between previously "on" and "off" trees were found in the roots of the weakest rootstock. The annual carbohydrate storage and mobilization pattern in canopy branches of heavily cropped pistachio trees appeared to be driven by carbohydrate demands related to nut development and untempered by tree vigor. Mobilization of carbohydrates from current-season and 1- and 2-year-old stem wood of "on" trees during the primary period of kernel fill corresponded with the period of inflorescence bud abscission. Thus, the alternate bearing pattern associated with inflorescence bud abscission in 'Kerman' pistachio may be a function of mid-season mobilization of stored carbohydrates in current-season stems resulting in stimulation of inflorescence bud abscission.

Trees as bioindicators of industrial air pollution during implementation of pro-environmental policy in Silesia region (Poland).

NASA Astrophysics Data System (ADS)

Sensuła, Barbara; Wilczyński, Slawomir; Opała, Magdalena; Pawełczyk, Sławomira; Piotrowska, Natalia

2015-04-01

The aim of research conducted within the project entitled "Trees as bioindicators of industrial air pollutants during the implementation of pro-environmental policies in the area of Silesia" (acronym BIOPOL) is the reconstruction of climate changes and anthropogenic effects and monitoring of the influence of human activities related to industrial development and the introduction of pro-environmental policy. The analysis will concern the climatic and anthropogenic signals recorded in annual tree rings width of Scots pine and in the isotopic composition of wood and its compenents (such as alpha-cellulose and glucose). Only a few studies made a complex multiproxies analysis of the influence of industrial air pollutants on changes in the tree rings width and their isotopic composition in any selected region. In addition, research is usually for a period of industrial development, is a lack of analysis for the period of implementation of EU law and standards on air quality to Polish law. The research area are the forests close to 3 different industrial plants (chemical- nitrogen plants, steel mills, power plants), in Silesia, where operating companies have strategic importance for the region and country. By analyzing the structure of land in Silesia noted a significant advantage of forest land and agricultural land. A large percentage of forest land providing protection for residents in case of failure in any of the plants. A cloud of noxious fumes is possible in large part retained in the trees. Waste generated by the chemical industry, metallurgy and energy represent the largest proportion of waste generated in the region. Already in the beginning of 21stcentury, the Waste Management Plans for various cities in Silesia are set out various strategic objectives to 2015, including in the economic sector: the implementation of non-waste technology and less and the best available techniques (BAT), the introduction of the principles of "cleaner production". The BIOPOL innovation is: a) multiproxy spatio-temporal analysis of the effects of climate changes and emission of air industrial pollution on trees during the development of industry and the implementation of pro-environmental policies in Silesia: - Analysis of the width of annual tree rings (since 1975) - Analysis of underestimation of the 14C concentration during the implementation of European standards (since 2000) - Analysis of the recorded signals of environmental changes in the composition of stable isotopes in annual tree rings - wood and its components b) modeling of the influence of pollutants emitted into the atmosphere on the width of annual growth of trees and C,O,N stable isotopes and radiocarbon - Spatio-temporal model of environmental change in the tree rings width and their isotopic composition close to each of the selected plants - comparison to the impact of climate change and industrial pollution for 3 different industries (steel mills, power plants, nitrogen plants) in the period from 1975 to present - Space model of environmental changes in the isotopic composition of trees near each of the selected plants (at varying distances from the chosen site) based on analysis of isotopic composition of annual shoots of pine trees in three consecutive years: from 2012 to 2014) - Estimation of emission components originating from industrial pollution for individual plants This project was funded by the National Science Centre allocated on the basis of the decision number DEC-2011/03/D/ST10/05251

Apple dwarfing rootstocks exhibit an imbalance in carbohydrate allocation and reduced cell growth and metabolism

PubMed Central

Foster, Toshi M; McAtee, Peter A; Waite, Chethi N; Boldingh, Helen L; McGhie, Tony K

2017-01-01

Apple dwarfing rootstocks cause earlier shoot termination and reduced root and shoot mass. To identify physiological factors responsible for rootstock-induced growth restriction, we compared vascular-enriched gene expression between two dwarfing rootstocks (‘M27’ and ‘M9’) and the vigorous rootstock ‘M793’ using RNA sequencing and quantitative reverse transcriptase PCR. Differentially expressed genes common to both dwarfing rootstocks belonged to five main biological processes: (1) primary metabolism, (2) cell wall synthesis and modification, (3) secondary metabolism, (4) hormone signalling and response and (5) redox homeostasis. Genes promoting the biosynthesis of amino acids, lipids and cell walls were downregulated in dwarfing rootstocks, whereas genes promoting the breakdown of these compounds were upregulated. The only exception to this trend was the upregulation of starch synthesis genes in dwarfing rootstocks. Non-structural carbohydrate analysis demonstrated that starch concentrations in ‘M9’ roots, stems and grafted ‘Royal Gala’ (‘RG’) scions were double that of equivalent tissues from ‘RG’ homo-grafted trees (‘RG’/‘RG’). Fructose and glucose concentrations were much lower in all three tissues of the ‘RG’/‘M9’ trees. Together, these data indicate that dwarfing rootstocks are in a state of sugar depletion and reduced cellular activity despite having large starch reserves. Another significant finding was the over-accumulation of flavonoids and the downregulation of auxin influx transporters MdAUX1 and MdLAX2 in dwarfing rootstocks. We propose that both factors reduce polar auxin transport. The results of this study contribute novel information about the physiological state of dwarfing rootstocks. PMID:28435686

Alteration of TAC1 expression in Prunus species leads to pleiotropic shoot phenotypes

USDA-ARS?s Scientific Manuscript database

Prunus persica (peach) trees carrying the ‘Pillar’ or ‘Broomy’ trait (br) have vertically oriented branches caused by loss of function mutations in a gene called TILLER ANGLE CONTROL 1 (TAC1). TAC1 encodes a protein in the IGT gene family that includes LAZY1 and DEEPER ROOTING 1 (DRO1), which regul...

Using Historical Temperature Records To Adjust The Federal Quarantine Of The Pine Shoot Beetle

Treesearch

Robert A. Haack; Poland M. Therese; Warren E. Heilman

1998-01-01

In 1992, a federal quarantine was imposed by the United States Department of Agriculture (USDA)Animal and Plant Health Inspection Service (APHIS) on the movement of pine from infested counties to uninfested counties within the US (Haack 1997; Haack et al. 1997). The Tomicus quarantine allows for the movement of pine logs, pine Christmas trees, and...

Six-Year Effects of Two Late Spring Frosts on Appalachian Hardwoods

Treesearch

Everette D. Rast; Robert L. Brisbin; Robert L. Brisbin

1987-01-01

Severe late spring frosts can kill new shoots and leaves on commercial tree species at higher elevations. A previous short-term study has shown that the resulting defoliation and dieback does not seriously affect the radial growth or mortality of most species except American beech. In this study we found that defoliation, dieback, and radial growth increment were...

Effects of competition from young northern hardwoods on red pine seedling growth, nutrient use efficiency, and leaf morphology

Treesearch

Katherine J. Elliott; Alan S. White

1993-01-01

The effects of competition from three northern hardwood tree species on red pine (Pinus resinosa Ait.) seedlings were examined on two clear-cut sites in western Maine. We examined how planted red pine seedlings altered their nutrient use efficiency and shoot morphology under changing environmental conditions and how these changes related to their...

Age-class differences in shoot photosynthesis and water relations of Fraser fir (Abies fraseri), southern Appalachian Mountains, USA

Treesearch

Keith Reinhardt; Daniel M. Johnson; William K. Smith

2009-01-01

Fraser fir (Abies fraseri (Pursh) Poir.) is an endemic tree species found only in refugial mountain-top forests in the southern Appalachian Mountains, USA. Very few studies have investigated the ecophysiology of this species in its natural environment. We measured and compared photosynthetic gas exchange and water relations of understory germinant...

How much older are Appalachian oaks below-ground than above-ground?

Treesearch

Daniel J. Heggenstaller; Eric K. Zenner; Patrick H. Brose; Jerilynn E. Peck

2012-01-01

Young oaks (Quercus spp.) are known to invest more in early root growth than shoot growth, enabling seedlings to tolerate stem die-back and resprouting. The resulting disparity in age between above- and below-ground tissues has been previously demonstrated for seedling-sized stems, but not for successful canopy-ascending trees. We compared the age of stem cross...

Date of Pollen Shedding by Longleaf Pine Advanced by Increased Temperatures at Strobili

Treesearch

W.D. Boyer; F.W. Woods

1973-01-01

Air temperatures in the microenvironments of flower buds of Pinus palustris Mill. appear to be a major determinant of flowering date. Shoots bearing staminate strobili on each of 10 trees were bagged at different times and for varying lengths of time in January and February. Bagging treatments provided 488 to 3,852 additional degree-hr of heat...

Crown characteristics of juvenile loblolly pine 6 years after application of thinning and fertilization

Treesearch

Shufang Yu; Jim L. Chambers; Zhenmin Tang; James P. Barnett

2003-01-01

Total foliage dry mass and leaf area at the canopy hierarchical level of needle, shoot, branch and crown were measured in 48 trees harvested from a 14-year-old loblolly pine (Pinus taeda L.) plantation, six growing seasons after thinning and fertilization treatments. In the unthinned treatment, upper crown needles were heavier and had more leaf area...

High-resolution transcript profiling reveals shoot abscission process of spruce dwarf mistletoe Arceuthobium sichuanense in response to ethephon

PubMed Central

Wang, Yonglin; Xiong, Dianguang; Jiang, Ning; Li, Xuewu; Yang, Qiqing; Tian, Chengming

2016-01-01

Arceuthobium (dwarf mistletoes) are hemiparasites that may cause great damage to infected trees belonging to Pinaceae and Cupressaceae. Currently, dwarf mistletoe control involves the use of the ethylene-producing product ethephon (ETH), which acts by inducing dwarf mistletoe shoot abscission. However, the process by which ETH functions is mostly unknown. Therefore, the transcriptome of the ETH-exposed plants was compared to non-exposed controls to identify genes associated with the response to ethephon. In this study, the reference transcriptome was contained 120,316 annotated unigenes, with a total of 21,764 ETH-responsive differentially expressed unigenes were identified. These ETH-associated genes clustered into 20 distinctly expressed pattern groups, providing a view of molecular events with good spatial and temporal resolution. As expected, the greatest number of unigenes with changed expression were observed at the onset of abscission, suggesting induction by ethylene. ETH also affected genes associated with shoot abscission processes including hormone biosynthesis and signaling, cell wall hydrolysis and modification, lipid transference, and more. The comprehensive transcriptome data set provides a wealth of genomic resources for dwarf mistletoe communities and contributes to a better understanding of the molecular regulatory mechanism of ethylene-caused shoots abscission. PMID:27941945

Constitutive expression of two apple (Malus x domestica Borkh.) homolog genes of LIKE HETEROCHROMATIN PROTEIN1 affects flowering time and whole-plant growth in transgenic Arabidopsis.

PubMed

Mimida, Naozumi; Kidou, Shin-Ichiro; Kotoda, Nobuhiro

2007-09-01

Fruit trees, such as apple (Malus x domestica Borkh.), are woody perennial plants with a long juvenile phase. The biological analysis for the regulation of flowering time provides insights into the reduction of juvenile phase and the acceleration of breeding in fruit trees. In Arabidopsis, LIKE HETEROCHROMATIN PROTEIN1 (LHP1) is involved in epigenetic silencing of the target genes such as flowering genes. We isolated and characterized twin apple LHP1 homolog genes, MdLHP1a and MdLHP1b. These genes may have been generated as a result of ancient genome duplication. Although the putative MdLHP1 proteins showed lower similarity to any other known plant LHP1 homologs, a chromo domain, a chromo shadow domain, and the nuclear localization signal motifs were highly conserved among them. RT-PCR analysis showed that MdLHP1a and MdLHP1b were expressed constantly in developing shoot apices of apple trees throughout the growing season. Constitutive expression of MdLHP1a or MdLHP1b could compensate for the pleiotropic phenotype of lhp1/tfl2 mutant, suggesting that apple LHP1 homolog genes are involved in the regulation of flowering time and whole-plant growth. Based on these results, LHP1 homolog genes might have rapidly evolved among plant species, but the protein functions were conserved, at least between Arabidopsis and apple.

Temperature dependence of needle and shoot elongation before bud break in Scots pine.

PubMed

Schiestl-Aalto, Pauliina; Mäkelä, Annikki

2017-03-01

Knowledge about the early part of needle growth is deficient compared with what is known about shoot growth. It is however important to understand growth of different organs to be able to estimate the changes in whole tree growth in a changing environment. The onset of growth in spring has been observed to occur over some certain threshold value of momentary temperature or temperature accumulation. We measured the length growth of Scots pine (Pinus sylvestris L.) needles and shoots from March until bud break over 3 years. We first compared needle growth with concurrent shoot growth. Then, we quantified threshold temperature of growth (i) with a logistic regression based on momentary temperatures and (ii) with the temperature sum accumulation method. Temperature sum was calculated with combinations of various time steps, starting dates and threshold temperature values. Needle elongation began almost concurrently with shoot elongation and proceeded linearly in relation to shoot growth until bud break. When studying the threshold temperature for growth, the method with momentary temperature effect on growth onset yielded ambiguous results in our conditions. The best fit of an exponential regression between needle growth or length and temperature sum was obtained with threshold temperatures -1 to +2 °C, with several combinations of starting date and time step. We conclude that although growth onset is a momentary event the process leading to it is a long-term continuum where past time temperatures have to be accounted for, rather than a sudden switch from quiescence to active growth. Further, our results indicate that lower temperatures than the commonly used +5 °C are sufficient for actuating the growth process. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Dynamic control of osmolality and ionic composition of the xylem sap in two mangrove species.

PubMed

López-Portillo, Jorge; Ewers, Frank W; Méndez-Alonzo, Rodrigo; Paredes López, Claudia L; Angeles, Guillermo; Alarcón Jiménez, Ana Luisa; Lara-Domínguez, Ana Laura; Torres Barrera, María Del Carmen

2014-06-01

• Premise of the study: Xylem sap osmolality and salinity is a critical unresolved issue in plant function with impacts on transport efficiency, pressure gradients, and living cell turgor pressure, especially for halophytes such as mangrove trees.• Methods: We collected successive xylem vessel sap samples from stems and shoots of Avicennia germinans and Laguncularia racemosa using vacuum and pressure extraction and measured their osmolality. Following a series of extractions with the pressure chamber, we depressurized the shoot and pressurized again after various equilibration periods (minutes to hours) to test for dynamic control of osmolality. Transpiration and final sap osmolality were measured in shoots perfused with deionized water or different seawater dilutions.• Key results: For both species, the sap osmolality values of consecutive samples collected by vacuum extraction were stable and matched those of the initial samples extracted with the pressure chamber. Further extraction of samples with the pressure chamber decreased sap osmolality, suggesting reverse osmosis occurred. However, sap osmolalities increased when longer equilibration periods after sap extraction were allowed. Analysis of expressed sap with HPLC indicated a 1:1 relation between measured osmolality and the osmolality of the inorganic ions in the sap (mainly Na + , K + , and Cl - ), suggesting no contamination by organic compounds. In stems perfused with deionized water, the sap osmolality increased to mimic the native sap osmolality.• Conclusions: Xylem sap osmolality and ionic contents are dynamically adjusted by mangroves and may help modulate turgor pressure, hydraulic conductivity, and water potential, thus being important for mangrove physiology, survival, and distribution. © 2014 Botanical Society of America, Inc.

Analysis of Differentially Expressed Genes Associated with Coronatine-Induced Laticifer Differentiation in the Rubber Tree by Subtractive Hybridization Suppression

PubMed Central

Zhang, Shi-Xin; Wu, Shao-Hua; Chen, Yue-Yi; Tian, Wei-Min

2015-01-01

The secondary laticifer in the secondary phloem is differentiated from the vascular cambia of the rubber tree (Hevea brasiliensis Muell. Arg.). The number of secondary laticifers is closely related to the rubber yield potential of Hevea. Pharmacological data show that jasmonic acid and its precursor linolenic acid are effective in inducing secondary laticifer differentiation in epicormic shoots of the rubber tree. In the present study, an experimental system of coronatine-induced laticifer differentiation was developed to perform SSH identification of genes with differential expression. A total of 528 positive clones were obtained by blue-white screening, of which 248 clones came from the forward SSH library while 280 clones came from the reverse SSH library. Approximately 215 of the 248 clones and 171 of the 280 clones contained cDNA inserts by colony PCR screening. A total of 286 of the 386 ESTs were detected to be differentially expressed by reverse northern blot and sequenced. Approximately 147 unigenes with an average length of 497 bp from the forward and 109 unigenes with an average length of 514 bp from the reverse SSH libraries were assembled and annotated. The unigenes were associated with the stress/defense response, plant hormone signal transduction and structure development. It is suggested that Ca2+ signal transduction and redox seem to be involved in differentiation, while PGA and EIF are associated with the division of cambium initials for COR-induced secondary laticifer differentiation in the rubber tree. PMID:26147807

Proximate analysis, in vitro organic matter digestibility, and energy content of common guava (Psidium guajava L.) and yellow, strawberry guava (Psidium cattleianum Var. lucidum) tree parts and fruits as potential forage.

PubMed

Adrian, Julie Ann Luiz; Arancon, Norman Q; Mathews, Bruce W; Carpenter, James R

2012-10-24

The nutrient composition of common guava, Psidium guajava L., and strawberry guava (waiwi), Psidium cattleianum var. lucidum, tree parts and fruits was determined during three seasons for six locations in Hawaii to assess guava as a potential feed for cattle. All guava plant parts were higher (p < 0.001) in crude protein than waiwi, but there were no differences in the fiber and energy densities for bark, shoots, and branches. Guava leaves were higher in fiber and had lower energy densities (p < 0.05) than waiwi. Ripe and breaker stage fruits were lower (p < 0.05) in fiber, similar in protein (CP), and higher (p < 0.05) in energy density than immature fruits. Guava fruits were higher in CP (p < 0.05) and organic matter (p < 0.001) and lower in ash (p < 0.001) than waiwi fruits. The primary nutritional concern with guava is low in vitro organic matter digestibility as compared to tropical forage grasses; therefore, it is not recommended as a feedstock for livestock.

An Analysis of US School Shooting Data (1840-2015)

ERIC Educational Resources Information Center

Paradice, David

2017-01-01

This paper describes the construction and descriptive analysis of a data set of United States school shooting events. Three hundred forty-three shooting events are included, spanning 175 years of United States educational history. All levels of US educational institution are included. Events are included when a firearm is discharged, regardless of…

Modeling of SAR returns from a red pine stand

NASA Technical Reports Server (NTRS)

Lang, R. H.; Kilic, O.; Chauhan, N. S.; Ranson, J.

1992-01-01

Bright P-band radar returns from red pine forests have been observed on synthetic aperture radar (SAR) images in Bangor, Maine. A plot of red pine trees was selected for the characterization and modeling to understand the cause of the high P-band returns. The red pine stand under study consisted of mature trees. Diameter at breast height (DBH) measurements were made to determine stand density as a function of tree diameter. Soil moisture and bulk density measurements were taken along with ground rough surface profiles. Detailed biomass measurements of the needles, shoots, branches, and trunks were also taken. These site statistics have been used in a distorted Born approximation model of the forest. Computations indicate that the direct-reflected or the double-bounce contributions from the ground are responsible for the high observed P-band returns for HH polarization.

Growing trees on completed sanitary landfills. [Nyssa sylvatica, Picea abies, Ginkgo biloba

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

Leone, I.A.; Gilman, E.F.; Flower, F.B.

1983-01-01

A 10-year old completed landfill in New Jersey consisting of 9 m (depth) of refuse covered with 15-25 cm of soil was cleared of debris and vegetation and covered with 30 cm of subsoil and 15-25 cm of topsoil. Nineteen coniferous and broadleaved species were planted on the landfill and on a control site in 1975, and trees were maintained and growth and condition monitored over 4 years. On the basis of shoot length and stem area increase, the most successful of the surviving trees were Nyssa sylvatica, Picea abies and Ginkgo biloba, in decreasing order of tolerance. Tolerance ofmore » landfill conditions appeared to be greatest in those species with low water requirements, a slow growth rate, high acid tolerance and a shallow root system. (Refs. 11).« less

Effect of Thawing Time, Cooling Rate and Boron Nutrition on Freezing Point of the Primordial Shoot in Norway Spruce Buds

PubMed Central

RÄISÄNEN, MIKKO; REPO, TAPANI; LEHTO, TARJA

2006-01-01

• Background Effects of cooling rates on bud frost hardiness have been studied but there is little information on bud responses to thawing. Since the cell wall pore size has been found to increase with boron (B) deficiency, B deficiency may affect the supercooling ability of buds in winter. • Methods The effects of duration of thawing time and rate of cooling on bud frost hardiness of Norway spruce (Picea abies) were studied in a B fertilization trial in February 2003 and March 2005. Frost hardiness of apical buds was determined by differential thermal analysis (DTA) and visual scoring of damage. • Key Results In 2003, the freezing point of primordial shoots of buds (Tf), i.e. the low-temperature exotherm (LTE), was, on average, −39 °C when buds were thawed for less than 3 h and the Tf increased to −21 °C after 18 h of thawing. During the first 4 h of thawing, the rate of dehardening was 6 °C h−1. In 2005, buds dehardened linearly from −39 °C to −35 °C at a rate of 0·7 °C h−1. In 2003, different cooling rates of 1–5 °C h−1 had a minor effect on Tf but in 2005 with slow cooling rates Tf decreased. In both samplings, at cooling rates of 2 and 1 °C h−1, Tf was slightly higher in B-fertilized than in non-fertilized trees. By contrast, at very short thawing times in 2003, Tf was somewhat lower in B-fertilized trees. • Conclusions There was little evidence of reduced frost hardiness in trees with low B status. This study showed that buds deharden rapidly when exposed to above-freezing temperatures in winter, but if cooled again they reharden more slowly. According to this study, rapid dehardening of buds has to be taken into account in assessments of frost hardiness. PMID:16464880

Effect of Soil Water Potential on Growth of Apple Trees Infected with Pratylenchus penetrans

PubMed Central

Jaffee, B. A.; Mai, W. F.

1979-01-01

Malling-Merton 106 apple rootstocks inoculated with Pratylenchus penetrans, or uninoculated, were grown in a growth chamber in pots of loamy sand maintained at two moisture levels, 0 to -0.4 bar or 0 to -10 bars. Either inoculation or low soil moisture suppressed shoot growth and increased root necrosis. However, the nematode-soil moisture interaction was not significant. PMID:19305552

Exotic Forest Insect Pests and Their Impact on Forest Management

Treesearch

Therese M. Poland; Robert A. Haack

2003-01-01

More than 4500 exotic organisms are now established in the United States, of which over 400 are insects that feed on trees and shrubs. While most exotic insects cause little or no damage, a few have become serious pests and have greatly altered native forest ecosystems. Three of the most recently introduced exotic forest pests are the pine shoot beetle, the Asian...

Effect of girdling at various positions of 'Huang Zhi Xiang' tea tree (Camellia sinensis) on the contents of catechins and starch in fresh leaf.

PubMed

Chen, Yulong; Jiang, Yueming; Shi, John; Xu, Xinlan; Yang, Shaoyu; Duan, Jun

2011-06-01

The contents of starch and catechins in the fresh leaf of 'Huang Zhi Xiang' Oolong tea trees girdled at the bottom, middle (on the big branches) and top (on the small branches) were determined. The study demonstrated that the starch contents from girdled trees were significantly higher (p<0.05) than that from non-girdled ones. Furthermore, the contents of (-)-epicatechin (EC), (-)-epigallocatechin (EGC), total catechins (TC) and simple catechins (SC) from girdled trees were significantly higher (p<0.05) than those from non-girdled ones. Especially, the contents of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and catechin gallate (CG) from girdled at the middle were also significantly higher (p<0.05) than those from the non-girdled. The starch contents were negatively correlated with the contents of (-)-gallocatechin (GC), EC, SC, TC and EGC, while positively correlated with the contents of EGCG and CG in fresh shoots.

Tree seedlings respond to both light and soil nutrients in a Patagonian evergreen-deciduous forest.

PubMed

Promis, Alvaro; Allen, Robert B

2017-01-01

Seedlings of co-occurring species vary in their response to resource availability and this has implications for the conservation and management of forests. Differential shade-tolerance is thought to influence seedling performance in mixed Nothofagus betuloides-Nothofagus pumilio forests of Patagonia. However, these species also vary in their soil nutrient requirements. To determine the effects of light and soil nutrient resources on small seedlings we examined responses to an experimental reduction in canopy tree root competition through root trenching and restricting soil nutrient depletion through the addition of fertilizer. To understand the effect of light these treatments were undertaken in small canopy gaps and nearby beneath undisturbed canopy with lower light levels. Seedling diameter growth was greater for N. pumilio and height growth was greater for N. betuloides. Overall, diameter and height growth were greater in canopy gaps than beneath undisturbed canopy. Such growths were also greater with fertilizer and root trenching treatments, even beneath undisturbed canopy. Seedling survival was lower under such treatments, potentially reflecting thinning facilitated by resource induced growth. Finally, above-ground biomass did not vary among species although the less shade tolerant N. pumilio had higher below-ground biomass and root to shoot biomass ratio than the more shade tolerant N. betuloides. Above- and below-ground biomass were higher in canopy gaps so that the root to shoot biomass ratio was similar to that beneath undisturbed canopy. Above-ground biomass was also higher with fertilizer and root trenching treatments and that lowered the root to shoot biomass ratio. Restricting soil nutrient depletion allowed seedlings of both species to focus their responses above-ground. Our results support a view that soil nutrient resources, as well as the more commonly studied light resources, are important to seedlings of Nothofagus species occurring on infertile soils.

Fruit Self-Thinning: A Trait to Consider for Genetic Improvement of Apple Tree

PubMed Central

Celton, Jean-Marc; Kelner, Jean-Jacques; Martinez, Sébastien; Bechti, Abdel; Khelifi Touhami, Amina; James, Marie José; Durel, Charles-Eric; Laurens, François; Costes, Evelyne

2014-01-01

In apple (Malus×domestica Borkh), as in many fruiting crops, fruit maintenance vs abscission is a major criteria for production profitability. Growers routinely make use of chemical thinning agents to control total fruit load. However, serious threats for the environment lead to the demand for new apple cultivars with self-thinning properties. In this project, we studied the genetic determinism of this trait using a F1 progeny derived from the cross between the hybrid INRA X3263, assumed to possess the self-thinning trait, and the cultivar ‘Belrène’. Both counting and percentage variables were considered to capture the fruiting behaviour on different shoot types and over three consecutive years. Besides low to moderate but significant genetic effects, mixed models showed considerable effects of the year and the shoot type, as well as an interaction effect. Year effect resulted mainly from biennial fruiting. Eight Quantitative Trait Locus (QTL) were detected on several linkage groups (LG), either independent or specific of the year of observation or the shoot type. The QTL with highest LOD value was located on the top third of LG10. The screening of three QTL zones for candidate genes revealed a list of transcription factors and genes involved in fruit nutrition, xylem differentiation, plant responses to starvation and organ abscission that open new avenues for further molecular investigations. The detailed phenotyping performed revealed the dependency between the self-thinning trait and the fruiting status of the trees. Despite a moderate genetic control of the self-thinning trait, QTL and candidate genes were identified which will need further analyses involving other progenies and molecular investigations. PMID:24625529

Variation in drought resistance, drought acclimation and water conservation in four willow cultivars used for biomass production.

PubMed

Wikberg, Jenny; Ogren, Erling

2007-09-01

Growth and water-use parameters of four willow (Salix spp.) clones grown in a moderate drought regime or with ample water supply were determined to characterize their water-use efficiency, drought resistance and capacity for drought acclimation. At the end of the 10-week, outdoor pot experiment, clonal differences were observed in: (1) water-use efficiency of aboveground biomass production (WUE); (2) resistance to xylem cavitation; and (3) stomatal conductance to leaf-specific, whole-plant hydraulic conductance ratio (g(st)/K(P); an indicator of water balance). Across clones and regimes, WUE was positively correlated with the assimilation rate to stomatal conductance ratio (A/g(st)), a measure of instantaneous water-use efficiency. Both of these water-use efficiency indicators were generally higher in drought-treated trees compared with well-watered trees. However, the between-treatment differences in (shoot-based) WUE were smaller than expected, considering the differences in A/g(st) for two of the clones, possibly because plants reallocated dry mass from shoots to roots when subject to drought. Higher root hydraulic conductance to shoot hydraulic conductance ratios (K(R)/K(S)) during drought supports this hypothesis. The same clones were also the most sensitive to xylem cavitation and, accordingly, showed the strongest reduction in g(st)/K(P) in response to drought. Drought acclimation was manifested in decreased g(st), g(st)/K(P), osmotic potential and leaf area to vessel internal cross-sectional area ratio, and increased K(R), K(P) and WUE. Increased resistance to stem xylem cavitation in response to drought was observed in only one clone. It is concluded that WUE and drought resistance traits are inter-linked and that both may be enhanced by selection and breeding.

Underground riparian wood: Reconstructing the processes influencing buried stem and coarse root structures of Black Poplar (Populus nigra L.)

NASA Astrophysics Data System (ADS)

Holloway, James V.; Rillig, Matthias C.; Gurnell, Angela M.

2017-02-01

Following analysis of morphological (including dendrochronological and sedimentological) aspects of buried stem and coarse root structures of eight mature P. nigra individuals located within two sites along the middle to lower Tagliamento River, Italy (Holloway et al., 2017), this paper introduces information on the historical processes of vegetation development and river flow and links this to the form of these eight trees. Aerial images and flow time series are assembled to reconstruct the flood history, potential recruitment periods, and vegetation cover development in the vicinity of the studied trees. This information is combined with previous morphological evidence to reconstruct the development history of each tree via three-element summary diagrams showing (i) a time series of floods, aerial imagery dates, and potential recruitment periods, with colour-coded bars indicating likely key stages in the development of the tree; (ii) colour-coded overlays on an SfM photogrammetric model of each tree; and (iii) colour-coded text boxes providing explanatory annotations. The combined morphology-process analysis reveals complex three-dimensional underground structures, incorporating buried stems, shoots, and adventitious roots that are sometimes joined by grafting, linking the standing tree with the buried gravel surface on which it was recruited. Analysis of process data provides a firm basis for identifying and dating influential flow disturbance events and recruitment windows and shows that a relatively small number of flood events have significantly impacted the studied trees, which are mainly but not exclusively the largest floods in the record. Nevertheless, we stress that all suggested dates are best estimates in the light of the combined evidence. There is undoubted potential for building different interpretations of belowground woody structure development in light of such evidence, but we feel that the form and timing of the developmental trajectories we have proposed are reasonable and give balanced insights into the many possible ways in which this hidden component of riparian trees may develop. Our results are relevant to river research and management issues concerning riparian woodland, fluvial wood dynamics, and wood budgets, as they indicate (i) a large hidden volume of wood that is often ignored; (ii) complex, deep, coarse anchorage structures that have relevance for rates of fluvial wood recruitment associated with lateral bank erosion/stability or wind throw; and (iii) a wood element that may significantly affect wood transport and retention within fluvial systems.

Below and above-ground carbon distribution along a rainfall gradient. A case of the Zambezi teak forests, Zambia

NASA Astrophysics Data System (ADS)

Ngoma, Justine; Moors, Eddy; Kruijt, Bart; Speer, James H.; Vinya, Royd; Chidumayo, Emmanuel N.; Leemans, Rik

2018-02-01

Understanding carbon (C) stocks or biomass in forests is important to examine how forests mitigate climate change. To estimate biomass in stems, branches and roots takes intensive fieldwork to uproot, cut and weigh the mass of each component. Different models or equations are also required. Our research focussed on the dry tropical Zambezi teak forests and we studied their structure at three sites following a rainfall gradient in Zambia. We sampled 3558 trees at 42 plots covering a combined area of 15ha. Using data from destructive tree samples, we developed mixed-species biomass models to estimate above ground biomass for small (<5 cm diameter at breast height (DBH, 1.3 m above-ground)) and large (≥5 cm DBH) trees involving 90 and 104 trees respectively, that belonged to 12 species. A below-ground biomass model was developed from seven trees of three species (16-44 cm DBH) whose complete root systems were excavated. Three stump models were also derived from these uprooted trees. Finally, we determined the C fractions from 194 trees that belonged to 12 species. The analysis revealed that DBH was the only predictor that significantly correlated to both above-ground and below-ground biomass. We found a mean root-to-shoot ratio of 0.38:0.62. The C fraction in leaves ranged from 39% to 42%, while it varied between 41% and 46% in wood. The C fraction was highest at the Kabompo site that received the highest rainfall, and lowest at the intermediate Namwala site. The C stocks varied between 15 and 36 ton C ha-1 and these stocks where highest at the wetter Kabompo site and lowest at the drier Sesheke site. Our results indicate that the projected future rainfall decrease for southern Africa, will likely reduce the C storage potential of the Zambezi teak forests, thereby adversely affecting their mitigating role in climate change.

Patterns of auxin distribution during gravitational induction of reaction wood in poplar and pine.

PubMed

Hellgren, Jenny M; Olofsson, Kjell; Sundberg, Björn

2004-05-01

Gravistimulation of tree stems affects wood development by unilaterally inducing wood with modified properties, called reaction wood. Commonly, it also stimulates cambial growth on the reaction wood side. Numerous experiments involving applications of indole-3-acetic acid (IAA) or IAA-transport inhibitors have suggested that reaction wood is induced by a redistribution of IAA around the stem. However, in planta proof for this model is lacking. Therefore, we have mapped endogenous IAA distribution across the cambial region tissues in both aspen (Populus tremula, denoted poplar) and Scots pine (Pinus sylvestris) trees forming reaction wood, using tangential cryosectioning combined with sensitive gas chromatography-mass spectrometry analysis. Moreover, we have documented the kinetics of IAA during reaction wood induction in these species. Our analysis of endogenous IAA demonstrates that reaction wood is formed without any obvious alterations in IAA balance. This is in contrast to gravitropic responses in roots and shoots where a redistribution of IAA has been documented. It is also of interest that cambial growth on the tension wood side was stimulated without an increase in IAA. Taken together, our results suggest a role for signals other than IAA in the reaction wood response, or that the gravitational stimulus interacts with the IAA signal transduction pathway.

Response of different-aged black cherry trees to ambient ozone exposure

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

Fredericksen, T.S.; Joyce, B.J.; Kouterick, K.B.

1994-06-01

Black cherry (Prunus serotina Ehrh.) is a valuable commercial timber species which is also highly sensitive to ozone relative to other eastern deciduous tree species. Studies of ozone effects on forest trees have been restricted mostly to experiments using small seedlings under controlled conditions. Yet, mature trees may differ from seedlings in physiology, morphology, and exposure to air pollutants. An experiment was conducted in 1993 to determine differences in ozone uptake and foliar injury symptoms between open-ground seedlings, forest saplings, and mature forest trees of black cherry in northcentral Pennsylvania. Seedlings grew under the highest ozone concentrations and also hadmore » greater seasonal ozone uptake due to higher rates of stomatal conductance. However, because of their indeterminate growth habit, seedlings had lower cumulative ozone uptake per leaf lifespan than saplings or mature trees, both of which had determinate shoot growth. Although greater initially for seedlings, foliar injury was nearly identical between size classes by the end of the growing season. Leaves in the lower crown of larger trees had lower ozone uptake than leaves in the upper crown, but exhibited more foliar injury symptoms. Lower crown leaves received more effective exposure to ozone because of their thinner leaves and had less available photosynthate for repair or replacement of damaged tissue.« less

Ethylene induced shikonin biosynthesis in shoot culture of Lithospermum erythrorhizon.

PubMed

Touno, Kaori; Tamaoka, Jin; Ohashi, Yuko; Shimomura, Koichiro

2005-02-01

Lithospermum erythrorhizon shoots, cultured on phytohormone-free Murashige and Skoog solid medium, produced shikonin derivatives, whereas shoots cultured in well-ventilated petri dishes, produced small amount. Analysis by gas chromatography revealed the presence of ethylene in non-ventilated petri dishes where the shoots, producing shikonin derivatives, were cultured. Therefore, the possible involvement of ethylene in shikonin biosynthesis of shoot cultures was investigated. Treatment of ethylene or the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, resulted in increasing shikonin derivatives contents in cultured shoots. Silver ion, an ethylene-response inhibitor, or aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, decreased production of shikonin derivatives in cultured shoots. Our results indicate that ethylene is one of the regulatory elements of shikonin biosynthesis in L. erythrorhizon shoot culture.

Contrasting seasonal overlaps between primary and secondary growth are linked to wood anatomy in Mediterranean sub-shrubs.

PubMed

Camarero, J J; Palacio, S; Montserrat-Martí, G

2013-09-01

Whole-plant approaches allow quantification of the temporal overlap between primary and secondary growth. If the amount of time available to grow is short, there may be a high temporal overlap between shoot growth and wood formation. We hypothesise that such overlap depends on the duration of the growing season and relates to wood anatomy. We evaluated wood anatomy, shoot longitudinal and radial growth rates, fine root production and the concentrations of non-structural carbohydrates (NSC) in the wood of six sub-shrub species growing in sites with contrasting climatic conditions (Lepidium subulatum, Linum suffruticosum, Salvia lavandulifolia, Satureja montana, Ononis fruticosa, Echinospartum horridum). Sub-shrub species living in sites with a short growing season displayed a high overlap between aboveground primary and secondary growth and formed wide vessels, whereas species from the warmest and driest sites presented the reverse characteristics. The highest overlap was linked to a rapid shoot extension and thickening through the enhanced hydraulic conductivity provided by wide vessels. The reductions in NSC concentrations when growth peaked were low or moderate, indicating that sub-shrubs accumulate NSC in excess, as do trees. The temporal overlap among primary and secondary growth in woody plants may be connected to the duration and rates of shoot and wood growth, which in turn depend on the vessel lumen area. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Anthocyanins in different Citrus species: an UHPLC-PDA-ESI/MSn -assisted qualitative and quantitative investigation.

PubMed

Fabroni, Simona; Ballistreri, Gabriele; Amenta, Margherita; Rapisarda, Paolo

2016-11-01

Anthocyanins are water-soluble pigments belonging to the flavonoid family. They are typically present in the flesh and peel in the blood orange cultivars. Although blood orange young shoots and flowers are not anthocyanin-colored, lemon, citron, rangpur lime, and Meyer lemon young shoots and flowers exhibit marked pigmentation as a result of anthocyanins, demonstrating that anthocyanin biosynthesis in the Citrus genus is both tissue- and genotype-dependent. The present study aimed to examine the qualitative and quantitative anthocyanin profile of fruit and other tissues from different Citrus species. The presence of anthocyanin-pigmented stigmas in the young flowers of a blood orange tree (cv. 'Moro') was characterized and reported for the first time. The dominant pigments in blood orange fruits were cyanidin 3-glucoside and cyanidin 3-(6''-malonyl-glucoside), whereas different patterns were observed in the young shoots, flowers and peel tissues of different Citrus species. The present study is the first to report differentially expressed anthocyanin pigmentation patterns in different organs from several species of the genus Citrus. The results obtained could also represent a starting point for further investigations that aim to better understand which regulatory genes are involved in anthocyanin biosynthesis in the fruits, shoots and floral tissues of different Citrus species. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Morphological and phenological shoot plasticity in a Mediterranean evergreen oak facing long-term increased drought.

PubMed

Limousin, Jean-Marc; Rambal, Serge; Ourcival, Jean-Marc; Rodríguez-Calcerrada, Jesus; Pérez-Ramos, Ignacio M; Rodríguez-Cortina, Raquel; Misson, Laurent; Joffre, Richard

2012-06-01

Mediterranean trees must adjust their canopy leaf area to the unpredictable timing and severity of summer drought. The impact of increased drought on the canopy dynamics of the evergreen Quercus ilex was studied by measuring shoot growth, leaf production, litterfall, leafing phenology and leaf demography in a mature forest stand submitted to partial throughfall exclusion for 7 years. The leaf area index rapidly declined in the throughfall-exclusion plot and was 19% lower than in the control plot after 7 years of treatment. Consequently, leaf litterfall was significantly lower in the dry treatment. Such a decline in leaf area occurred through a change in branch allometry with a decreased number of ramifications produced and a reduction of the leaf area supported per unit sapwood area of the shoot (LA/SA). The leafing phenology was slightly delayed and the median leaf life span was slightly longer in the dry treatment. The canopy dynamics in both treatments were driven by water availability with a 1-year lag: leaf shedding and production were reduced following dry years; in contrast, leaf turnover was increased following wet years. The drought-induced decrease in leaf area, resulting from both plasticity in shoot development and slower leaf turnover, appeared to be a hydraulic adjustment to limit canopy transpiration and maintain leaf-specific hydraulic conductivity under drier conditions.

Cold temperature tolerance of apple rootstock trunk and root tissues

USDA-ARS?s Scientific Manuscript database

G.11, G.30, G.41, P.2 and B.9 apple (Malus xdomestica) rootstocks have root tissue hardiness similar to M.26, but G.935 has greater hardiness than M.26 when based on shoot regrowth in ungrafted trees. The LT50 of M.26 and P.2 roots ranged from -12 to -14 degrees C. The LT50 of B.9 was -13 degrees ...

Infection of non-host model plant species with the narrow-host-range Cacao swollen shoot virus.

PubMed

Friscina, Arianna; Chiappetta, Laura; Jacquemond, Mireille; Tepfer, Mark

2017-02-01

Cacao swollen shoot virus (CSSV) is a major pathogen of cacao (Theobroma cacao) in Africa, and long-standing efforts to limit its spread by the culling of infected trees have had very limited success. CSSV is a particularly difficult virus to study, as it has a very narrow host range, limited to several tropical tree species. Furthermore, the virus is not mechanically transmissible, and its insect vector can only be used with difficulty. Thus, the only efficient means to infect cacao plants that have been experimentally described so far are by particle bombardment or the agroinoculation of cacao plants with an infectious clone. We have genetically transformed three non-host species with an infectious form of the CSSV genome: two experimental hosts widely used in plant virology (Nicotiana tabacum and N. benthamiana) and the model species Arabidopsis thaliana. In transformed plants of all three species, the CSSV genome was able to replicate, and, in tobacco, CSSV particles could be observed by immunosorbent electron microscopy, demonstrating that the complete virus cycle could be completed in a non-host plant. These results will greatly facilitate the preliminary testing of CSSV control strategies using plants that are easy to raise and to transform genetically. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Origin and expansion of the Yunnan Shoot Borer, Tomicus yunnanensis (coleoptera: scolytinae): a mixture of historical natural expansion and contemporary human-mediated relocation.

PubMed

Lü, Jun; Hu, Shao-ji; Ma, Xue-yu; Chen, Jin-min; Li, Qing-qing; Ye, Hui

2014-01-01

The Yunnan shoot borer, Tomicus yunnanensis, is a recently-discovered, aggressive pest of the Yunnan pine stands in southwestern China. Despite many bionomics studies and massive controlling efforts, research on its population genetics is extremely limited. The present study, aimed at investigating the origin and dispersal of this important forestry pest, analyzed the population genetic structure and demographic history using a mitochondrial cox1 gene fragment. Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago. Host separation and specialization might have caused the speciation of T. yunnanensis. Genetic structure analyses identified two population groups, with six populations near the origin area forming one group and the remaining six populations from western and eastern Yunnan and southwestern Sichuan comprising the other. Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one. Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan. Our findings implied that T. yunnanensis underwent both historical expansion and recent dispersal. The historical expansion may relate to the oscillation of regional climate due to glacial and interglacial periods in the Pleistocene, while human-mediated transportation of pine-wood material might have assisted the relocation and establishment of this pest in novel habitats.

A novel substance with allelopathic activity in Ginkgo biloba.

PubMed

Kato-Noguchi, Hisashi; Takeshita, Sayaka; Kimura, Fukiko; Ohno, Osamu; Suenaga, Kiyotake

2013-12-15

Ginkgo (Ginkgo biloba) is one of the oldest living tree species and has been widely used in traditional medicine. Leaf extracts of ginkgo, such as the standardized extract EGb761, have become one of the best-selling herbal products. However, no bioactive compound directed at plants has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for allelopathically active substances in ginkgo leaves. An aqueous methanol leaf extract inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and an allelopathically active substance was isolated and identified by spectral analysis to be the novel compound 2-hydroxy-6-(10-hydroxypentadec-11-enyl)benzoic acid. The compound inhibited root and shoot growth of garden cress and timothy at concentrations greater than 3 μM. The activity of the compound was 10- to 52-fold that of nonanoic acid. These results suggest that 2-hydroxy-6-(10-hydroxypentadec-11-enyl)benzoic acid may contribute to the allelopathic effect caused by ginkgo leaf extract. The compound may also have potential as a template for the development of new plant control substances. Copyright © 2013 Elsevier GmbH. All rights reserved.

Phloem Girdling of Norway Spruce Alters Quantity and Quality of Wood Formation in Roots Particularly Under Drought

PubMed Central

Rainer-Lethaus, Gina; Oberhuber, Walter

2018-01-01

Carbon (C) availability plays an essential role in tree growth and wood formation. We evaluated the hypothesis that a decrease in C availability (i) triggers mobilization of C reserves in the coarse roots of Picea abies to maintain growth and (ii) causes modification of wood structure notably under drought. The 6-year-old saplings were subjected to two levels of soil moisture (watered versus drought conditions) and root C status was manipulated by physically blocking phloem transport in the stem at three girdling dates (GDs). Stem girdling was done before the onset of bud break [day of the year (doy) 77], during vigorous aboveground shoot and radial stem growth (GD doy 138), and after cessation of shoot growth (GD doy 190). The effect of blockage of C transport on root growth, root phenology, and wood anatomical traits [cell lumen diameter (CLD) and cell wall thickness (CWT)] in earlywood (EW) and latewood (LW) was determined. To evaluate changes in belowground C status caused by girdling, non-structural carbohydrates (soluble sugars and starch) in coarse roots were determined at the time of girdling and after the growing season. Although fine root mass significantly decreased in response to blockage of phloem C transport, the phenology of root elongation growth was not affected. Surprisingly, radial root growth and CLD of EW tracheids in coarse roots were strikingly increased in drought-stressed trees, when girdling occurred before bud break or during aboveground stem growth. In watered trees, the growth response to girdling was less distinct, but the CWT of EW significantly increased. Starch reserves in the roots of girdled trees significantly decreased in both soil moisture treatments and at all GDs. We conclude that (i) radial growth and wood development in coarse roots of P. abies saplings are not only dependent on current photosynthates, and (ii) blockage of phloem transport induces physiological changes that outweigh drought effects imposed on root cambial activity and cell differentiation. PMID:29636766

The response of mulberry trees after seedling hardening to summer drought in the hydro-fluctuation belt of Three Gorges Reservoir Areas.

PubMed

Huang, Xiaohui; Liu, Yun; Li, Jiaxing; Xiong, Xingzheng; Chen, Yang; Yin, Xiaohua; Feng, Dalan

2013-10-01

Interest has developed in the potential of mulberry (Morus alba), a woody perennial, for revegetating the hydro-fluctuation belt of the Three Gorges Reservoir due to its resistance to water-logging stress. To be useful, the trees must also be able to withstand dry conditions in summer when temperatures can be very high and droughts become severe quickly. Here, we report a study in which mulberry seedlings were grown in a greenhouse under a variety of simulated soil water conditions reflecting potential summer scenarios in the hydro-fluctuation belt of the Three Gorges Reservoir Area. We compared the responses of two pretreatment groups of mulberry seedlings to different levels of drought stress. The pretreatment groups differed with respect to drought hardening: the daily-managed (DM) group had relative soil moisture held constant in the range 70-80 %, while the drought-hardened (DH) group had relative soil moisture held constant at 40-50 %. Following the month-long pretreatment of seedlings, the two groups of young trees (DM and DH) were then respectively subjected to three levels of drought stress for a month: normal watering, moderate drought stress, and severe drought stress. A series of measurements comparing the physiological status of the plants in the two groups were then made, and the following results were obtained: (1) As drought stress increased, the heights, base diameters, root surface areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the mulberry trees in both groups (DM and DH) decreased significantly, while the specific root area and abscisic acid (ABA) contents had increasing trends. Root activity and instantaneous water use efficiency of mulberry trees in both groups (DM and DH) were all raised under drought stress conditions than under normal watering, but the root/shoot ratio and leaf water potential were lowered. (2) At the same level of soil water content, the heights, base diameters, root/shoot ratios, root surface areas, specific root areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the young mulberry trees in the DH were all significantly higher than those of the control group (DM). Leaf water potential, instantaneous water use efficiency, and abscisic acid content of DH were all significantly lower than DM. Under different degrees of drought stress, the growth of mulberry trees will be inhibited, but the trees can respond to the stress by increasing the root absorptive area and enhancing capacity for water retention. Mulberry trees demonstrate strong resistance to drought stress, and furthermore drought resistance can be improved by drought hardening during the seedling stage.

Form-function analysis of the effect of canopy morphology on leaf self-shading in the seagrass Thalassia testudinum.

PubMed

Enríquez, Susana; Pantoja-Reyes, Norma I

2005-09-01

The variation in seagrass morphology and the magnitude of leaf self-shading within the canopy of Thalassia testudinum, were compared among nine sites in a fringing reef lagoon. We found a significant variation in the growth-form of T. testudinum reflected in a 5.4-fold variation in the attenuation coefficient (K (d)) within the canopy. The largest morphological variation was observed in shoot density. Leaf biomass, leaf area index (LAI), and shoot density were positively associated with canopy-K (d) and with the percentage of surface irradiance received by the top of the seagrass canopy (% Es). These results provide an explanation for the consistent pattern of depth reduction in seagrass leaf biomass and shoot density reported in the literature. Shoot density and shoot size are two descriptors of the growth-form of T. testudinum related to its clonal life-form. Shoot size was not significantly correlated with canopy-K (d), nevertheless, it showed a significant effect on the slope of the relationship between shoot density and canopy-K (d). According to this model, shoot size also contributes to light attenuation within the seagrass canopy by increasing the effect of shoot density. This form-function analysis suggests that light may have a relevant role in the regulation of the optimal plant balance between horizontal (variation in shoot density) and vertical (variation in shoot size) growth of seagrasses. Other environmental factors and interactions also need to be examined to fully understand the mechanistic bases of the morphological responses of seagrasses to the environment.

Shooting Mechanisms in Nature: A Systematic Review.

PubMed

Sakes, Aimée; van der Wiel, Marleen; Henselmans, Paul W J; van Leeuwen, Johan L; Dodou, Dimitra; Breedveld, Paul

2016-01-01

In nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these mechanisms fulfill. We systematically searched the literature using Scopus and Web of Knowledge to retrieve articles about solid projectiles that either are produced in the body of the organism or belong to the body and undergo a ballistic phase. The shooting mechanisms were categorized based on the energy management prior to and during shooting. Shooting mechanisms were identified with projectile masses ranging from 1·10-9 mg in spores of the fungal phyla Ascomycota and Zygomycota to approximately 10,300 mg for the ballistic tongue of the toad Bufo alvarius. The energy for shooting is generated through osmosis in fungi, plants, and animals or muscle contraction in animals. Osmosis can be induced by water condensation on the system (in fungi), or water absorption in the system (reaching critical pressures up to 15.4 atmospheres; observed in fungi, plants, and animals), or water evaporation from the system (reaching up to -197 atmospheres; observed in plants and fungi). The generated energy is stored as elastic (potential) energy in cell walls in fungi and plants and in elastic structures in animals, with two exceptions: (1) in the momentum catapult of Basidiomycota the energy is stored in a stalk (hilum) by compression of the spore and droplets and (2) in Sphagnum energy is mainly stored in compressed air. Finally, the stored energy is transformed into kinetic energy of the projectile using a catapult mechanism delivering up to 4,137 J/kg in the osmotic shooting mechanism in cnidarians and 1,269 J/kg in the muscle-powered appendage strike of the mantis shrimp Odontodactylus scyllarus. The launch accelerations range from 6.6g in the frog Rana pipiens to 5,413,000g in cnidarians, the launch velocities from 0.1 m/s in the fungal phylum Basidiomycota to 237 m/s in the mulberry Morus alba, and the launch distances from a few thousands of a millimeter in Basidiomycota to 60 m in the rainforest tree Tetraberlinia moreliana. The mass-specific power outputs range from 0.28 W/kg in the water evaporation mechanism in Basidiomycota to 1.97·109 W/kg in cnidarians using water absorption as energy source. The magnitude of accelerations involved in shooting is generally scale-dependent with the smaller the systems, discharging the microscale projectiles, generating the highest accelerations. The mass-specific power output is also scale dependent, with smaller mechanisms being able to release the energy for shooting faster than larger mechanisms, whereas the mass-specific work delivered by the shooting mechanism is mostly independent of the scale of the shooting mechanism. Higher mass-specific work-values are observed in osmosis-powered shooting mechanisms (≤ 4,137 J/kg) when compared to muscle-powered mechanisms (≤ 1,269 J/kg). The achieved launch parameters acceleration, velocity, and distance, as well as the associated delivered power output and work, thus depend on the working principle and scale of the shooting mechanism.

Relationships between tree size, crown shape, gender segregation and sex allocation in Pinus halepensis, a Mediterranean pine tree.

PubMed

Ne'eman, Gidi; Goubitz, Shirrinka; Werger, Marinus J A; Shmida, Avi

2011-07-01

Sex allocation has been studied mainly in small herbaceous plants but much less in monoecious wind-pollinated trees. The aim of this study was to explore changes in gender segregation and sex allocation by Pinus halepensis, a Mediterranean lowland pine tree, within tree crowns and between trees differing in their size or crown shape. The production of new male and female cones and sex allocation of biomass, nitrogen and phosphorus were studied. The relationship between branch location, its reproductive status and proxies of branch vigour was also studied. Small trees produced only female cones, but, as trees grew, they produced both male and female cones. Female cones were produced mainly in the upper part of the crown, and male cones in its middle and lower parts. Lateral branch density was correlated with the number of male but not female cones; lateral branches were more dense in large than in small trees and even denser in hemispherical trees. Apical branches grew faster, were thicker and their phosphorus concentration was higher than in lateral shoots. Nitrogen concentration was higher in cone-bearing apical branches than in apical vegetative branches and in lateral branches with or without cones. Allocation to male relative to female function increased with tree size as predicted by sex allocation theory. The adaptive values of sex allocation and gender segregation patterns in P. halepensis, in relation to its unique life history, are demonstrated and discussed. Small trees produce only female cones that have a higher probability of being pollinated than the probability of male cones pollinating; the female-first strategy enhances population spread. Hemispherical old trees are loaded with serotinous cones that supply enough seeds for post-fire germination; thus, allocation to males is more beneficial than to females.

Bacterial rhizosphere and endosphere populations associated with grasses and trees to be used for phytoremediation of crude oil contaminated soil.

PubMed

Fatima, Kaneez; Afzal, Muhammad; Imran, Asma; Khan, Qaiser M

2015-03-01

Different grasses and trees were tested for their growth in a crude oil contaminated soil. Three grasses, Lolium perenne, Leptochloa fusca, Brachiaria mutica, and two trees, Lecucaena leucocephala and Acacia ampliceps, were selected to investigate the diversity of hydrocarbon-degrading rhizospheric and endophytic bacteria. We found a higher number of hydrocarbon degrading bacteria associated with grasses than trees and that the endophytic bacteria were taxonomically different from rhizosphere associated bacteria showing their spatial distribution with reference to plant compartment as well as genotype. The rhizospheric soil yielded 22 (59.45 %), root interior yielded 9 (24.32 %) and shoot interior yielded 6 (16.21 %) hydrocarbon-degrading bacteria. These bacteria possessed genes encoding alkane hydroxylase and showed multiple plant growth-promoting activities. Bacillus (48.64 %) and Acinetobacter (18.91 %) were dominant genera found in this study. At 2 % crude oil concentration, all bacterial isolates exhibited 25 %-78 % oil degradation and Acinetobacter sp. strain BRSI56 degraded maximum. Our study suggests that for practical application, support of potential bacteria combined with the grasses is more effective approach than trees to remediate oil contaminated soils.

Epicormic branching in red oak crop trees five years after thinning and fertilizer application in a bottomland hardwood stand

Treesearch

Brian Roy Lockhart; Alexander J. Michalek; Matthew W. Lowe

2006-01-01

Epicormic branches are defined as shoots arising from adventitious or dormant buds on the stem or branch of a woody plant, often following exposure to increased light levels or fire. They are a serious concern to hardwood forest managers because epicormic branches are considered defects and reduce the monetary value of logs and the lumber cut from them. The presence of...

Shoot winter injury and nut cold tolerance: Possible limitations for American chestnut restoration in cold environments? In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech

Treesearch

Thomas M. Saielli; Paul G. Schaberg; Gary J. Hawley; Joshua M. Halman; Kendra M. Gurney

2012-01-01

Approximately 100 years ago, American chestnut (Castanea dentata (Marsh.) Borkh.) was rapidly removed as an overstory tree by the fungal pathogen Cryphonectria parasitica (the causal agent of chestnut blight). Currently, the most effective method of restoration involves the hybridization of American chestnut with the...

Disruptant effects of 4-allylanisole and verbenone on Tomicus piniperda (Coleoptera: Scolitidae) response to baited traps and logs

Treesearch

Robert A. Haack; Robert K. Lawrence; Toby R. Petrice; Therese M. Poland

2004-01-01

We assessed the inhibitory effects of the host compound 4-allylanisole (release rates = 1 and 2 mg/d in 1994, and 1 and 10 mg/d in 2001) on the response of the pine shoot beetle, Tomicus piniperda (L.), adults to funnel traps baited with the attractant host compound α-pinene (release rate = 150 mg/d) in two pine Christmas tree...

Gene expression analysis of aquatic angiosperms podostemaceae to gain insight into the evolution of their enigmatic morphology.

PubMed

Koi, Satoshi; Katayama, Natsu

2013-01-01

Podostemaceae is a family of aquatic angiosperms growing submerged on rocks in fast-flowing water and called moss-like or alga-like riverweeds. It evolved remarkable innovations to adapt to such an extreme environment, one of which is reduced shoots borne on roots adhering to rock surface. Recent observations revealed that the basal subfamily Tristichoideae, like most other angiosperms, has typical shoot apical meristems (SAMs). In species of the subfamily Podostemoideae, however, shoot apical meristems (SAMs) are not formed during development and new leaves arise from the meristematic basal region of preexisting leaves. The genetic basis of this shoot organogenesis process, e.g., the expression patterns of genes homologous to transcription factors regulating shoot development, is essential to better understand the evolution of Podostemaceae. A gene expression analysis found that the SAM-less Podostemoideae leaf has mixed identity of SAM and leaf, and provided insight into the evolution of the shoot in Podostemaceae.

Gene Networks and Functional Features of Gravitropic response in Rice Shoot Bases

NASA Astrophysics Data System (ADS)

Hu, Liwei; Zang, Aiping; Ai, Qianru; Chen, Haiying; Li, Lin; Li, Rui; Su, Feng; Chen, Xijiang; Rong, Hui; Dou, Xianying; Reinhold-Hurek, Barbara; Li, Qi; Cai, Weiming

To delineate key genes and the corresponding physiological functions as well as the coordina-tion of genes involved in the gravitropism of rice shoot bases, we used whole-genome microarray analysis of upper and lower parts of rice shoot bases at 0.5 h and 6 h after gravistimulation. And bio-information analysis was applied including GO-analysis, expression tendency and net-work analysis. In the lower shoot bases, auxin-mediated signaling pathway and glutathione transferase activity with the biggest enrichment were activated at 0.5 h, while cytokinin stimu-lus and photosynthesis were activated at 6 h. Meanwhile, several processes were suppressed in the lower shoot bases, including: xyloglucan:xyloglucosyl transferase activity, glucan metabolic processes, and ATPase activity at 0.5 h; and tRNA isopentenyltransferase activity, and chiti-nase activity, etc. at 6 h. Gene expression profile responding to gravistimulation suggested that the asymmetrically activation of several phytohormone signaling pathways including auxin, gib-berellin and cytokinin brassinolide ethylene and cytokinin-related genes were involved in the differentially growth between the upper and lower parts of rice shoot bases, and so do cell wall-related genes. Topological analysis of the coexpression networks revealed the core statue of AY177699.1(apetala3-like protein) and AK105103.1 at 0.5 h; AK062612.1 (ethylene response factor) and AK099932.1 (lectin-like receptor kinase 72) at 6 h. All the core factors have the function "response to endogenous stimulus". Additionally, AK108057.1(similar to germin-like protein precursor) was discovered as the most important core gene in the upper shoot bases in 6h after gravistimualtion while AK067424.1(cellulose synthase-like protein), AK120101.1 (Zinc finger, B-box domain containing protein) and CR278698 (ATPase associated with various cel-lular activities cellulose synthase-like protein) contribute equally to gravitropic response in the lower shoot bases.

Influences of canopy photosynthesis and summer rain pulses on root dynamics and soil respiration in a young ponderosa pine forest.

PubMed

Misson, Laurent; Gershenson, Alexander; Tang, Jianwu; McKay, Megan; Cheng, Weixin; Goldstein, Allen

2006-07-01

Our first objective was to link the seasonality of fine root dynamics with soil respiration in a ponderosa pine (Pinus ponderosa P. & C. Lawson) plantation located in the Sierra Nevada of California. The second objective was to examine how canopy photosynthesis influences fine root initiation, growth and mortality in this ecosystem. We compared CO2 flux measurements with aboveground and belowground root dynamics. Initiation of fine root growth coincided with tree stem thickening and shoot elongation, preceding new needle growth. In the spring, root, shoot and stem growth occurred simultaneously with the increase in canopy photosynthesis. Compared with the other tree components, initial growth rate of fine roots was the highest and their growing period was the shortest. Both above and belowground components completed 90% of their growth by the end of July and the growing season lasted approximately 80 days. The period for optimal growth is short at the study site because of low soil temperatures during winter and low soil water content during summer. High photosynthetic rates were observed following unusual late-summer rains, but tree growth did not resume. The autotrophic contribution to soil respiration was 49% over the whole season, with daily contributions ranging between 18 and 87%. Increases in soil and ecosystem respiration were observed during spring growth; however, the largest variation in soil respiration occurred during summer rain events when no growth was observed. Both the magnitude and persistence of the soil respiration pulses were positively correlated with the amount of rain. These pulses accounted for 16.5% of soil respiration between Days 130 and 329.

Chemical Composition and Allelopathic Potential of Essential Oils from Citharexylum spinosum L. Grown in Tunisia.

PubMed

El Ayeb-Zakhama, Asma; Sakka-Rouis, Lamia; Flamini, Guido; Ben Jannet, Hichem; Harzallah-Skhiri, Fethia

2017-04-01

Citharexylum spinosum L. (Verbenaceae) also known as Citharexylum quadrangulare Jacq. or Citharexylum fruticosum L. is an exotic tree introduced many years ago in Tunisia, specially used as a street and park ornamental tree. Essential oils (EOs) were obtained by hydrodistillation of the different parts (roots, stems, leaves, flowers and fruits; drupes) collected from trees grown in the area of Monastir (Tunisia). In total, 84 compounds, representing 90.1 - 98.4% of the whole oil composition, were identified by GC-FID and GC/MS analyses. The root EO was distinguished by its high content in monoterpene hydrocarbons (α-phellandrene; 30.8%) whereas that obtained from stems was dominated by sesquiterpene hydrocarbons (cuparene; 16.4%). The leaf oil was rich in an apocarotenoid derivative (hexahydrofarnesylacetone; 26%) and an aliphatic hydrocarbon (nonadecane; 14.5%). Flowers oil was rich in esters (2-phenylethyl benzoate; 33.5%). Finally, drupes oil was rich in oxygenated sesquiterpenes (β-eudesmol; 33.1%). Flowers oil showed a significant phytotoxic effect against lettuce seeds germination, it induces a total inhibition when tested at 1 mg/ml. Root and shoot elongation seemed to be more affected than germination. The inhibition of the shoot length varied from 3.6% to 100% and that of the root from 16.1% to 100%. The highest inhibition of 100% was detected for flower oil tested at 1 mg/ml. Our in vitro studies suggest a possible and new alternative use of C. spinosum EOs in herbicidal formulations, further experiments involving field conditions are necessary to confirm its herbicidal potential. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Design of experiments on 135 cloned poplar trees to map environmental influence in greenhouse.

PubMed

Pinto, Rui Climaco; Stenlund, Hans; Hertzberg, Magnus; Lundstedt, Torbjörn; Johansson, Erik; Trygg, Johan

2011-01-31

To find and ascertain phenotypic differences, minimal variation between biological replicates is always desired. Variation between the replicates can originate from genetic transformation but also from environmental effects in the greenhouse. Design of experiments (DoE) has been used in field trials for many years and proven its value but is underused within functional genomics including greenhouse experiments. We propose a strategy to estimate the effect of environmental factors with the ultimate goal of minimizing variation between biological replicates, based on DoE. DoE can be analyzed in many ways. We present a graphical solution together with solutions based on classical statistics as well as the newly developed OPLS methodology. In this study, we used DoE to evaluate the influence of plant specific factors (plant size, shoot type, plant quality, and amount of fertilizer) and rotation of plant positions on height and section area of 135 cloned wild type poplar trees grown in the greenhouse. Statistical analysis revealed that plant position was the main contributor to variability among biological replicates and applying a plant rotation scheme could reduce this variation. Copyright © 2010 Elsevier B.V. All rights reserved.

Implications for Late Pleistocene Mastodon Diet from Opal Phytoliths in Tooth Calculus

NASA Astrophysics Data System (ADS)

Gobetz, Katrina E.; Bozarth, Steven R.

2001-03-01

Calculus removed from the molar teeth of four American mastodons (Mammut americanum) contained opal phytoliths which reflect major dietary components. Three samples contained abundant grass phytoliths (ca. 86% of total), with long cells and trapezoidal pooid short cells dominant (ca. 25 and 31%, respectively). Dicot phytoliths from hackberry (Celtis sp.) seeds and indeterminate deciduous trees were rare (1-3%), though well preserved, whereas phytoliths from conifer trees were not recognizable in any of the samples. Comparative analysis of calculus from modern and fossil browsers and mixed feeders implies that dicots and conifers are nearly invisible in the phytolith record. This scarcity may result from poor preservation, low silica production in woody taxa, and/or animals' selection of young, silica-poor leaves and shoots. However, abundant grass phytoliths in the mixed feeders suggest that presence versus absence of grass phytoliths may distinguish mixed feeders and grazers from browsers. Mastodons are traditionally considered browsers, but grass phytolith assemblages in three individual mastodons contained similarly high concentrations of pooids, suggesting that these grasses were a significant part of the diet. Abundant pooid phytoliths, in addition to diatoms, indicate that these mastodons grazed in a cool, moist late Pleistocene environment, possibly near water.

Boron deficiency in woody plants: various responses and tolerance mechanisms

PubMed Central

Wang, Nannan; Yang, Chengquan; Pan, Zhiyong; Liu, Yongzhong; Peng, Shu’ang

2015-01-01

Boron (B) is an essential microelement for higher plants, and its deficiency is widespread around the world and constrains the productivity of both agriculture and forestry. In the last two decades, numerous studies on model or herbaceous plants have contributed greatly to our understanding of the complex network of B-deficiency responses and mechanisms for tolerance. In woody plants, however, fewer studies have been conducted and they have not well been recently synthesized or related to the findings on model species on B transporters. Trees have a larger body size, longer lifespan and more B reserves than do herbaceous plants, indicating that woody species might undergo long-term or mild B deficiency more commonly and that regulation of B reserves helps trees cope with B deficiency. In addition, the highly heterozygous genetic background of tree species suggests that they may have more complex mechanisms of response and tolerance to B deficiency than do model plants. Boron-deficient trees usually exhibit two key visible symptoms: depression of growing points (root tip, bud, flower, and young leaf) and deformity of organs (root, shoot, leaf, and fruit). These symptoms may be ascribed to B functioning in the cell wall and membrane, and particularly to damage to vascular tissues and the suppression of both B and water transport. Boron deficiency also affects metabolic processes such as decreased leaf photosynthesis, and increased lignin and phenol content in trees. These negative effects will influence the quality and quantity of wood, fruit and other agricultural products. Boron efficiency probably originates from a combined effect of three processes: B uptake, B translocation and retranslocation, and B utilization. Root morphology and mycorrhiza can affect the B uptake efficiency of trees. During B translocation from the root to shoot, differences in B concentration between root cell sap and xylem exudate, as well as water use efficiency, may play key roles in tolerance to B deficiency. In addition, B retranslocation efficiency primarily depends on the extent of xylem-to-phloem transfer and the variety and amount of cis-diol moieties in the phloem. The B requirement for cell wall construction also contribute to the B use efficiency in trees. The present review will provide an update on the physiological and molecular responses and tolerance mechanisms to B deficiency in woody plants. Emphasis is placed on the roles of B reserves that are more important for tolerance to B deficiency in trees than in herbaceous plants and the possible physiological and molecular mechanisms of differential B efficiency in trees. We propose that B may be used to study the relationship between the cell wall and the membrane via the B-bridge. Transgenic B-efficient tree cultivars have considerable potential for forestry or fruit rootstock production on low B soils in the future. PMID:26579163

Micropropagation of Prunus species relevant to cherry fruit production.

PubMed

Druart, Philippe

2013-01-01

Cherry tree micropropagation is limited to the production of healthy cultivars of Prunus avium and Prunus cerasus, and their rootstocks; mainly the dwarfing ones. By using meristem-tip (0.1 mm long) or healthy shoot tips/nodes, four successive steps are needed to obtain whole plants capable of growing in the nursery: multiplication by axillary branching, shoot elongation, rooting, and plantlet acclimation. Along this process, several parameters have to be adjusted for each phase of the culture, including media composition, environmental culture conditions and plant handling. These parameters vary depending on genotypic response and specific vulnerability to physiological disorders such as hyperhydricity, apex necrosis, unstable propagation, and rooting rates. Based on a 40 year-long experience of study and application of culture conditions to large-scale plant production, this document summarizes the main problems (variability of the propagation rate, hyperhydricity, apex necrosis, plant re-growth) and solutions encountered to solve them, with means validated on many mericlones.

Transcriptome analysis in oak uncovers a strong impact of endogenous rhythmic growth on the interaction with plant-parasitic nematodes.

PubMed

Maboreke, Hazel R; Feldhahn, Lasse; Bönn, Markus; Tarkka, Mika T; Buscot, Francois; Herrmann, Sylvie; Menzel, Ralph; Ruess, Liliane

2016-08-12

Pedunculate oak (Quercus robur L.), an important forest tree in temperate ecosystems, displays an endogenous rhythmic growth pattern, characterized by alternating shoot and root growth flushes paralleled by oscillations in carbon allocation to below- and aboveground tissues. However, these common plant traits so far have largely been neglected as a determining factor for the outcome of plant biotic interactions. This study investigates the response of oak to migratory root-parasitic nematodes in relation to rhythmic growth, and how this plant-nematode interaction is modulated by an ectomycorrhizal symbiont. Oaks roots were inoculated with the nematode Pratylenchus penetrans solely and in combination with the fungus Piloderma croceum, and the systemic impact on oak plants was assessed by RNA transcriptomic profiles in leaves. The response of oaks to the plant-parasitic nematode was strongest during shoot flush, with a 16-fold increase in the number of differentially expressed genes as compared to root flush. Multi-layered defence mechanisms were induced at shoot flush, comprising upregulation of reactive oxygen species formation, hormone signalling (e.g. jasmonic acid synthesis), and proteins involved in the shikimate pathway. In contrast during root flush production of glycerolipids involved in signalling cascades was repressed, suggesting that P. penetrans actively suppressed host defence. With the presence of the mycorrhizal symbiont, the gene expression pattern was vice versa with a distinctly stronger effect of P. penetrans at root flush, including attenuated defence, cell and carbon metabolism, likely a response to the enhanced carbon sink strength in roots induced by the presence of both, nematode and fungus. Meanwhile at shoot flush, when nutrients are retained in aboveground tissue, oak defence reactions, such as altered photosynthesis and sugar pathways, diminished. The results highlight that gene response patterns of plants to biotic interactions, both negative (i.e. plant-parasitic nematodes) and beneficial (i.e. mycorrhiza), are largely modulated by endogenous rhythmic growth, and that such plant traits should be considered as an important driver of these relationships in future studies.

Genome-wide transcriptome analysis of the transition from primary to secondary stem development in Populus trichocarpa

PubMed Central

2010-01-01

Background With its genome sequence and other experimental attributes, Populus trichocarpa has become the model species for genomic studies of wood development. Wood is derived from secondary growth of tree stems, and begins with the development of a ring of vascular cambium in the young developing stem. The terminal region of the developing shoot provides a steep developmental gradient from primary to secondary growth that facilitates identification of genes that play specialized functions during each of these phases of growth. Results Using a genomic microarray representing the majority of the transcriptome, we profiled gene expression in stem segments that spanned primary to secondary growth. We found 3,016 genes that were differentially expressed during stem development (Q-value ≤ 0.05; >2-fold expression variation), and 15% of these genes encode proteins with no significant identities to known genes. We identified all gene family members putatively involved in secondary growth for carbohydrate active enzymes, tubulins, actins, actin depolymerizing factors, fasciclin-like AGPs, and vascular development-associated transcription factors. Almost 70% of expressed transcription factors were upregulated during the transition to secondary growth. The primary shoot elongation region of the stem contained specific carbohydrate active enzyme and expansin family members that are likely to function in primary cell wall synthesis and modification. Genes involved in plant defense and protective functions were also dominant in the primary growth region. Conclusion Our results describe the global patterns of gene expression that occur during the transition from primary to secondary stem growth. We were able to identify three major patterns of gene expression and over-represented gene ontology categories during stem development. The new regulatory factors and cell wall biogenesis genes that we identified provide candidate genes for further functional characterization, as well as new tools for molecular breeding and biotechnology aimed at improvement of tree growth rate, crown form, and wood quality. PMID:20199690

Exogenous application of the plant signalers methyl jasmonate and salicylic acid induces changes in volatile emissions from citrus foliage and influences the aggregation behavior of Asian citrus psyllid (Diaphorina citri), vector of Huanglongbing

PubMed Central

Robbins, Paul S.; Niedz, Randy; McCollum, Greg; Alessandro, Rocco

2018-01-01

Huanglongbing, also known as citrus greening, is a destructive disease that threatens citrus production worldwide. It is putatively caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (Las). Currently, the disease is untreatable and efforts focus on intensive insecticide use to control the vector, Asian citrus psyllid (Diaphorina citri). Emerging psyllid resistance to multiple insecticides has generated investigations into the use of exogenously applied signaling compounds to enhance citrus resistance to D. citri and Las. In the present study, we examined whether foliar applications of methyl jasmonate (MJ), a volatile signaling compound associated with the induced systemic resistance pathway, and salicylic acid, a constituent of the systemic acquired resistance pathway, would elicit the emission of defense-related volatiles in citrus foliage, and what effect this might have on the host-plant searching behavior of D. citri. Comparisons were made of volatiles emitted from growing shoots of uninfected and Las-infected ‘Valencia’ sweet orange (Citrus sinensis) trees over two consecutive sampling days. A settling behavioral assay was used to compare psyllid attraction to MJ-treated vs. Tween-treated citrus sprigs. All three main effects, Las infection status, plant signaler application, and sampling day, influenced the proportions of individual volatile compounds emitted in different treatment groups. MJ- and SA-treated trees had higher emission rates than Tween-treated trees. Methyl salicylate (MeSA) and β-caryophyllene were present in higher proportions in the volatiles collected from Las-infected + trees. On the other hand, Las-infected + MJ-treated trees emitted lower proportions of MeSA than did Las-infected + Tween-treated trees. Because MeSA is a key D. citri attractant, this result suggests that MJ application could suppress MeSA emission from Las-infected trees, an approach that could be used to discourage psyllid colonization during shoot growth. MJ application enhanced emission of E-β-ocimene, indole, volatiles attractive to many of the psyllid’s natural enemies, indicating that MJ application could be used in an ‘attract and reward’ conservation biological control strategy. Volatile emissions in SA-treated trees were dominated by MeSA. MJ application elicited aggregation behavior in D. citri. Similar numbers of psyllids settled on MJ-treated versus Tween-treated sprigs, but a significantly greater percentage of the MJ-treated sprigs had aggregations of nine or more psyllids on them. Taken together, the results of this study indicate that exogenous applications of MJ or SA could be used to influence Asian citrus psyllid settling behavior and attract its natural enemies. PMID:29596451

Exogenous application of the plant signalers methyl jasmonate and salicylic acid induces changes in volatile emissions from citrus foliage and influences the aggregation behavior of Asian citrus psyllid (Diaphorina citri), vector of Huanglongbing.

PubMed

Patt, Joseph M; Robbins, Paul S; Niedz, Randy; McCollum, Greg; Alessandro, Rocco

2018-01-01

Huanglongbing, also known as citrus greening, is a destructive disease that threatens citrus production worldwide. It is putatively caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (Las). Currently, the disease is untreatable and efforts focus on intensive insecticide use to control the vector, Asian citrus psyllid (Diaphorina citri). Emerging psyllid resistance to multiple insecticides has generated investigations into the use of exogenously applied signaling compounds to enhance citrus resistance to D. citri and Las. In the present study, we examined whether foliar applications of methyl jasmonate (MJ), a volatile signaling compound associated with the induced systemic resistance pathway, and salicylic acid, a constituent of the systemic acquired resistance pathway, would elicit the emission of defense-related volatiles in citrus foliage, and what effect this might have on the host-plant searching behavior of D. citri. Comparisons were made of volatiles emitted from growing shoots of uninfected and Las-infected 'Valencia' sweet orange (Citrus sinensis) trees over two consecutive sampling days. A settling behavioral assay was used to compare psyllid attraction to MJ-treated vs. Tween-treated citrus sprigs. All three main effects, Las infection status, plant signaler application, and sampling day, influenced the proportions of individual volatile compounds emitted in different treatment groups. MJ- and SA-treated trees had higher emission rates than Tween-treated trees. Methyl salicylate (MeSA) and β-caryophyllene were present in higher proportions in the volatiles collected from Las-infected + trees. On the other hand, Las-infected + MJ-treated trees emitted lower proportions of MeSA than did Las-infected + Tween-treated trees. Because MeSA is a key D. citri attractant, this result suggests that MJ application could suppress MeSA emission from Las-infected trees, an approach that could be used to discourage psyllid colonization during shoot growth. MJ application enhanced emission of E-β-ocimene, indole, volatiles attractive to many of the psyllid's natural enemies, indicating that MJ application could be used in an 'attract and reward' conservation biological control strategy. Volatile emissions in SA-treated trees were dominated by MeSA. MJ application elicited aggregation behavior in D. citri. Similar numbers of psyllids settled on MJ-treated versus Tween-treated sprigs, but a significantly greater percentage of the MJ-treated sprigs had aggregations of nine or more psyllids on them. Taken together, the results of this study indicate that exogenous applications of MJ or SA could be used to influence Asian citrus psyllid settling behavior and attract its natural enemies.

Molecular Responses to Photooxidative Stress in Pinus sylvestris (L.) (II. Differential Expression of CuZn-Superoxide Dismutases and Glutathione Reductase.

PubMed Central

Karpinski, S.; Wingsle, G.; Karpinska, B.; Hallgren, J. E.

1993-01-01

The influence of photooxidative stress on genes expressing superoxide dismutase (Sod) and glutathione reductase (Gor) was analyzed in needles of top and side shoots of 3-year-old Pinus sylvestris (L.) seedlings. The study was carried out in the field during spring recovery. From mid-April the top shoots of seedlings protruded above the snow and thus were exposed to sunlight, whereas the side shoots were covered with snow until May 4. Needles were sampled from top and side shoots on five different occasions. At the beginning of May the mRNA levels for cytosolic CuZn-Sod were significantly higher in top-shoot needles than in side-shoot needles. Similar results were obtained for chloroplastic CuZn-Sod mRNA. After May 6 we could not detect any significant differences between top- and side-shoot needles for either CuZn-Sod mRNA level. Transcript accumulation for the chloroplastic CuZn-Sod was up to 4-fold higher than for cytosolic CuZn-Sod in both types of shoots. On June 1 minimum transcript levels were observed for both CuZn-SOD isoforms. Protein activity analysis for CuZn-SOD isozymes did not reveal any significant differences between top- and side-shoot needles during the whole period of measurements. The mRNA level for chloroplastic Gor was similar in both types of shoots. However, the total GR activity was significantly higher in top-shoot needles than in side-shoot needles at the beginning of May. The analysis of mRNA accumulation for chloroplastic CuZn-Sod and Gor indicates that transcript levels were at least 5- to 20-fold higher for CuZn-Sod than for chloroplastic Gor. The differential expressions of Sod and Gor genes are discussed in relation to regulation of the enzymic scavenging system during photooxidative stress conditions. PMID:12232032

Mapping in an apple (Malus x domestica) F1 segregating population based on physical clustering of differentially expressed genes.

PubMed

Jensen, Philip J; Fazio, Gennaro; Altman, Naomi; Praul, Craig; McNellis, Timothy W

2014-04-04

Apple tree breeding is slow and difficult due to long generation times, self-incompatibility, and complex genetics. The identification of molecular markers linked to traits of interest is a way to expedite the breeding process. In the present study, we aimed to identify genes whose steady-state transcript abundance was associated with inheritance of specific traits segregating in an apple (Malus × domestica) rootstock F1 breeding population, including resistance to powdery mildew (Podosphaera leucotricha) disease and woolly apple aphid (Eriosoma lanigerum). Transcription profiling was performed for 48 individual F1 apple trees from a cross of two highly heterozygous parents, using RNA isolated from healthy, actively-growing shoot tips and a custom apple DNA oligonucleotide microarray representing 26,000 unique transcripts. Genome-wide expression profiles were not clear indicators of powdery mildew or woolly apple aphid resistance phenotype. However, standard differential gene expression analysis between phenotypic groups of trees revealed relatively small sets of genes with trait-associated expression levels. For example, thirty genes were identified that were differentially expressed between trees resistant and susceptible to powdery mildew. Interestingly, the genes encoding twenty-four of these transcripts were physically clustered on chromosome 12. Similarly, seven genes were identified that were differentially expressed between trees resistant and susceptible to woolly apple aphid, and the genes encoding five of these transcripts were also clustered, this time on chromosome 17. In each case, the gene clusters were in the vicinity of previously identified major quantitative trait loci for the corresponding trait. Similar results were obtained for a series of molecular traits. Several of the differentially expressed genes were used to develop DNA polymorphism markers linked to powdery mildew disease and woolly apple aphid resistance. Gene expression profiling and trait-associated transcript analysis using an apple F1 population readily identified genes physically linked to powdery mildew disease resistance and woolly apple aphid resistance loci. This result was especially useful in apple, where extreme levels of heterozygosity make the development of reliable DNA markers quite difficult. The results suggest that this approach could prove effective in crops with complicated genetics, or for which few genomic information resources are available.

Shooting Mechanisms in Nature: A Systematic Review

PubMed Central

Sakes, Aimée; van der Wiel, Marleen; Henselmans, Paul W. J.; van Leeuwen, Johan L.; Dodou, Dimitra; Breedveld, Paul

2016-01-01

Background In nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these mechanisms fulfill. Methods We systematically searched the literature using Scopus and Web of Knowledge to retrieve articles about solid projectiles that either are produced in the body of the organism or belong to the body and undergo a ballistic phase. The shooting mechanisms were categorized based on the energy management prior to and during shooting. Results Shooting mechanisms were identified with projectile masses ranging from 1·10−9 mg in spores of the fungal phyla Ascomycota and Zygomycota to approximately 10,300 mg for the ballistic tongue of the toad Bufo alvarius. The energy for shooting is generated through osmosis in fungi, plants, and animals or muscle contraction in animals. Osmosis can be induced by water condensation on the system (in fungi), or water absorption in the system (reaching critical pressures up to 15.4 atmospheres; observed in fungi, plants, and animals), or water evaporation from the system (reaching up to −197 atmospheres; observed in plants and fungi). The generated energy is stored as elastic (potential) energy in cell walls in fungi and plants and in elastic structures in animals, with two exceptions: (1) in the momentum catapult of Basidiomycota the energy is stored in a stalk (hilum) by compression of the spore and droplets and (2) in Sphagnum energy is mainly stored in compressed air. Finally, the stored energy is transformed into kinetic energy of the projectile using a catapult mechanism delivering up to 4,137 J/kg in the osmotic shooting mechanism in cnidarians and 1,269 J/kg in the muscle-powered appendage strike of the mantis shrimp Odontodactylus scyllarus. The launch accelerations range from 6.6g in the frog Rana pipiens to 5,413,000g in cnidarians, the launch velocities from 0.1 m/s in the fungal phylum Basidiomycota to 237 m/s in the mulberry Morus alba, and the launch distances from a few thousands of a millimeter in Basidiomycota to 60 m in the rainforest tree Tetraberlinia moreliana. The mass-specific power outputs range from 0.28 W/kg in the water evaporation mechanism in Basidiomycota to 1.97·109 W/kg in cnidarians using water absorption as energy source. Discussion and conclusions The magnitude of accelerations involved in shooting is generally scale-dependent with the smaller the systems, discharging the microscale projectiles, generating the highest accelerations. The mass-specific power output is also scale dependent, with smaller mechanisms being able to release the energy for shooting faster than larger mechanisms, whereas the mass-specific work delivered by the shooting mechanism is mostly independent of the scale of the shooting mechanism. Higher mass-specific work-values are observed in osmosis-powered shooting mechanisms (≤ 4,137 J/kg) when compared to muscle-powered mechanisms (≤ 1,269 J/kg). The achieved launch parameters acceleration, velocity, and distance, as well as the associated delivered power output and work, thus depend on the working principle and scale of the shooting mechanism. PMID:27454125

Mediation of seed provisioning in the transmission of environmental maternal effects in Maritime pine (Pinus pinaster Aiton).

PubMed

Zas, R; Cendán, C; Sampedro, L

2013-09-01

Although maternal environmental effects are increasingly recognized as an important source of phenotypic variation with relevant impacts in evolutionary processes, their relevance in long-lived plants such as pine trees is largely unknown. Here, we used a powerful sample size and a strong quantitative genetic approach to analyse the sources of variation of early seedling performance and to identify seed mass (SM)-dependent and -independent maternal environmental effects in Maritime pine. We measured SM of 8924 individual seeds collected from 10 genotypes clonally replicated in two environments of contrasting quality (favourable and stressful), and we measured seedling growth rate and biomass allocation to roots and shoots. SM was extremely variable (up to 14-fold) and strongly determined by the maternal environment and the genotype of the mother tree. The favourable maternal environment led to larger cones, larger seeds and reduced SM variability. The maternal environment also determined the offspring phenotype, with seedlings coming from the favourable environment being 35% larger and with greater root/shoot ratio. Transgenerational plasticity appears, thus, to be a relevant source of phenotypic variation in the early performance of this pine species. Seed provisioning explained most of the effect of the maternal environment on seedling total biomass. Environmental maternal effects on seedling biomass allocation were, however, determined through SM-independent mechanisms, suggesting that other epigenetic regulation channels may be involved.

Physiological acclimation dampens initial effects of elevated temperature and atmospheric CO2 concentration in mature boreal Norway spruce.

PubMed

Lamba, Shubhangi; Hall, Marianne; Räntfors, Mats; Chaudhary, Nitin; Linder, Sune; Way, Danielle; Uddling, Johan; Wallin, Göran

2018-02-01

Physiological processes of terrestrial plants regulate the land-atmosphere exchange of carbon, water, and energy, yet few studies have explored the acclimation responses of mature boreal conifer trees to climate change. Here we explored the acclimation responses of photosynthesis, respiration, and stomatal conductance to elevated temperature and/or CO 2 concentration ([CO 2 ]) in a 3-year field experiment with mature boreal Norway spruce. We found that elevated [CO 2 ] decreased photosynthetic carboxylation capacity (-23% at 25 °C) and increased shoot respiration (+64% at 15 °C), while warming had no significant effects. Shoot respiration, but not photosynthetic capacity, exhibited seasonal acclimation. Stomatal conductance at light saturation and a vapour pressure deficit of 1 kPa was unaffected by elevated [CO 2 ] but significantly decreased (-27%) by warming, and the ratio of intercellular to ambient [CO 2 ] was enhanced (+17%) by elevated [CO 2 ] and decreased (-12%) by warming. Many of these responses differ from those typically observed in temperate tree species. Our results show that long-term physiological acclimation dampens the initial stimulation of plant net carbon assimilation to elevated [CO 2 ], and of plant water use to warming. Models that do not account for these responses may thus overestimate the impacts of climate change on future boreal vegetation-atmosphere interactions. © 2017 John Wiley & Sons Ltd.

Linking belowground and aboveground phenology in two boreal forests in Northeast China.

PubMed

Du, Enzai; Fang, Jingyun

2014-11-01

The functional equilibrium between roots and shoots suggests an intrinsic linkage between belowground and aboveground phenology. However, much less understanding of belowground phenology hinders integrating belowground and aboveground phenology. We measured root respiration (Ra) as a surrogate for root phenology and integrated it with observed leaf phenology and radial growth in a birch (Betula platyphylla)-aspen (Populus davidiana) forest and an adjacent larch (Larix gmelinii) forest in Northeast China. A log-normal model successfully described the seasonal variations of Ra and indicated the initiation, termination and peak date of root phenology. Both root phenology and leaf phenology were highly specific, with a later onset, earlier termination, and shorter period of growing season for the pioneer tree species (birch and aspen) than the dominant tree species (larch). Root phenology showed later initiation, later peak and later termination dates than leaf phenology. An asynchronous correlation of Ra and radial growth was identified with a time lag of approximately 1 month, indicating aprioritization of shoot growth. Furthermore, we found that Ra was strongly correlated with soil temperature and air temperature, while radial growth was only significantly correlated with air temperature, implying a down-regulating effect of temperature. Our results indicate different phenologies between pioneer and dominant species and support a down-regulation hypothesis of plant phenology which can be helpful in understanding forest dynamics in the context of climate change.

Mediation of seed provisioning in the transmission of environmental maternal effects in Maritime pine (Pinus pinaster Aiton)

PubMed Central

Zas, R; Cendán, C; Sampedro, L

2013-01-01

Although maternal environmental effects are increasingly recognized as an important source of phenotypic variation with relevant impacts in evolutionary processes, their relevance in long-lived plants such as pine trees is largely unknown. Here, we used a powerful sample size and a strong quantitative genetic approach to analyse the sources of variation of early seedling performance and to identify seed mass (SM)-dependent and -independent maternal environmental effects in Maritime pine. We measured SM of 8924 individual seeds collected from 10 genotypes clonally replicated in two environments of contrasting quality (favourable and stressful), and we measured seedling growth rate and biomass allocation to roots and shoots. SM was extremely variable (up to 14-fold) and strongly determined by the maternal environment and the genotype of the mother tree. The favourable maternal environment led to larger cones, larger seeds and reduced SM variability. The maternal environment also determined the offspring phenotype, with seedlings coming from the favourable environment being 35% larger and with greater root/shoot ratio. Transgenerational plasticity appears, thus, to be a relevant source of phenotypic variation in the early performance of this pine species. Seed provisioning explained most of the effect of the maternal environment on seedling total biomass. Environmental maternal effects on seedling biomass allocation were, however, determined through SM-independent mechanisms, suggesting that other epigenetic regulation channels may be involved. PMID:23652562

Growth Response of Drought-Stressed Pinus sylvestris Seedlings to Single- and Multi-Species Inoculation with Ectomycorrhizal Fungi

PubMed Central

Kipfer, Tabea; Wohlgemuth, Thomas; van der Heijden, Marcel G. A.; Ghazoul, Jaboury; Egli, Simon

2012-01-01

Many trees species form symbiotic associations with ectomycorrhizal (ECM) fungi, which improve nutrient and water acquisition of their host. Until now it is unclear whether the species richness of ECM fungi is beneficial for tree seedling performance, be it during moist conditions or drought. We performed a pot experiment using Pinus sylvestris seedlings inoculated with four selected ECM fungi (Cenococcum geophilum, Paxillus involutus, Rhizopogon roseolus and Suillus granulatus) to investigate (i) whether these four ECM fungi, in monoculture or in species mixtures, affect growth of P. sylvestris seedlings, and (ii) whether this effect can be attributed to species number per se or to species identity. Two different watering regimes (moist vs. dry) were applied to examine the context-dependency of the results. Additionally, we assessed the activity of eight extracellular enzymes in the root tips. Shoot growth was enhanced in the presence of S. granulatus, but not by any other ECM fungal species. The positive effect of S. granulatus on shoot growth was more pronounced under moist (threefold increase) than under dry conditions (twofold increase), indicating that the investigated ECM fungi did not provide additional support during drought stress. The activity of secreted extracellular enzymes was higher in S. granulatus than in any other species. In conclusion, our findings suggest that ECM fungal species composition may affect seedling performance in terms of aboveground biomass. PMID:22496914

Growth response of drought-stressed Pinus sylvestris seedlings to single- and multi-species inoculation with ectomycorrhizal fungi.

PubMed

Kipfer, Tabea; Wohlgemuth, Thomas; van der Heijden, Marcel G A; Ghazoul, Jaboury; Egli, Simon

2012-01-01

Many trees species form symbiotic associations with ectomycorrhizal (ECM) fungi, which improve nutrient and water acquisition of their host. Until now it is unclear whether the species richness of ECM fungi is beneficial for tree seedling performance, be it during moist conditions or drought. We performed a pot experiment using Pinus sylvestris seedlings inoculated with four selected ECM fungi (Cenococcum geophilum, Paxillus involutus, Rhizopogon roseolus and Suillus granulatus) to investigate (i) whether these four ECM fungi, in monoculture or in species mixtures, affect growth of P. sylvestris seedlings, and (ii) whether this effect can be attributed to species number per se or to species identity. Two different watering regimes (moist vs. dry) were applied to examine the context-dependency of the results. Additionally, we assessed the activity of eight extracellular enzymes in the root tips. Shoot growth was enhanced in the presence of S. granulatus, but not by any other ECM fungal species. The positive effect of S. granulatus on shoot growth was more pronounced under moist (threefold increase) than under dry conditions (twofold increase), indicating that the investigated ECM fungi did not provide additional support during drought stress. The activity of secreted extracellular enzymes was higher in S. granulatus than in any other species. In conclusion, our findings suggest that ECM fungal species composition may affect seedling performance in terms of aboveground biomass.

Influence of Diffused Solar Radiation on the Solar Concentrating System of a Plant Shoot Configuration

NASA Astrophysics Data System (ADS)

Obara, Shin'ya

Investigation of a plant shoot configuration is used to obtain valuable information concerning the received light system. Additionally, analysis results concerning a plant shoot configuration interaction with direct solar radiation were taken from a past study. However, in order to consider a plant shoot as a received sunlight system, it is necessary to understand the received light characteristics of both direct solar radiation and diffused solar radiation. Under a clear sky, the ratio of direct solar radiation to diffused solar radiation is large. However, under a clouded sky, the amount of diffused solar radiation becomes larger. Therefore, in this paper, we investigate the received light characteristics of a plant shoot configuration under the influence of diffused solar radiation. As a result, we clarify the relationship between the amount of diffused solar radiation and the amount of received light as a function of the characteristics of the plant shoot configuration. In order to obtain diffused solar radiation, it is necessary to correspond to the radiation of the multi-directions. In the analysis, the characteristic of the difference in arrangement of the top leaf and the other leaf was obtained. Therefore, in analysis, leaves other than the top were distributed in the wide range.

CCS52A2/FZR1, a cell cycle regulator, is an essential factor for shoot apical meristem maintenance in Arabidopsis thaliana.

PubMed

Liu, Yajie; Ye, Wei; Li, Beibei; Zhou, Xiaojing; Cui, Yuhai; Running, Mark P; Liu, Kede

2012-08-08

Cell division and cell fate decisions regulate organ formation and function in plant growth and development. It is still unclear how specific meristematic regulatory networks operate with the cell cycle machinery to translate stem cell identity and maintenance into cellular behavior. In this study, we address these questions by analysis of a shoot apex defective mutant, namely xcm9. Phenotypic analysis of the xcm9 mutant reveals concomitant premature termination of floral shoots with frequent bifurcation of the shoot apices, stems, and flowers. Microscopic observations show irregular cell organization in shoot apical meristems of xcm9. Positional cloning revealed that xcm9 is a loss of function allele of the CCS52A2/FZR1 gene, which has previously been implicated in root development. Expression analysis demonstrated that CCS52A2 maintains a higher transcriptional expression level in actively dividing tissue. Genetic studies indicated that the CCS52A2 gene functions together with WUSCHEL (WUS) and CLAVATA3 (CLV3) in regulating the development of the shoot meristem, and also contributes to this regulation together with the chromatin remodeling pathway. In addition, fewer xcm9 cells express CYCLIN B1:1, showing that cell cycle progression is disrupted in the mutant. We propose that the CCS52A2 gene is a mediator that functions together with meristematic genes to regulate meristem organization, and cross-functions with chromatin regulators in cell cycle progression during shoot apical meristem development.

Revisiting the Virginia Tech Shootings: An Ecological Systems Analysis

ERIC Educational Resources Information Center

Hong, Jun Sung; Cho, Hyunkag; Lee, Alvin Shiulain

2010-01-01

School shooting cases since the late 1990s have prompted school officials and legislators to develop and implement programs and measures that would prevent violence in school. Despite the number of explanations by the media, politicians, organizations, and researchers about the etiology of school shootings, we are not united in our understanding…

Two-dimensional liquid chromatography (LC) of phenolic compounds from the shoots of Rubus idaeus 'Glen Ample' cultivar variety.

PubMed

Kula, Marta; Głód, Daniel; Krauze-Baranowska, Mirosława

2016-03-20

In this study the application of two-dimensional LC (2D LC) for qualitative analysis of polyphenols and simple phenols in the shoots of Rubus idaeus 'Glen Ample' variety is presented. In the preliminary analysis, the methanol extract of the shoots was analyzed by one-dimensional LC. One-dimensional LC separation profiles of phenolics from R. idaeus 'Glen Ample' shoots were dependent on column type, mobile phase composition and gradient program used. Two-dimensional LC system was built from connecting an octadecyl C-18 silica column in the first dimension and pentafluorophenyl column in the second dimension, coupled with DAD and MS (ESI, APCI, DUIS ionization) detectors. A total of 34 phenolic compounds belonging to the groups of phenolic acids, ellagitannins, flavan-3-ols, flavonols and ellagic acid conjugates were identified in the shoots of R. idaeus 'Glen Ample'. The established 2D LC method offers an effective tool for analysis of phenolics present in Rubus species. Copyright © 2015 Elsevier B.V. All rights reserved.

Markov and semi-Markov switching linear mixed models used to identify forest tree growth components.

PubMed

Chaubert-Pereira, Florence; Guédon, Yann; Lavergne, Christian; Trottier, Catherine

2010-09-01

Tree growth is assumed to be mainly the result of three components: (i) an endogenous component assumed to be structured as a succession of roughly stationary phases separated by marked change points that are asynchronous among individuals, (ii) a time-varying environmental component assumed to take the form of synchronous fluctuations among individuals, and (iii) an individual component corresponding mainly to the local environment of each tree. To identify and characterize these three components, we propose to use semi-Markov switching linear mixed models, i.e., models that combine linear mixed models in a semi-Markovian manner. The underlying semi-Markov chain represents the succession of growth phases and their lengths (endogenous component) whereas the linear mixed models attached to each state of the underlying semi-Markov chain represent-in the corresponding growth phase-both the influence of time-varying climatic covariates (environmental component) as fixed effects, and interindividual heterogeneity (individual component) as random effects. In this article, we address the estimation of Markov and semi-Markov switching linear mixed models in a general framework. We propose a Monte Carlo expectation-maximization like algorithm whose iterations decompose into three steps: (i) sampling of state sequences given random effects, (ii) prediction of random effects given state sequences, and (iii) maximization. The proposed statistical modeling approach is illustrated by the analysis of successive annual shoots along Corsican pine trunks influenced by climatic covariates. © 2009, The International Biometric Society.

Pattern and process of clonal growth in a common cattail (Typha latifolia L. ) population

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

Dickerman, J.A.

1982-01-01

A detailed analysis of individually identified Typha latifolia shoots quantified the births, deaths, life histories and productivities of the shoots. Three levels of plant structure were addressed: Inter-shoot relationships, individual shoot behavior and leaf dynamics. Shoots emerged in three major emergence pulses each year, and were grouped by these pulses into three major cohorts. The first cohort emerged in early spring, grew throughout the growing season, and died in late autumn. The second cohort emerged in midsummer; 70 to 80 percent of these shoots died in autumn, while the remainder resumed growth in the following spring. The third cohort emergedmore » in late summer and early autumn; 80 to 90 percent of all third cohort shoots resumed growth the following spring. An intrinsic or self-regulation of density through reallocation of assimilates between shoots and rhizomes adequately explained the density patterns. This regulation is based on the growth pattern and the differing roles of the cohorts: The first and third cohorts are predominately regenerative, while the second cohort is proliferative, and fills in shoot density if, in early spring, density is below a shoot saturation level that apparently effectively holds marsh space.« less

Linking cases of illegal shootings of the endangered California condor using stable lead isotope analysis

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

Finkelstein, Myra E., E-mail: myraf@ucsc.edu; Kuspa, Zeka E.; Welch, Alacia

Lead poisoning is preventing the recovery of the critically endangered California condor (Gymnogyps californianus) and lead isotope analyses have demonstrated that ingestion of spent lead ammunition is the principal source of lead poisoning in condors. Over an 8 month period in 2009, three lead-poisoned condors were independently presented with birdshot embedded in their tissues, evidencing they had been shot. No information connecting these illegal shooting events existed and the timing of the shooting(s) was unknown. Using lead concentration and stable lead isotope analyses of feathers, blood, and recovered birdshot, we observed that: i) lead isotope ratios of embedded shot frommore » all three birds were measurably indistinguishable from each other, suggesting a common source; ii) lead exposure histories re-constructed from feather analysis suggested that the shooting(s) occurred within the same timeframe; and iii) two of the three condors were lead poisoned from a lead source isotopically indistinguishable from the embedded birdshot, implicating ingestion of this type of birdshot as the source of poisoning. One of the condors was subsequently lead poisoned the following year from ingestion of a lead buckshot (blood lead 556 µg/dL), illustrating that ingested shot possess a substantially greater lead poisoning risk compared to embedded shot retained in tissue (blood lead ∼20 µg/dL). To our knowledge, this is the first study to use lead isotopes as a tool to retrospectively link wildlife shooting events. - Highlights: • We conducted a case-based analysis of illegal shootings of California condors. • Blood and feather Pb isotopes were used to reconstruct the illegal shooting events. • Embedded birdshot from the three condors had the same Pb isotope ratios. • Feather and blood Pb isotopes indicated that the condors were shot in a common event. • Ingested shot causes substantially greater lead exposure compared to embedded shot.« less

Dynamics of leaf gas exchange, xylem and phloem transport, water potential and carbohydrate concentration in a realistic 3-D model tree crown.

PubMed

Nikinmaa, Eero; Sievänen, Risto; Hölttä, Teemu

2014-09-01

Tree models simulate productivity using general gas exchange responses and structural relationships, but they rarely check whether leaf gas exchange and resulting water and assimilate transport and driving pressure gradients remain within acceptable physical boundaries. This study presents an implementation of the cohesion-tension theory of xylem transport and the Münch hypothesis of phloem transport in a realistic 3-D tree structure and assesses the gas exchange and transport dynamics. A mechanistic model of xylem and phloem transport was used, together with a tested leaf assimilation and transpiration model in a realistic tree architecture to simulate leaf gas exchange and water and carbohydrate transport within an 8-year-old Scots pine tree. The model solved the dynamics of the amounts of water and sucrose solute in the xylem, cambium and phloem using a fine-grained mesh with a system of coupled ordinary differential equations. The simulations predicted the observed patterns of pressure gradients and sugar concentration. Diurnal variation of environmental conditions influenced tree-level gradients in turgor pressure and sugar concentration, which are important drivers of carbon allocation. The results and between-shoot variation were sensitive to structural and functional parameters such as tree-level scaling of conduit size and phloem unloading. Linking whole-tree-level water and assimilate transport, gas exchange and sink activity opens a new avenue for plant studies, as features that are difficult to measure can be studied dynamically with the model. Tree-level responses to local and external conditions can be tested, thus making the approach described here a good test-bench for studies of whole-tree physiology.

Deep Phenotyping of Coarse Root Architecture in R. pseudoacacia Reveals That Tree Root System Plasticity Is Confined within Its Architectural Model

PubMed Central

Danjon, Frédéric; Khuder, Hayfa; Stokes, Alexia

2013-01-01

This study aims at assessing the influence of slope angle and multi-directional flexing and their interaction on the root architecture of Robinia pseudoacacia seedlings, with a particular focus on architectural model and trait plasticity. 36 trees were grown from seed in containers inclined at 0° (control) or 45° (slope) in a glasshouse. The shoots of half the plants were gently flexed for 5 minutes a day. After 6 months, root systems were excavated and digitized in 3D, and biomass measured. Over 100 root architectural traits were determined. Both slope and flexing increased significantly plant size. Non-flexed trees on 45° slopes developed shallow roots which were largely aligned perpendicular to the slope. Compared to the controls, flexed trees on 0° slopes possessed a shorter and thicker taproot held in place by regularly distributed long and thin lateral roots. Flexed trees on the 45° slope also developed a thick vertically aligned taproot, with more volume allocated to upslope surface lateral roots, due to the greater soil volume uphill. We show that there is an inherent root system architectural model, but that a certain number of traits are highly plastic. This plasticity will permit root architectural design to be modified depending on external mechanical signals perceived by young trees. PMID:24386227

Tree growth and management in Ugandan agroforestry systems: effects of root pruning on tree growth and crop yield.

PubMed

Wajja-Musukwe, Tellie-Nelson; Wilson, Julia; Sprent, Janet I; Ong, Chin K; Deans, J Douglas; Okorio, John

2008-02-01

Tree root pruning is a potential tool for managing belowground competition when trees and crops are grown together in agroforestry systems. We investigated the effects of tree root pruning on shoot growth and root distribution of Alnus acuminata (H.B. & K.), Casuarina equisetifolia L., Grevillea robusta A. Cunn. ex R. Br., Maesopsis eminii Engl. and Markhamia lutea (Benth.) K. Schum. and on yield of adjacent crops in sub-humid Uganda. The trees were 3 years old at the commencement of the study, and most species were competing strongly with crops. Tree roots were pruned 41 months after planting by cutting and back-filling a trench to a depth of 0.3 m, at a distance of 0.3 m from the trees, on one side of the tree row. The trench was reopened and roots recut at 50 and 62 months after planting. We assessed the effects on tree growth and root distribution over a 3 year period, and crop yield after the third root pruning at 62 months. Overall, root pruning had only a slight effect on aboveground tree growth: height growth was unaffected and diameter growth was reduced by only 4%. A substantial amount of root regrowth was observed by 11 months after pruning. Tree species varied in the number and distribution of roots, and C. equisetifolia and M. lutea had considerably more roots per unit of trunk volume than the other species, especially in the surface soil layers. Casuarina equisetifolia and M. eminii were the tree species most competitive with crops and G. robusta and M. lutea the least competitive. Crop yield data provided strong evidence of the redistribution of root activity following root pruning, with competition increasing on the unpruned side of tree rows. Thus, one-sided root pruning will be useful in only a few circumstances.

Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

PubMed

Silva, Lucas C R; Salamanca-Jimenez, Alveiro; Doane, Timothy A; Horwath, William R

2015-08-21

The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

Effects of soil freezing and drought stress on abscisic acid content of sugar maple sap and leaves.

PubMed

Bertrand, A; Robitaille, G; Nadeau, P; Boutin, R

1994-04-01

In 1991 and 1992, mature maple trees (Acer saccharum Marsh.) were freeze-stressed or drought-stressed by preventing precipitation (snow or rain) from reaching the forest floor under selected trees. Lack of snow cover caused a decrease in soil temperature to well below 0 degrees C from December to April and a lowering of the soil water content to 10%. The abscisic acid (ABA) concentration in the spring sap of deep-soil frost-stressed trees was significantly higher than in control or drought-stressed trees. The increase in ABA concentration in the xylem sap in the spring of 1991 and 1992 preceded symptoms of canopy decline and a decrease in leaf area that were observed during the summers of 1991 and 1992. These results suggest a role for ABA in root-to-shoot communication in response to environmental stress. The largest differences in ABA concentration induced by the treatments was found in sap collected at the end of sap flow. The increase in ABA concentration in spring sap at the end of the sap flow could be used as an early indicator of stress suffered by trees during the winter. Not only did the increase in ABA concentration occur before any visible symptoms of tree decline appeared, but the trees that showed the most evident decline had the highest ABA concentrations in the spring sap. Leaf ABA concentration was not a good indicator of induced stress.

Nutrient Intake of the Repatriated United States Army, Navy and Marine Corps Prisoners-of-War of the Vietnam War

DTIC Science & Technology

1978-11-01

species Banana flowers Hoa hien Cucurbita papo Linn. Pumpkin Cu toi Allium sativum Linn. Garlic Cu don do Daucus carota Linn. Carrot Cu he Allium...Jan Bananas Whole Year Round Nov - Jan Mangoes Apr - Jul May - Jun Pineapples Whole Year Round Jun - Aug Soybeans Jul - Jan Oct - Nov Coconuts Whole...Mang Tre Bambus a Ba,&boo shoots Hai Saccharum officinarum Linn. Sugar cane Choux Brassica Brussel sprouts Chuoi Musa Banana tree Bap chuol Musa

Spine micromorphology of normal and hyperhydric Mammillaria gracilis Pfeiff. (Cactaceae) shoots.

PubMed

Peharec, P; Posilović, H; Balen, B; Krsnik-Rasol, M

2010-07-01

Artificial conditions of tissue culture affect growth and physiology of crassulacean acid metabolism plants which often results in formation of hyperhydric shoots. In in vitro conditions Mammillaria gracilis Pfeiff. (Cactaceae) growth switches from organized to unorganized way, producing a habituated organogenic callus which simultaneously regenerates morphologically normal as well as altered hyperhydric shoots. In this study, influence of tissue culture conditions on morphology of cactus spines of normal and hyperhydric shoots was investigated. Spines of pot-grown Mammillaria plants and of in vitro regenerated shoots were examined with stereo microscope and scanning electron microscope. The pot-grown plants had 16-17 spines per areole. In vitro grown normal shoots, even though they kept typical shoot morphology, had lower number of spines (11-12) and altered spine morphology. This difference was even more pronounced in spine number (six to seven) and morphology of the hyperhydric shoots. Scanning electron microscopy analysis revealed remarkable differences in micromorphology of spine surface between pot-grown and in vitro grown shoots. Spines of in vitro grown normal shoots showed numerous long trichomes, which were more elongated on spines of the hyperhydric shoots; the corresponding structures on spine surface of pot-grown plants were noticed only as small protrusions. Scanning electron microscopy morphometric studies showed that the spines of pot-grown plants were significantly longer compared to the spines of shoots grown in tissue culture. Moreover, transverse section shape varies from elliptical in pot-grown plants to circular in normal and hyperhydric shoots grown in vitro. Cluster and correspondence analyses performed on the scanning electron microscope obtained results suggest great variability among spines of pot-grown plants. Spines of in vitro grown normal and hyperhydric shoots showed low level of morphological variation among themselves despite the significant difference in shoot morphology.

Novel species of Botryosphaeriaceae associated with shoot blight of pistachio.

PubMed

Chen, ShuaiFei; Li, GuoQing; Liu, FeiFei; Michailides, Themis J

2015-01-01

Various species of phytopathogenic Botryosphaeriaceae were identified previously from pistachio trees worldwide. Disease symptoms caused by pathogens in Botryosphaeriaceae on pistachio include panicle and shoot blight, leaf defoliation, fruit discoloration and decay. In this study species of Botryosphaeriaceae were collected from blighted pistachio shoots in Arizona, USA, and Greece. The aims of this study were to identify these Botryosphaeriaceae isolates and to test their pathogenicity to pistachio. The fungi were identified based on comparisons of DNA sequence data of the nuclear rDNA internal transcribed spacer region (ITS), a partial translation elongation factor 1-alpha gene (TEF1), a partial β-tubulin gene (TUB2) and morphological characteristics. Results indicated that some isolates collected from pistachio represent two previously undescribed species, which we described here as Lasiodiplodia americana sp. nov. from the United States and Neofusicoccum hellenicum sp. nov. from Greece. Field inoculations of L. americana and N. hellenicum on branches of four pistachio cultivars showed that both L. americana and N. hellenicum are pathogenic on pistachio. The four pistachio cultivars differed in their susceptibility to the Botryosphaeriaceae species. Results of this study suggested that the two new species of Botryosphaeriaceae need to be monitored carefully to determine the distribution of these pathogens and the possible spread to other areas. © 2015 by The Mycological Society of America.

Partial Root-Zone Drying of Olive (Olea europaea var. 'Chetoui') Induces Reduced Yield under Field Conditions.

PubMed

Dbara, Soumaya; Haworth, Matthew; Emiliani, Giovani; Ben Mimoun, Mehdi; Gómez-Cadenas, Aurelio; Centritto, Mauro

2016-01-01

The productivity of olive trees in arid and semi-arid environments is closely linked to irrigation. It is necessary to improve the efficiency of irrigation techniques to optimise the amount of olive fruit produced in relation to the volume of water used. Partial root-zone drying (PRD) is a water saving irrigation technique that theoretically allows the production of a root-to-shoot signal that modifies the physiology of the above-ground parts of the plant; specifically reducing stomatal conductance (gs) and improving water use efficiency (WUE). Partial root-zone drying has been successfully applied under field conditions to woody and non-woody crops; yet the few previous trials with olive trees have produced contrasting results. Thirty year-old olive trees (Olea europaea 'var. Chetoui') in a Tunisian grove were exposed to four treatments from May to October for three-years: 'control' plants received 100% of the potential evapotranspirative demand (ETc) applied to the whole root-zone; 'PRD100' were supplied with an identical volume of water to the control plants alternated between halves of the root-zone every ten-days; 'PRD50' were given 50% of ETc to half of the root-system, and; 'rain-fed' plants received no supplementary irrigation. Allowing part of the root-zone to dry resulted in reduced vegetative growth and lower yield: PRD100 decreased yield by ~47% during productive years. During the less productive years of the alternate bearing cycle, irrigation had no effect on yield; this suggests that withholding of water during 'off-years' may enhance the effectiveness of irrigation over a two-year cycle. The amount and quality of oil within the olive fruit was unaffected by the irrigation treatment. Photosynthesis declined in the PRD50 and rain-fed trees due to greater diffusive limitations and reduced biochemical uptake of CO2. Stomatal conductance and the foliar concentration of abscisic acid (ABA) were not altered by PRD100 irrigation, which may indicate the absence of a hormonal root-to-shoot signal. Rain-fed and PRD50 treatments induced increased stem water potential and increased foliar concentrations of ABA, proline and soluble sugars. The stomata of the olive trees were relatively insensitive to super-ambient increases in [CO2] and higher [ABA]. These characteristics of 'hydro-passive' stomatal behaviour indicate that the 'Chetoui' variety of olive tree used in this study lacks the physiological responses required for the successful exploitation of PRD techniques to increase yield and water productivity. Alternative irrigation techniques such as partial deficit irrigation may be more suitable for 'Chetoui' olive production.

Ephemerality of a Spring Ephemeral Gagea lutea (L.) is Attributable to Shoot Senescence Induced by Free Linolenic Acid.

PubMed

Iwanami, Hiroko; Takada, Noboru; Koda, Yasunori

2017-10-01

Spring ephemerals are a group of herbaceous plants that fulfill their life cycle on the floor of deciduous forests in temperate and boreal regions during a short period of time between snowmelt and closure of the tree canopy. Near the closure, these plants' shoots senesce rapidly and the plants disappear from the floor. Since the major role of the synchronous senescence is thought to be the recycling of nutrients from vegetative organs to seeds or storage organs, some endogenous compound that is capable of promoting senescence must be involved in the timely senescence. Strong senescence-promoting activity was found in extracts of shoots of a spring ephemeral, Gagea lutea (Liliaceae), and the activity in basal leaves reached a maximum just before the commencement of senescence. The active compound was identified as α-linolenic acid. The level, very low 1 week before flowering, increased rapidly with time and reached a maximum 1 week after flowering. Senescence was readily observed thereafter. The maximum amount of linolenic acid was >1 mmol kg FW-1 and could fully induce senescence of the leaves. The results suggest that the ephemerality of the plant or, in other words, short longevity of shoots, is brought about by the accumulation of linolenic acid. Programmed senescence, which can mitigate the cost of survival and reproduction, enables the plant to occupy a narrow niche on the forest floor. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

miRNA and Degradome Sequencing Reveal miRNA and Their Target Genes That May Mediate Shoot Growth in Spur Type Mutant “Yanfu 6”

PubMed Central

Song, Chunhui; Zhang, Dong; Zheng, Liwei; Zhang, Jie; Zhang, Baojuan; Luo, Wenwen; Li, Youmei; Li, Guangfang; Ma, Juanjuan; Han, Mingyu

2017-01-01

The spur-type growth habit in apple trees is characterized by short internodes, increased number of fruiting spurs, and compact growth that promotes flowering and facilitates management practices, such as pruning. The molecular mechanisms responsible for regulating spur-type growth have not been elucidated. In the present study, miRNAs and the expression of their potential target genes were evaluated in shoot tips of “Nagafu 2” (CF) and spur-type bud mutation “Yanfu 6” (YF). A total of 700 mature miRNAs were identified, including 202 known apple miRNAs and 498 potential novel miRNA candidates. A comparison of miRNA expression in CF and YF revealed 135 differentially expressed genes, most of which were downregulated in YF. YF also had lower levels of GA, ZR, IAA, and ABA hormones, relative to CF. Exogenous applications of GA promoted YF shoot growth. Based on the obtained results, a regulatory network involving plant hormones, miRNA, and their potential target genes is proposed for the molecular mechanism regulating the growth of YF. miRNA164, miRNA166, miRNA171, and their potential targets, and associated plant hormones, appear to regulate shoot apical meristem (SAM) growth. miRNA159, miRNA167, miRNA396, and their potential targets, and associated plant hormones appear to regulate cell division and internode length. This study provides a foundation for further studies designed to elucidate the mechanism underlying spur-type apple architecture. PMID:28424721

Changes in wood density, wood anatomy and hydraulic properties of the xylem along the root-to-shoot flow path in tropical rainforest trees.

PubMed

Schuldt, Bernhard; Leuschner, Christoph; Brock, Nicolai; Horna, Viviana

2013-02-01

It is generally assumed that the largest vessels are occurring in the roots and that vessel diameters and the related hydraulic conductance in the xylem are decreasing acropetally from roots to leaves. With this study in five tree species of a perhumid tropical rainforest in Sulawesi (Indonesia), we searched for patterns in hydraulic architecture and axial conductivity along the flow path from small-diameter roots through strong roots and the trunk to distal sun-canopy twigs. Wood density differed by not more than 10% across the different flow path positions in a species, and branch and stem wood density were closely related in three of the five species. Other than wood density, the wood anatomical and xylem hydraulic traits varied in dependence on the position along the flow path, but were unrelated to wood density within a tree. In contrast to reports from conifers and certain dicotyledonous species, we found a hump-shaped variation in vessel diameter and sapwood area--specific conductivity along the flow path in all five species with a maximum in the trunk and strong roots and minima in both small roots and twigs; the vessel size depended on the diameter of the organ. This pattern might be an adaptation to the perhumid climate with a low risk of hydraulic failure. Despite a similar mean vessel diameter in small roots and twigs, the two distal organs, hydraulically weighted mean vessel diameters were on average 30% larger in small roots, resulting in ∼ 85% higher empirical and theoretical specific conductivities. Relative vessel lumen area in percent of sapwood area decreased linearly by 70% from roots to twigs, reflecting the increase in sclerenchymatic tissue and tracheids in acropetal direction in the xylem. Vessel size was more closely related to the organ diameter than to the distance along the root-to-shoot flow path. We conclude that (i) the five co-occurring tree species show convergent patterns in their hydraulic architecture despite different growth strategies, and (ii) the paradigm assuming continuous acropetal vessel tapering and decrease in specific conductance from fine roots towards distal twigs needs reconsideration.

A Secondary Spatial Analysis of Gun Violence near Boston Schools: a Public Health Approach.

PubMed

Barboza, Gia

2018-06-01

School neighborhood violence continues to be a major public health problem among urban students. A large body of research addresses violence at school; however, fewer studies have explored concentrations of violence in areas proximal to schools. This study aimed to quantify the concentration of shootings near schools to elucidate the place-based dynamics that may be focal points for violence prevention. Geocoded databases of shooting and school locations were used to examine locational patterns of firearm shootings and elementary, middle, and high schools in Boston, Massachusetts. Analyses utilized spatial statistics for point pattern data including distance matrix and K function methodology to quantify the degree of spatial dependence of shootings around schools. Results suggested that between 2012 and 2015, there were 678 shooting incidents in Boston; the average density was 5.1 per square kilometer. The nearest neighbor index (NNI = 0.335 km, p < .001, O = 0.95 km, E = 0.28 km) and G function analysis revealed a clustered pattern of gun shooting incidents indicative of a spatially non-random process. The mean and median distance from any school to the nearest shooting location was 0.35 and 0.33 km, respectively. A majority (56%, 74/133) of schools in Boston had at least one shooting incident within 400 m, a distance that would take about 5 min to walk if traveling by foot. The bivariate K function indicated that a significantly greater number of shootings were clustered within short distances from schools than would be expected under a null hypothesis of no spatial dependence. Implications for students attending schools in racially homogenous neighborhoods across all income levels are discussed.

Drive-by shootings by violent street gangs in Los Angeles: a five-year review from 1989 to 1993.

PubMed

Huston, H R; Anglin, D; Eckstein, M

1996-04-01

To determine trends in the numbers of drive-by shootings, individuals shot at, innocent bystanders shot at, and homicides by drive-by shootings in the city of Los Angeles from 1989 to 1993. A retrospective analysis of police records was performed for all gang-related drive-by shootings that occurred in the city of Los Angeles between 1989 and 1993. From 1989 to 1993, there were 6,327 drive-by shootings, 9,053 people shot at, and 590 homicides. There was an increase in drive-by shootings, people shot at, and homicides between 1989 and 1991, followed by a decrease between 1991 and 1993. The case fatality ratio of individuals killed to individuals shot at increased from 1989 to 1993 (p = 0.0011). Forty-seven percent of the people shot at, and 23% of the homicide victims, were innocent bystanders. Drive-by shootings are a major public health problem in Los Angeles. While the rate of drive-by shootings decreased in 1992 and 1993, the proportion of fatal cases increased. To prevent drive-by shootings, the root causes of violent street gang formation must be addressed.

Genetic stability assessment of wWasabi plants regenerated from long-term cryopreserved shoot tips using morphological, biochemical and molecular analysis.

PubMed

Matsumoto, Toshikazu; Akihiro, Takashi; Maki, Shinya; Mochida, Kouhei; Kitagawa, Masaru; Tanaka, Daisuke; Yamamoto, Shin-Ichi; Niino, Takao

2013-01-01

This study compared the effect of cryopreserved storage duration of wasabi shoot tips, which derived from the same in vitro mother-plant. We compared the survival of shoot tips and the genetic stability of regenerated plants originating from four experimental groups: shoot tips stored in a -150°C deep-freezer for 10 years; shoot tips stored in liquid nitrogen for 2 h; shoot tips treated with PVS2 vitrification solution; and untreated controls. No significant difference in survival was observed between the four experimental groups. Survival ranged between 93 and 100%. Genetic stability of plants regenerated from cryopreserved shoot tips was assessed over a period of 24 months using morphological, biochemical and molecular markers. While glucose, fructose and glutamic acid concentrations differed slightly between experimental groups after 16 months, these differences disappeared after 24 months. No significant differences were noted for the morphological markers studied (petiole length, shoot number and leaf index). No differences were observed in RAPD profiles obtained with the six primers tested.

Effects of mistletoe removal on growth, N and C reserves, and carbon and oxygen isotope composition in Scots pine hosts

PubMed Central

Yan, Cai-Feng; Gessler, Arthur; Rigling, Andreas; Dobbertin, Matthias; Han, Xing-Guo; Li, Mai-He

2016-01-01

Most mistletoes are xylem-tapping hemiparasites, which derive their resources from the host’s xylem solution. Thus, they affect the host’s water relations and resource balance. To understand the physiological mechanisms underlying the mistletoe–host relationship, we experimentally removed Viscum album ssp. austriacum (Wiesb.) Vollmann from adult Pinus sylvestris L. host trees growing in a Swiss dry valley. We analyzed the effects of mistletoe removal over time on host tree growth and on concentrations of nonstructural carbohydrates (NSC) and nitrogen (N) in needles, fine roots and sapwood. In addition, we assessed the δ13C and δ18O in host tree rings. After mistletoe removal, δ13C did not change in newly produced tree rings compared with tree rings in control trees (still infected with mistletoe), but δ18O values increased. This pattern might be interpreted as a decrease in assimilation (A) and stomatal conductance (gs), but in our study, it most likely points to an inadequacy of the dual isotope approach. Instead, we interpret the unchanged δ13C in tree rings upon mistletoe removal as a balanced increase in A and gs that resulted in a constant intrinsic water use efficiency (defined as A/gs). Needle area-based concentrations of N, soluble sugars and NSC, as well as needle length, single needle area, tree ring width and shoot growth, were significantly higher in trees from which mistletoe was removed than in control trees. This finding suggests that mistletoe removal results in increased N availability and carbon gain, which in turn leads to increased growth rates of the hosts. Hence, in areas where mistletoe is common and the population is large, mistletoe management (e.g., removal) may be needed to improve the host vigor, growth rate and productivity, especially for relatively small trees and crop trees in xeric growth conditions. PMID:27083524

Effects of mistletoe removal on growth, N and C reserves, and carbon and oxygen isotope composition in Scots pine hosts.

PubMed

Yan, Cai-Feng; Gessler, Arthur; Rigling, Andreas; Dobbertin, Matthias; Han, Xing-Guo; Li, Mai-He

2016-05-01

Most mistletoes are xylem-tapping hemiparasites, which derive their resources from the host's xylem solution. Thus, they affect the host's water relations and resource balance. To understand the physiological mechanisms underlying the mistletoe-host relationship, we experimentally removed Viscum album ssp. austriacum (Wiesb.) Vollmann from adult Pinus sylvestris L. host trees growing in a Swiss dry valley. We analyzed the effects of mistletoe removal over time on host tree growth and on concentrations of nonstructural carbohydrates (NSC) and nitrogen (N) in needles, fine roots and sapwood. In addition, we assessed the δ(13)C and δ(18)O in host tree rings. After mistletoe removal, δ(13)C did not change in newly produced tree rings compared with tree rings in control trees (still infected with mistletoe), but δ(18)O values increased. This pattern might be interpreted as a decrease in assimilation (A) and stomatal conductance (gs), but in our study, it most likely points to an inadequacy of the dual isotope approach. Instead, we interpret the unchanged δ(13)C in tree rings upon mistletoe removal as a balanced increase in A and gs that resulted in a constant intrinsic water use efficiency (defined as A/gs). Needle area-based concentrations of N, soluble sugars and NSC, as well as needle length, single needle area, tree ring width and shoot growth, were significantly higher in trees from which mistletoe was removed than in control trees. This finding suggests that mistletoe removal results in increased N availability and carbon gain, which in turn leads to increased growth rates of the hosts. Hence, in areas where mistletoe is common and the population is large, mistletoe management (e.g., removal) may be needed to improve the host vigor, growth rate and productivity, especially for relatively small trees and crop trees in xeric growth conditions. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

In vitro regeneration and ploidy level analysis of Eulophia ochreata Lindl.

PubMed

Shriram, Varsha; Nanekar, Vikas; Kumar, Vinay; Kavi Kishor, P B

2014-11-01

Various parameters including explant-type, medium compositions, use of phytohormones and additives were optimized for direct and indirect regeneration of E. ochreata, a medicinal orchid under threat. Protocorm-like-bodies (PLBs) proved to be the best explants for shoot initiation, proliferation and callus induction. Murashige and Skoog's (MS) medium containing 2.5 mg L(-1) 6-benzylaminopurine (BAP), 1.0 mg L(-1) kinetin (Kin) and additives (adenine sulfate, arginine, citric acid, 30 mg L(-1) each and 50 mg L(-1) ascorbic acid) was optimal for shoot multiplication (12.1 shoots and 7.1 PLBs per explant with synchronized growth), which also produced callus. Shoot number was further increased with three successive subcultures on same media and approximately 40 shoots per explant were achieved after 3 cycles of 30 days each. Additives and casein hydrolysate (CH) showed advantageous effects on indirect shoot regeneration via protocorm-derived callus. Optimum indirect regeneration was achieved on MS containing additives, 500 mg L(-1) CH, 2.5 mg L(-1) BAP and 1.0 mg L(-1) Kin with 30 PLBs and 6 shoots per callus mass (approximately 5 mm size). The shoots were rooted (70% frequency) on one by fourth-MS medium containing 2.0 mg L(-1) indole-3-butyric acid, 200 mg L(-1) activated charcoal and additives. The rooted plantlets were hardened and transferred to greenhouse with 63% survival rate. Flow-cytometry based DNA content analysis revealed that the ploidy levels were maintained in in vitro regenerated plants. This is the first report for in vitro plant regeneration in E. ochreata.

In vitro propagation of persimmon (Diospyros kaki Thunb.).

PubMed

Giordani, Edgardo; Naval, Mar; Benelli, Carla

2013-01-01

Persimmon (Diospyros kaki Thunb.) is a temperate fruit tree species diffused in all continents. The traditional propagation method adopted by the nursery industry is based on budding/grafting scion cultivars on seedlings from D. kaki, Diospyros lotus, and Diospyros virginiana, the most important species used as rootstock, reproduced by seeds since they are not easy to root. Furthermore, most of nonastringent cultivars of persimmon are not compatible with D. lotus, a rootstock largely utilized because of its hardiness and frost resistance. The main in vitro tissue culture techniques, developed for persimmon, deal with direct regeneration (from dormant buds and root tips), and indirect regeneration through callus from dormant buds, apexes, and leaves. The bottlenecks of micropropagation are (1) the recalcitrance of many cultivars to in vitro establishment, (2) the low multiplication ratio of D. kaki compared to other fruit tree species, (3) the very low rooting ability of ex novo microcuttings both from direct and indirect regeneration, (4) the high sensitivity to transplant from in vitro to in vivo conditions. The development of reliable in vitro regeneration procedures is likely to play a key role for production of both clonal rootstocks and self-rooted cultivars. The general protocol for micropropagation of persimmon reported here is based on the establishment of winter dormant buds in vitro, shoot development, multiplication and elongation, and shoot rooting, using cytokinins (BA or zeatin) in a MS media along with an auxinic pretreatment for rooting induction.

Site-Dependent Differences in DNA Methylation and Their Impact on Plant Establishment and Phosphorus Nutrition in Populus trichocarpa.

PubMed

Schönberger, Brigitte; Chen, Xiaochao; Mager, Svenja; Ludewig, Uwe

2016-01-01

The propagation via clonal stem cuttings is a frequent practice in tree plantations. Despite their clonal origin, the trees establish differently according to weather, temperature and nutrient availability, as well as the presence of various stresses. Here, clonal Populus trichocarpa (cv. Muhle Larson) cuttings from different sites were transferred into a common, fully nutrient supplied environment. Despite identical underlying genetics, stem cuttings derived from sites with lower phosphorus availability established worse, independent of phosphorus (P) level after transplantation. Differential growth of material from the sites was reflected in differences in the whole genome DNA methylome. Methylation differences were sequence context-dependent, but differentially methylated regions (DMRs) were apparently unrelated to P nutrition genes. Despite the undisputed negative general correlation of DNA promoter methylation with gene repression, only few of the top-ranked DMRs resulted in differential gene expression in roots or shoots. However, differential methylation was associated with site-dependent, different total amounts of microRNAs (miRNAs), with few miRNAs sequences directly targeted by differential methylation. Interestingly, in roots and shoots, the miRNA amount was dependent on the previous habitat and changed in roots in a habitat-dependent way under phosphate starvation conditions. Differentially methylated miRNAs, together with their target genes, showed P-dependent expression profiles, indicating miRNA expression differences as a P-related epigenetic modification in poplar. Together with differences in DNA methylation, such epigenetic mechanisms may explain habitat or seasonal memory in perennials and site-dependent growth performances.

Post-transcriptional gene silencing in the root system of the actinorhizal tree Allocasuarina verticillata.

PubMed

Gherbi, Hassen; Nambiar-Veetil, Mathish; Zhong, Chonglu; Félix, Jessy; Autran, Daphné; Girardin, Raphaël; Vaissayre, Virginie; Auguy, Florence; Bogusz, Didier; Franche, Claudine

2008-05-01

In recent years, RNA interference has been exploited as a tool for investigating gene function in plants. We tested the potential of double-stranded RNA interference technology for silencing a transgene in the actinorhizal tree Allocasuarina verticillata. The approach was undertaken using stably transformed shoots expressing the beta-glucuronidase (GUS) gene under the control of the constitutive promoter 35S; the shoots were further transformed with the Agrobacterium rhizogenes A4RS containing hairpin RNA (hpRNA) directed toward the GUS gene, and driven by the 35S promoter. The silencing and control vectors contained the reporter gene of the green fluorescent protein (GFP), thus allowing a screening of GUS-silenced composite plantlets for autofluorescence. With this rapid procedure, histochemical data established that the reporter gene was strongly silenced in both fluorescent roots and actinorhizal nodules. Fluorometric data further established that the level of GUS silencing was usually greater than 90% in the hairy roots containing the hairpin GUS sequences. We found that the silencing process of the reporter gene did not spread to the aerial part of the composite A. verticillata plants. Real-time quantitative polymerase chain reaction showed that GUS mRNAs were substantially reduced in roots and, thereby, confirmed the knock-down of the GUS transgene in the GFP(+) hairy roots. The approach described here will provide a versatile tool for the rapid assessment of symbiotically related host genes in actinorhizal plants of the Casuarinaceae family.

Actinomycetes from Eucalyptus and their biological activities for controlling Eucalyptus leaf and shoot blight.

PubMed

Himaman, Winanda; Thamchaipenet, Arinthip; Pathom-Aree, Wasu; Duangmal, Kannika

2016-01-01

In Thailand, Eucalyptus plantations rapidly expand across the country. Leaf and shoot blight caused by Cryptosporiopsis eucalypti, Cylindrocladium sp. and Teratosphaeria destructans is a serious disease in Eucalyptus plantations. In this study, a total of 477 actinomycete strains were successfully isolated from roots and rhizosphere soil of Eucalyptus. Four hundred and thirty nine isolates were classified as streptomycetes and 38 isolates were non-streptomycetes. Among these isolates, 272 (57.0%), 118 (24.7%) and 241 (50.5%) isolates were antagonistic to Cryptosporiopsis eucalypti, Cylindrocladium sp. and Teratosphaeria destructans, respectively. All isolates were tested for their abilities to produce siderophores, indole acetic acid (IAA) and solubilise phosphate. Most isolates (464, 97.3%) produced siderophores. The majority of isolates (345, 72.3%) solubilised phosphate. In addition, almost half of these isolates (237, 49.7%) produced indole acetic acid. Strain EUSKR2S82 which showed the strongest inhibitory effect against all tested fungi with plant growth promoting ability was selected to test with Eucalyptus. This strain could colonize plant roots and increase Eucalyptus roots length. In a detached leaves bioassay, the disease severity of EUSKR2S82-inoculated Eucalyptus leaves was only 30% compared to 95% in the control treatment. The 16S rRNA gene sequence analysis revealed that the strain EUSKR2S82 was related to Streptomyces ramulosus NRRL-B 2714(T) (99.44% similarity). Identification of non-streptomycete isolates using 16S rRNA gene sequences classified them into 9 genera: Actinoallomurus, Actinomadura, Amycolatopsis, Cryptosporangium, Microbispora, Micromonospora, Nocardia, Nonomuraea and Pseudonocardia. It is evident that Eucalyptus tree harbored several genera of actinomycetes. The selected isolate, EUSKR2S82 showed potential as a candidate for biocontrol agent of leaf and shoot blight of Eucalyptus and to promote growth. Copyright © 2016 Elsevier GmbH. All rights reserved.

Dress-Related Responses to the Columbine Shootings: Other-Imposed and Self-Designed.

ERIC Educational Resources Information Center

Ogle, Jennifer Paff; Eckman, Molly

2002-01-01

An inductive content analysis approach was used to examine 155 dress-related newspaper articles following the Columbine High School shootings in 1999. Analysis revealed two dress-related responses: (1) other-imposed regulation to protect students and deter them from expressing hatred and (2) self-designed acts of resistance for grieving. (Contains…

Above and below ground carbohydrate allocation differs between ash (Fraxinus excelsior L.) and beech (Fagus sylvatica L.)

PubMed Central

Thoms, Ronny; Köhler, Michael; Gessler, Arthur

2017-01-01

We investigated soluble carbohydrate transport in trees that differed in their phloem loading strategies in order to better understand the transport of photosynthetic products into the roots and the rhizosphere as this knowledge is needed to better understand the respiratory processes in the rhizosphere. We compared beech, which is suggested to use mainly passive loading of transport sugars along a concentration gradient into the phloem, with ash that uses active loading and polymer trapping of raffinose family oligosaccharides (RFOs). We pulse-labeled 20 four-year old European beech and 20 four-year old ash trees with 13CO2 and tracked the fate of the label within different plant compartments. We extracted soluble carbohydrates from leaves, bark of stems and branches, and fine roots, measured their amount and isotopic content and calculated their turnover times. In beech one part of the sucrose was rapidly transported into sink tissues without major exchange with storage pools whereas another part of sucrose was strongly exchanged with unlabeled possibly stored sucrose. In contrast the storage and allocation patterns in ash depended on the identity of the transported sugars. RFO were the most important transport sugars that had highest turnover in all shoot compartments. However, the turnover of RFOs in the roots was uncoupled from the shoot. The only significant relation between sugars in the stem base and in the roots of ash was found for the amount (r2 = 0.50; p = 0.001) and isotopic content (r2 = 0.47; p = 0.01) of sucrose. The negative relation of the amounts suggested an active transport of sucrose into the roots of ash. Sucrose concentration in the root also best explained the concentration of RFOs in the roots suggesting that RFO in the roots of ash may be resynthesized from sucrose. Our results interestingly suggest that in both tree species only sucrose directly entered the fine root system and that in ash RFOs are transported indirectly into the fine roots only. The direct transport of sucrose might be passive in beech but active in ash (sustained active up- and unloading to co-cells), which would correspond to the phloem loading strategies. Our results give first hints that the transport of carbohydrates between shoot and root is not necessarily continuous and involves passive (beech) and active (ash) transport processes, which may be controlled by the phloem unloading. PMID:28934229

Hydraulic constraints modify optimal photosynthetic profiles in giant sequoia trees.

PubMed

Ambrose, Anthony R; Baxter, Wendy L; Wong, Christopher S; Burgess, Stephen S O; Williams, Cameron B; Næsborg, Rikke R; Koch, George W; Dawson, Todd E

2016-11-01

Optimality theory states that whole-tree carbon gain is maximized when leaf N and photosynthetic capacity profiles are distributed along vertical light gradients such that the marginal gain of nitrogen investment is identical among leaves. However, observed photosynthetic N gradients in trees do not follow this prediction, and the causes for this apparent discrepancy remain uncertain. Our objective was to evaluate how hydraulic limitations potentially modify crown-level optimization in Sequoiadendron giganteum (giant sequoia) trees up to 90 m tall. Leaf water potential (Ψ l ) and branch sap flow closely followed diurnal patterns of solar radiation throughout each tree crown. Minimum leaf water potential correlated negatively with height above ground, while leaf mass per area (LMA), shoot mass per area (SMA), leaf nitrogen content (%N), and bulk leaf stable carbon isotope ratios (δ(13)C) correlated positively with height. We found no significant vertical trends in maximum leaf photosynthesis (A), stomatal conductance (g s), and intrinsic water-use efficiency (A/g s), nor in branch-averaged transpiration (E L), stomatal conductance (G S), and hydraulic conductance (K L). Adjustments in hydraulic architecture appear to partially compensate for increasing hydraulic limitations with height in giant sequoia, allowing them to sustain global maximum summer water use rates exceeding 2000 kg day(-1). However, we found that leaf N and photosynthetic capacity do not follow the vertical light gradient, supporting the hypothesis that increasing limitations on water transport capacity with height modify photosynthetic optimization in tall trees.

Trade-offs between water transport capacity and drought resistance in neotropical canopy liana and tree species.

PubMed

De Guzman, Mark E; Santiago, Louis S; Schnitzer, Stefan A; Álvarez-Cansino, Leonor

2017-10-01

In tropical forest canopies, it is critical for upper shoots to efficiently provide water to leaves for physiological function while safely preventing loss of hydraulic conductivity due to cavitation during periods of soil water deficit or high evaporative demand. We compared hydraulic physiology of upper canopy trees and lianas in a seasonally dry tropical forest to test whether trade-offs between safety and efficiency of water transport shape differences in hydraulic function between these two major tropical woody growth forms. We found that lianas showed greater maximum stem-specific hydraulic conductivity than trees, but lost hydraulic conductivity at less negative water potentials than trees, resulting in a negative correlation and trade-off between safety and efficiency of water transport. Lianas also exhibited greater diurnal changes in leaf water potential than trees. The magnitude of diurnal water potential change was negatively correlated with sapwood capacitance, indicating that lianas are highly reliant on conducting capability to maintain leaf water status, whereas trees relied more on stored water in stems to maintain leaf water status. Leaf nitrogen concentration was related to maximum leaf-specific hydraulic conductivity only for lianas suggesting that greater water transport capacity is more tied to leaf processes in lianas compared to trees. Our results are consistent with a trade-off between safety and efficiency of water transport and may have implications for increasing liana abundance in neotropical forests. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Seasonal changes in amino acids, protein and total nitrogen in needles of fertilized Scots pine trees.

PubMed

Näsholm, T; Ericsson, A

1990-09-01

Seasonal changes in amino acids, protein and total nitrogen in needles of 30-year-old, fertilized Scots pine (Pinus sylvestris L.) trees growing in Northern Sweden were investigated over two years in field experiments. The studied plots had been fertilized annually for 17 years with (i) a high level of N, (ii) a medium level of N, or (iii) a medium level of N, P and K. Trees growing on unfertilized plots served as controls. In control trees, glutamine, glutamic acid, gamma-aminobutyric acid, aspartic acid and proline represented 50-70% of the total free amino acids determined. Arginine was present only in low concentrations in control trees throughout the year, but it was usually the most abundant amino acid in fertilized trees. Glutamine concentrations were high during the spring and summer in both years of study, whereas proline concentrations were high in the spring but otherwise low throughout the year. In the first year of study, glutamic acid concentrations were high during the spring and summer, whereas gamma-aminobutyric acid was present in high concentrations during the winter months. This pattern was less pronounced in the second year of investigation. The concentrations of most amino acids, except glutamic acid, increased in response to fertilization. Nitrogen fertilization increased the foliar concentration of arginine from < 1 micromol g(dw) (-1) in control trees to a maximum of 110 micromol g(dw) (-1). Trees fertilized with nitrogen, phosphorus and potassium had significantly lower arginine concentrations than trees fertilized with the same amount of nitrogen only. Protein concentrations were similar in all fertilized trees but higher than those in control trees. For all treatments, protein concentrations were high in winter and at a minimum in early spring. In summer, the protein concentration remained almost constant except for a temporary decrease which coincided with the expansion of new shoots. Apart from arginine, the amino acid composition of proteins was similar in all treatments.

RESEARCH: Shrub Propagation Techniques for Biological Control ofInvading Tree Species

PubMed

Meilleur; Veronneau; Bouchard

1997-05-01

/ The use of relatively stable shrub communities to control invasionby trees could be an efficient way of reducing herbicide applications, andthus represents an environmental gain, in areas such as rights-of-way. Thequestion is how to favor the expansion of these relatively stable shrubcommunities using different propagation techniques. Three experimentaltreatments, cutting back, layering, and cutting back-layering were performedon Cornus stolonifera, Salix petiolaris, and Spiraea albaclones already located within the corridor of an electrical power line. Toestablish the efficiency of treatments, we examined the statisticaldifferences of growth traits between species and treatments.An analysis of the effects of layering shows, after the first growth season,differences for all growth traits in only one species, Spiraea alba.After the second growth season, we observed the development of new aerialstems. Layering favors horizontal expansion of shrubs over heightdevelopment. The third year after treatment, the effect of layering isreduced except for Cornus stolonifera, which continuously increases,as shown by the significant progression of the clone issued from the layereven five years after treatments. With the cutting back technique, weexpected a distinct vertical growth of the shrubs at the expense ofincreasing the crown diameter. This technique would be best associated withthe rejuvenation of clones, followed by a layering of new shoots to allow ahorizontal expansion of the shrubs. Therefore, the formation of a dense shrubcommunity by layering should be considered a valuable approach for thebiological control of undesirable trees in powerline rights-of-way.KEY WORDS: Layering; Cutting back; Right-of-way; Cornus stolonifera;Salix petiolaris; Spiraea alba; Quebec

Identifying ontogenetic, environmental and individual components of forest tree growth

PubMed Central

Chaubert-Pereira, Florence; Caraglio, Yves; Lavergne, Christian; Guédon, Yann

2009-01-01

Background and Aims This study aimed to identify and characterize the ontogenetic, environmental and individual components of forest tree growth. In the proposed approach, the tree growth data typically correspond to the retrospective measurement of annual shoot characteristics (e.g. length) along the trunk. Methods Dedicated statistical models (semi-Markov switching linear mixed models) were applied to data sets of Corsican pine and sessile oak. In the semi-Markov switching linear mixed models estimated from these data sets, the underlying semi-Markov chain represents both the succession of growth phases and their lengths, while the linear mixed models represent both the influence of climatic factors and the inter-individual heterogeneity within each growth phase. Key Results On the basis of these integrative statistical models, it is shown that growth phases are not only defined by average growth level but also by growth fluctuation amplitudes in response to climatic factors and inter-individual heterogeneity and that the individual tree status within the population may change between phases. Species plasticity affected the response to climatic factors while tree origin, sampling strategy and silvicultural interventions impacted inter-individual heterogeneity. Conclusions The transposition of the proposed integrative statistical modelling approach to cambial growth in relation to climatic factors and the study of the relationship between apical growth and cambial growth constitute the next steps in this research. PMID:19684021

Effects of alternate drip irrigation and superabsorbent polymers on growth and water use of young coffee tree.

PubMed

Liu, Xiaogang; Li, Fusheng; Yang, Qiliang; Wang, Xinle

2016-07-01

To obtain optimal irrigation management for young coffee tree, the effects of alternate drip irrigation (ADI) and superabsorbent polymers on physiology, growth, dry mass accumulation and water use on one-year old Coffea arabica L. tree were investigated. This experiment had three drip irrigation methods, i.e., conventional drip irrigation (CDI), alternate drip irrigation (ADI) and fixed drip irrigation (FDI), and two levels of superabsorbent polymers, i.e., no superabsorbent polymers (NSAP) and added superabsorbent polymers (SAP). Compared to CDI, ADI saved irrigation water by 32.1% and increased water use efficiency (WUE) by 29.9%. SAP increased root-shoot ratio, total dry mass and WUE by 20.3, 24.9 and 33.0%, respectively, when compared to NSAP. Compared to CDI with NSAP treatment, ADI with SAP treatment increased total dry mass by 13.8% and saved irrigation water by 34.4%, thus increased WUE by 73.4%, and it increased root activity, the contents of chlorophyll and soluble sugar in leaves by 162.4, 38.0 and 8.5%, but reduced the contents of proline and malondialdehyde in leaves by 7.2 and 9.7%, respectively. Thus, alternate drip irrigation with superabsorbent polymers increased the growth and WUE of young Coffea arabica L. tree and was optimal irrigation management for young coffee tree.

Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees

PubMed Central

Silva, Lucas C. R.; Salamanca-Jimenez, Alveiro; Doane, Timothy A.; Horwath, William R.

2015-01-01

The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases (13CO2 and 15NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the 13CO2 pulse, assimilation and transport of the 15NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history. PMID:26294035

Trees Containing Built-In Pulping Catalysts - Final Report - 08/18/1997 - 08/18/2000

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

Pullman, G.; Dimmel, D.; Peter, G.

2000-08-18

Several hardwood and softwood trees were analyzed for the presence of anthraquinone-type molecules. Low levels of anthraquinone (AQ) and anthrone components were detected using gas chromatography-mass spectroscopy and sensitive selected-ion monitoring techniques. Ten out of seventeen hardwood samples examined contained AQ-type components; however, the levels were typically below {approximately}6 ppm. No AQs were observed in the few softwood samples that were examined. The AQs were more concentrated in the heartwood of teak than in the sapwood. The delignification of pine was enhanced by the addition of teak chips ({approximately}0.7% AQ-equivalence content) to the cook, suggesting that endogenous AQs can bemore » released from wood during pulping and can catalyze delignification reactions. Eastern cottonwood contained AQ, methyl AQ, and dimethyl AQ, all useful for wood pulping. This is the first time unsubstituted AQ has been observed in wood extracts. Due to the presence of these pulping catalysts, rapid growth rates in plantation settings, and the ease of genetic transformation, eastern cottonwood is a suitable candidate for genetic engineering studies to enhance AQ content. To achieve effective catalytic pulping activity, poplar and cottonwood, respectively, require {approximately}100 and 1000 times more for pulping catalysts. A strategy to increase AQ concentration in natural wood was developed and is currently being tested. This strategy involves ''turning up'' isochorismate synthase (ICS) through genetic engineering. Isochorismate synthase is the first enzyme in the AQ pathway branching from the shikimic acid pathway. In general, the level of enzyme activity at the first branch point or committed step controls the flux through a biosynthetic pathway. To test if the level of ICS regulates AQ biosynthesis in plant tissues, we proposed to over-express this synthase in plant cells. A partial cDNA encoding a putative ICS was available from the random cDNA sequencing project carried out with Arabidopsis thaliana. We used this putative plant ICS gene fragment to isolate and sequence a full-length ICS cDNA from Arabidopsis thaliana. The putative full-length cDNA encodes for a 569 amino acid protein of {approximately}62kDa. This sequence represents the first full-length ICS cDNA isolated from a plant. When inserted into E. coli, our isolated cDNA over-expressed ICS protein in the insoluble inclusion bodies. A plant expression vector containing the ICS cDNA, NP II for selection on the antibiotic kanamycin, and duplicated 35S-cauliflower mosaic virus promoter were inserted into Agrobacterium tumefaciens strain GV3101. Transformation experiments for insertion of these foreign genes into Populus deltoides 'C175' resulted in eight lines able to regenerate shoots and grow roots in the presence of kanamycin. Plants from these eight lines have acclimated to growth in sterile soil and will be moved to a greenhouse environment in spring 2001. Non rooted shoots from each line are currently being multiplied by shoot culture. When enough shoot tissue and/or greenhouse plant stem tissue is available, AQ analysis will be done and compared with non transformed control tissue.« less

Genetic and environmental control of seasonal carbohydrate dynamics in trees of diverse Pinus sylvestris populations.

PubMed

Oleksyn, J.; Zytkowiak, R.; Karolewski, P.; Reich, P. B.; Tjoelker, M. G.

2000-06-01

We explored environmental and genetic factors affecting seasonal dynamics of starch and soluble nonstructural carbohydrates in needle and twig cohorts and roots of Scots pine (Pinus sylvestris L.) trees of six populations originating between 49 degrees and 60 degrees N, and grown under common garden conditions in western Poland. Trees of each population were sampled once or twice per month over a 3-year period from age 15 to 17 years. Based on similarity in starch concentration patterns in needles, two distinct groups of populations were identified; one comprised northern populations from Sweden and Russia (59-60 degrees N), and another comprised central European populations from Latvia, Poland, Germany and France (49-56 degrees N). Needle starch concentrations of northern populations started to decline in late spring and reached minimum values earlier than those of central populations. For all populations, starch accumulation in spring started when minimum air temperature permanently exceeded 0 degrees C. Starch accumulation peaked before bud break and was highest in 1-year-old needles, averaging 9-13% of dry mass. Soluble carbohydrate concentrations were lowest in spring and summer and highest in autumn and winter. There were no differences among populations in seasonal pattern of soluble carbohydrate concentrations. Averaged across all populations, needle soluble carbohydrate concentrations increased from about 4% of needle dry mass in developing current-year needles, to about 9% in 1- and 2-year-old needles. Root carbohydrate concentration exhibited a bimodal pattern with peaks in spring and autumn. Northern populations had higher concentrations of fine-root starch in spring and autumn than central populations. Late-summer carbohydrate accumulation in roots started only after depletion of starch in needles and woody shoots. We conclude that Scots pine carbohydrate dynamics depend partially on inherited properties that are probably related to phenology of root and shoot growth.

Competitive success of southern populations of Betula pendula and Sorbus aucuparia under simulated southern climate experiment in the subarctic.

PubMed

Taulavuori, Kari; Taulavuori, Erja; Saravesi, Karita; Jylänki, Tanja; Kainulainen, Aila; Pajala, Jonna; Markkola, Annamari; Suominen, Otso; Saikkonen, Kari

2017-06-01

Global warming has been commonly accepted to facilitate species' range shifts across latitudes. Cross-latitudinal transplantations support this; many tree species can well adapt to new geographical areas. However, these studies fail to capture species' adaptations to new light environment because the experiments were not designed to explicitly separate species' responses to light and temperature. Here we tested reaction norms of tree seedlings in reciprocal transplantations 1,000 km apart from each other at two latitudes (60°N and 69°N). In contrast to past studies, we exposed our experimental plants to same temperature in both sites (temperature of 60°N growing site is recorded to adjust temperature of 69°N site in real time via Internet connection) while light environment (photoperiod, light quality) remained ambient. Shoot elongation and autumn coloration were studied in seedlings of two deciduous trees ( Betula pendula and Sorbus aucuparia ), which were expected to respond differently to day length. Sorbus as a member of Rosaceae family was assumed to be indifferent to photoperiod, while Betula responds strongly to day length. We hypothesized that (1) southern and northern populations of both species perform differently; (2) southern populations perform better in both sites; (3) autumn phenology of southern populations may delay in the northern site; (4) and Sorbus aucuparia is less dependent on light environment. According to the hypotheses, shoot elongation of northern population was inherently low in both species. An evolutionary consequence of this may be a competitive success of southern populations under warming climate. Southern population of B. pendula was delayed in autumn coloration, but not in growth cessation. Sorbus aucuparia was less responsive to light environment. The results suggest that light provides selection pressure in range shifts, but the response is species dependent.

76 FR 59156 - Notice of Availability of the Proposed Ironwood Forest National Monument Resource Management Plan...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-23

... issues, recreation, social and economic conditions, soils, wilderness characteristics, transportation and... allow recreational shooting in specific areas, and the inclusion of a shooting analysis of the planning...

Forensic analysis of hallucinogenic mushrooms and khat (Catha edulis Forsk) using cation-exchange liquid chromatography.

PubMed

Laussmann, Tim; Meier-Giebing, Sigrid

2010-02-25

Hallucinogenic mushrooms (e.g. Psilocybe and Panaeolus species) as well as leaves and young shoots of the khat tree (Catha edulis Forsk) are illicit drugs in many countries. The exact concentration of the hallucinogenic alkaloids psilocin and psilocybin in mushrooms and the sympathomimetic alkaloids cathinone and cathine in khat is usually essential for jurisdiction. Facing an increasing number of mushroom and khat seizures by German customs authorities, a convenient comprehensive quantitative HPLC method based on cation-exchange liquid chromatography for these rather "exotic" drugs has been developed which avoids time-consuming multi-step sample preparation or chemical derivatization procedures. Using this method a number of different hallucinogenic fungi species and products that are mainly distributed via the internet have been analysed (dried and fresh Psilocybe cubensis Singer as well as P. cubensis collected from "grow boxes", Panaeolus cyanescens Berkeley and Broome and so-called "philosopher stones" (sclerotia of Psilocybe species)). Highest total amounts of psilocin have been detected in dried P. cyanescens reaching up to 3.00+/-0.24 mg per 100 mg. The distribution of khat alkaloids in different parts of the khat shoots has been studied. High concentrations of cathinone have not only been detected in leaves but also in green parts and barks of stalks. Additionally, the sample treatment for fresh mushroom and khat samples has been optimised. Highest amounts of alkaloids were found when fresh material was freeze-dried. 2009 Elsevier Ireland Ltd. All rights reserved.

Transcriptome Analysis of ABA/JA-Dual Responsive Genes in Rice Shoot and Root.

PubMed

Kim, Jin-Ae; Bhatnagar, Nikita; Kwon, Soon Jae; Min, Myung Ki; Moon, Seok-Jun; Yoon, In Sun; Kwon, Taek-Ryoun; Kim, Sun Tae; Kim, Beom-Gi

2018-01-01

The phytohormone abscisic acid (ABA) enables plants to adapt to adverse environmental conditions through the modulation of metabolic pathways and of growth and developmental programs. We used comparative microarray analysis to identify genes exhibiting ABA-dependent expression and other hormone-dependent expression among them in Oryza sativa shoot and root. We identified 854 genes as significantly up- or down-regulated in root or shoot under ABA treatment condition. Most of these genes had similar expression profiles in root and shoot under ABA treatment condition, whereas 86 genes displayed opposite expression responses in root and shoot. To examine the crosstalk between ABA and other hormones, we compared the expression profiles of the ABA-dependently regulated genes under several different hormone treatment conditions. Interestingly, around half of the ABA-dependently expressed genes were also regulated by jasmonic acid based on microarray data analysis. We searched the promoter regions of these genes for cis-elements that could be responsible for their responsiveness to both hormones, and found that ABRE and MYC2 elements, among others, were common to the promoters of genes that were regulated by both ABA and JA. These results show that ABA and JA might have common gene expression regulation system and might explain why the JA could function for both abiotic and biotic stress tolerance.

Early Summer Drought Stress During the First Growing Year Stimulates Extra Shoot Growth in Oak Seedlings (Quercus petraea)

PubMed Central

Turcsán, Arion; Steppe, Kathy; Sárközi, Edit; Erdélyi, Éva; Missoorten, Marc; Mees, Ghislain; Mijnsbrugge, Kristine V.

2016-01-01

More severe summer droughts are predicted for mid-latitudes in Europe. To evaluate the impact on forest ecosystems and more specifically on forest regeneration, we studied the response to summer drought in oak seedlings (Quercus petraea). Acorns were collected from different mother trees in three stands in Belgium, sown in pots and grown in non-heated greenhouse conditions. We imposed drought on the seedlings in early summer by first watering the pots to saturation and then stopping any watering. Weight of the pots and stomatal conductance were regularly measured. Re-watering followed this drought period of 5 weeks. Height of the seedlings and apical bud development were observed. Stomatal resistance increased toward the end of the experiment in the drought-treated group and was restored after re-watering. The seedlings from the drought treatment displayed a higher probability to produce additional shoot growth after re-watering (p ≤ 0.05). A higher competition for water (two plants per pot) increased this chance. Although this chance was also higher for smaller seedlings, the actual length of the extra growth after re-watering was higher for larger seedlings (p ≤ 0.01). Both in the drought-treated and in the control group the autochthonous provenance growing on a xeric site produced less extra shoots compared to the two other provenances. Finally, stressed plants showed less developed apical buds compared to the control group after re-watering, suggesting a phenological effect on the growth cycle of oaks (p ≤ 0.0001). The higher chance for an extra shoot growth after the drought period can be considered as a compensation for the induced growth arrest during the drought period. PMID:26941760

Hunting of roe deer and wild boar in Germany: Is non-lead ammunition suitable for hunting?

PubMed

Martin, Annett; Gremse, Carl; Selhorst, Thomas; Bandick, Niels; Müller-Graf, Christine; Greiner, Matthias; Lahrssen-Wiederholt, Monika

2017-01-01

Non-lead hunting ammunition is an alternative to bullets that contain lead. The use of lead ammunition can result in severe contamination of game meat, thus posing a health risk to consumers. With any kind of ammunition for hunting, the terminal effectiveness of bullets is an animal welfare issue. Doubts about the effectiveness of non-lead bullets for a humane kill of game animals in hunting have been discussed. The length of the escape distance after the shot has been used previously as an indicator for bullet performance. The object of this study was to determine how the bullet material (lead or non-lead) influences the observed escape distances. 1,234 records of the shooting of roe deer (Capreolus capreolus) and 825 records of the shooting of wild boar (Sus scrofa) were evaluated. As the bullet material cannot be regarded as the sole cause of variability of escape distances, interactions of other potential influencing variables like shot placement, shooting distance, were analyzed using conditional regression trees and two-part hurdle models. The length of the escape distance is not influenced by the use of lead or non-lead ammunition with either roe deer or wild boar. With roe deer, the length of the escape distance is influenced significantly by the shot placement and the type of hunting. Increasing shooting distances increased the length of the escape distance. With wild boar, shot placement and the age of the animals were found to be a significant influencing factor on the length of the escape distance. The length of the escape distance can be used as an indicator for adequate bullet effectiveness for humane killings of game animals in hunting.Non-lead bullets already exist which have an equally reliable killing effect as lead bullets.

Transcriptomic and Hormonal Analyses Reveal that YUC-Mediated Auxin Biogenesis Is Involved in Shoot Regeneration from Rhizome in Cymbidium.

PubMed

Liu, Yang; Zhang, Hai-Liang; Guo, He-Rong; Xie, Li; Zeng, Rui-Zhen; Zhang, Xiang-Qian; Zhang, Zhi-Sheng

2017-01-01

Cymbidium , one of the most important orchid genera in horticulture, can be classified into epiphytic and terrestrial species. Generally, epiphytic Cymbidium seedlings can be easily propagated by tissue culture, but terrestrial seedlings are difficult to propagate. To date, the molecular mechanisms underlying the differences in the ease with which terrestrial and epiphytic cymbidiums can be propagated are largely unknown. Using RNA-sequencing, quantitative reverse transcription PCR and enzyme-linked immunosorbent assay, Cymbidium 'Xiaofeng' (CXF), which can be efficiently micropropagated, and terrestrial Cymbidium sinense 'Qijianbaimo' (CSQ), which has a low regeneration ability, were used to explore the molecular mechanisms underlying the micropropagation ability of Cymbidium species. To this end, 447 million clean short reads were generated, and 31,264 annotated unigenes were obtained from 10 cDNA libraries. A total of 1,290 differentially expressed genes (DEGs) were identified between CXF and CSQ during shoot induction. Gene ontology (GO) enrichment analysis indicated that the DEGs were significantly enriched in auxin pathway-related GO terms. Further analysis demonstrated that YUC and GH3 family genes, which play crucial roles in the regulation of auxin/IAA (indole-3-acetic acid) metabolism, acted quickly in response to shoot induction culture in vitro and were closely correlated with variation in shoot regeneration between CXF and CSQ. In addition, the study showed that IAA accumulated rapidly and significantly during shoot induction in CXF compared to that in CSQ; in contrast, no significant changes in other hormones were observed between CXF and CSQ. Furthermore, shoot regeneration in CXF was inhibited by a yucasin-auxin biosynthesis inhibitor, indicating that increased IAA level is required for high-frequency shoot regeneration in CXF. In conclusion, our study revealed that YUC-mediated auxin biogenesis is involved in shoot regeneration from rhizome in Cymbidium.

Mapping in an apple (Malus x domestica) F1 segregating population based on physical clustering of differentially expressed genes

PubMed Central

2014-01-01

Background Apple tree breeding is slow and difficult due to long generation times, self-incompatibility, and complex genetics. The identification of molecular markers linked to traits of interest is a way to expedite the breeding process. In the present study, we aimed to identify genes whose steady-state transcript abundance was associated with inheritance of specific traits segregating in an apple (Malus × domestica) rootstock F1 breeding population, including resistance to powdery mildew (Podosphaera leucotricha) disease and woolly apple aphid (Eriosoma lanigerum). Results Transcription profiling was performed for 48 individual F1 apple trees from a cross of two highly heterozygous parents, using RNA isolated from healthy, actively-growing shoot tips and a custom apple DNA oligonucleotide microarray representing 26,000 unique transcripts. Genome-wide expression profiles were not clear indicators of powdery mildew or woolly apple aphid resistance phenotype. However, standard differential gene expression analysis between phenotypic groups of trees revealed relatively small sets of genes with trait-associated expression levels. For example, thirty genes were identified that were differentially expressed between trees resistant and susceptible to powdery mildew. Interestingly, the genes encoding twenty-four of these transcripts were physically clustered on chromosome 12. Similarly, seven genes were identified that were differentially expressed between trees resistant and susceptible to woolly apple aphid, and the genes encoding five of these transcripts were also clustered, this time on chromosome 17. In each case, the gene clusters were in the vicinity of previously identified major quantitative trait loci for the corresponding trait. Similar results were obtained for a series of molecular traits. Several of the differentially expressed genes were used to develop DNA polymorphism markers linked to powdery mildew disease and woolly apple aphid resistance. Conclusions Gene expression profiling and trait-associated transcript analysis using an apple F1 population readily identified genes physically linked to powdery mildew disease resistance and woolly apple aphid resistance loci. This result was especially useful in apple, where extreme levels of heterozygosity make the development of reliable DNA markers quite difficult. The results suggest that this approach could prove effective in crops with complicated genetics, or for which few genomic information resources are available. PMID:24708064

In vitro conservation and sustained production of breadfruit ( Artocarpus altilis, Moraceae): modern technologies for a traditional tropical crop

NASA Astrophysics Data System (ADS)

Murch, Susan J.; Ragone, Diane; Shi, Wendy Lei; Alan, Ali R.; Saxena, Praveen K.

2008-02-01

Breadfruit ( Artocarpus altilis, Moraceae) is a traditionally cultivated, high-energy, high-yield crop, but widespread use of the plant for food is limited by poor quality and poor storage properties of the fruit. A unique field genebank of breadfruit species and cultivars exists at the National Tropical Botanical Garden in the Hawaiian Islands and is an important global resource for conservation and sustainable use of breadfruit. However, this plant collection could be damaged by a random natural disaster such as a hurricane. We have developed a highly efficient in vitro plant propagation system to maintain, conserve, mass propagate, and distribute elite varieties of this important tree species. Mature axillary shoot buds were collected from three different cultivars of breadfruit and proliferated using a cytokinin-supplemented medium. The multiple shoots were maintained as stock cultures and repeatedly used to develop whole plants after root differentiation on a basal or an auxin-containing medium. The plantlets were successfully grown under greenhouse conditions and were reused to initiate additional shoot cultures for sustained production of plants. Flow cytometry was used to determine the nuclear deoxyribonucleic acid content and the ploidy status of the in vitro grown population. The efficacy of the micropropagation protocols developed in this study represents a significant advancement in the conservation and sustained mass propagation of breadfruit germplasm in a controlled environment free from contamination.

Genders in Juniperus thurifera have different functional responses to variations in nutrient availability.

PubMed

Montesinos, D; Villar-Salvador, P; García-Fayos, P; Verdú, M

2012-02-01

• Differences in reproductive investment can trigger asymmetric, context-dependent, functional strategies between genders in dioecious species. However, little is known about the gender responses of dioecious species to nutrient availability. • We experimentally fertirrigated a set of male and female Juniperus thurifera trees monthly for 2 yr. Water potential, photosynthesis rate and stomatal conductance were measured monthly for 2 yr, while shoot nitrogen (N) concentration, carbon isotopic composition (δ(13) C), branch growth, trunk radial growth and reproductive investment per branch were measured yearly. • Control males had lower gas exchange rates and radial growth but greater reproductive investment and higher water use efficiency (WUE; as inferred from more positive δ(13) C values) than females. Fertirrigation did not affect water potential or WUE but genders responded differently to increased nutrient availability. The two genders similarly increased shoot N concentration when fertilized. The increase in shoot N was associated with increased photosynthesis in males but not in females, which presented consistently high photosynthetic rates across treatments. • Our results suggest that genders invest N surplus in different functions, with females presenting a long-term strategy by increasing N storage to compensate for massive reproductive masting events, while males seem to be more reactive to current nutrient availability, promoting gas-exchange capacity. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Mycorrhizal networks and distance from mature trees alter patterns of competition and facilitation in dry Douglas-fir forests.

PubMed

Teste, François P; Simard, Suzanne W

2008-11-01

The distribution of dry Douglas-fir forests in western North America is expected to shift northward with climate change and disappear from the grassland interface in the southern interior of British Columbia. This shift may be accentuated by clearcutting, a common harvesting practice that aims to reduce the competitive effects of residual mature trees on new regeneration, but in so doing, ignores their facilitative effects. In this study, we investigated the net effects of competition from and facilitation by mature trees retained on harvested sites on seedling establishment in the dry interface Douglas-fir forests. We demonstrate that access to a mycorrhizal network (MN) and proximity to trees have important influences on seedling performance. On six sites, we established trenched plots around 24 mature Pseudotsuga menziesii var. glauca (Douglas-fir) trees, then planted Douglas-fir seedlings into four mesh treatments that served to restrict MN access (i.e., planted into mesh bags with 0.5-, 35-, or 250-microm pores, or without mesh) or into impermeable bags (grown in isolation) at four distances (0.5, 1.0, 2.5, or 5.0 m). Seedling survival tended to be greater and water stress lower where seedlings had full access to the MN. Seedling height, shoot biomass, needle biomass, and nutrient uptake peaked at 2.5-5.0 m from mature trees. Seedlings 0.5 m from mature trees had lower CO2 assimilation rates and wood delta(13)C compared to seedlings 5.0 m away. Competition for soil resources was highest near mature trees but facilitation was relatively greater at further distances, resulting in a zone of net benefit for seedlings. These results show that intraspecific tree-seedling interactions are both competitive and facilitative in dry Douglas-fir forests, and that they are spatially dependent. After disturbance, maintaining residual mature trees may be important for their beneficial regeneration zones.

Changes in avian and plant communities of aspen woodlands over 12 years after livestock removal in the northwestern Great Basin

USGS Publications Warehouse

Earnst, Susan L.; Dobkin, David S.; Ballard, Jennifer A.

2012-01-01

Riparian and quaking aspen (Populus tremuloides) woodlands are centers of avian abundance and diversity in the western United States, but they have been affected adversely by land use practices, particularly livestock grazing. In 1990, cattle were removed from a 112,500-ha national wildlife refuge in southeastern Oregon. Thereafter, we monitored changes in vegetation and bird abundance in years 1–3 (phase 1) and 10–12 (phase 2) in 17 riparian and 9 snow-pocket aspen plots. On each 1.5-ha plot, we sampled vegetation in 6 transects. Three times during each breeding season, observers recorded all birds 50 m to each side of the plot's 150-m centerline for 25 minutes. We analyzed data with multivariate analysis of variance and paired t tests with p values adjusted for multiple comparisons. In both periods, riparian and snow-pocket aspen produced extensive regeneration of new shoots (x̄ = 2646 stems/ha and 7079 stems/ha, respectively). By phase 2, a 64% increase in medium-diameter trees in riparian stands indicated successful recruitment into the overstory, but this pattern was not seen in snow-pocket stands, where the density of trees was over 2 times greater. By phase 2 in riparian and snow-pocket stands, native forb cover had increased by 68% and 57%, respectively, mesic shrub cover had increased by 29% and 58%, and sagebrush cover had decreased by 24% and 31%. Total avian abundance increased by 33% and 39% in riparian and snow-pocket aspen, respectively, ground or understory nesters increased by 133% and 67% and overstory nesters increased by 34% and 33%. Similarly, ground or understory foragers increased by 25% and 32%, aerial foragers by 55% and 57%, and overstory foragers by 66% and 43%. We interpreted the substantial regeneration of aspen shoots, increased densities of riparian forbs and shrubs, and increased avian abundances as a multitrophic-level response to the total removal of livestock and as substantial movement toward recovery of biological integrity.

Spatial and temporal distribution of trunk-injected (14) C-imidacloprid in Fraxinus trees.

PubMed

Tanis, Sara R; Cregg, Bert M; Mota-Sanchez, David; McCullough, Deborah G; Poland, Therese M

2012-04-01

Since the discovery of Agrilus planipennis Fairmaire (emerald ash borer) in 2002, researchers have tested several methods of chemical control. Soil drench or trunk injection products containing imidacloprid are commonly used to control adults. However, efficacy can be highly variable and may be due to uneven translocation of systemic insecticides. The purpose of this study was to determine whether sectored xylem anatomy might influence imidacloprid distribution in tree crowns. Imidacloprid equivalent concentrations were higher in leaves from branches in the plane of the injection point (0°) than in leaves from branches on the opposite side of the injection point (180°). Leaves from branches 90° to the right of injection points had higher imidacloprid equivalent concentrations than leaves from branches 90° to the left of injection points. Leaves and shoots had higher imidacloprid equivalent concentrations than roots and trunk cores, indicating that imidacloprid moves primarily through the xylem. Imidacloprid equivalent concentration in leaves varied over time and in relation to injection points. It is concluded that ash trees have sectored 'zigzag' xylem architecture patterns consistent with sectored flow distribution. This could lead to variable distribution of imidacloprid in tree crowns and therefore to variable control of A. planipennis. Copyright © 2012 Society of Chemical Industry.

CASSIA--a dynamic model for predicting intra-annual sink demand and interannual growth variation in Scots pine.

PubMed

Schiestl-Aalto, Pauliina; Kulmala, Liisa; Mäkinen, Harri; Nikinmaa, Eero; Mäkelä, Annikki

2015-04-01

The control of tree growth vs environment by carbon sources or sinks remains unresolved although it is widely studied. This study investigates growth of tree components and carbon sink-source dynamics at different temporal scales. We constructed a dynamic growth model 'carbon allocation sink source interaction' (CASSIA) that calculates tree-level carbon balance from photosynthesis, respiration, phenology and temperature-driven potential structural growth of tree organs and dynamics of stored nonstructural carbon (NSC) and their modifying influence on growth. With the model, we tested hypotheses that sink demand explains the intra-annual growth dynamics of the meristems, and that the source supply is further needed to explain year-to-year growth variation. The predicted intra-annual dimensional growth of shoots and needles and the number of cells in xylogenesis phases corresponded with measurements, whereas NSC hardly limited the growth, supporting the first hypothesis. Delayed GPP influence on potential growth was necessary for simulating the yearly growth variation, indicating also at least an indirect source limitation. CASSIA combines seasonal growth and carbon balance dynamics with long-term source dynamics affecting growth and thus provides a first step to understanding the complex processes regulating intra- and interannual growth and sink-source dynamics. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Partial Root-Zone Drying of Olive (Olea europaea var. 'Chetoui') Induces Reduced Yield under Field Conditions

PubMed Central

Dbara, Soumaya; Haworth, Matthew; Emiliani, Giovani; Ben Mimoun, Mehdi; Gómez-Cadenas, Aurelio; Centritto, Mauro

2016-01-01

The productivity of olive trees in arid and semi-arid environments is closely linked to irrigation. It is necessary to improve the efficiency of irrigation techniques to optimise the amount of olive fruit produced in relation to the volume of water used. Partial root-zone drying (PRD) is a water saving irrigation technique that theoretically allows the production of a root-to-shoot signal that modifies the physiology of the above-ground parts of the plant; specifically reducing stomatal conductance (gs) and improving water use efficiency (WUE). Partial root-zone drying has been successfully applied under field conditions to woody and non-woody crops; yet the few previous trials with olive trees have produced contrasting results. Thirty year-old olive trees (Olea europaea ‘var. Chetoui’) in a Tunisian grove were exposed to four treatments from May to October for three-years: ‘control’ plants received 100% of the potential evapotranspirative demand (ETc) applied to the whole root-zone; ‘PRD100’ were supplied with an identical volume of water to the control plants alternated between halves of the root-zone every ten-days; ‘PRD50’ were given 50% of ETc to half of the root-system, and; ‘rain-fed’ plants received no supplementary irrigation. Allowing part of the root-zone to dry resulted in reduced vegetative growth and lower yield: PRD100 decreased yield by ~47% during productive years. During the less productive years of the alternate bearing cycle, irrigation had no effect on yield; this suggests that withholding of water during ‘off-years’ may enhance the effectiveness of irrigation over a two-year cycle. The amount and quality of oil within the olive fruit was unaffected by the irrigation treatment. Photosynthesis declined in the PRD50 and rain-fed trees due to greater diffusive limitations and reduced biochemical uptake of CO2. Stomatal conductance and the foliar concentration of abscisic acid (ABA) were not altered by PRD100 irrigation, which may indicate the absence of a hormonal root-to-shoot signal. Rain-fed and PRD50 treatments induced increased stem water potential and increased foliar concentrations of ABA, proline and soluble sugars. The stomata of the olive trees were relatively insensitive to super-ambient increases in [CO2] and higher [ABA]. These characteristics of ‘hydro-passive’ stomatal behaviour indicate that the ‘Chetoui’ variety of olive tree used in this study lacks the physiological responses required for the successful exploitation of PRD techniques to increase yield and water productivity. Alternative irrigation techniques such as partial deficit irrigation may be more suitable for ‘Chetoui’ olive production. PMID:27315081

Strong Coupling of Shoot Assimilation and Soil Respiration during Drought and Recovery Periods in Beech As Indicated by Natural Abundance δ13C Measurements.

PubMed

Blessing, Carola H; Barthel, Matti; Gentsch, Lydia; Buchmann, Nina

2016-01-01

Drought down-regulates above- and belowground carbon fluxes, however, the resilience of trees to drought will also depend on the speed and magnitude of recovery of these above- and belowground fluxes after re-wetting. Carbon isotope composition of above- and belowground carbon fluxes at natural abundance provides a methodological approach to study the coupling between photosynthesis and soil respiration (SR) under conditions (such as drought) that influence photosynthetic carbon isotope discrimination. In turn, the direct supply of root respiration with recent photoassimilates will impact on the carbon isotope composition of soil-respired CO 2 . We independently measured shoot and soil CO 2 fluxes of beech saplings ( Fagus sylvatica L.) and their respective δ 13 C continuously with laser spectroscopy at natural abundance. We quantified the speed of recovery of drought stressed trees after re-watering and traced photosynthetic carbon isotope signal in the carbon isotope composition of soil-respired CO 2 . Stomatal conductance responded strongly to the moderate drought (-65%), induced by reduced soil moisture content as well as increased vapor pressure deficit. Simultaneously, carbon isotope discrimination decreased by 8‰, which in turn caused a significant increase in δ 13 C of recent metabolites (1.5-2.5‰) and in δ 13 C of SR (1-1.5‰). Generally, shoot and soil CO 2 fluxes and their δ 13 C were in alignment during drought and subsequent stress release, clearly demonstrating a permanent dependence of root respiration on recently fixed photoassimilates, rather than on older reserves. After re-watering, the drought signal persisted longer in δ 13 C of the water soluble fraction that integrates multiple metabolites (soluble sugars, amino acids, organic acids) than in the neutral fraction which represents most recently assimilated sugars or in the δ 13 C of SR. Nevertheless, full recovery of all aboveground physiological variables was reached within 4 days - and within 7 days for SR - indicating high resilience of (young) beech against moderate drought.

Diplodia quercivora sp. nov.: a new species of Diplodia found on declining Quercus canariensis trees in Tunisia.

PubMed

Linaldeddu, Benedetto T; Franceschini, Antonio; Alves, Artur; Phillips, Alan J L

2013-01-01

During a study of the species of Botryosphaeriaceae associated with oak decline in Tunisia, a large collection of Diplodia strains were isolated from Quercus afares, Q. canariensis and Q. suber trees showing a progressive dieback of shoots and branches, trunk canker and exudates and collar rot. Most of the isolates were identified as Diplodia corticola, while two isolates from Q. canariensis were morphologically and phylogenetically (ITS and tef1-α sequences data) distinct from all other known species of Diplodia. They are described here as Diplodia quercivora sp. nov. In addition, phylogenetic analyses showed for the first time the existence of two distinct lineages within D. corticola. In artificial inoculation experiments, D. quercivora caused necrotic lesions on bark and wood of three Mediterranean oak species, Q. ilex, Q. pubescens and Q. suber. In particular, among the oak species tested, Q. pubescens was the most susceptible.

The role of forest floor and trees to the ecosystem scale methane budget of boreal forests

NASA Astrophysics Data System (ADS)

Pihlatie, Mari; Halmeenmäki, Elisa; Peltola, Olli; Haikarainen, Iikka; Heinonsalo, Jussi; Santalahti, Minna; Putkinen, Anuliina; Fritze, Hannu; Urban, Otmar; Machacova, Katerina

2016-04-01

Boreal forests are considered as a sink of atmospheric methane (CH4) due to the activity of CH4 oxidizing bacteria (methanotrophs) in the soil. This soil CH4 sink is especially strong for upland forest soils, whereas forests growing on organic soils may act as small sources due to the domination of CH4 production by methanogens in the anaerobic parts of the soil. The role of trees to the ecosystem-scale CH4 fluxes has until recently been neglected due to the perception that trees do not contribute to the CH4 exchange, and also due to difficulties in measuring the CH4 exchange from trees. Findings of aerobic CH4 formation in plants and emissions from tree-stems in temperate and tropical forests during the past decade demonstrate that our understanding of CH4 cycling in forest ecosystems is not complete. Especially the role of forest canopies still remain unresolved, and very little is known of CH4 fluxes from trees in boreal region. We measured the CH4 exchange of tree-stems and tree-canopies from pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pubescens, Betula pendula) trees growing in Southern Finland (SMEAR II station) on varying soil conditions, from upland mineral soils to paludified soil. We compared the CH4 fluxes from trees to forest-floor CH4 exchange, both measured by static chambers, and to CH4 fluxes measured above the forest canopy by a flux gradient technique. We link the CH4 fluxes from trees and forest floor to physiological activity of the trees, such as transpiration, sap-flow, CO2 net ecosystem exchange (NEE), soil properties such as temperature and moisture, and to the presence of CH4 producing methanogens and CH4 oxidizing methanotrophs in trees or soil. The above canopy CH4 flux measurements show that the whole forest ecosystem was a small source of CH4 over extended periods in the spring and summer 2012, 2014 and 2015. Throughout the 2013-2014 measurements, the forest floor was in total a net sink of CH4, with variation between high CH4 uptake in the dominating dry upland areas and high emissions from the few wet spots of the forest. All the studied tree species emitted small amounts of CH4 from the stems and shoots, with emission rates depending on the season, tree species and soil conditions. Especially, CH4 emissions from birch canopies were high and can therefore contribute significantly to the ecosystem-scale CH4 fluxes. Processes behind the canopy and stem CH4emission remain unresolved, however, ongoing analysis of the methanogens and methanotrophs within the plant-soil systems will reveal whether CH4 production or consumption is of microbial origin. Also, comparison of the CH4 fluxes from trees and forest floor to sap-flow, transpiration, and NEE as well as soil parameters will help to explain the seasonality and mechanisms involved in the CH4 emissions.

Phylogenetic Variation in the Silicon Composition of Plants

PubMed Central

HODSON, M. J.; WHITE, P. J.; MEAD, A.; BROADLEY, M. R.

2005-01-01

• Background and Aims Silicon (Si) in plants provides structural support and improves tolerance to diseases, drought and metal toxicity. Shoot Si concentrations are generally considered to be greater in monocotyledonous than in non-monocot plant species. The phylogenetic variation in the shoot Si concentration of plants reported in the primary literature has been quantified. • Methods Studies were identified which reported Si concentrations in leaf or non-woody shoot tissues from at least two plant species growing in the same environment. Each study contained at least one species in common with another study. • Key Results Meta-analysis of the data revealed that, in general, ferns, gymnosperms and angiosperms accumulated less Si in their shoots than non-vascular plant species and horsetails. Within angiosperms and ferns, differences in shoot Si concentration between species grouped by their higher-level phylogenetic position were identified. Within the angiosperms, species from the commelinoid monocot orders Poales and Arecales accumulated substantially more Si in their shoots than species from other monocot clades. • Conclusions A high shoot Si concentration is not a general feature of monocot species. Information on the phylogenetic variation in shoot Si concentration may provide useful palaeoecological and archaeological information, and inform studies of the biogeochemical cycling of Si and those of the molecular genetics of Si uptake and transport in plants. PMID:16176944

Racial and mental illness stereotypes and discrimination: an identity-based analysis of the Virginia Tech and Columbine shootings.

PubMed

Chen, Charlene Y; Purdie-Vaughns, Valerie; Phelan, Jo C; Yu, Gary; Yang, Lawrence H

2015-04-01

The Virginia Tech and Columbine High shootings are 2 of the deadliest school massacres in the United States. The present study investigates in a nationally representative sample how White Americans' causal attributions of these shooting moderate their attitudes toward the shooter's race. White Americans shown a vignette based on the Virginia Tech shooting were more likely to espouse negative beliefs about Korean American men and distance themselves from this group the more they believed that the shooter's race caused the shooting. Among those who were shown a vignette based on the Columbine High shooting, believing that mental illness caused the shooting was associated with weaker negative beliefs about White American men. White Americans in a third condition who were given the Virginia Tech vignette and prompted to subtype the shooter according to his race were less likely to possess negative beliefs about Korean American men the more they believed that mental illness caused the shooting. There was no evidence for the ultimate attribution error. Theoretical accounts based on the stereotype and in-group-out-group bias literature are presented. The current findings have important implications for media depictions of minority group behavior and intergroup relations. (c) 2015 APA, all rights reserved).

Racial and Mental Illness Stereotypes and Discrimination: An Identity-Based Analysis of the Virginia Tech and Columbine Shootings

PubMed Central

Chen, Charlene Y.; Purdie-Vaughns, Valerie; Phelan, Jo C.; Yu, Gary; Yang, Lawrence H.

2015-01-01

The Virginia Tech and Columbine High shootings are 2 of the deadliest school massacres in the United States. The present study investigates in a nationally representative sample how White Americans’ causal attributions of these shooting moderate their attitudes toward the shooter’s race. White Americans shown a vignette based on the Virginia Tech shooting were more likely to espouse negative beliefs about Korean American men and distance themselves from this group the more they believed that the shooter’s race caused the shooting. Among those who were shown a vignette based on the Columbine High shooting, believing that mental illness caused the shooting was associated with weaker negative beliefs about White American men. White Americans in a third condition who were given the Virginia Tech vignette and prompted to subtype the shooter according to his race were less likely to possess negative beliefs about Korean American men the more they believed that mental illness caused the shooting. There was no evidence for the ultimate attribution error. Theoretical accounts based on the stereotype and in-group-out-group bias literature are presented. The current findings have important implications for media depictions of minority group behavior and intergroup relations. PMID:25198415

Gravitropism of cut shoots is mediated by oxidative processes: A physiological and molecular study

NASA Astrophysics Data System (ADS)

Philosoph-Hadas, Sonia; Friedman, Haya; Meir, Shimon

2012-07-01

The signal transduction events occurring during shoot gravitropism are mediated through amyloplasts sedimentation, reorientation of actin filaments in the endodermis, and differential changes in level and action of auxin, associated with differential growth leading to shoot curvature. Since increase in reactive oxygen species (ROS) was shown to be associated with growth, we examined the possible use of antioxidants in controlling the gravitropic response, via their interaction with events preceding shoot bending. Reoriented snapdragon (Antirrhinum majus L.) spikes and tomato (Solanum lycopersicum cv. MicroTom) shoots showed a visual upward bending after a lag period of 3 or 5 h, respectively, which was inhibited by the antioxidants N-acetyl-cysteine (NAC) and reduced glutathione (GSH). This suggests the involvement of oxidative reactions in the process. The two antioxidants prevented the sedimentation of amyloplasts to the bottom of the endodermis cells following 0.5-5 h of snapdragon shoot reorientation, suggesting that oxidative reactions are involved already at a very early signal perception stage prior to the visual bending. In addition, a differential distribution in favor of the lower shoot side of various oxidative elements, including H2O2 concentrations and activity of the NADPH-oxidase enzyme, was observed during reorientation of snapdragon spikes. Application of the two antioxidants reduced the levels of these elements and abolished their differential distribution across the shoot. On the other hand, the activity of the antioxidative enzyme, superoxide dismutase (SOD), which was not differentially distributed across the shoot, increased significantly following application of the two antioxidants. The auxin redistribution in reoriented shoots was analyzed using transgenic tomato plants expressing the GUS reporter gene under the Aux/IAA4 promoter (a generous gift of M. Bouzayen, France). GUS response, detected in control shoots 4 h after their reorientation in favor of the lower shoot side was completely eliminated in the NAC-treated shoots, in which the bending response was inhibited. These results suggest that the gravitropic-induced asymmetric auxin redistribution precedes shoot bending, and NAC inhibits this response by abolishing the auxin gradient across the shoot. Our microarray analysis of tomato shoots, using the Affymetrix Tomato GeneChip, revealed differential changes in expression of 266 genes, occurring during the initial 0.5-5 h of shoot reorientation prior to bending. The differential changes in expression of auxin-related genes in favor of the lower shoot side occurred already following 0.5 h of reorientation, while those of cell wall-related genes, associated with shoot bending, occurred only 3 h following shoot reorientation. Among the identified genes, 11 genes were related to auxin, and 36 genes were associated with oxidative processes, demonstrating the involvement of ROS in early events of shoot gravitropism. Taken together, our results suggest that ROS mediate the early gravity-induced amyloplast sedimentation required for signal perception, as well as the lateral auxin movement across the shoot, which is necessary for the auxin asymmetric distribution leading to shoot upward bending.

Body sway, aim point fluctuation and performance in rifle shooters: inter- and intra-individual analysis.

PubMed

Ball, Kevin A; Best, Russell J; Wrigley, Tim V

2003-07-01

In this study, we examined the relationships between body sway, aim point fluctuation and performance in rifle shooting on an inter- and intra-individual basis. Six elite shooters performed 20 shots under competition conditions. For each shot, body sway parameters and four aim point fluctuation parameters were quantified for the time periods 5 s to shot, 3 s to shot and 1 s to shot. Three parameters were used to indicate performance. An AMTI LG6-4 force plate was used to measure body sway parameters, while a SCATT shooting analysis system was used to measure aim point fluctuation and shooting performance. Multiple regression analysis indicated that body sway was related to performance for four shooters. Also, body sway was related to aim point fluctuation for all shooters. These relationships were specific to the individual, with the strength of association, parameters of importance and time period of importance different for different shooters. Correlation analysis of significant regressions indicated that, as body sway increased, performance decreased and aim point fluctuation increased for most relationships. We conclude that body sway and aim point fluctuation are important in elite rifle shooting and performance errors are highly individual-specific at this standard. Individual analysis should be a priority when examining elite sports performance.

Elucidating the Population Dynamics of Japanese Knotweed Using Integral Projection Models

PubMed Central

Dauer, Joseph T.; Jongejans, Eelke

2013-01-01

Plant demographic studies coupled with population modeling are crucial components of invasive plant management because they inform managers when in a plant’s life cycle it is most susceptible to control efforts. Providing land managers with appropriate data can be especially challenging when there is limited data on potentially important transitions that occur belowground. For 2 years, we monitored 4 clonal Japanese knotweed ( Polygonum cuspidatum ) infestations for emergence, survival, shoot height until leaf senescence, dry shoot biomass after senescence, and rhizome connections for 424 shoots. We developed an integral projection model using both final autumn shoot height and shoot biomass as predictors of survival between years, growth from year to year, and number of rhizomes produced by a shoot (fecundity). Numbers of new shoots within an infestation (population growth rate λ) were projected to increase 13-233% in a year, with the greatest increase at the most frequently disturbed site. Elasticity analysis revealed population growth at 3 of the 4 sites was primarily due to ramet survival between years and to year-to-year growth in shoot height and shoot biomass. Population growth at the fourth site, the most disturbed, was due to the large production of new rhizomes and associated shoots. In contrast to previous studies, our excavation revealed that most of the shoots were not interconnected, suggesting rhizome production may be limited by the size or age of the plants, resource availability, disturbance frequency, or other factors. Future integration of plant population models with more data on belowground growth structures will clarify the critical stages in Japanese knotweed life cycle and support land managers in their management decisions. PMID:24073249

The effects of cleared larch canopy and nitrogen supply on gas exchange and leaf traits in deciduous broad-leaved tree seedlings.

PubMed

Kitaoka, Satoshi; Watanabe, Yoko; Koike, Takayoshi

2009-12-01

To understand the leaf-level responses of successional tree species to forest gap formation and nitrogen deposition, we performed canopy clearing and nitrogen-amendment treatments in larch plantations and investigated the changes in the light-use characteristics and the leaf structure of the invading deciduous broad-leaved tree seedlings. We hypothesized that the responses of the tree seedlings to clearing and nitrogen input would reflect specific traits in the shoot development that would be related to the species-specific successional characteristics. The gap phase species Magnolia hyporeuca Siebold et Zucc. and the mid-late successional tree species Quercus mongolica Fischer ex Ledeb. var. crispula (Blume) Ohashi., which grow in or near the forest gaps, had higher light-saturated photosynthetic rates (Psat), enhanced mesophyll surface area (Smes) and increased leaf mass per area (LMA) under both the clearing treatment and the clearing with nitrogen-amendment treatment. These two species therefore increased their Psat via an increase in Smes and LMA. The LMA values of the late successional tree species Prunus ssiori F. Schmidt and Carpinus cordata Blume, which grow in the forest understory, were enhanced by the clearing treatment. However, they displayed lesser responses to the clearing treatment under which there were no marked increases in Psat or Smes values in the second year. These results indicate distinct and varied responses to disturbance regimes among the four seral tree seedlings. The Psat value largely increased in line with the increase in Smes value during the second year in M. hyporeuca and Q. mongolica. The nitrogen supply accelerated the change in LMA and increased the Smes value in the leaves of Q. mongolica.

Phytoextraction of potentially toxic elements by six tree species growing on hazardous mining sludge.

PubMed

Mleczek, Mirosław; Goliński, Piotr; Krzesłowska, Magdalena; Gąsecka, Monika; Magdziak, Zuzanna; Rutkowski, Paweł; Budzyńska, Sylwia; Waliszewska, Bogusława; Kozubik, Tomisław; Karolewski, Zbigniew; Niedzielski, Przemysław

2017-10-01

The aim of the study was to compare the phytoextraction abilities of six tree species (Acer platanoides L., Acer pseudoplatanus L., Betula pendula Roth, Quercus robur L., Tilia cordata Miller, Ulmus laevis Pall.), cultivated on mining sludge contaminated with arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), thallium (Tl), and zinc (Zn). All six tree species were able to survive on such an unpromising substrate. However, A. platanoides and T. cordata seedlings grown on the polluted substrate showed significantly lower biomass than control plants (55.5 and 45.6%, respectively). As, Cd, Cu, Pb, and Tl predominantly accumulated in the roots of all the analyzed tree species with the following highest contents: 1616, 268, 2432, 547, and 856 mg kg -1 , respectively. Zn was predominantly localized in shoots with the highest content of 5801 and 5732 mg kg -1 for U. laevis and A. platanoides, respectively. A. platanoides was the most effective in Zn phytoextaction, with a bioconcentration factor (BCF) of 8.99 and a translocation factor (TF) of 1.5. Furthermore, with the exception of A. pseudoplatanus, the analyzed tree species showed a BCF > 1 for Tl, with the highest value for A. platanoides (1.41). However, the TF for this metal was lower than 1 in all the analyzed tree species. A. platanoides showed the highest BCF and a low TF and could, therefore, be a promising species for Tl phytostabilization. In the case of the other analyzed tree species, their potential for effective phytoextraction was markedly lower. Further studies on the use of A. platanoides in phytoremediation would be worth conducting.

Electrical signaling, stomatal conductance, ABA and Ethylene content in avocado trees in response to root hypoxia

PubMed Central

Gurovich, Luis; Schaffer, Bruce; García, Nicolás; Iturriaga, Rodrigo

2009-01-01

Avocado (Persea americana Mill.) trees are among the most sensitive of fruit tree species to root hypoxia as a result of flooded or poorly drained soil. Similar to drought stress, an early physiological response to root hypoxia in avocado is a reduction of stomatal conductance. It has been previously determined in avocado trees that an extracellular electrical signal between the base of stem and leaves is produced and related to reductions in stomatal conductance in response to drought stress. The current study was designed to determine if changes in the extracellular electrical potential between the base of the stem and leaves in avocado trees could also be detected in response to short-term (min) or long-term (days) root hypoxia, and if these signals could be related to stomatal conductance (gs), root and leaf ABA and ACC concentrations, ethylene emission from leaves and leaf abscission. In contrast to previous observations for drought-stressed trees, short-term or long-term root hypoxia did not stimulate an electrical potential difference between the base of the stem and leaves. Short-term hypoxia did not result in a significant decrease in gs compared with plants in the control treatment, and no differences in ABA concentration were found between plants subjected to hypoxia and control plants. Long-term hypoxia in the root zone resulted in a significant decrease in gs, increased leaf ethylene and increased leaf abscission. The results indicate that for avocado trees exposed to root hypoxia, electrical signals do not appear to be the primary root-to-shoot communication mechanism involved in signaling for stomatal closure as a result of hypoxia in the root zone. PMID:19649181

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.

Stochastic modelling of tree architecture and biomass allocation: application to teak (Tectona grandis L. f.), a tree species with polycyclic growth and leaf neoformation.

PubMed

Tondjo, Kodjo; Brancheriau, Loïc; Sabatier, Sylvie; Kokutse, Adzo Dzifa; Kokou, Kouami; Jaeger, Marc; de Reffye, Philippe; Fourcaud, Thierry

2018-06-08

For a given genotype, the observed variability of tree forms results from the stochasticity of meristem functioning and from changing and heterogeneous environmental factors affecting biomass formation and allocation. In response to climate change, trees adapt their architecture by adjusting growth processes such as pre- and neoformation, as well as polycyclic growth. This is the case for the teak tree. The aim of this work was to adapt the plant model, GreenLab, in order to take into consideration both these processes using existing data on this tree species. This work adopted GreenLab formalism based on source-sink relationships at organ level that drive biomass production and partitioning within the whole plant over time. The stochastic aspect of phytomer production can be modelled by a Bernoulli process. The teak model was designed, parameterized and analysed using the architectural data from 2- to 5-year-old teak trees in open field stands. Growth and development parameters were identified, fitting the observed compound organic series with the theoretical series, using generalized least squares methods. Phytomer distributions of growth units and branching pattern varied depending on their axis category, i.e. their physiological age. These emerging properties were in accordance with the observed growth patterns and biomass allocation dynamics during a growing season marked by a short dry season. Annual growth patterns observed on teak, including shoot pre- and neoformation and polycyclism, were reproduced by the new version of the GreenLab model. However, further updating is discussed in order to ensure better consideration of radial variation in basic specific gravity of wood. Such upgrading of the model will enable teak ideotypes to be defined for improving wood production in terms of both volume and quality.

Site-Dependent Differences in DNA Methylation and Their Impact on Plant Establishment and Phosphorus Nutrition in Populus trichocarpa

PubMed Central

Schönberger, Brigitte; Chen, Xiaochao; Mager, Svenja

2016-01-01

The propagation via clonal stem cuttings is a frequent practice in tree plantations. Despite their clonal origin, the trees establish differently according to weather, temperature and nutrient availability, as well as the presence of various stresses. Here, clonal Populus trichocarpa (cv. Muhle Larson) cuttings from different sites were transferred into a common, fully nutrient supplied environment. Despite identical underlying genetics, stem cuttings derived from sites with lower phosphorus availability established worse, independent of phosphorus (P) level after transplantation. Differential growth of material from the sites was reflected in differences in the whole genome DNA methylome. Methylation differences were sequence context-dependent, but differentially methylated regions (DMRs) were apparently unrelated to P nutrition genes. Despite the undisputed negative general correlation of DNA promoter methylation with gene repression, only few of the top-ranked DMRs resulted in differential gene expression in roots or shoots. However, differential methylation was associated with site-dependent, different total amounts of microRNAs (miRNAs), with few miRNAs sequences directly targeted by differential methylation. Interestingly, in roots and shoots, the miRNA amount was dependent on the previous habitat and changed in roots in a habitat-dependent way under phosphate starvation conditions. Differentially methylated miRNAs, together with their target genes, showed P-dependent expression profiles, indicating miRNA expression differences as a P-related epigenetic modification in poplar. Together with differences in DNA methylation, such epigenetic mechanisms may explain habitat or seasonal memory in perennials and site-dependent growth performances. PMID:27992519

Effects of GhWUS from upland cotton (Gossypium hirsutum L.) on somatic embryogenesis and shoot regeneration.

PubMed

Xiao, Yanqing; Chen, Yanli; Ding, Yanpeng; Wu, Jie; Wang, Peng; Yu, Ya; Wei, Xi; Wang, Ye; Zhang, Chaojun; Li, Fuguang; Ge, Xiaoyang

2018-05-01

The WUSCHEL (WUS) gene encodes a plant-specific homeodomain-containing transcriptional regulator, which plays important roles during embryogenesis, as well as in the formation of shoot and flower meristems. Here, we isolated two homologues of Arabidopsis thaliana WUS (AtWUS), GhWUS1a_At and GhWUS1b_At, from upland cotton (Gossypium hirsutum). Domain analysis suggested that the two putative GhWUS proteins contained a highly conserved DNA-binding HOX domain and a WUS-box. Expression profile analysis showed that GhWUSs were predominantly expressed during the embryoid stage. Ectopic expression of GhWUSs in Arabidopsis could induce somatic embryo and shoot formation from seedling root tips. Furthermore, in the absence of exogenous hormone, overexpression of GhWUSs in Arabidopsis could promote shoot regeneration from excised roots, and in the presence of exogenous auxin, excised roots expressing GhWUS could be induced to produce somatic embryo. In addition, expression of the chimeric GhWUS repressor in cotton callus inhibited embryogenic callus formation. Our results show that GhWUS is an important regulator of somatic embryogenesis and shoot regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Insect Infestations Linked to Shifts in Microclimate: Important Climate Change Implications

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

Classen, Aimee T; Hart, Stephen C; Whitham, Thomas G

Changes in vegetation due to drought-influenced herbivory may influence microclimate in ecosystems. In combination with studies of insect resistant and susceptible trees, we used long-term herbivore removal experiments with two herbivores of pinon (Pinus edulis Endelm.) to test the general hypothesis that herbivore alteration of plant architecture affects soil microclimate, a major driver of ecosystem-level processes. The pinon needle scale (Matsucoccus acalyptus, Herbert) attacks needles of juvenile trees causing them to develop an open crown. In contrast, the stem-boring moth (Dioryctria albovittella Hulst.) kills the terminal shoots of mature trees, causing the crown to develop a dense form. Our studiesmore » focused on how the microclimate effects of these architectural changes are likely to accumulate over time. Three patterns emerged: (1) scale herbivory reduced leaf area index (LAI) of susceptible trees by 39%, whereas moths had no effect on LAI; (2) scale herbivory increased soil moisture and temperature beneath susceptible trees by 35 and 26%, respectively, whereas moths had no effect; and (3) scale and moth herbivory decreased crown interception of precipitation by 51 and 29%, respectively. From these results, we conclude: (1) the magnitude of scale effects on soil moisture and temperature is large, similar to global change scenarios, and sufficient to drive changes in ecosystem processes. (2) The larger sizes of moth-susceptible trees apparently buffered them from most microclimate effects of herbivory, despite marked changes in crown architecture. (3) The phenotypic expression of susceptibility or resistance to scale insects extends beyond plant-herbivore interactions to the physical environment.« less

Content Analysis of Select YouTube Postings: Comparisons of Reactions to the Sandy Hook and Aurora Shootings and Hurricane Sandy.

PubMed

Miller, Eric D

2015-11-01

This study details an innovative and methodical content analysis of 2,207 YouTube comments from four different YouTube videos (e.g., breaking news or memorials) related to the 2012 Sandy Hook Elementary School and Aurora theater mass shootings and the catastrophic Hurricane Sandy. As expected, YouTube comments associated with the Sandy Hook shootings (particularly those from a memorial video) were especially likely to feature compassion and grief with lessened hostility. This study highlights differing online contexts by which individuals show grief and related emotions following man-made and natural calamities and how-even in an online environment-powerful situational contexts greatly guide behavior.

Ferns: the missing link in shoot evolution and development.

PubMed

Plackett, Andrew R G; Di Stilio, Verónica S; Langdale, Jane A

2015-01-01

Shoot development in land plants is a remarkably complex process that gives rise to an extreme diversity of forms. Our current understanding of shoot developmental mechanisms comes almost entirely from studies of angiosperms (flowering plants), the most recently diverged plant lineage. Shoot development in angiosperms is based around a layered multicellular apical meristem that produces lateral organs and/or secondary meristems from populations of founder cells at its periphery. In contrast, non-seed plant shoots develop from either single apical initials or from a small population of morphologically distinct apical cells. Although developmental and molecular information is becoming available for non-flowering plants, such as the model moss Physcomitrella patens, making valid comparisons between highly divergent lineages is extremely challenging. As sister group to the seed plants, the monilophytes (ferns and relatives) represent an excellent phylogenetic midpoint of comparison for unlocking the evolution of shoot developmental mechanisms, and recent technical advances have finally made transgenic analysis possible in the emerging model fern Ceratopteris richardii. This review compares and contrasts our current understanding of shoot development in different land plant lineages with the aim of highlighting the potential role that the fern C. richardii could play in shedding light on the evolution of underlying genetic regulatory mechanisms.

Unintended shootings in a large metropolitan area: an incident-based analysis.

PubMed

Ismach, Richard B; Reza, Avid; Ary, Roy; Sampson, Tomoko Rie; Bartolomeos, Kidist; Kellermann, Arthur L

2003-01-01

We determine the proportion of unintended shootings that might be prevented by promoting safe storage, safe handling, and/or safer firearm designs. A regional firearm injury surveillance system was used to identify fatal and nonfatal unintentional shootings in a 5-county metropolitan area. Case reports were reviewed, and the causes of each shooting were independently classified by 4 members of the research team. A consensus conference was held to resolve disagreements. Between May 1, 1996, and June 30, 2000, 216 cases of unintentional firearm injury were identified, 3.8% of the shootings documented during the study period. Six (2.8%) were fatal. The majority of victims were between 15 and 34 years of age. One fourth (54) of the shootings involved victims younger than 18 years. Handguns were involved in 87% of the incidents. Enough information was available to characterize the incident in 122 (57%) cases. All but 6 fell into 1 or more of 3 broad categories of causation: Child access (14%), mishandling (74%), and/or deficiencies in firearm design (32%). Many unintentional shootings could be prevented by promoting safe storage of guns in the home, promoting safe handling of firearms, and requiring that all new handguns incorporate basic safety features.

Disentangling the Effects of Water Stress on Carbon Acquisition, Vegetative Growth, and Fruit Quality of Peach Trees by Means of the QualiTree Model.

PubMed

Rahmati, Mitra; Mirás-Avalos, José M; Valsesia, Pierre; Lescourret, Françoise; Génard, Michel; Davarynejad, Gholam H; Bannayan, Mohammad; Azizi, Majid; Vercambre, Gilles

2018-01-01

Climate change projections predict warmer and drier conditions. In general, moderate to severe water stress reduce plant vegetative growth and leaf photosynthesis. However, vegetative and reproductive growths show different sensitivities to water deficit. In fruit trees, water restrictions may have serious implications not only on tree growth and yield, but also on fruit quality, which might be improved. Therefore, it is of paramount importance to understand the complex interrelations among the physiological processes involved in within-tree carbon acquisition and allocation, water uptake and transpiration, organ growth, and fruit composition when affected by water stress. This can be studied using process-based models of plant functioning, which allow assessing the sensitivity of various physiological processes to water deficit and their relative impact on vegetative growth and fruit quality. In the current study, an existing fruit-tree model (QualiTree) was adapted for describing the water stress effects on peach ( Prunus persica L. Batsch) vegetative growth, fruit size and composition. First, an energy balance calculation at the fruit-bearing shoot level and a water transfer formalization within the plant were integrated into the model. Next, a reduction function of vegetative growth according to tree water status was added to QualiTree. Then, the model was parameterized and calibrated for a late-maturing peach cultivar ("Elberta") under semi-arid conditions, and for three different irrigation practices. Simulated vegetative and fruit growth variability over time was consistent with observed data. Sugar concentrations in fruit flesh were well simulated. Finally, QualiTree allowed for determining the relative importance of photosynthesis and vegetative growth reduction on carbon acquisition, plant growth and fruit quality under water constrains. According to simulations, water deficit impacted vegetative growth first through a direct effect on its sink strength, and; secondly, through an indirect reducing effect on photosynthesis. Fruit composition was moderately affected by water stress. The enhancements performed in the model broadened its predictive capabilities and proved that QualiTree allows for a better understanding of the water stress effects on fruit-tree functioning and might be useful for designing innovative horticultural practices in a changing climate scenario.

Single-provenance mature conifers show higher non-structural carbohydrate storage and reduced growth in a drier location.

PubMed

Piper, Frida I; Fajardo, Alex; Hoch, Günter

2017-08-01

Since growth is more sensitive to drought than photosynthesis, trees inhabiting dry regions are expected to exhibit higher carbohydrate storage and less growth than their conspecifics from more humid regions. However, the same pattern can be the result of different genotypes inhabiting contrasting humidity conditions. To test if reduced growth and high carbohydrate storage are environmentally driven by drought, we examined the growth and non-structural carbohydrate (NSC) concentrations in single-provenance stands of mature trees of Pinus contorta Douglas and Pinus ponderosa Douglas ex C. Lawson planted at contrasting humidity conditions (900 versus 300 mm of annual precipitation) in Patagonia, Chile. Individual tree growth was measured for each species and at each location as mean basal area increment of the last 10 years (BAI10), annual shoot elongation for the period 2011-14, and needle length for 2013 and 2014 cohorts. Additionally, needle, branch, stem sapwood and roots were collected from each sampled tree to determine soluble sugars, starch and total NSC concentrations. The two species showed lower mean BAI10 and 2013 needle length in the dry site; P. ponderosa also had lower annual shoot extension for 2011 and 2014, and lower 2014 needle length, in the dry than in the mesic site. By contrast, NSC concentrations of all woody tissues for both species were either similar or higher in the dry site when compared with the mesic site. Patterns of starch and sugars were substantially different: starch concentrations were similar between sites except for roots of P. ponderosa, which were higher in the dry site, while sugar concentrations of all woody tissues in both species were higher in the dry site. Overall, our study provides evidence that reduced growth along with carbon (C) accumulation is an environmentally driven response to drought. Furthermore, the significant accumulation of low-molecular weight sugars in the dry site is compatible with a prioritized C allocation for osmoregulation. However, since this accumulation did not come at the expense of reduced starch, it is unlikely that growth was limited by C supply in the dry site. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Auxin regulated OsRGP1 and OsSuS are involved in the gravitropic bending of rice shoot bases

NASA Astrophysics Data System (ADS)

Hu, Liwei; Cui, Dayong; Cai, Weiming

The gravitropic bending of rice shoot in horizontal position results from differential elongation of cells between two halves of shoot bases. In our experiment, reversibly glycosylated polypeptide (OsRGP1), sucrose synthase (OsSuS) genes which related to sugar metabolism were identified by suppressive subtractive hybridization (SSH) in gravitropism in rice shoot bases. Realtime RT-PCR were used to study the expression of two genes in detail. OsRGP1 and OsSuS were differentially induced in the abaxial (lower) side of rice shoot bases during gravitropism. The OsRGP1 and OsSuS expression were regulated by auxin. The sequence analysis of their promoters was in concurrence. TIBA treatment could inhibit the asymmetrical expression of OsRGP1 and OsSuS in gravitropism in rice shoot bases. In addition, there was more hexose in the lower side of rice shoot bases in gravitropism. Our data suggested that asymmetric redistribution of auxin following gravistimulation resulted in the different localized expression of OsRGP1 and OsSuS. It is possible that asymmetrical expression of OsSuS resulted in the asymmetrical distribution of hexose and asymmetrical expression of OsRGP1 induced the synthesis of cell wall polysaccharides in the lower half of rice shoot bases. Hexose and cell wall polysaccharides accumulation in lower side of rice shoot bases might contribute to the cell expansion, thus leading to gravitropic bending.

Seed germination, seedling traits, and seed bank of the tree Moringa peregrina (Moringaceae) in a hyper-arid environment.

PubMed

Gomaa, Nasr H; Picó, F Xavier

2011-06-01

Water-limited hot environments are good examples of hyper-aridity. Trees are scarce in these environments but some manage to survive, such as the tree Moringa peregrina. Understanding how trees maintain viable populations in extremely arid environments may provide insight into the adaptive mechanisms by which trees cope with extremely arid weather conditions. This understanding is relevant to the current increasing aridity in several regions of the world. Seed germination experiments were conducted to assess variation in seed mass, seed germination, and seedling traits of Moringa peregrina plants and the correlations among these traits. A seed burial experiment was also designed to study the fate of M. peregrina seeds buried at two depths in the soil for two time periods. On average, seeds germinated in three days and seedling shoots grew 0.7 cm per day over three weeks. Larger seeds decreased germination time and increased seedling growth rates relative to smaller seeds. Seeds remained quiescent in the soil and germination was very high at both depths and burial times. The after-ripening time of Moringa peregrina seeds is short and seeds germinate quickly after imbibition. Plants of M. peregrina may increase in hyper-arid environments from seeds with larger mass, shorter germination times, and faster seedling growth rates. The results also illustrate the adjustment in allocation to seed biomass and correlations among seed and seedling traits that allows M. peregrina to be successful in coping with aridity in its environment.

Searching for early-warning signals of impending dieback and death in Mediterranean oaks

NASA Astrophysics Data System (ADS)

Colangelo, Michele; Ripullone, Francesco; Julio Camarero, Jesus; De Micco, Veronica; Gazol, Antonio; Gentilesca, Tiziana; Borghetti, Marco

2017-04-01

In recent decades, forest dieback episodes have been recorded worldwide affecting different tree species. In particular, several cases of widespread dieback and increased mortality rates have been described for Mediterranean oak (Quercus spp.) species. These dieback cases are revealing the high vulnerability of Mediterranean oaks, manifested as a loss in tree vigour (leaf shedding, canopy and shoot dieback), growth decline and sometimes tree death, as a consequence of temperatures rising at unprecedented rates and drying trends. However, in the wake of the so-called 'oak decline phenomenon', the attention on these species has generally been limited, perhaps because they are often regarded as well-adapted to the dry conditions typical of Mediterranean areas. Indeed, according to recent studies, the reduced size, the ability to sprout and the anisohydric behavior of Mediterranean oak species (reduced control of water loss and high stomatal conductance rates) would make them better adapted to withstand heat and drought stress then taller and non-sprouting isohydric species (e.g. conifer, with strict control of water loss by closing stomata). Here, we investigated the vulnerability of Mediterranean oaks by comparing neighboring living and recently dead trees in species with low (Q. pubescens), intermediate (Q. cerris, Q. frainetto) and high (Q. robur) sensitivity to water shortage. We analysed changes in tree vigour using tree-ring width and functional wood anatomical traits as proxies to search for early-warning signals of dieback, in connection with the main proposed dieback mechanisms (hydraulic failure and/or carbon starvation). We also modeled the probability of tree death as a function of tree size (diameter, height) by quantifying recent changes in growth and wood anatomy along tree-ring series. Contrary to the general concept that trees tend to experience increasing cavitation risk with increasing height, our studies show that smaller oaks are more prone to die than taller conspecifics. Further, irrespective of differences in drought sensitivity, dead trees showed lower radial-growth rates than surviving trees from 10 to 20 years prior to tree death. Contrastingly, differences in wood anatomical traits (vessel lumen size, vessel density) between dead and living trees were not always significant, being species-dependent. Our findings indicate that: (i) tree height is a proxy of the probability of drought-induced death, and (ii) recent growth trends constitute valuable early-warning signals of impending dieback and death in Mediterranean oak species.

A Multi-Level Bayesian Analysis of Racial Bias in Police Shootings at the County-Level in the United States, 2011-2014.

PubMed

Ross, Cody T

2015-01-01

A geographically-resolved, multi-level Bayesian model is used to analyze the data presented in the U.S. Police-Shooting Database (USPSD) in order to investigate the extent of racial bias in the shooting of American civilians by police officers in recent years. In contrast to previous work that relied on the FBI's Supplemental Homicide Reports that were constructed from self-reported cases of police-involved homicide, this data set is less likely to be biased by police reporting practices. County-specific relative risk outcomes of being shot by police are estimated as a function of the interaction of: 1) whether suspects/civilians were armed or unarmed, and 2) the race/ethnicity of the suspects/civilians. The results provide evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being {black, unarmed, and shot by police} is about 3.49 times the probability of being {white, unarmed, and shot by police} on average. Furthermore, the results of multi-level modeling show that there exists significant heterogeneity across counties in the extent of racial bias in police shootings, with some counties showing relative risk ratios of 20 to 1 or more. Finally, analysis of police shooting data as a function of county-level predictors suggests that racial bias in police shootings is most likely to emerge in police departments in larger metropolitan counties with low median incomes and a sizable portion of black residents, especially when there is high financial inequality in that county. There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates.

A Multi-Level Bayesian Analysis of Racial Bias in Police Shootings at the County-Level in the United States, 2011–2014

PubMed Central

Ross, Cody T.

2015-01-01

A geographically-resolved, multi-level Bayesian model is used to analyze the data presented in the U.S. Police-Shooting Database (USPSD) in order to investigate the extent of racial bias in the shooting of American civilians by police officers in recent years. In contrast to previous work that relied on the FBI’s Supplemental Homicide Reports that were constructed from self-reported cases of police-involved homicide, this data set is less likely to be biased by police reporting practices. County-specific relative risk outcomes of being shot by police are estimated as a function of the interaction of: 1) whether suspects/civilians were armed or unarmed, and 2) the race/ethnicity of the suspects/civilians. The results provide evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being {black, unarmed, and shot by police} is about 3.49 times the probability of being {white, unarmed, and shot by police} on average. Furthermore, the results of multi-level modeling show that there exists significant heterogeneity across counties in the extent of racial bias in police shootings, with some counties showing relative risk ratios of 20 to 1 or more. Finally, analysis of police shooting data as a function of county-level predictors suggests that racial bias in police shootings is most likely to emerge in police departments in larger metropolitan counties with low median incomes and a sizable portion of black residents, especially when there is high financial inequality in that county. There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates. PMID:26540108

Transcriptomic and Hormonal Analyses Reveal that YUC-Mediated Auxin Biogenesis Is Involved in Shoot Regeneration from Rhizome in Cymbidium

PubMed Central

Liu, Yang; Zhang, Hai-Liang; Guo, He-Rong; Xie, Li; Zeng, Rui-Zhen; Zhang, Xiang-Qian; Zhang, Zhi-Sheng

2017-01-01

Cymbidium, one of the most important orchid genera in horticulture, can be classified into epiphytic and terrestrial species. Generally, epiphytic Cymbidium seedlings can be easily propagated by tissue culture, but terrestrial seedlings are difficult to propagate. To date, the molecular mechanisms underlying the differences in the ease with which terrestrial and epiphytic cymbidiums can be propagated are largely unknown. Using RNA-sequencing, quantitative reverse transcription PCR and enzyme-linked immunosorbent assay, Cymbidium ‘Xiaofeng’ (CXF), which can be efficiently micropropagated, and terrestrial Cymbidium sinense ‘Qijianbaimo’ (CSQ), which has a low regeneration ability, were used to explore the molecular mechanisms underlying the micropropagation ability of Cymbidium species. To this end, 447 million clean short reads were generated, and 31,264 annotated unigenes were obtained from 10 cDNA libraries. A total of 1,290 differentially expressed genes (DEGs) were identified between CXF and CSQ during shoot induction. Gene ontology (GO) enrichment analysis indicated that the DEGs were significantly enriched in auxin pathway-related GO terms. Further analysis demonstrated that YUC and GH3 family genes, which play crucial roles in the regulation of auxin/IAA (indole-3-acetic acid) metabolism, acted quickly in response to shoot induction culture in vitro and were closely correlated with variation in shoot regeneration between CXF and CSQ. In addition, the study showed that IAA accumulated rapidly and significantly during shoot induction in CXF compared to that in CSQ; in contrast, no significant changes in other hormones were observed between CXF and CSQ. Furthermore, shoot regeneration in CXF was inhibited by a yucasin-auxin biosynthesis inhibitor, indicating that increased IAA level is required for high-frequency shoot regeneration in CXF. In conclusion, our study revealed that YUC-mediated auxin biogenesis is involved in shoot regeneration from rhizome in Cymbidium. PMID:29163591

Handgun Acquisitions in California After Two Mass Shootings.

PubMed

Studdert, David M; Zhang, Yifan; Rodden, Jonathan A; Hyndman, Rob J; Wintemute, Garen J

2017-05-16

Mass shootings are common in the United States. They are the most visible form of firearm violence. Their effect on personal decisions to purchase firearms is not well-understood. To determine changes in handgun acquisition patterns after the mass shootings in Newtown, Connecticut, in 2012 and San Bernardino, California, in 2015. Time-series analysis using seasonal autoregressive integrated moving-average (SARIMA) models. California. Adults who acquired handguns between 2007 and 2016. Excess handgun acquisitions (defined as the difference between actual and expected acquisitions) in the 6-week and 12-week periods after each shooting, overall and within subgroups of acquirers. In the 6 weeks after the Newtown and San Bernardino shootings, there were 25 705 (95% prediction interval, 17 411 to 32 788) and 27 413 (prediction interval, 15 188 to 37 734) excess acquisitions, respectively, representing increases of 53% (95% CI, 30% to 80%) and 41% (CI, 19% to 68%) over expected volume. Large increases in acquisitions occurred among white and Hispanic persons, but not among black persons, and among persons with no record of having previously acquired a handgun. After the San Bernardino shootings, acquisition rates increased by 85% among residents of that city and adjacent neighborhoods, compared with 35% elsewhere in California. The data relate to handguns in 1 state. The statistical analysis cannot establish causality. Large increases in handgun acquisitions occurred after these 2 mass shootings. The spikes were short-lived and accounted for less than 10% of annual handgun acquisitions statewide. Further research should examine whether repeated shocks of this kind lead to substantial increases in the prevalence of firearm ownership. None.

Accumulation of flavonoids and related compounds in birch induced by UV-B irradiance.

PubMed

Lavola, Anu

1998-01-01

A growth chamber experiment was conducted to examine the effects of UV-B exposure (4.9 kJ m(-2) day(-1) of biologically effective UV-B, 280-320 nm) on shoot growth and secondary metabolite production in Betula pendula (Roth) and B. resinifera (Britt.) seedlings originating from environments in Finland, Germany and Alaska differing in solar UV-B radiation and climate. Neither shoot growth nor the composition of secondary metabolites was affected by UV-B irradiance, but the treatment induced significant changes in the amounts of individual secondary metabolites in leaves. Leaves of seedlings exposed to UV-B radiation contained higher concentrations of several flavonoids, condensed tannins and some hydroxycinnamic acids than leaves of control seedlings that received no UV-B radiation. At the population level, there was considerable variation in secondary metabolite responses to UV-B radiation: among populations, the induced response was most prominent in Alaskan populations, which were adapted to the lowest ambient UV-B radiation environment. I conclude that solar UV-B radiation plays an important role in the formation of secondary chemical characteristics in birch trees.

Toasted vine-shoot chips as enological additive.

PubMed

Cebrián-Tarancón, Cristina; Sánchez-Gómez, Rosario; Salinas, M Rosario; Alonso, Gonzalo L; Oliva, José; Zalacain, Amaya

2018-10-15

Different ways of vine-shoots revalorization have been proposed, but not in wine yet, as for example in the same way as oak chips are being used. In this work, vine-shoot samples were submitted to a thermogravimetric analysis to establish the temperature range for its lignin structure decomposition, resulting between 160 and 180 °C. Then, vine-shoot chips from Airén and Cencibel cultivars, with a particle size around 2.5-3.5 cm, were submitted to six toasting conditions: 160 °C and 180 °C for 45, 60 and 75 min. Their volatile composition was very similar to oak chips, being vanillin the most important compound. Moreover, such vine-shoots have an interesting content of prodelphinidins that together with the stilbenes may contribute to wine antioxidant activity. The toasting conditions at 180 °C/45 min were the most suitable one for releasing the mentioned valuable compounds in order to propose vine-shoots as new enological additive similar to oak chips. Copyright © 2018. Published by Elsevier Ltd.

Exposure to lead in South African shooting ranges.

PubMed

Mathee, Angela; de Jager, Pieter; Naidoo, Shan; Naicker, Nisha

2017-02-01

Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly higher blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10μg/dl (p<0.001). Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Mixed, short rotation culture of red alder and black cottonwood: growth, coppicing, nitrogen fixation, and allelopathy

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

Heilman, P.; Stettler, R.F.

1985-01-01

Alnus rubra seedlings were grown in a 1:1 mixture at a spacing of 1.2 x 1.2 m with 28 Populus clones (25 clones pf P. trichocarpa, 2 of P. deltoides x P. trichocarpa, and one P. deltoides x P. nigra) in a study established in W. Washington in March 1979. Trees were harvested at 4 yr old. At harvest, average heights were: pure Populus, 10.2 m; Populus in the mixed stand 11.0 m; and alder 8.4 m. Most Populus sprouted satisfactorily after harvest (6.6 shoots/plant when pure, 7.6 shoots/plant in the mixture), but alder sprouted poorly (3.6 shoots/plant). Above-ground biomassmore » at harvest was 15.9 t/ha p.a. for the mixture and 16.7 t/ha p.a. for pure Populus, although the mixture had been more productive at 2 yr. Nitrogenase activity (nitrogen fixation as measured by acetylene reduction) of alder declines in the 4th season; competition was the most important factor influencing this decline. Soil N content had no effect on fixation. A pot study showed that ground Populus leaf and litter material inhibited the growth of red alder seedlings, although soil collected from Populus plots had no effect. Results indicated that allelopathy is probably a minor factor under field conditions, at most, and that growing mixed stands may, on balance, be beneficial. 20 references.« less

Evaluation of the hormonal state of columnar apple trees (Malus x domestica) based on high throughput gene expression studies.

PubMed

Krost, Clemens; Petersen, Romina; Lokan, Stefanie; Brauksiepe, Bastienne; Braun, Peter; Schmidt, Erwin R

2013-02-01

The columnar phenotype of apple trees (Malus x domestica) is characterized by a compact growth habit with fruit spurs instead of lateral branches. These properties provide significant economic advantages by enabling high density plantings. The columnar growth results from the presence of a dominant allele of the gene Columnar (Co) located on chromosome 10 which can appear in a heterozygous (Co/co) or homozygous (Co/Co) state. Although two deep sequencing approaches could shed some light on the transcriptome of columnar shoot apical meristems (SAMs), the molecular mechanisms of columnar growth are not yet elaborated. Since the influence of phytohormones is believed to have a pivotal role in the establishment of the phenotype, we performed RNA-Seq experiments to study genes associated with hormone homeostasis and clearly affected by the presence of Co. Our results provide a molecular explanation for earlier findings on the hormonal state of columnar apple trees. Additionally, they allow hypotheses on how the columnar phenotype might develop. Furthermore, we show a statistically approved enrichment of differentially regulated genes on chromosome 10 in the course of validating RNA-Seq results using additional gene expression studies.

Environmental and hormonal control of cambial stem cell dynamics.

PubMed

Bhalerao, Rishikesh P; Fischer, Urs

2017-01-01

Perennial trees have the amazing ability to adjust their growth rate to both adverse and favorable seasonally reoccurring environmental conditions over hundreds of years. In trunks and stems, the basis for the tuning of seasonal growth rate is the regulation of cambial stem cell activity. Cambial stem cell quiescence and dormancy protect the tree from potential physiological and genomic damage caused by adverse growing conditions and may permit a long lifespan. Cambial dormancy and longevity are both aspects of a tree's life for which the study of cambial stem cell behavior in the annual model plant Arabidopsis is inadequate. Recent functional analyses of hormone perception and catabolism mutants in Populus indicate that shoot-derived long-range signals, as well as local cues, steer cambial activity. Auxin is central to the regulation of cambial activity and probably also maintenance. Emerging genome editing and phenotyping technologies will enable the identification of down-stream targets of hormonal action and facilitate the genetic dissection of complex traits of cambial biology. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Ferns: the missing link in shoot evolution and development

PubMed Central

Plackett, Andrew R. G.; Di Stilio, Verónica S.; Langdale, Jane A.

2015-01-01

Shoot development in land plants is a remarkably complex process that gives rise to an extreme diversity of forms. Our current understanding of shoot developmental mechanisms comes almost entirely from studies of angiosperms (flowering plants), the most recently diverged plant lineage. Shoot development in angiosperms is based around a layered multicellular apical meristem that produces lateral organs and/or secondary meristems from populations of founder cells at its periphery. In contrast, non-seed plant shoots develop from either single apical initials or from a small population of morphologically distinct apical cells. Although developmental and molecular information is becoming available for non-flowering plants, such as the model moss Physcomitrella patens, making valid comparisons between highly divergent lineages is extremely challenging. As sister group to the seed plants, the monilophytes (ferns and relatives) represent an excellent phylogenetic midpoint of comparison for unlocking the evolution of shoot developmental mechanisms, and recent technical advances have finally made transgenic analysis possible in the emerging model fern Ceratopteris richardii. This review compares and contrasts our current understanding of shoot development in different land plant lineages with the aim of highlighting the potential role that the fern C. richardii could play in shedding light on the evolution of underlying genetic regulatory mechanisms. PMID:26594222

Changing the spatial pattern of TFL1 expression reveals its key role in the shoot meristem in controlling Arabidopsis flowering architecture

PubMed Central

Baumann, Kim; Venail, Julien; Berbel, Ana; Domenech, Maria Jose; Money, Tracy; Conti, Lucio; Hanzawa, Yoshie; Madueno, Francisco; Bradley, Desmond

2015-01-01

Models for the control of above-ground plant architectures show how meristems can be programmed to be either shoots or flowers. Molecular, genetic, transgenic, and mathematical studies have greatly refined these models, suggesting that the phase of the shoot reflects different genes contributing to its repression of flowering, its vegetativeness (‘veg’), before activators promote flower development. Key elements of how the repressor of flowering and shoot meristem gene TFL1 acts have now been tested, by changing its spatiotemporal pattern. It is shown that TFL1 can act outside of its normal expression domain in leaf primordia or floral meristems to repress flower identity. These data show how the timing and spatial pattern of TFL1 expression affect overall plant architecture. This reveals that the underlying pattern of TFL1 interactors is complex and that they may be spatially more widespread than TFL1 itself, which is confined to shoots. However, the data show that while TFL1 and floral genes can both act and compete in the same meristem, it appears that the main shoot meristem is more sensitive to TFL1 rather than floral genes. This spatial analysis therefore reveals how a difference in response helps maintain the ‘veg’ state of the shoot meristem. PMID:26019254

DNA methylation and genome rearrangement characteristics of phase change in cultured shoots of Sequoia sempervirens.

PubMed

Huang, Li-Chun; Hsiao, Lin-June; Pu, Szu-Yuan; Kuo, Ching-I; Huang, Bau-Lian; Tseng, Tsung-Che; Huang, Hao-Jen; Chen, Yu-Ting

2012-06-01

Epigenetic machinery regulates the expression of individual genes and plays a crucial role in globally shaping and maintaining developmental patterning. We studied the extent of DNA methylation in the nucleus, mitochondrion and chloroplast in cultured Sequoia sempervirens (coast redwood) adult, juvenile and rejuvenated shoots by measuring the ratio of methylcytosine to total cytosine using high-performance liquid chromatography (HPLC). We also analyzed nuclear DNA (nuDNA) polymorphisms of different shoot types by methylation-sensitive amplified fragment length polymorphism (MSAP) and Southern blot analysis. The extent of nuDNA methylation was greater in the adult vegetative than juvenile and rejuvenated shoots (8% vs 6.5-7.5%). In contrast, the proportion of methylcytosine was higher in mitochondrial DNA (mDNA) of juvenile and rejuvenated shoots than adult shoots (6.6% vs 7.8-8.2%). MSAP and Southern blot analyses identified three MSAP fragments which could be applied as phase-specific molecular markers. We also found nuclear genome and mtDNA rearrangement may be as important as DNA methylation status during the phase change. Our findings strongly suggest that DNA methylation and genome rearrangement may affect the dynamic tissue- and cell type-specific changes that determine the developmental phase of S. sempervirens shoots. Copyright © Physiologia Plantarum 2012.

Genetic and phenotypic analysis of shoot apical and floral meristem development

USDA-ARS?s Scientific Manuscript database

The shoot apical and floral meristems (SAM and FM, respectively) of Arabidopsis thaliana contain reservoirs of self-renewing stem cells that function as sources of progenitor cells for organ formation during development. The primary SAM produces all of the aerial structures of the adult plant, where...

Whitebark pine facilitation at treeline: potential interactions for disruption by an invasive pathogen.

PubMed

Tomback, Diana F; Blakeslee, Sarah C; Wagner, Aaron C; Wunder, Michael B; Resler, Lynn M; Pyatt, Jill C; Diaz, Soledad

2016-08-01

In stressful environments, facilitation often aids plant establishment, but invasive plant pathogens may potentially disrupt these interactions. In many treeline communities in the northern Rocky Mountains of the U.S. and Canada, Pinus albicaulis, a stress-tolerant pine, initiates tree islands at higher frequencies than other conifers - that is, leads to leeward tree establishment more frequently. The facilitation provided by a solitary (isolated) P. albicaulis leading to tree island initiation may be important for different life-history stages for leeward conifers, but it is not known which life-history stages are influenced and protection provided. However, P. albicaulis mortality from the non-native pathogen Cronartium ribicola potentially disrupts these facilitative interactions, reducing tree island initiation. In two Rocky Mountain eastern slope study areas, we experimentally examined fundamental plant-plant interactions which might facilitate tree island formation: the protection offered by P. albicaulis to leeward seed and seedling life-history stages, and to leeward krummholz conifers. In the latter case, we simulated mortality from C. ribicola for windward P. albicaulis to determine whether loss of P. albicaulis from C. ribicola impacts leeward conifers. Relative to other common solitary conifers at treeline, solitary P. albicaulis had higher abundance. More seeds germinated in leeward rock microsites than in conifer or exposed microsites, but the odds of cotyledon seedling survival during the growing season were highest in P. albicaulis microsites. Planted seedling survival was low among all microsites examined. Simulating death of windward P. albicaulis by C. ribicola reduced shoot growth of leeward trees. Loss of P. albicaulis to exotic disease may limit facilitation interactions and conifer community development at treeline and potentially impede upward movement as climate warms.

Metabolomic homeostasis shifts after callus formation and shoot regeneration in tomato

PubMed Central

Kumari, Alka; Ray, Kamalika; Sadhna, Sadhna; Pandey, Arun Kumar; Sreelakshmi, Yellamaraju; Sharma, Rameshwar

2017-01-01

Plants can regenerate from a variety of tissues on culturing in appropriate media. However, the metabolic shifts involved in callus formation and shoot regeneration are largely unknown. The metabolic profiles of callus generated from tomato (Solanum lycopersicum) cotyledons and that of shoot regenerated from callus were compared with the pct1-2 mutant that exhibits enhanced polar auxin transport and the shr mutant that exhibits elevated nitric oxide levels. The transformation from cotyledon to callus involved a major shift in metabolite profiles with denser metabolic networks in the callus. In contrast, the transformation from callus to shoot involved minor changes in the networks. The metabolic networks in pct1-2 and shr mutants were distinct from wild type and were rewired with shifts in endogenous hormones and metabolite interactions. The callus formation was accompanied by a reduction in the levels of metabolites involved in cell wall lignification and cellular immunity. On the contrary, the levels of monoamines were upregulated in the callus and regenerated shoot. The callus formation and shoot regeneration were accompanied by an increase in salicylic acid in wild type and mutants. The transformation to the callus and also to the shoot downregulated LST8 and upregulated TOR transcript levels indicating a putative linkage between metabolic shift and TOR signalling pathway. The network analysis indicates that shift in metabolite profiles during callus formation and shoot regeneration is governed by a complex interaction between metabolites and endogenous hormones. PMID:28481937

Responses to Systemic Nitrogen Signaling in Arabidopsis Roots Involve trans-Zeatin in Shoots.

PubMed

Poitout, Arthur; Crabos, Amandine; Petřík, Ivan; Novák, Ondřej; Krouk, Gabriel; Lacombe, Benoît; Ruffel, Sandrine

2018-05-15

Plants face temporal and spatial variation in nitrogen (N) availability. This includes heterogeneity in soil nitrate (NO3-) content. To overcome these constraints, plants modify their gene expression and physiological processes to optimize N acquisition. This plasticity relies on a complex long-distance root-shoot-root signaling network that remains poorly understood. We previously showed that cytokinin (CK) biosynthesis is required to trigger systemic N signaling. Here, we performed split-root experiments and used a combination of CK-related mutant analyses, hormone profiling, transcriptomic analysis, NO3- uptake assays, and root growth measurements to gain insight into systemic N signaling in Arabidopsis thaliana. By comparing wild-type plants and mutants affected in CK biosynthesis and ABCG14-dependent root-to-shoot translocation of CK, we revealed an important role for active trans-Zeatin (tZ) in systemic N signaling. Both rapid sentinel gene regulation and long-term functional acclimation to heterogeneous NO3- supply, including NO3- transport and root growth regulation, are likely mediated by the integration of tZ content in shoots. Furthermore, shoot transcriptome profiling revealed that glutamate/glutamine metabolism is likely a target of tZ root-to-shoot translocation, prompting an interesting hypothesis regarding shoot-to-root communication. Finally, this study highlights tZ-independent pathways regulating gene expression in shoots as well as NO3- uptake activity in response to total N-deprivation. © 2018 American Society of Plant Biologists. All rights reserved.

Dieback of Acacia koa in Hawaii: Ecological and pathological characteristics of affected stands

USGS Publications Warehouse

Anderson, R.C.; Gardner, D.E.; Daehler, C.C.; Meinzer, F.C.

2002-01-01

Koa (Acacia koa) is an endemic Hawaiian tree that serves as a keystone species in the upper elevation forests of all the main islands. In the Mauna Loa Strip area of Hawaii Volcanoes National Park, mature koa stands are suffering from an unexplained dieback that has increased in severity since it was first noticed approximately 25 years ago. The dieback is often evident in patches, and generally spreads within stands in a radial fashion from a localized infection center. Entire crowns of affected trees become wilted, with foliage gradually progressing from an apparent healthy to a completely chlorotic condition. Although most trees die soon after the onset of symptoms, some trees are able to survive crown death by producing epicormic shoots on the lower portions of the trunk. Previously published studies reported that a vascular wilt fungus (Fusarium oxysporum f. sp. koae) was associated with koa seeds and the rhizosphere of healthy and dieback-affected koa stands. The purpose of this study was to characterize the stand structure, soil conditions, and physiological condition of dieback-affected trees, and to assess the possible role of F. oxysporum f. sp. koae in the current dieback stands. This fungus was isolated from branches of symptomatic koa in dieback-affected stands and roots from healthy and dieback-affected stands. Possible differences in the pathogenicity and virulence of F. oxysporum f. sp. koae isolates obtained from the roots of healthy koa in unaffected stands and those from branches of dieback-affected koa were determined by greenhouse inoculations of koa seedlings. Healthy koa saplings in stands unaffected by dieback were also inoculated to determine if disease symptoms could be induced by inoculation of injured roots in the field. Both branch and root isolates were pathogenic; with the percent mortality of inoculated seedlings ranging from 30 to 60% for all isolates. Disease severity between branch and root isolates was not significantly different. Wilt symptoms were not observed in field inoculations of koa saplings after 8 months. Investigation of the dieback stand structure determined that the larger size classes (i.e., DBH > 3 cm) were all affected equally, with the smallest size class (i.e., 0-3 cm DBH) having the lowest percentage of dieback at each site. Soil from dieback stands had higher water content and was more acidic than that from neighboring unaffected stands. Phyllodes on epicormic shoots of dieback trees had a reduced area, mass, and mass to area ratio. Phyllodes on dieback trees also had reduced stomatal conductance and higher (less negative) leaf water potential. Results from the greenhouse inoculations demonstrated that F. oxysporum f. sp. koae is pathogenic to koa, but the pathogen's activity in the field may be influenced by predisposing factors such as temperature fluctuations, water availability, soil type, and interactions with other soil organisms. F. oxysporum f. sp. koae appears to play an important role in regulating koa stand dynamics, growth, and physiology under environmental and edaphic conditions favorable for disease development. ?? 2002 Elsevier Science B.V. All rights reserved.

Mycorrhizal symbiosis effects on growth of chalk false-brome (Brachypodium pinnatum) are dependent on the environmental light regime.

PubMed

Füzy, Anna; Bothe, Hermann; Molnár, Edit; Biró, Borbála

2014-03-01

AMF (arbuscular mycorrhizal fungi) colonization of the grass chalk false-brome (Brachypodium pinnatum (L.) P. B.) was studied in selected habitats under spatially different light regimes: (a) shade condition under oak trees, (b) half shade in a shrubby area and (c) full-sun conditions on unshaded grassland. This study assessed the variations in AMF colonization of the grass dependent on the light supply in field habitats. Soil, root and shoot samples were collected four times during the vegetation period (in June, July, September and October). Root colonization, root and shoot biomass as well as soil water content were determined. The highest rate of AMF colonization was detected in June under half-sun and full-sun conditions, where about 50% of the roots were colonized. The average amount of arbuscules was less than 20% in the roots at the three sites, with the highest number of arbuscules in June, under half-sun and full-sun conditions, however, not under the trees. Overall, best mycorrhizal colonization occurred during summer, and its rate decreased in autumn. This tendency inversely correlated with the amount of precipitation, and thus with the water content of soils. The high colonization rate of the examined root samples, and also its seasonal fluctuation, might reflect the importance of the symbiosis where inorganic nutrients and water are the growth-limiting factors. The marginal AMF colonization of chalk false-brome under shade conditions indicates that plants do not use AMF under all stress conditions. When low light limits photosynthesis and thus growth of the plants, they dispense with the colonization of AMF in order to save the expenditure of organic carbon. Copyright © 2013 Elsevier GmbH. All rights reserved.

Micropropagation and Biomass Production of True-to-Type Stevia rebaudiana Bertoni.

PubMed

Modi, Arpan R; Sharma, Vikas; Patil, Ghanshyam; Singh, Amritpal S; Subhash, N; Kumar, Nitish

2016-01-01

Here we describe an efficient micropropagation protocol for Stevia rebaudiana Bertoni. We present experiments carried out to optimize the suitable media for in vitro shoot multiplication and root induction and to study the effect of culture vessel on shoot multiplication. Among all different media tested for in vitro shoot multiplication, hormone-free liquid medium is most suitable. The highest number of nodes per shoot (5.4) and length of shoot (4.76 cm) at 4 weeks after subculturing are observed when single node explants are placed on modified MS medium supplemented with 1 % sucrose and 0.7 % agar. The highest response of multiplication rate (9.56) is observed on half strength of macroelement of MS with full strength of microelement of MS and 170 mg/l KH2PO4, and 185 mg/l MgSO4 in plastic growth container. Further, RAPD marker analysis of in vitro-raised plants maintained their clonal fidelity and true-to-type without showing any somaclonal variation.

How far does it get?--The effect of shooting distance and type of firearm on the simultaneous analysis of DNA and RNA from backspatter recovered from inside and outside surfaces of firearms.

PubMed

Grabmüller, Melanie; Cachée, Philipp; Madea, Burkhard; Courts, Cornelius

2016-01-01

When a firearm projectile hits a biological target a spray of biological material (e.g. blood and tissue) is ejected from the entrance wound and propelled back into the direction of the firearm. This phenomenon has been termed 'backspatter' and if backspattered biological material reaches the firearm on its backward trajectory it may persist on and be recovered from the firearm's inside surfaces. Molecular genetic analysis of backspatter generated by contact shots and shots from very short distances has already been demonstrated to critically contribute to victim identification and the reconstruction of firearm-related crimes. It is not known, however, up to what shooting distance can backspatter be found on firearms' inside surfaces and what influence the weapon's type and caliber has on backspatter attributes (e.g. reach, amount and distribution). Therefore, the present pilot study investigated the effect of serval combinations of shooting distances and types of firearms and ammunitions on the analyzability of co-extracted DNA and micro-RNA in samples of backspatter collected from interior and exterior surfaces of the firearms after experimental shootings employing standardized ballistic models. We demonstrate the limiting effect of shooting distance and the type of firearm on the yield of nucleic acids recovered from backspatter and the success rates of forensic DNA profiling and RNA based body-fluid and organ tissue identification in experimental shootings. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Growth and phenology of three dwarf shrub species in a six-year soil warming experiment at the alpine treeline.

PubMed

Anadon-Rosell, Alba; Rixen, Christian; Cherubini, Paolo; Wipf, Sonja; Hagedorn, Frank; Dawes, Melissa A

2014-01-01

Global warming can have substantial impacts on the phenological and growth patterns of alpine and Arctic species, resulting in shifts in plant community composition and ecosystem dynamics. We evaluated the effects of a six-year experimental soil warming treatment (+4°C, 2007-2012) on the phenology and growth of three co-dominant dwarf shrub species growing in the understory of Larix decidua and Pinus uncinata at treeline in the Swiss Alps. We monitored vegetative and reproductive phenology of Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum throughout the early growing season of 2012 and, following a major harvest at peak season, we measured the biomass of above-ground ramet fractions. For all six years of soil warming we measured annual shoot growth of the three species and analyzed ramet age and xylem ring width of V. myrtillus. Our results show that phenology of the three species was more influenced by snowmelt timing, and also by plot tree species (Larix or Pinus) in the case of V. myrtillus, than by soil warming. However, the warming treatment led to increased V. myrtillus total above-ground ramet biomass (+36% in 2012), especially new shoot biomass (+63% in 2012), as well as increased new shoot increment length and xylem ring width (+22% and +41%, respectively; average for 2007-2012). These results indicate enhanced overall growth of V. myrtillus under soil warming that was sustained over six years and was not caused by an extended growing period in early summer. In contrast, E. hermaphroditum only showed a positive shoot growth response to warming in 2011 (+21%), and V. gaultherioides showed no significant growth response. Our results indicate that V. myrtillus might have a competitive advantage over the less responsive co-occurring dwarf shrub species under future global warming.

Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn.

PubMed

Linkosalo, Tapio; Heikkinen, Juha; Pulkkinen, Pertti; Mäkipää, Raisa

2014-01-01

We studied the photosynthetic activity of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst) in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 1-3 times per week. We began by measuring shoots present in late winter (i.e., March 2013) before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only. We analyzed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence. The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 2013-2014 was unusually mild and similar to future conditions predicted by global climate models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration.

Hunting of roe deer and wild boar in Germany: Is non-lead ammunition suitable for hunting?

PubMed Central

Gremse, Carl; Selhorst, Thomas; Bandick, Niels; Müller-Graf, Christine; Greiner, Matthias; Lahrssen-Wiederholt, Monika

2017-01-01

Background Non-lead hunting ammunition is an alternative to bullets that contain lead. The use of lead ammunition can result in severe contamination of game meat, thus posing a health risk to consumers. With any kind of ammunition for hunting, the terminal effectiveness of bullets is an animal welfare issue. Doubts about the effectiveness of non-lead bullets for a humane kill of game animals in hunting have been discussed. The length of the escape distance after the shot has been used previously as an indicator for bullet performance. Objective The object of this study was to determine how the bullet material (lead or non-lead) influences the observed escape distances. Methods 1,234 records of the shooting of roe deer (Capreolus capreolus) and 825 records of the shooting of wild boar (Sus scrofa) were evaluated. As the bullet material cannot be regarded as the sole cause of variability of escape distances, interactions of other potential influencing variables like shot placement, shooting distance, were analyzed using conditional regression trees and two-part hurdle models. Results The length of the escape distance is not influenced by the use of lead or non-lead ammunition with either roe deer or wild boar. With roe deer, the length of the escape distance is influenced significantly by the shot placement and the type of hunting. Increasing shooting distances increased the length of the escape distance. With wild boar, shot placement and the age of the animals were found to be a significant influencing factor on the length of the escape distance. Conclusions The length of the escape distance can be used as an indicator for adequate bullet effectiveness for humane killings of game animals in hunting.Non-lead bullets already exist which have an equally reliable killing effect as lead bullets. PMID:28926620

Growth and Phenology of Three Dwarf Shrub Species in a Six-Year Soil Warming Experiment at the Alpine Treeline

PubMed Central

Anadon-Rosell, Alba; Rixen, Christian; Cherubini, Paolo; Wipf, Sonja; Hagedorn, Frank; Dawes, Melissa A.

2014-01-01

Global warming can have substantial impacts on the phenological and growth patterns of alpine and Arctic species, resulting in shifts in plant community composition and ecosystem dynamics. We evaluated the effects of a six-year experimental soil warming treatment (+4°C, 2007–2012) on the phenology and growth of three co-dominant dwarf shrub species growing in the understory of Larix decidua and Pinus uncinata at treeline in the Swiss Alps. We monitored vegetative and reproductive phenology of Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum throughout the early growing season of 2012 and, following a major harvest at peak season, we measured the biomass of above-ground ramet fractions. For all six years of soil warming we measured annual shoot growth of the three species and analyzed ramet age and xylem ring width of V. myrtillus. Our results show that phenology of the three species was more influenced by snowmelt timing, and also by plot tree species (Larix or Pinus) in the case of V. myrtillus, than by soil warming. However, the warming treatment led to increased V. myrtillus total above-ground ramet biomass (+36% in 2012), especially new shoot biomass (+63% in 2012), as well as increased new shoot increment length and xylem ring width (+22% and +41%, respectively; average for 2007–2012). These results indicate enhanced overall growth of V. myrtillus under soil warming that was sustained over six years and was not caused by an extended growing period in early summer. In contrast, E. hermaphroditum only showed a positive shoot growth response to warming in 2011 (+21%), and V. gaultherioides showed no significant growth response. Our results indicate that V. myrtillus might have a competitive advantage over the less responsive co-occurring dwarf shrub species under future global warming. PMID:24956273

Rapid in vitro propagation, conservation and analysis of genetic stability of Viola pilosa.

PubMed

Soni, Madhvi; Kaur, Rajinder

2014-01-01

A protocol for in vitro propagation was developed for Viola pilosa, a plant of immense medicinal value. To start with in vitro propagation, the sterilized explants (buds) were cultured on MS basal medium supplemented with various concentrations of growth regulators. One of the medium compositions MS basal + 0.5 mg/l BA + 0.5 mg/l TDZ + 0.5 mg/l GA3 gave best results for in vitro shoot bud establishment. Although the problem of shoot vitrification occurred on this medium but this was overcome by transferring the vitrified shoots on MS medium supplemented with 1 mg/l BA and 0.25 mg/l Kn. The same medium was found to be the best medium for further in vitro shoot multiplication. 100 % root induction from in vitro grown shoots was obtained on half strength MS medium supplemented with 1 mg/l IBA. In vitro formed plantlets were hardened and transferred to soil with 83 % survival. Additionally, conservation of in vitro multiplying shoots was also attempted using two different approaches namely slowing down the growth at low temperature and cryopreservation following vitrification. At low temperature retrieval rate was better at 10 °C than at 4 °C after conservation of in vitro multiplying shoots. In cryopreservation-vitrification studies, the vitrified shoot buds gave maximum retrieval of 41.66 % when they were precooled at 4 °C, while only 16.66 % vitrified shoots were retrieved from those precooled at 10 °C. Genetic stability of the in vitro grown plants was analysed by RAPD and ISSR markers which indicated no somaclonal variation among in vitro grown plants demonstrating the feasibility of using the protocol without any adverse genetical effects.

Organ-specific analysis of the anaerobic primary metabolism in rice and wheat seedlings. I: Dark ethanol production is dominated by the shoots.

PubMed

Mustroph, Angelika; Boamfa, Elena I; Laarhoven, Lucas J J; Harren, Frans J M; Albrecht, Gerd; Grimm, Bernhard

2006-12-01

During anaerobiosis in darkness the main route for ATP production in plants is through glycolysis in combination with fermentation. We compared the organ-specific anaerobic fermentation of flooding-tolerant rice (Oryza sativa) and sensitive wheat (Triticum aestivum) seedlings. A sensitive laser-based photoacoustic trace gas detection system was used to monitor emission of ethanol and acetaldehyde by roots and shoots of intact seedlings. Dark-incubated rice seedlings released 3 times more acetaldehyde and 14 times more ethanol than wheat seedlings during anaerobiosis. Ninety percent of acetaldehyde originated from shoots of both species. In comparison to wheat shoots, the high ethanol production of rice shoots correlated with larger amounts of soluble carbohydrates, and higher activities of fermentative enzymes. After 24 h of anaerobiosis in darkness rice shoots still contained 30% of aerated ATP level, which enabled seedlings to survive this period. In contrast, ATP content declined almost to zero in wheat shoots and roots, which were irreversibly damaged after a 24-h anaerobic period. When plants were anaerobically and dark incubated for 4 h and subsequently transferred back to aeration, shoots showed a transient peak of acetaldehyde release indicating prompt re-oxidation of ethanol. Post-anoxic acetaldehyde production was lower in rice seedlings than in wheat. This observation accounts for a more effective acetaldehyde detoxification system in rice. Compared to wheat the greater tolerance of rice seedlings to transient anaerobic periods is explained by a faster fermentation rate of their shoots allowing a sufficient ATP production and an efficient suppression of toxic acetaldehyde formation in the early re-aeration period.

Characteristics of the Light Reception Systems Concerning a Kenaf Individual Model

NASA Astrophysics Data System (ADS)

Obara, Shin'ya

It is thought that plants have evolved to modulate the amount of light received by the leaves in order to raise the photosynthetic rate. By investigating a plant condensing system, it is small and a directive low condensing system may be able to develop. A compact condensing system with low directivity may be able to be developed by investigating the condensing method by a plant. This paper presents the results of an investigation into light reception characteristics using the numerical-analysis program (LAPS), with emphasis on a kenaf plant (Hibiscus cannabinus) with division leaf of diversity. From this analysis, the relationship between the range of movement for the light source (sun) and the shoot configuration of a kenaf plant were clarified. There is a suitable shoot configuration, and the shoot configuration has a strong influence over the efficiency of light reception. The summer season is characterized by wide oscillations of the light source, and it is therefore necessary for the kenaf plant to adjust its shoot configuration in order to improve light reception.

APETALA2 regulates the stem cell niche in the Arabidopsis shoot meristem.

PubMed

Würschum, Tobias; Gross-Hardt, Rita; Laux, Thomas

2006-02-01

Postembryonic organ formation in higher plants relies on the activity of stem cell niches in shoot and root meristems where differentiation of the resident cells is repressed by signals from surrounding cells. We searched for mutations affecting stem cell maintenance and isolated the semidominant l28 mutant, which displays premature termination of the shoot meristem and differentiation of the stem cells. Allele competition experiments suggest that l28 is a dominant-negative allele of the APETALA2 (AP2) gene, which previously has been implicated in floral patterning and seed development. Expression of both WUSCHEL (WUS) and CLAVATA3 (CLV3) genes, which regulate stem cell maintenance in the wild type, were disrupted in l28 shoot apices from early stages on. Unlike in floral patterning, AP2 mRNA is active in the center of the shoot meristem and acts via a mechanism independent of AGAMOUS, which is a repressor of WUS and stem cell maintenance in the floral meristem. Genetic analysis shows that termination of the primary shoot meristem in l28 mutants requires an active CLV signaling pathway, indicating that AP2 functions in stem cell maintenance by modifying the WUS-CLV3 feedback loop.

A collocation-shooting method for solving fractional boundary value problems

NASA Astrophysics Data System (ADS)

Al-Mdallal, Qasem M.; Syam, Muhammed I.; Anwar, M. N.

2010-12-01

In this paper, we discuss the numerical solution of special class of fractional boundary value problems of order 2. The method of solution is based on a conjugating collocation and spline analysis combined with shooting method. A theoretical analysis about the existence and uniqueness of exact solution for the present class is proven. Two examples involving Bagley-Torvik equation subject to boundary conditions are also presented; numerical results illustrate the accuracy of the present scheme.

The impact of long-term water stress on relative growth rate and morphology of needles and shoots of Metasequoia glyptostroboides seedlings: research toward identifying mechanistic models.

PubMed

Zhang, Yanxiang; Equiza, Maria Alejandra; Zheng, Quanshui; Tyree, Melvin T

2011-09-01

Leaf morphology in the upper canopy of trees tends to be different from that lower down. The effect of long-term water stress on leaf growth and morphology was studied in seedlings of Metasequoia glyptostroboides to understand how tree height might affect leaf morphology in larger trees. Tree height increases water stress on growing leaves through increased hydraulic resistance to water flow and increased gravitational potential, hence we assume that water stress imposed by soil dehydration will have an effect equivalent to stress induced by height. Seedlings were subjected to well-watered and two constant levels of long-term water stress treatments. Drought treatment significantly reduced final needle count, area and mass per area (leaf mass area, LMA) and increased needle density. Needles from water-stressed plants had lower maximum volumetric elastic modulus (ε(max)), osmotic potential at full turgor (Ψ¹⁰⁰(π)) (and at zero turgor (Ψ⁰(π)) (than those from well-watered plants. Palisade and spongy mesophyll cell size and upper epidermal cell size decreased significantly in drought treatments. Needle relative growth rate, needle length and cell sizes were linear functions of the daily average water potential at the time of leaf growth (r² 0.88-0.999). We conclude that water stress alone does mimic the direction and magnitude of changes in leaf morphology observed in tall trees. The results are discussed in terms of various models for leaf growth rate. Copyright © Physiologia Plantarum 2011.

Genetic analysis of the role of amyloplasts in shoot gravisensing

NASA Astrophysics Data System (ADS)

Tasaka, M.; Morita, M.

Plant can change the growth direction after sensing the gravity orientation This response calls gravitropism and the initial step is the gravisensing We have isolated many Arabidopsis mutants shoot gravitropism sgr with reduced or no gravitropic response in inflorescence stems The analysis of sgr1 and sgr7 revealed that endoderm cells in the inflorescence stems were gravisensing sites zig zigzag sgr4 and sgr3 showed no or reduced gravitropism in shoot respectively and their amyloplasts thought to be statoliths did not sedimented to the orientation of gravity in the endoderm cells ZIG encoded a SNARE AtVTI11 and SGR3 encoded other SNARE AtVAM3 These two SNAREs made a complex in the shoot endoderm cells suggesting that the vesicle transport from trans-Golgi network TGN to prevacuolar compartment PVC and or vacuole was involved in the amyloplasts localization and movement The analysis to visualize amyloplasts and vacuolar membrane in living endoderm cells supported that the vacuole function was important for the amyloplasts movement Recently we have isolated many suppressor mutants of zig One of them named zig suppressor zip 1 had a point mutation in the gene encoded other SNARE of AtVTI12 This protein is a homologous to ZIG AtVTI11 and these two proteins have partially redundant functions Although wild type At VTI 12 could not rescued zig mutated AtVTI12 protein ZIP1 could almost completely play the part of ZIG In zigzip1 amyloplasts in endoderm cells sedimented normally and the shoots showed normal gravitropic response The other

Establishment and analysis of in vitro biomass from Salvia corrugata Vahl. and evaluation of antimicrobial activity.

PubMed

Bisio, Angela; Fraternale, Daniele; Schito, Anna Maria; Parricchi, Anita; Dal Piaz, Fabrizio; Ricci, Donata; Giacomini, Mauro; Ruffoni, Barbara; De Tommasi, Nunziatina

2016-02-01

Demethylfruticuline A and fruticuline A, the most abundant compounds from the surface extract of Salvia corrugata Vahl., have shown antibacterial, antitumor and cytotoxic activities. In order to obtain these icetexane diterpenes from in vitro cultures of S. corrugata, protocols were developed for callus production, micropropagation and shoot regeneration. Analysis of the regenerated shoots showed the presence of both icetexanes, micropropagated plants contained only fruticuline A, while the callus contained trace amounts of both diterpenes. The yield of fruticuline A was higher in the methanolic extract of regenerated shoots than in those of fresh leaves and fresh shoot tips. In addition to these diterpenes, the regenerated shoot and micropropagated plant extracts afforded seven other diterpenes, one icetexane and six abietanes, identified by UV, IR, 1D- and 2D-NMR and HR-MS analysis. Five compounds (19-acetoxy-7α-hydroxyroyleanone, 7β,20-epoxy-11,12,19-trihydroxyabieta-8,11,13-triene, 7,20-dihydrofruticuline A, 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone, 7β-ethoxy-6β,20:19,20-diepoxyroyleanone) were previously undescribed. Although the crude plant surface extract did not possess any antibacterial activity, methanolic extracts of in vitro tissues and two compounds, namely 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone and 7β-ethoxy-6β,20:19,20-diepoxyroyleanone, isolated in suitable amounts, were active in varying degrees against multidrug resistant clinical strains of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium, displaying MIC values ranging from 32, 64 to 128μg/mL. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tree CH4 fluxes in forestry drained peatland in southern Finland

NASA Astrophysics Data System (ADS)

Haikarainen, Iikka; Putkinen, Anuliina; Pyykkö, Petteri; Halmeenmäki, Elisa; Pihlatie, Mari

2017-04-01

Methane (CH4) is among the most important greenhouse gases and its atmospheric concentration is increasing. Boreal forests are commonly considered a net sink of atmospheric CH4 due to CH4 consuming bacteria in aerated soil layers. Recent studies have, however, demonstrated that trees are capable of emitting CH4 from their stems and shoots by transporting anaerobically produced CH4 from deeper soil layers to the atmosphere. Furthermore, trees may act as independent sources of CH4. We have measured tree stem CH4 exchange of boreal tree species at Lettosuo, a nutrient rich peatland forest in Tammela, southern Finland (60˚ 38' N, 23˚ 57' E), using the static chamber technique. Three species, downy birch (Betula pubescens), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), were selected under investigation as they represent common boreal tree species. Fluxes of CH4 were measured during 7.6.2016 - 17.10.2016 from in total 25 sample trees growing on two different plots: a treatment plot where all the pines were removed to raise the water table level (WTL) and a control plot. Three birches from the treatment plot were selected to measure CH4 flux variation within vertical profile of the trees. Characterization of microbial communities, quantification of methanogenic and methanotrophic functional genes, and measurements of potential CH4 production and consumption from peat profile and forest floor moss samples were also carried out to obtain insight to the CH4 flux dynamics at the studied sites. The pine removal treatment did not markedly change the average WTL, but it made the WTL more variable with frequently 10-15 cm closer to soil surface compared to the WTL on the control plot. We found small and variable CH4 emissions from the stems of trees on both of the plots, while occasional consumption of CH4 was also present. Generally the CH4 emissions were higher and more dominant at the treatment plot compared to the control plot, and the fluxes were significantly different between the plots (p < 0.001). The CH4 emission rates from the birches at the treatment plot decreased exponentially in the stem vertical profile. Clear seasonal flux dynamics or significant differences in the CH4 flux between the species were not found at either of the plots. Microbial experiments showed that anaerobic CH4 production, CH4 oxidation potential (under 1000 ppm CH4) and the amount of methanogens were higher in the peat of the treatment site. The difference in the CH4 flux rates between the plots indicates that the WTL is a major regulator of tree CH4 emissions on forestry drained peatlands, supporting our hypothesis that the stem emitted CH4 originates from anaerobic soil conditions. This hypothesis is further supported by the results of the microbial analysis and by the observation that more CH4 is emitting from the lower parts of the stems compared to the upper stem.

Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals

PubMed Central

Schmalenberger, A.; Duran, A. L.; Bray, A. W.; Bridge, J.; Bonneville, S.; Benning, L. G.; Romero-Gonzalez, M. E.; Leake, J. R.; Banwart, S. A.

2015-01-01

Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using 14CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These findings confirmed the role of mineral-specific oxalate exudation in ectomycorrhizal weathering to dissolve calcium bearing minerals, thus contributing to the geochemical carbon cycle. PMID:26197714

Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals

NASA Astrophysics Data System (ADS)

Schmalenberger, A.; Duran, A. L.; Bray, A. W.; Bridge, J.; Bonneville, S.; Benning, L. G.; Romero-Gonzalez, M. E.; Leake, J. R.; Banwart, S. A.

2015-07-01

Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using 14CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These findings confirmed the role of mineral-specific oxalate exudation in ectomycorrhizal weathering to dissolve calcium bearing minerals, thus contributing to the geochemical carbon cycle.

Stable transformation via particle bombardment in two different soybean regeneration systems.

PubMed

Sato, S; Newell, C; Kolacz, K; Tredo, L; Finer, J; Hinchee, M

1993-05-01

The Biolistics(®) particle delivery system for the transformation of soybean (Glycine max L. Merr.) was evaluated in two different regeneration systems. The first system was multiple shoot proliferation from shoot tips obtained from immature zygotic embryos of the cultivar Williams 82, and the second was somatic embryogenesis from a long term proliferative suspension culture of the cultivar Fayette. Bombardment of shoot tips with tungsten particles, coated with precipitated DNA containing the gene for β-glucuronidase (GUS), produced GUS-positive sectors in 30% of the regenerated shoots. However, none of the regenerants which developed into plants continued to produce GUS positive tissue. Bombardment of embryogenic suspension cultures produced GUS positive globular somatic embryos which proliferated into GUS positive somatic embryos and plants. An average of 4 independent transgenic lines were generated per bombarded flask of an embryogenic suspension. Particle bombardment delivered particles into the first two cell layers of either shoot tips or somatic embryos. Histological analysis indicated that shoot organogenesis appeared to involve more than the first two superficial cell layers of a shoot tip, while somatic embryo proliferation occurred from the first cell layer of existing somatic embryos. The different transformation results obtained with these two systems appeared to be directly related to differences in the cell types which were responsible for regeneration and their accessibility to particle penetration.

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

Mathee, Angela

Introduction: Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. Methods: An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. Results: A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly highermore » blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10 μg/dl (p<0.001). Conclusion: Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. - Highlights: • This is the first study, to our knowledge, of lead exposure in shooting ranges in an African setting. • This study indicates highly elevated lead exposure amongst the users of certain private shooting ranges in South Africa. • Lead exposure may be a serious, yet under-studied, source of adult lead exposure in South Africa, and possibly elsewhere on the African continent.« less

Analysis of two potential long-distance signaling molecules, LjCLE-RS1/2 and jasmonic acid, in a hypernodulating mutant too much love.

PubMed

Magori, Shimpei; Kawaguchi, Masayoshi

2010-04-01

Legume plants tightly control the number and development of root nodules. This is partly regulated by a long-distance signaling known as auto-regulation of nodulation (AON). AON signaling involves at least two potential long-distance signals: root-derived signal and shoot-derived signal. However, their molecular characteristics and the mode of action remain unclear. In our recent study, we isolated a novel Lotus japonicus hypernodulating mutant too much love (tml). Based on several grafting experiments, we concluded that its causative gene TML functions as a receptor of the shoot-derived signal. This finding prompted us to ask how the candidates of the long-distance signal molecules, LjCLE-RS1/2 and jasmonic acid (JA), are affected in tml mutants. Expression analysis revealed that rapid induction of LjCLE-RS1/2 upon rhizobial inoculation is still intact in tml, supporting that TML plays a role in reception of the shoot-derived signal but not in generation of the root-derived signal. Furthermore, physiological analysis showed that JA, a candidate of the shoot-derived signal, can suppress tml hypernodulation. Therefore, contrary to the previous report, JA might not be a component of AON signaling.

Persistent Supercooling of Reproductive Shoots Is Enabled by Structural Ice Barriers Being Active Despite an Intact Xylem Connection

PubMed Central

Pfaller, Kristian; Wagner, Johanna

2016-01-01

Extracellular ice nucleation usually occurs at mild subzero temperatures in most plants. For persistent supercooling of certain plant parts ice barriers are necessary to prevent the entry of ice from already frozen tissues. The reproductive shoot of Calluna vulgaris is able to supercool down to below -22°C throughout all developmental stages (shoot elongation, flowering, fruiting) despite an established xylem conductivity. After localization of the persistent ice barrier between the reproductive and vegetative shoot at the base of the pedicel by infrared differential thermal analysis, the currently unknown structural features of the ice barrier tissue were anatomically analyzed on cross and longitudinal sections. The ice barrier tissue was recognized as a 250 μm long constriction zone at the base of the pedicel that lacked pith tissue and intercellular spaces. Most cell walls in this region were thickened and contained hydrophobic substances (lignin, suberin, and cutin). A few cell walls had what appeared to be thicker cellulose inclusions. In the ice barrier tissue, the area of the xylem was as much as 5.7 times smaller than in vegetative shoots and consisted of tracheids only. The mean number of conducting units in the xylem per cross section was reduced to 3.5% of that in vegetative shoots. Diameter of conducting units and tracheid length were 70% and 60% (respectively) of that in vegetative shoots. From vegetative shoots water transport into the ice barrier must pass pit membranes that are likely impermeable to ice. Pit apertures were about 1.9 μm x 0.7 μm, which was significantly smaller than in the vegetative shoot. The peculiar anatomical features of the xylem at the base of the pedicel suggest that the diameter of pores in pit membranes could be the critical constriction for ice propagation into the persistently supercooled reproductive shoots of C. vulgaris. PMID:27632365

Persistent Supercooling of Reproductive Shoots Is Enabled by Structural Ice Barriers Being Active Despite an Intact Xylem Connection.

PubMed

Kuprian, Edith; Tuong, Tan D; Pfaller, Kristian; Wagner, Johanna; Livingston, David P; Neuner, Gilbert

2016-01-01

Extracellular ice nucleation usually occurs at mild subzero temperatures in most plants. For persistent supercooling of certain plant parts ice barriers are necessary to prevent the entry of ice from already frozen tissues. The reproductive shoot of Calluna vulgaris is able to supercool down to below -22°C throughout all developmental stages (shoot elongation, flowering, fruiting) despite an established xylem conductivity. After localization of the persistent ice barrier between the reproductive and vegetative shoot at the base of the pedicel by infrared differential thermal analysis, the currently unknown structural features of the ice barrier tissue were anatomically analyzed on cross and longitudinal sections. The ice barrier tissue was recognized as a 250 μm long constriction zone at the base of the pedicel that lacked pith tissue and intercellular spaces. Most cell walls in this region were thickened and contained hydrophobic substances (lignin, suberin, and cutin). A few cell walls had what appeared to be thicker cellulose inclusions. In the ice barrier tissue, the area of the xylem was as much as 5.7 times smaller than in vegetative shoots and consisted of tracheids only. The mean number of conducting units in the xylem per cross section was reduced to 3.5% of that in vegetative shoots. Diameter of conducting units and tracheid length were 70% and 60% (respectively) of that in vegetative shoots. From vegetative shoots water transport into the ice barrier must pass pit membranes that are likely impermeable to ice. Pit apertures were about 1.9 μm x 0.7 μm, which was significantly smaller than in the vegetative shoot. The peculiar anatomical features of the xylem at the base of the pedicel suggest that the diameter of pores in pit membranes could be the critical constriction for ice propagation into the persistently supercooled reproductive shoots of C. vulgaris.

Nickel-tolerant ectomycorrhizal Pisolithus albus ultramafic ecotype isolated from nickel mines in New Caledonia strongly enhance growth of the host plant Eucalyptus globulus at toxic nickel concentrations.

PubMed

Jourand, Philippe; Ducousso, Marc; Reid, Robert; Majorel, Clarisse; Richert, Clément; Riss, Jennifer; Lebrun, Michel

2010-10-01

Ectomycorrhizal (ECM) Pisolithus albus (Cooke & Massee), belonging to the ultramafic ecotype isolated in nickel-rich serpentine soils from New Caledonia (a tropical hotspot of biodiversity) and showing in vitro adaptive nickel tolerance, were inoculated to Eucalyptus globulus Labill used as a Myrtaceae plant-host model to study ectomycorrhizal symbiosis. Plants were then exposed to a nickel (Ni) dose-response experiment with increased Ni treatments up to 60 mg kg( - )(1) soil as extractable Ni content in serpentine soils. Results showed that plants inoculated with ultramafic ECM P. albus were able to tolerate high and toxic concentrations of Ni (up to 60 μg g( - )(1)) while uninoculated controls were not. At the highest Ni concentration tested, root growth was more than 20-fold higher and shoot growth more than 30-fold higher in ECM plants compared with control plants. The improved growth in ECM plants was associated with a 2.4-fold reduction in root Ni concentration but a massive 60-fold reduction in transfer of Ni from root to shoots. In vitro, P. albus strains could withstand high Ni concentrations but accumulated very little Ni in its tissue. The lower Ni uptake by mycorrhizal plants could not be explained by increased release of metal-complexing chelates since these were 5- to 12-fold lower in mycorrhizal plants at high Ni concentrations. It is proposed that the fungal sheath covering the plant roots acts as an effective barrier to limit transfer of Ni from soil into the root tissue. The degree of tolerance conferred by the ultramafic P. albus isolates to growth of the host tree species is considerably greater than previously reported for other ECM. The primary mechanisms underlying this improved growth were identified as reduced Ni uptake into the roots and markedly reduced transfer from root to shoot in mycorrhizal plants. The fact that these positive responses were observed at Ni concentrations commonly observed in serpentinic soils suggests that ultramafic ecotypes of P. albus could play an important role in the adaptation of tree species to soils containing high concentrations of heavy metals and aid in strategies for ecological restoration.

Physiological and morphological response patterns of Populus deltoides to alluvial groundwater

USGS Publications Warehouse

Cooper, D.J.; D'Amico, D.R.; Scott, M.L.

2003-01-01

We examined the physiological and morphological response patterns of plains cottonwood [Populus deltoides subsp. monilifera (Aiton) Eck.] to acute water stress imposed by groundwater pumping. Between 3 and 27 July 1996, four large pumps were used to withdraw alluvial groundwater from a cottonwood forest along the South Platte River, near Denver, Colorado, USA. The study was designed as a stand-level, split-plot experiment with factorial treatments including two soil types (a gravel soil and a loam topsoil over gravel), two water table drawdown depths (∼0.5 m and >1.0 m), and one water table control (no drawdown) per soil type. Measurements of water table depth, soil water potential (Ψs), predawn and midday shoot water potential (Ψpd and Ψmd), and D/H (deuterium/hydrogen) ratios of different water sources were made in each of six 600-m2 plots prior to, during, and immediately following pumping. Two additional plots were established and measured to examine the extent to which surface irrigation could be used to mitigate the effects of deep drawdown on P. deltoides for each soil type. Recovery of tree water status following pumping was evaluated by measuring stomatal conductance (gs) and xylem water potential (Ψxp) on approximately hourly time steps from before dawn to mid-afternoon on 11 August 1996 in watered and unwatered, deep-drawdown plots on gravel soils. P. deltoides responded to abrupt alluvial water table decline with decreased shoot water potential followed by leaf mortality. Ψpd and percent leaf loss were significantly related to the magnitude of water table declines. The onset and course of these responses were influenced by short-term variability in surface and ground water levels, acting in concert with physiological and morphological adjustments. Decreases in Ψpd corresponded with increases in Ψmd, suggesting shoot water status improved in response to stomatal closure and crown dieback. Crown dieback caused by xylem cavitation likely occurred when Ψpd reached −0.4 to −0.8 MPa. The application of surface irrigation allowed trees to maintain favorable water status with little or no apparent cavitation, even in deep-drawdown plots. Two weeks after the partial canopy dieback and cessation of pumping, gs and Ψxp measurements indicated that water stress persisted in unwatered P. deltoides in deep-drawdown plots.

A design and critical technology issues for on-orbit resupply of superfluid helium

NASA Technical Reports Server (NTRS)

Hopkins, Richard A.; Mord, Allan J.

1990-01-01

The issues of and the solutions to the critical design and technology areas of the Superfluid Helium On-Orbit Transfer (SHOOT) experiment, presently under development at the NASA Goddard Spaceflight Center, are discussed. Special attention is given to the SHOOT design requirements for the 10,000-liter superfluid He resupply tanker system, the concept details of the system, and the resupply operations and their analysis. A block diagram of the SHOOT system is included along with fluid management schematic and configuration diagrams of the system and its subsystems. A summary of the dewar performance is also presented.

Shoot development in grapevine (Vitis vinifera) is affected by the modular branching pattern of the stem and intra- and inter-shoot trophic competition.

PubMed

Lebon, Eric; Pellegrino, Anne; Tardieu, Francois; Lecoeur, Jeremie

2004-03-01

Shoot architecture variability in grapevine (Vitis vinifera) was analysed using a generic modelling approach based on thermal time developed for annual herbaceous species. The analysis of shoot architecture was based on various levels of shoot organization, including pre-existing and newly formed parts of the stem, and on the modular structure of the stem, which consists of a repeated succession of three phytomers (P0-P1-P2). Four experiments were carried out using the cultivar 'Grenache N': two on potted vines (one of which was carried out in a glasshouse) and two on mature vines in a vineyard. These experiments resulted in a broad diversity of environmental conditions, but none of the plants experienced soil water deficit. Development of the main axis was highly dependent on air temperature, being linearly related to thermal time for all stages of leaf development from budbreak to veraison. The stable progression of developmental stages along the main stem resulted in a thermal-time based programme of leaf development. Leaf expansion rate varied with trophic competition (shoot and cluster loads) and environmental conditions (solar radiation, VPD), accounting for differences in final leaf area. Branching pattern was highly variable. Classification of the branches according to ternary modular structure increased the accuracy of the quantitative analysis of branch development. The rate and duration of leaf production were higher for branches derived from P0 phytomers than for branches derived from P1 or P2 phytomers. Rates of leaf production, expressed as a -function of thermal time, were not stable and depended on trophic competition and environmental conditions such as solar radiation or VPD. The application to grapevine of a generic model developed in annual plants made it possible to identify constants in main stem development and to determine the hierarchical structure of branches with respect to the modular structure of the stem in response to intra- and inter-shoot trophic competition.

Cultivation Versus Molecular Analysis of Banana (Musa sp.) Shoot-Tip Tissue Reveals Enormous Diversity of Normally Uncultivable Endophytic Bacteria.

PubMed

Thomas, Pious; Sekhar, Aparna Chandra

2017-05-01

The interior of plants constitutes a unique environment for microorganisms with various organisms inhabiting as endophytes. Unlike subterranean plant parts, aboveground parts are relatively less explored for endophytic microbial diversity. We employed a combination of cultivation and molecular approaches to study the endophytic bacterial diversity in banana shoot-tips. Cultivable bacteria from 20 sucker shoot-tips of cv. Grand Naine included 37 strains under 16 genera and three phyla (Proteobacteria, Actinobacteria, Firmicutes). 16S rRNA gene-ribotyping approach on 799f and 1492r PCR-amplicons to avoid plant organelle sequences was ineffective showing limited bacterial diversity. 16S rRNA metagene profiling targeting the V3-V4 hypervariable region after filtering out the chloroplast (74.2 %), mitochondrial (22.9 %), and unknown sequences (1.1 %) revealed enormous bacterial diversity. Proteobacteria formed the predominant phylum (64 %) succeeded by Firmicutes (12.1 %), Actinobacteria (9.5 %), Bacteroidetes (6.4 %), Planctomycetes, Cyanobacteria, and minor shares (<1 %) of 14 phyla including several candidate phyla besides the domain Euryarchaeota (0.2 %). Microbiome analysis of single shoot-tips through 16S rRNA V3 region profiling showed similar taxonomic richness and diversity and was less affected by plant sequence interferences. DNA extraction kit ominously influenced the phylogenetic diversity. The study has revealed vast diversity of normally uncultivable endophytic bacteria prevailing in banana shoot-tips (20 phyla, 46 classes) with about 2.6 % of the deciphered 269 genera and 1.5 % of the 656 observed species from the same source of shoot-tips attained through cultivation. The predominant genera included several agriculturally important bacteria. The study reveals an immense ecosystem of endophytic bacteria in banana shoot tissues endorsing the earlier documentation of intracellular "Cytobacts" and "Peribacts" with possible roles in plant holobiome and hologenome.

Transcript Profile of the Response of Two Soybean Genotypes to Potassium Deficiency

PubMed Central

Hao, QingNan; Sha, AiHua; Shan, ZhiHui; Chen, LiMiao; Zhou, Rong; Zhi, HaiJian; Zhou, XinAn

2012-01-01

The macronutrient potassium (K) is essential to plant growth and development. Crop yield potential is often affected by lack of soluble K. The molecular regulation mechanism of physiological and biochemical responses to K starvation in soybean roots and shoots is not fully understood. In the present study, two soybean varieties were subjected to low-K stress conditions: a low-K-tolerant variety (You06-71) and a low-K-sensitive variety (HengChun04-11). Eight libraries were generated for analysis: 2 genotypes ×2 tissues (roots and shoots) ×2 time periods [short term (0.5 to 12 h) and long term (3 to 12 d)]. RNA derived from the roots and shoots of these two varieties across two periods (short term and long term) were sequenced and the transcriptomes were compared using high-throughput tag-sequencing. To this end, a large number of clean tags (tags used for analysis after removal of dirty tags) corresponding to distinct tags (all types of clean tags) were identified in eight libraries (L1, You06-71-root short term; L2, HengChun04-11-root short term; L3, You06-71-shoot short term; L4, HengChun04-11-shoot short term; L5, You06-71-root long term; L6, HengChun04-11-root long term; L7, You06-71-shoot long term; L8, HengChun04-11-shoot long term). All clean tags were mapped to the available soybean (Glycine max) transcript database (http://www.soybase.org). Many genes showed substantial differences in expression across the libraries. In total, 5,440 transcripts involved in 118 KEGG pathways were either up- or down-regulated. Fifteen genes were randomly selected and their expression levels were confirmed using quantitative RT-PCR. Our results provide preliminary information on the molecular mechanism of potassium absorption and transport under low-K stress conditions in different soybean tissues. PMID:22792192

Identification and expression analysis of the IPT and CKX gene families during axillary bud outgrowth in apple (Malus domestica Borkh.).

PubMed

Tan, Ming; Li, Guofang; Qi, Siyan; Liu, Xiaojie; Chen, Xilong; Ma, Juanjuan; Zhang, Dong; Han, Mingyu

2018-04-20

Cytokinins (CKs) play a crucial role in promoting axillary bud outgrowth and targeting the control of CK metabolism can be used to enhance branching in plants. CK levels are maintained mainly by CK biosynthesis (isopentenyl transferase, IPT) and degradation (dehydrogenase, CKX) genes in plants. A systematic study of the IPT and CKX gene families in apple, however, has not been conducted. In the present study, 12 MdIPTs and 12 MdCKXs were identified in the apple genome. Systematic phylogenetic, structural, and synteny analyses were performed. Expression analysis of these genes in different tissues was also assessed. MdIPT and MdCKX genes exhibit distinct expression patterns in different tissues. The response of MdIPT, MdCKX, and MdPIN1 genes to various treatments (6-BA, decapitation and Lovastatin, an inhibitor of CKs synthesis) that impact branching were also investigated. Results indicated that most of the MdIPT and MdCKX, and MdPIN1 genes were upregulated by 6-BA and decapitation treatment, but inhibited by Lovastatin, a compound that effectively suppresses axillary bud outgrowth induced by decapitation. These findings suggest that cytokinin biosynthesis is required for the activation of bud break and the export of auxin from buds in apple tree with intact primary shoot apex or decapitated apple tree. MdCKX8 and MdCKX10, however, exhibited little response to decapitation, but were significantly up-regulated by 6-BA and Lovastatin, a finding that warrants further investigation in order to understand their function in bud-outgrowth. Copyright © 2018 Elsevier B.V. All rights reserved.

Expression of FcFT1, a FLOWERING LOCUS T-like gene, is regulated by light and associated with inflorescence differentiation in fig (Ficus carica L.).

PubMed

Ikegami, Hidetoshi; Nogata, Hitoshi; Inoue, Yoshiaki; Himeno, Shuichi; Yakushiji, Hiroshi; Hirata, Chiharu; Hirashima, Keita; Mori, Masashi; Awamura, Mitsuo; Nakahara, Takao

2013-12-16

Because the floral induction occurs in many plants when specific environmental conditions are satisfied, most plants bloom and bear fruit during the same season each year. In fig, by contrast, the time interval during which inflorescence (flower bud, fruit) differentiation occurs corresponds to the shoot elongation period. Fig trees thus differ from many species in their reproductive growth characteristics. To date, however, the molecular mechanisms underlying this unorthodox physiology of floral induction and fruit setting in fig trees have not been elucidated. We isolated a FLOWERING LOCUS T (FT)-like gene from fig and examined its function, characteristics, and expression patterns. The isolated gene, F. carica FT (FcFT1), is single copy in fig and shows the highest similarity at the amino acid level (93.1%) to apple MdFT2. We sequenced its upstream region (1,644 bp) and identified many light-responsive elements. FcFT1 was mainly expressed in leaves and induced early flowering in transgenic tobacco, suggesting that FcFT1 is a fig FT ortholog. Real-time reverse-transcription PCR analysis revealed that FcFT1 mRNA expression occurred only in leaves at the lower nodes, the early fruit setting positions. mRNA levels remained a constant for approximately 5 months from spring to autumn, corresponding almost exactly to the inflorescence differentiation season. Diurnal variation analysis revealed that FcFT1 mRNA expression increased under relative long-day and short-day conditions, but not under continuous darkness. These results suggest that FcFT1 activation is regulated by light conditions and may contribute to fig's unique fruit-setting characteristics.

Experimental quantification of radiocesium recycling in a coniferous tree after aerial contamination: Field loss dynamics, translocation and final partitioning.

PubMed

Thiry, Y; Garcia-Sanchez, L; Hurtevent, P

2016-09-01

After foliar interception of radioactive atmospheric fallout by forest trees, the short-term recycling dynamics of radiocesium from the tree to the soil as well as within the tree is a primary area of uncertainty in the modeling of the overall cycle. The partitioning of radiocesium transfers in a spruce tree exposed to aerial deposits was investigated during one growth season to reveal the dynamics and significance of underlying processes. The rate of radiocesium loss resulting from foliage leaching (wash-off) was shown to have a functional dependence on the frequency of rainy episodes in a first early stage (weathering 60% of initial contamination during 70 days) and on the amount of precipitation in a second stage (weathering 10% of initial deposits during the following 80 days). A classical single exponential decay model with offset and continuous time as predictor lead to a removal half-life t1/2 of intercepted radiocesium of 25 days. During the growth season, the similar pattern of the internal (134)Cs content in new shoots and initially contaminated foliage confirmed that radiocesium was readily absorbed from needle surfaces and efficiently translocated to growing organs. In the crown, a pool of non-leachable (134)Cs (15-30%) was associated with the abiotic layer covering the twigs and needle surfaces. At the end of the growth season, 30% of the initial deposits were relocated to different tree parts, including organs like stemwood (5%) and roots (6%) not directly exposed to deposition. At the scale of the tree, 84% of the residual activity was assimilated by living tissues which corresponds to a foliar absorption rate coefficient of 0.25 year(-1) for modeling purposes. According to the significant amount of radiocesium which can be incorporated in tree through foliar uptake, our results support the hypothesis that further internal transfers could supply the tree internal cycle of radiocesium extensively, and possibly mask the contribution of root uptake for a long time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Shoot differentiation from protocorm callus cultures of Vanilla planifolia (Orchidaceae): proteomic and metabolic responses at early stage

PubMed Central

2010-01-01

Background Vanilla planifolia is an important Orchid commercially cultivated for the production of natural vanilla flavour. Vanilla plants are conventionally propagated by stem cuttings and thus causing injury to the mother plants. Regeneration and in vitro mass multiplication are proposed as an alternative to minimize damage to mother plants. Because mass production of V. planifolia through indirect shoot differentiation from callus culture is rare and may be a successful use of in vitro techniques for producing somaclonal variants, we have established a novel protocol for the regeneration of vanilla plants and investigated the initial biochemical and molecular mechanisms that trigger shoot organogenesis from embryogenic/organogenic callus. Results For embryogenic callus induction, seeds obtained from 7-month-old green pods of V. planifolia were inoculated on MS basal medium (BM) containing TDZ (0.5 mg l-1). Germination of unorganized mass callus such as protocorm -like structure (PLS) arising from each seed has been observed. The primary embryogenic calli have been formed after transferring on BM containing IAA (0.5 mg l-1) and TDZ (0.5 mg l-1). These calli were maintained by subculturing on BM containing IAA (0.5 mg l-1) and TDZ (0.3 mg l-1) during 6 months and formed embryogenic/organogenic calli. Histological analysis showed that shoot organogenesis was induced between 15 and 20 days after embryogenic/organogenic calli were transferred onto MS basal medium with NAA (0.5 mg l-1). By associating proteomics and metabolomics analyses, the biochemical and molecular markers responsible for shoot induction have been studied in 15-day-old calli at the stage where no differentiating part was visible on organogenic calli. Two-dimensional electrophoresis followed by matrix-assisted laser desorption ionization time-of-flight-tandem mass spectrometry (MALDI-TOF-TOF-MS) analysis revealed that 15 protein spots are significantly expressed (P < 0.05) at earlier stages of shoot differentiation. The majority of these proteins are involved in amino acid-protein metabolism and photosynthetic activity. In accordance with proteomic analysis, metabolic profiling using 1D and 2D NMR techniques showed the importance of numerous compounds related with sugar mobilization and nitrogen metabolism. NMR analysis techniques also allowed the identification of some secondary metabolites such as phenolic compounds whose accumulation was enhanced during shoot differentiation. Conclusion The subculture of embryogenic/organogenic calli onto shoot differentiation medium triggers the stimulation of cell metabolism principally at three levels namely (i) initiation of photosynthesis, glycolysis and phenolic compounds synthesis; (ii) amino acid - protein synthesis, and protein stabilization; (iii) sugar degradation. These biochemical mechanisms associated with the initiation of shoot formation during protocorm - like body (PLB) organogenesis could be coordinated by the removal of TDZ in callus maintenance medium. These results might contribute to elucidate the complex mechanism that leads to vanilla callus differentiation and subsequent shoot formation into PLB organogenesis. Moreover, our results highlight an early intermediate metabolic event in vanillin biosynthetic pathway with respect to secondary metabolism. Indeed, for the first time in vanilla tissue culture, phenolic compounds such as glucoside A and glucoside B were identified. The degradation of these compounds in specialized tissue (i.e. young green beans) probably contributes to the biosynthesis of glucovanillin, the parent compound of vanillin. PMID:20444255

Shoot differentiation from protocorm callus cultures of Vanilla planifolia (Orchidaceae): proteomic and metabolic responses at early stage.

PubMed

Palama, Tony L; Menard, Patrice; Fock, Isabelle; Choi, Young H; Bourdon, Emmanuel; Govinden-Soulange, Joyce; Bahut, Muriel; Payet, Bertrand; Verpoorte, Robert; Kodja, Hippolyte

2010-05-05

Vanilla planifolia is an important Orchid commercially cultivated for the production of natural vanilla flavour. Vanilla plants are conventionally propagated by stem cuttings and thus causing injury to the mother plants. Regeneration and in vitro mass multiplication are proposed as an alternative to minimize damage to mother plants. Because mass production of V. planifolia through indirect shoot differentiation from callus culture is rare and may be a successful use of in vitro techniques for producing somaclonal variants, we have established a novel protocol for the regeneration of vanilla plants and investigated the initial biochemical and molecular mechanisms that trigger shoot organogenesis from embryogenic/organogenic callus. For embryogenic callus induction, seeds obtained from 7-month-old green pods of V. planifolia were inoculated on MS basal medium (BM) containing TDZ (0.5 mg l(-1)). Germination of unorganized mass callus such as protocorm -like structure (PLS) arising from each seed has been observed. The primary embryogenic calli have been formed after transferring on BM containing IAA (0.5 mg l(-1)) and TDZ (0.5 mg l(-1)). These calli were maintained by subculturing on BM containing IAA (0.5 mg l(-1)) and TDZ (0.3 mg l(-1)) during 6 months and formed embryogenic/organogenic calli. Histological analysis showed that shoot organogenesis was induced between 15 and 20 days after embryogenic/organogenic calli were transferred onto MS basal medium with NAA (0.5 mg l(-1)). By associating proteomics and metabolomics analyses, the biochemical and molecular markers responsible for shoot induction have been studied in 15-day-old calli at the stage where no differentiating part was visible on organogenic calli. Two-dimensional electrophoresis followed by matrix-assisted laser desorption ionization time-of-flight-tandem mass spectrometry (MALDI-TOF-TOF-MS) analysis revealed that 15 protein spots are significantly expressed (P < 0.05) at earlier stages of shoot differentiation. The majority of these proteins are involved in amino acid-protein metabolism and photosynthetic activity. In accordance with proteomic analysis, metabolic profiling using 1D and 2D NMR techniques showed the importance of numerous compounds related with sugar mobilization and nitrogen metabolism. NMR analysis techniques also allowed the identification of some secondary metabolites such as phenolic compounds whose accumulation was enhanced during shoot differentiation. The subculture of embryogenic/organogenic calli onto shoot differentiation medium triggers the stimulation of cell metabolism principally at three levels namely (i) initiation of photosynthesis, glycolysis and phenolic compounds synthesis; (ii) amino acid-protein synthesis, and protein stabilization; (iii) sugar degradation. These biochemical mechanisms associated with the initiation of shoot formation during protocorm-like body (PLB) organogenesis could be coordinated by the removal of TDZ in callus maintenance medium. These results might contribute to elucidate the complex mechanism that leads to vanilla callus differentiation and subsequent shoot formation into PLB organogenesis. Moreover, our results highlight an early intermediate metabolic event in vanillin biosynthetic pathway with respect to secondary metabolism. Indeed, for the first time in vanilla tissue culture, phenolic compounds such as glucoside A and glucoside B were identified. The degradation of these compounds in specialized tissue (i.e. young green beans) probably contributes to the biosynthesis of glucovanillin, the parent compound of vanillin.

A digital photography and analysis system for estimation of root and shoot development in rice weed suppression studies in the field

USDA-ARS?s Scientific Manuscript database

Rice germplasm with an inherent ability to suppress weeds can potentially improve the economics and sustainability of weed control in rice. We devised a simple, rapid, and inexpensive digital imaging system to quantify several shoot and root growth characteristics in field-grown rice plants that ha...

Timing of the inhibitory effect of fruit on return bloom of 'Valencia' sweet orange (Citrus sinensis (L.) Osbeck).

PubMed

Martínez-Fuentes, Amparo; Mesejo, Carlos; Reig, Carmina; Agustí, Manuel

2010-08-30

In Citrus the inhibitory effect of fruit on flower formation is the main cause of alternate bearing. Although there are some studies reporting the effect on flowering of the time of fruit removal in a well-defined stage of fruit development, few have investigated the effect throughout the entire fruit growth stage from early fruitlet growth to fruit maturity. The objective of this study was to determine the phenological fruit developmental stage at which the fruit begins its inhibitory effect on flowering in sweet orange by manual removal of fruits, and the role of carbohydrates and nitrogen in the process. Fruit exerted its inhibitory effect from the time it was close to reaching its maximum weight, namely 90% of its final size (November) in the present experiments, to bud sprouting (April). The reduction in flowering paralleled the reduction in bud sprouting. This reduction was due to a decrease in the number of generative sprouted buds, whereas mixed-typed shoots were largely independent of the time of fruit removal, and vegetative shoots increased in frequency. The number of leaves and/or flowers per sprouted shoot was not significantly modified by fruit load. In 'Valencia' sweet orange, fruit inhibits flowering from the time it completes its growth. Neither soluble sugar content nor starch accumulation in leaves due to fruit removal was related to flowering intensity, but some kind of imbalance in nitrogen metabolism was observed in trees tending to flower scarcely. Copyright (c) 2010 Society of Chemical Industry.

Conservative decrease in water potential in existing leaves during new leaf expansion in temperate and tropical evergreen Quercus species.

PubMed

Saito, Takami; Naiola, B Paul; Terashima, Ichiro

2007-12-01

This study aimed at clarifying how the water potential gradient (deltapsi) is maintained in the shoots of evergreen trees with expanding leaves, whose leaf water potentials at the turgor loss point (psi(tlp)) are generally high. The water relations were examined in current-year expanding (CEX) and 1-year-old (OLD) leaves on the same shoots in temperate (Osaka, Japan) and tropical (Bogor, Indonesia) areas. A temperate evergreen species, Quercus glauca growing in both sites, was compared with a temperate deciduous species, Q. serrata, in Osaka, and two tropical evergreen species, Q. gemelliflora and Q. subsericea, in Bogor. (1) In Osaka, the midday leaf water potential (psi(midday)) was slightly higher in OLD (-0.5 MPa) than in CEX leaves (-0.6 MPa), whereas psi(tlp) was significantly lower in OLD (-2.9 MPa) than in CEX leaves (-1.0 MPa). In Bogor, psi(midday) was also higher in OLD leaves (-1.0 MPa) despite the low psi(tlp) (-1.9 MPa), although stomatal conductance was not always low in OLD leaves. In the branch bearing CEX and OLD leaves, most of the hydraulic resistance (86 %) exists in the current-year branch, leading to differences in water supply between CEX and OLD leaves. The removal of buds just before breaking did not affect the high psi(midday) in OLD leaves after 1 month. Psi(midday) in OLD leaves thus appears to be independent of that in CEX leaves. The moderate decrease in psi(midday) in OLD leaves would contribute to maintenance of deltapsi in the shoots during leaf expansion.

Temporal and spatial variations in microclimate influence the larval foraging behaviors and performance of a conifer-feeding sawfly.

PubMed

Johns, R C; Boone, J; Leggo, J J; Smith, S; Carleton, D; Quiring, D T

2012-06-01

Herbivorous insects are often exposed to broad temporal and spatial variations in microclimate conditions within their host plants and have adapted a variety of behaviors, such as avoidance or basking, to either offset or benefit from such variation. Field experiments were carried out to investigate the influence of daily and intratree variations in microclimate on the behaviors (feeding, resting, dispersal, and hiding) and associated performance of late-instar larvae of the yellowheaded spruce sawfly, Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) within crowns of 1.25-1.5 m tall black spruce (Picea mariana [Miller] Britton Sterns Poggenburg); late instars feed on developing shoots of young spruce and are often exposed to microclimatic extremes with unknown effects on performance. Larvae fed diurnally from just after dawn (0800 h) until dusk (2000 h) and rested throughout the night, with brief periods of dispersal occurring in the morning and evening. Neither larval behavior nor abiotic conditions differed significantly between the upper and lower crowns of trees. Temperature, humidity, and solar insolation all explained >90% of variation in feeding; however, sunrise and sunset were the most likely cues influencing diurnal behavior. Most larvae (94%) fed on the bottom, shaded side of shoots, and field experiments indicated that this behavior is adaptive with respect to microclimate, probably reducing hygrothermal stress. Thus, behavioral adaptations by P. alaskensis to daily and within-shoot microclimatic variation may reduce the risk of hygrothermal stress during dispersal or feeding, while still allowing larvae to feed on the preferred and highly nutritious upper crown foliage of young spruce.

Chilling of Dormant Buds Hyperinduces FLOWERING LOCUS T and Recruits GA-Inducible 1,3-β-Glucanases to Reopen Signal Conduits and Release Dormancy in Populus[W][OA

PubMed Central

Rinne, Päivi L.H.; Welling, Annikki; Vahala, Jorma; Ripel, Linda; Ruonala, Raili; Kangasjärvi, Jaakko; van der Schoot, Christiaan

2011-01-01

In trees, production of intercellular signals and accessibility of signal conduits jointly govern dormancy cycling at the shoot apex. We identified 10 putative cell wall 1,3-β-glucanase genes (glucan hydrolase family 17 [GH17]) in Populus that could turn over 1,3-β-glucan (callose) at pores and plasmodesmata (PD) and investigated their regulation in relation to FT and CENL1 expression. The 10 genes encode orthologs of Arabidopsis thaliana BG_ppap, a PD-associated glycosylphosphatidylinositol (GPI) lipid-anchored protein, the Arabidopsis PD callose binding protein PDCB, and a birch (Betula pendula) putative lipid body (LB) protein. We found that these genes were differentially regulated by photoperiod, by chilling (5°C), and by feeding of gibberellins GA3 and GA4. GA3 feeding upregulated all LB-associated GH17s, whereas GA4 upregulated most GH17s with a GPI anchor and/or callose binding motif, but only GA4 induced true bud burst. Chilling upregulated a number of GA biosynthesis and signaling genes as well as FT, but not CENL1, while the reverse was true for both GA3 and GA4. Collectively, the results suggest a model for dormancy release in which chilling induces FT and both GPI lipid-anchored and GA3-inducible GH17s to reopen signaling conduits in the embryonic shoot. When temperatures rise, the reopened conduits enable movement of FT and CENL1 to their targets, where they drive bud burst, shoot elongation, and morphogenesis. PMID:21282527

De Novo Assembly and Comparative Transcriptome Analysis Provide Insight into Lysine Biosynthesis in Toona sinensis Roem.

PubMed

Zhang, Xia; Song, Zhenqiao; Liu, Tian; Guo, Linlin; Li, Xingfeng

2016-01-01

Toona sinensis Roem is a popular leafy vegetable in Chinese cuisine and is also used as a traditional Chinese medicine. In this study, leaf samples were collected from the same plant on two development stages and then used for high-throughput Illumina RNA-sequencing (RNA-Seq). 125,884 transcripts and 54,628 unigenes were obtained through de novo assembly. A total of 25,570 could be annotated with known biological functions, which indicated that the T. sinensis leaves and shoots were undergoing multiple developmental processes especially for active metabolic processes. Analysis of differentially expressed unigenes between the two libraries showed that the lysine biosynthesis was an enriched KEGG pathway, and candidate genes involved in the lysine biosynthesis pathway in T. sinensis leaves and shoots were identified. Our results provide a primary analysis of the gene expression files of T. sinensis leaf and shoot on different development stages and afford a valuable resource for genetic and genomic research on plant lysine biosynthesis.

Construction and application of EST library from Setaria italica in response to dehydration stress.

PubMed

Zhang, Jinpeng; Liu, Tingsong; Fu, Junjie; Zhu, Yun; Jia, Jinping; Zheng, Jun; Zhao, Yinhe; Zhang, Ying; Wang, Guoying

2007-07-01

Foxtail millet is a gramineous crop with low water requirement. Despite its high water use efficiency, less attention has been paid to the molecular genetics of foxtail millet. This article reports the construction of subtracted cDNA libraries from foxtail millet seedlings under dehydration stress and the expression profile analysis of 1947 UniESTs from the subtracted cDNA libraries by a cDNA microarray. The results showed that 95 and 57 ESTs were upregulated by dehydration stress, respectively, in roots and shoots of seedlings and that 10 and 27 ESTs were downregulated, respectively, in roots and shoots. The expression profile analysis showed that genes induced in foxtail millet roots were different from those in shoots during dehydration stress and that the early response to dehydration stress in foxtail millet roots was the activation of the glycolysis metabolism. Moreover, protein degradation pathway may also play a pivotal role in drought-tolerant responses of foxtail millet. Finally, Northern blot analysis validated well the cDNA microarray data.

A Core Regulatory Pathway Controlling Rice Tiller Angle Mediated by the LAZY1-dependent Asymmetric Distribution of Auxin.

PubMed

Zhang, Ning; Yu, Hong; Yu, Hao; Cai, Yueyue; Huang, Linzhou; Xu, Cao; Xiong, Guosheng; Meng, Xiangbing; Wang, Jiyao; Chen, Haofeng; Liu, Guifu; Jing, Yanhui; Yuan, Yundong; Liang, Yan; Li, Shujia; Smith, Steven M; Li, Jiayang; Wang, Yonghong

2018-06-18

Tiller angle in cereals is a key shoot architecture trait that strongly influences grain yield. Studies in rice (Oryza sativa L.) have implicated shoot gravitropism in the regulation of tiller angle. However, the functional link between shoot gravitropism and tiller angle is unknown. Here, we conducted a large-scale transcriptome analysis of rice shoots in response to gravistimulation and identified two new nodes of a shoot gravitropism regulatory gene network that also controls rice tiller angle. We demonstrate that HEAT STRESS TRANSCRIPTION FACTOR 2D (HSFA2D) is an upstream positive regulator of the LAZY1-mediated asymmetric auxin distribution pathway. We also show that two functionally redundant transcription factor genes, WUSCHEL RELATED HOMEOBOX6 (WOX6) and WOX11, are expressed asymmetrically in response to auxin to connect gravitropism responses with the control of rice tiller angle. These findings define upstream and downstream genetic components that link shoot gravitropism, asymmetric auxin distribution, and rice tiller angle. The results highlight the power of the high-temporal-resolution RNA-seq dataset, and its use to explore further genetic components controlling tiller angle. Collectively these approaches will identify genes to improve grain yields by facilitating the optimization of plant architecture. © 2018 American Society of Plant Biologists. All rights reserved.

Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

PubMed

Soolanayakanahally, Raju Y; Guy, Robert D; Street, Nathaniel R; Robinson, Kathryn M; Silim, Salim N; Albrectsen, Benedicte R; Jansson, Stefan

2015-01-01

Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g s) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ(13)C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects.

Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens

PubMed Central

Soolanayakanahally, Raju Y.; Guy, Robert D.; Street, Nathaniel R.; Robinson, Kathryn M.; Silim, Salim N.; Albrectsen, Benedicte R.; Jansson, Stefan

2015-01-01

Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (gs) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ13C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects. PMID:26236324

Possibilities of cultivating ornamental trees and shrubs under conditions of air pollution with oxides of sulfur

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

Bialobok, S.; Bartkowiak, S.; Rachwal, L.

1974-01-01

The field work conducted has shown that high concentrations of SO/sub 2/ in the air can be withstood by the following trees and shrubs. Trees: Acer campestris, A. platanoides, Ailanthus altissima, Aesculus hippocastanum, Morus alba, Platanus acerifolia, Pinus strobur, P. nigra, Populus Berolinensis, P. candicans, P. Hybr. 27, P. Marilandica, P. simonii, P. Serotina, Quercus robus, Robinia pseudoacacia. Shrubs: Caragana arborescens, Crataegus oxyacantha, C. monogyna, Cerasus mehaleb, Forsythia/most of the species and varieties/, Ligustrum vulgare, Philadelphus coronaria, Ptelea trifoliata, Sambucus nigra, Salix caprea, Sorbaria sorbifolia, Sorbus aucuparia, Taxus baccata. For the selection of trees and shrubs in the laboratory, highmore » concentrations of SO/sub 2/ were used (60-150 ppm for a period of 10 minutes). Experiments were conducted on cut shrubs kept in the gas chambers. In order to estimate the degree of their injury, they were transferred to a shaded greenhouse. A concentration of 65 ppm of SO/sub 2/ could be withstood by the following Forsythias: Forsythia intermedia Primulina, F. Densiflora, F. Spectabilis, F. giraldina, F. suspensa, F. koreana, F. ovata, F. japonica and Hippophae rhamnoides. A concentration of 130 ppm could be withstood only by F. intermedia Vitelina. A similarly high concentration of SO/sub 2/ could be withstood by shoots and leaves of Ailanthus girladii Duclouxii and by Platanus acerifolia. From among the lilacs Syringa pekinensis and S. amurensis proved resistant to high concentrations of SO/sub 2/.« less

Seasonal carbohydrate dynamics and growth in Douglas-fir trees experiencing chronic, fungal-mediated reduction in functional leaf area.

PubMed

Saffell, Brandy J; Meinzer, Frederick C; Woodruff, David R; Shaw, David C; Voelker, Steven L; Lachenbruch, Barbara; Falk, Kristen

2014-03-01

Stored non-structural carbohydrates (NSCs) could play an important role in tree survival in the face of a changing climate and associated stress-related mortality. We explored the effects of the stomata-blocking and defoliating fungal disease called Swiss needle cast on Douglas-fir carbohydrate reserves and growth to evaluate the extent to which NSCs can be mobilized under natural conditions of low water stress and restricted carbon supply in relation to potential demands for growth. We analyzed the concentrations of starch, sucrose, glucose and fructose in foliage, twig wood and trunk sapwood of 15 co-occurring Douglas-fir trees expressing a gradient of Swiss needle cast symptom severity quantified as previous-year functional foliage mass. Growth (mean basal area increment, BAI) decreased by ∼80% and trunk NSC concentration decreased by 60% with decreasing functional foliage mass. The ratio of relative changes in NSC concentration and BAI, an index of the relative priority of storage versus growth, more than doubled with increasing disease severity. In contrast, twig and foliage NSC concentrations remained nearly constant with decreasing functional foliage mass. These results suggest that under disease-induced reductions in carbon supply, Douglas-fir trees retain NSCs (either actively or due to sequestration) at the expense of trunk radial growth. The crown retains the highest concentrations of NSC, presumably to maintain foliage growth and shoot extension in the spring, partially compensating for rapid foliage loss in the summer and fall.

A new approach for in vitro regeneration of tomato plants devoid of exogenous plant growth hormones.

PubMed

Plana, Dagmara; Fuentes, Alejandro; Alvarez, Marta; Lara, Regla M; Alvarez, Félix; Pujol, Merardo

2006-10-01

Many available methodologies for in vitro regeneration of commercial tomato varieties promote not only the production of normal shoots but also individual leaves, shoots without apical meristems and vitrified structures. All these abnormal formations influence and diminish the regeneration efficiency. At the basis of this phenomenon lies callus development. We optimized an alternative procedure by which the regeneration occurs without abnormal shoot formation. The portion including the proximal part of hypocotyls and the radicle was cultured on medium consisting of Murashige and Skoog salts, 4 mg/L thiamine, 100 mg/L mio-inositol and 3% sucrose. After two-three weeks, 60% explants showed adventitious shoot formation. No changes in the morphological characteristics of regenerated plants and fruits were observed as compared with parents. Karyotypic analysis of regenerated plants showed no variations in chromosome number. The optimized procedure offers the advantage of tomato plant regeneration avoiding callus formation, which enables normal plant recovery with an efficiency ranging from 1.45 +/- 0.05 to 2.57 +/- 0.06 shoots per explant in Campbell-28, Amalia, Lignon, and Floradel cultivars.

Variable Levels of Glutathione S-Transferases Are Responsible for the Differential Tolerance to Metolachlor between Maize (Zea mays) Shoots and Roots.

PubMed

Li, Dongzhi; Xu, Li; Pang, Sen; Liu, Zhiqian; Wang, Kai; Wang, Chengju

2017-01-11

Glutathione S-transferases (GSTs) play important roles in herbicide tolerance. However, studies on GST function in herbicide tolerance among plant tissues are still lacking. To explore the mechanism of metolachlor tolerance difference between maize shoots and roots, the effects of metolachlor on growth, GST activity, and the expression of the entire GST gene family were investigated. It was found that this differential tolerance to metolachlor was correlated with contrasting GST activity between the two tissues and can be eliminated by a GST inhibitor. An in vitro metolachlor-glutathione conjugation assay confirmed that the transformation of metolachlor is 2-fold faster in roots than in shoots. The expression analysis of the GST gene family revealed that most GST genes are expressed much higher in roots than shoots, both in control and in metolachlor-treated plants. Taken together, higher level expression of most GST genes, leading to higher GST activity and faster herbicide transformation, appears to be responsible for the higher tolerance to metolachlor of maize roots than shoots.

Effects of summer and winter harvesting on element phytoextraction efficiency of Salix and Populus clones planted on contaminated soil.

PubMed

Kubátová, Pavla; Száková, Jiřina; Břendová, Kateřina; Kroulíková-Vondráčková, Stanislava; Mercl, Filip; Tlustoš, Pavel

2018-04-16

The clones of fast-growing trees (FGTs) were investigated for phytoextraction of soil contaminated with risk elements (REs), especially Cd, Pb, and Zn. As a main experimental factor, the potential effect of biomass harvesting time was assessed. The field experiment with two Salix clones (S1 - (Salix schwerinii × Salix viminalis) × S. viminalis, S2 - S. × smithiana) and two Populus clones (P1 - Populus maximowiczii × Populus nigra, P2 - P. nigra) was established in April 2009. Shoots of all clones were first harvested in February 2012. After two further growing seasons, the first half of the trees was harvested in September 2013 before leaf fall (summer harvest) and the second half in February 2014 (winter harvest). Remediation factors (RFs) for all clones and all REs (except Pb for clone S1) were higher in the summer harvest. The highest annual RFs for Cd and for Zn (1.34 and 0.67%, respectively) were found for clone S2 and were significantly higher than other clones. Although no increased mortality of trees harvested in the summer was detected in the following season, the effect of summer harvesting on the phytoextraction potential of FGTs clones should be investigated in long-term studies.

Enhanced micropropagation and tiller formation in sugarcane through pretreatment of explants with thidiazuron (TDZ).

PubMed

Kumari, Kavita; Lal, Madan; Saxena, Sangeeta

2017-10-01

An efficient, simple and commercially applicable protocol for rapid micropropagation of sugarcane has been designed using variety Co 05011. Pretreatment of shoot tip explants with thidiazuron (TDZ) induced high frequency regeneration of shoot cultures with improved multiplication ratio. The highest frequency (80%) of shoot initiation in explants pretreated with 10 mg/l of TDZ was obtained during the study. Maximum 65% shoot cultures could be established from the explants pretreated with TDZ as compared to minimum 40% establishment in explants without pretreatment. The explants pretreated with 10 mg/l of TDZ required minimum 40 days for the establishment of shoot cultures as compared to untreated explants which required 60 days. The highest average number of shoots per culture (19.1) could be obtained from the explants pretreated with 10 mg/l of TDZ, indicating the highest multiplication ratio (1:6). Highest rooting (over 94%) was obtained in shoots regenerated from pretreated explants on ½ strength MS medium containing 5.0 mg/l of NAA and 50 g/l of sucrose within 15 days. Higher number of tillers/clump (15.3) could be counted in plants regenerated from pretreated explants than untreated ones (10.9 tillers/clump) in field condition, three months after transplantation. Molecular analysis using RAPD and DAMD markers suggested that the pretreatment of explants with TDZ did not adversely affect the genetic stability of regenerated plants and maintained high clonal purity.

Comparative transcriptome analysis of shoot and root tissue of Bacopa monnieri identifies potential genes related to triterpenoid saponin biosynthesis.

PubMed

Jeena, Gajendra Singh; Fatima, Shahnoor; Tripathi, Pragya; Upadhyay, Swati; Shukla, Rakesh Kumar

2017-06-28

Bacopa monnieri commonly known as Brahmi is utilized in Ayurveda to improve memory and many other human health benefits. Bacosides enriched standardized extract of Bacopa monnieri is being marketed as a memory enhancing agent. In spite of its well known pharmacological properties it is not much studied in terms of transcripts involved in biosynthetic pathway and its regulation that controls the secondary metabolic pathway in this plant. The aim of this study was to identify the potential transcripts and provide a framework of identified transcripts involved in bacosides production through transcriptome assembly. We performed comparative transcriptome analysis of shoot and root tissue of Bacopa monnieri in two independent biological replicate and obtained 22.48 million and 22.0 million high quality processed reads in shoot and root respectively. After de novo assembly and quantitative assessment total 26,412 genes got annotated in root and 18,500 genes annotated in shoot sample. Quality of raw reads was determined by using SeqQC-V2.2. Assembled sequences were annotated using BLASTX against public database such as NR or UniProt. Searching against the KEGG pathway database indicated that 37,918 unigenes from root and 35,130 unigenes from shoot were mapped to 133 KEGG pathways. Based on the DGE data we found that most of the transcript related to CYP450s and UDP-glucosyltransferases were specifically upregulated in shoot tissue as compared to root tissue. Finally, we have selected 43 transcripts related to secondary metabolism including transcription factor families which are differentially expressed in shoot and root tissues were validated by qRT-PCR and their expression level were monitored after MeJA treatment and wounding for 1, 3 and 5 h. This study not only represents the first de novo transcriptome analysis of Bacopa monnieri but also provides information about the identification, expression and differential tissues specific distribution of transcripts related to triterpenoid sapogenin which is one of the most important pharmacologically active secondary metabolite present in Bacopa monnieri. The identified transcripts in this study will establish a foundation for future studies related to carrying out the metabolic engineering for increasing the bacosides biosynthesis and its regulation for human health benefits.

British game shooting in transition, 1900-1945.

PubMed

Martin, John

2011-01-01

This article explores the transformation of lowland game shooting from its heyday in the late Victorian and Edwardian periods to state-imposed rationalization during the Second World War. It evaluates the extent to which the interwar years constituted a period of depression or regeneration in the way the activity was organized and pursued, followed by an in-depth analysis of the impact of the Second World War. The study shows that the prevailing wisdom about the reasons for the decline of game shooting merits reappraisal, particularly in view of the unprecedented changes to the sport that resulted from the government's control and direction of food production during World War II.

Shooting Performance as a Function of Shooters’ Anthropometrics, Weapon Design Attributes, Firing Position, Range, and Sex

DTIC Science & Technology

2014-10-01

time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the... data , weapon design data , firing posture, range and sex. 15. SUBJECT TERMS Soldier shooting performance, anthropometrics, weapon design, range, sex...Conditions and Test Matrix ......................................................................9 7. Data Analysis 9 7.1 Data Stratification

Functional analysis of the GmESR1 gene associated with soybean regeneration

PubMed Central

Chen, Qingshan; Liu, Ming; Xin, Dawei; Qi, Zhaoming; Li, Sinan; Ma, Yanlong; Wang, Lingshuang; Jin, Yangmei; Li, Wenbin; Wu, Xiaoxia; Su, An-yu

2017-01-01

Plant regeneration can occur via in vitro tissue culture through somatic embryogenesis or de novo shoot organogenesis. Transformation of soybean (Glycine max) is difficult, hence optimization of the transformation system for soybean regeneration is required. This study investigated ENHANCER OF SHOOT REGENERATION 1 (GmESR1), a soybean transcription factor that targets regeneration-associated genes. Sequence analysis showed that GmESR1 contained a conserved 57 amino acid APETALA 2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) DNA-binding domain. The relative expression level of GmESR1 was highest in young embryos, flowers and stems in the soybean cultivar ‘Dongnong 50’. To examine the function of GmESR1, transgenic Arabidopsis (Arabidopsis thaliana) and soybean plants overexpressing GmESR1 were generated. In Arabidopsis, overexpression of GmESR1 resulted in accelerated seed germination, and seedling shoot and root elongation. In soybean overexpression of GmESR1 also led to faster seed germination, and shoot and root elongation. GmESR1 specifically bound to the GCC-box. The results provide a foundation for the establishment of an efficient and stable transformation system for soybean. PMID:28403182

Identification of Quantitative Trait Loci Controlling Root and Shoot Traits Associated with Drought Tolerance in a Lentil (Lens culinaris Medik.) Recombinant Inbred Line Population

PubMed Central

Idrissi, Omar; Udupa, Sripada M.; De Keyser, Ellen; McGee, Rebecca J.; Coyne, Clarice J.; Saha, Gopesh C.; Muehlbauer, Fred J.; Van Damme, Patrick; De Riek, Jan

2016-01-01

Drought is one of the major abiotic stresses limiting lentil productivity in rainfed production systems. Specific rooting patterns can be associated with drought avoidance mechanisms that can be used in lentil breeding programs. In all, 252 co-dominant and dominant markers were used for Quantitative Trait Loci (QTL) analysis on 132 lentil recombinant inbred lines based on greenhouse experiments for root and shoot traits during two seasons under progressive drought-stressed conditions. Eighteen QTLs controlling a total of 14 root and shoot traits were identified. A QTL-hotspot genomic region related to a number of root and shoot characteristics associated with drought tolerance such as dry root biomass, root surface area, lateral root number, dry shoot biomass and shoot length was identified. Interestingly, a QTL (QRSratioIX-2.30) related to root-shoot ratio, an important trait for drought avoidance, explaining the highest phenotypic variance of 27.6 and 28.9% for the two consecutive seasons, respectively, was detected. This QTL was closed to the co-dominant SNP marker TP6337 and also flanked by the two SNP TP518 and TP1280. An important QTL (QLRNIII-98.64) related to lateral root number was found close to TP3371 and flanked by TP5093 and TP6072 SNP markers. Also, a QTL (QSRLIV-61.63) associated with specific root length was identified close to TP1873 and flanked by F7XEM6b SRAP marker and TP1035 SNP marker. These two QTLs were detected in both seasons. Our results could be used for marker-assisted selection in lentil breeding programs targeting root and shoot characteristics conferring drought avoidance as an efficient alternative to slow and labor-intensive conventional breeding methods. PMID:27602034

Apricot (Prunus armeniaca L.).

PubMed

Petri, César; Alburquerque, Nuria; Burgos, Lorenzo

2015-01-01

A protocol for Agrobacterium-mediated stable transformation of whole leaf explants of the apricot (Prunus armeniaca) cultivars 'Helena' and 'Canino' is described. Regenerated buds were selected using a two-step selection strategy with paromomycin sulfate and transferred to bud multiplication medium 1 week after they were detected for optimal survival. After buds were transferred to bud multiplication medium, antibiotic was changed to kanamycin and concentration increased gradually at each transfer to fresh medium in order to eliminate possible escapes and chimeras. Transformation efficiency, based on PCR analysis of individual putative transformed shoots from independent lines, was 5.6%. Green and healthy buds, surviving high kanamycin concentration, were transferred to shoot multiplication medium where they elongated in shoots and proliferated. Elongated transgenic shoots were rooted in a medium containing 70 μM kanamycin. Rooted plants were acclimatized following standard procedures. This constitutes the only transformation protocol described for apricot clonal tissues and one of the few of Prunus.

Disruption of the rice nitrate transporter OsNPF2.2 hinders root-to-shoot nitrate transport and vascular development

PubMed Central

Li, Yuge; Ouyang, Jie; Wang, Ya-Yun; Hu, Rui; Xia, Kuaifei; Duan, Jun; Wang, Yaqin; Tsay, Yi-Fang; Zhang, Mingyong

2015-01-01

Plants have evolved to express some members of the nitrate transporter 1/peptide transporter family (NPF) to uptake and transport nitrate. However, little is known of the physiological and functional roles of this family in rice (Oryza sativa L.). Here, we characterized the vascular specific transporter OsNPF2.2. Functional analysis using cDNA-injected Xenopus laevis oocytes revealed that OsNPF2.2 is a low-affinity, pH-dependent nitrate transporter. Use of a green fluorescent protein tagged OsNPF2.2 showed that the transporter is located in the plasma membrane in the rice protoplast. Expression analysis showed that OsNPF2.2 is nitrate inducible and is mainly expressed in parenchyma cells around the xylem. Disruption of OsNPF2.2 increased nitrate concentration in the shoot xylem exudate when nitrate was supplied after a deprivation period; this result suggests that OsNPF2.2 may participate in unloading nitrate from the xylem. Under steady-state nitrate supply, the osnpf2.2 mutants maintained high levels of nitrate in the roots and low shoot:root nitrate ratios; this observation suggests that OsNPF2.2 is involved in root-to-shoot nitrate transport. Mutation of OsNPF2.2 also caused abnormal vasculature and retarded plant growth and development. Our findings demonstrate that OsNPF2.2 can unload nitrate from the xylem to affect the root-to-shoot nitrate transport and plant development. PMID:25923512

CEP genes regulate root and shoot development in response to environmental cues and are specific to seed plants.

PubMed

Delay, Christina; Imin, Nijat; Djordjevic, Michael A

2013-12-01

The manifestation of repetitive developmental programmes during plant growth can be adjusted in response to various environmental cues. During root development, this means being able to precisely control root growth and lateral root development. Small signalling peptides have been found to play roles in many aspects of root development. One member of the CEP (C-TERMINALLY ENCODED PEPTIDE) gene family has been shown to arrest root growth. Here we report that CEP genes are widespread among seed plants but are not present in land plants that lack true branching roots or root vasculature. We have identified 10 additional CEP genes in Arabidopsis. Expression analysis revealed that CEP genes are regulated by environmental cues such as nitrogen limitation, increased salt levels, increased osmotic strength, and increased CO2 levels in both roots and shoots. Analysis of synthetic CEP variants showed that both peptide sequence and modifications of key amino acids affect CEP biological activity. Analysis of several CEP over-expression lines revealed distinct roles for CEP genes in root and shoot development. A cep3 knockout mutant showed increased root and shoot growth under a range of abiotic stress, nutrient, and light conditions. We demonstrate that CEPs are negative regulators of root development, slowing primary root growth and reducing lateral root formation. We propose that CEPs are negative regulators that mediate environmental influences on plant development.

Influence of Tree Size and Application Rate on Expression of Thiamethoxam in Citrus and Its Efficacy Against Diaphorina citri (Hemiptera: Liviidae).

PubMed

Langdon, K W; Schumann, R; Stelinski, L L; Rogers, M E

2018-04-02

Neonicotinoids are a key group of insecticides used to manage Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Florida citrus. Diaphorina citri is the vector of Candidatus Liberibacter asiaticus, the presumed causal agent of huanglongbing, a worldwide disease of citrus. A two-season field study was conducted to evaluate the effect of tree size and application rate on the expression of thiamethoxam in young citrus following application to the soil. D. citri adult and nymph abundance was also correlated with thiamethoxam titer in leaves. Tree size and application rate each significantly affected thiamethoxam titer in leaf tissue. The highest mean thiamethoxam titer observed (33.39 ppm) in small trees (mean canopy volume = 0.08 m3) occurred after application of the high rate (0.74 g Platinum 75SG per tree) tested. There was a negative correlation between both nymph and adult abundance with increasing thiamethoxam titer in leaves. A concentration of 64.63 ppm thiamethoxam was required to reach a 1% probability of encountering a flush shoot with at least one adult D. citri, while 19.05 ppm was required for the same probability of encountering nymphs. The LC90 for the field population was 7.62 ppm thiamethoxam when administered through ingestion. Exposure to dosages as low as 7.62 ppm would likely result in sublethal exposure of some proportion of the population, which could exacerbate resistance development. Based on our results, subsequent work should investigate the use of neonicotinoids by foliar rather than soil application to maintain the chemical class in future insecticide management programs in Florida citrus.

Expression patterns of flowering genes in leaves of 'Pineapple' sweet orange [Citrus sinensis (L.) Osbeck] and pummelo (Citrus grandis Osbeck).

PubMed

Pajon, Melanie; Febres, Vicente J; Moore, Gloria A

2017-08-30

In citrus the transition from juvenility to mature phase is marked by the capability of a tree to flower and fruit consistently. The long period of juvenility in citrus severely impedes the use of genetic based strategies to improve fruit quality, disease resistance, and responses to abiotic environmental factors. One of the genes whose expression signals flower development in many plant species is FLOWERING LOCUS T (FT). In this study, gene expression levels of flowering genes CiFT1, CiFT2 and CiFT3 were determined using reverse-transcription quantitative real-time PCR in citrus trees over a 1 year period in Florida. Distinct genotypes of citrus trees of different ages were used. In mature trees of pummelo (Citrus grandis Osbeck) and 'Pineapple' sweet orange (Citrus sinensis (L.) Osbeck) the expression of all three CiFT genes was coordinated and significantly higher in April, after flowering was over, regardless of whether they were in the greenhouse or in the field. Interestingly, immature 'Pineapple' seedlings showed significantly high levels of CiFT3 expression in April and June, while CiFT1 and CiFT2 were highest in June, and hence their expression induction was not simultaneous as in mature plants. In mature citrus trees the induction of CiFTs expression in leaves occurs at the end of spring and after flowering has taken place suggesting it is not associated with dormancy interruption and further flower bud development but is probably involved with shoot apex differentiation and flower bud determination. CiFTs were also seasonally induced in immature seedlings, indicating that additional factors must be suppressing flowering induction and their expression has other functions.

Food selection of the Malayan tapir (Tapirus indicus) under semi-wild conditions

NASA Astrophysics Data System (ADS)

Simpson, Boyd K.; Shukor, M. N.; Magintan, David

2013-11-01

A study on the selection of food plants by captive Malayan tapirs (Tapirus indicus) was undertaken in a 30 hectare natural forest enclosure at the Sungai Dusun Wildlife Reserve, Malaysia. Tapirs browsed on 217 species of plants (from 99 genera and 49 families) from a total of the 1142 specimens collected and identified. Food plants were heavily dominated by sapling trees and shrubs which comprised 93% of all plants taken, with the remainder comprising woody lianas, vines and herbaceous plants. Although tapirs browsed on a wide variety of plant species, the top 30 species consumed represented more than 60% of all the plants selected, whilst the vast majority of species were rarely eaten. More than 80 species of trees and shrubs were available, but not eaten at all. The most readily consumed species were the sub-canopy and understorey trees Xerospermum noronhianum, Aporosa prainiana and Baccaurea parviflora, while Aporosa, Knema and Xerospermum were the dominant plant genera. The Phyllanthaceae (leaf flowers), Myristicaceae (nutmegs) and Sapindaceae (rambutans) were the most commonly selected families comprising 45% of the diet. Tapirs fed on saplings trees up to 8.3 m in height, while plants taller than about 1.6 m were bent, broken or pushed to the ground to gain access to the foliage. Sapling stems up to 4.2 cm in diameter could be snapped by biting, while larger trees to 7 cm diameter could be pushed down. Tapirs typically fed on the newer leaves and shoots, however, often only consuming half of the available foliage on a plant. This study documents 160 new plant species suitable as Malayan tapir food, and is consistent with the generalist, but selective browsing nature of the Tapirus species in general.

Distribution and persistence of emamectin benzoate at efficacious concentrations in pine tissues after injection of a liquid formulation.

PubMed

Takai, Kazuya; Suzuki, Toshio; Kawazu, Kazuyoshi

2004-01-01

In an earlier paper the authors reported the creation of a novel emamectin benzoate 40 g litre(-1) liquid formulation (Shot Wan Liquid Formulation). The injection of this formulation exerted a preventative effect against the pine wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and this effect lasted for at least 3 years. The present study was carried out to show experimentally that the marked effect of this formulation was due to the presence and persistence in pine tissues of sufficient amounts of emamectin benzoate to inhibit nematode propagation. A cleanup procedure prior to quantitative analysis of emamectin benzoate by fluorescence HPLC was devised. The presence of the compound in concentrations sufficient to inhibit nematode propagation in the shoots of current growth and its persistence for 3 years explained the marked preventative effect. Non-distribution of emamectin benzoate in some parts of the lower trunk suggested that the formulation should be injected at several points for large trees in order to distribute the compound uniformly to lower branches.

Arbuscular mycorrhizal symbiosis elicits shoot proteome changes that are modified during cadmium stress alleviation in Medicago truncatula

PubMed Central

2011-01-01

Background Arbuscular mycorrhizal (AM) fungi, which engage a mutualistic symbiosis with the roots of most plant species, have received much attention for their ability to alleviate heavy metal stress in plants, including cadmium (Cd). While the molecular bases of Cd tolerance displayed by mycorrhizal plants have been extensively analysed in roots, very little is known regarding the mechanisms by which legume aboveground organs can escape metal toxicity upon AM symbiosis. As a model system to address this question, we used Glomus irregulare-colonised Medicago truncatula plants, which were previously shown to accumulate and tolerate heavy metal in their shoots when grown in a substrate spiked with 2 mg Cd kg-1. Results The measurement of three indicators for metal phytoextraction showed that shoots of mycorrhizal M. truncatula plants have a capacity for extracting Cd that is not related to an increase in root-to-shoot translocation rate, but to a high level of allocation plasticity. When analysing the photosynthetic performance in metal-treated mycorrhizal plants relative to those only Cd-supplied, it turned out that the presence of G. irregulare partially alleviated the negative effects of Cd on photosynthesis. To test the mechanisms by which shoots of Cd-treated mycorrhizal plants avoid metal toxicity, we performed a 2-DE/MALDI/TOF-based comparative proteomic analysis of the M. truncatula shoot responses upon mycorrhization and Cd exposure. Whereas the metal-responsive shoot proteins currently identified in non-mycorrhizal M. truncatula indicated that Cd impaired CO2 assimilation, the mycorrhiza-responsive shoot proteome was characterised by an increase in photosynthesis-related proteins coupled to a reduction in glugoneogenesis/glycolysis and antioxidant processes. By contrast, Cd was found to trigger the opposite response coupled the up-accumulation of molecular chaperones in shoot of mycorrhizal plants relative to those metal-free. Conclusion Besides drawing a first picture of shoot proteome modifications upon AM symbiosis and/or heavy metal stress in legume plants, the current work argues for allocation plasticity as the main driving force for Cd extraction in aboveground tissues of M. truncatula upon mycorrhization. Additionally, according to the retrieved proteomic data, we propose that shoots of mycorrhizal legume plants escape Cd toxicity through a metabolic shift implying the glycolysis-mediated mobilization of defence mechanisms at the expense of the photosynthesis-dependent symbiotic sucrose sink. PMID:21545723

Pre-hospital management of mass casualty civilian shootings: a systematic literature review.

PubMed

Turner, Conor D A; Lockey, David J; Rehn, Marius

2016-11-08

Mass casualty civilian shootings present an uncommon but recurring challenge to emergency services around the world and produce unique management demands. On the background of a rising threat of transnational terrorism worldwide, emergency response strategies are of critical importance. This study aims to systematically identify, describe and appraise the quality of indexed and non-indexed literature on the pre-hospital management of modern civilian mass shootings to guide future practice. Systematic literature searches of PubMed, Cochrane Database of Systematic Reviews and Scopus were conducted in conjunction with simple searches of non-indexed databases; Web of Science, OpenDOAR and Evidence Search. The searches were last carried out on 20 April 2016 and only identified those papers published after the 1 January 1980. Included documents had to contain descriptions, discussions or experiences of the pre-hospital management of civilian mass shootings. From the 494 identified manuscripts, 73 were selected on abstract and title and after full text reading 47 were selected for inclusion in analysis. The search yielded reports of 17 mass shooting events, the majority from the USA with additions from France, Norway, the UK and Kenya. Between 1994 and 2015 the shooting of 1649 people with 578 deaths at 17 separate events are described. Quality appraisal demonstrated considerable heterogeneity in reporting and revealed limited data on mass shootings globally. Key themes were identified to improve future practice: tactical emergency medical support may harmonise inner cordon interventions, a need for inter-service education on effective haemorrhage control, the value of senior triage operators and the need for regular mass casualty incident simulation.

Analysis of Rhizome Development in Oryza longistaminata, a Wild Rice Species.

PubMed

Yoshida, Akiko; Terada, Yasuhiko; Toriba, Taiyo; Kose, Katsumi; Ashikari, Motoyuki; Kyozuka, Junko

2016-10-01

Vegetative reproduction is a form of asexual propagation in plants. A wide range of plants develop rhizomes, modified stems that grow underground horizontally, as a means of vegetative reproduction. In rhizomatous species, despite their distinct developmental patterns, both rhizomes and aerial shoots derive from axillary buds. Therefore, it is of interest to understand the basis of rhizome initiation and development. Oryza longistaminata, a wild rice species, develops rhizomes. We analyzed bud initiation and growth of O. longistaminata rhizomes using various methods of morphological observation. We show that, unlike aerial shoot buds that contain a few leaves only, rhizome buds initiate several leaves and bend to grow at right angles to the original rhizome. Rhizomes are maintained in the juvenile phase irrespective of the developmental phase of the aerial shoot. Stem elongation and reproductive transition are tightly linked in the aerial shoots, but are uncoupled in the rhizome. Our findings indicate that developmental programs operate independently in the rhizomes and aerial shoots. Temporal modification of the developmental pathways that are common to rhizomes and aerial shoots may be the source of developmental plasticity. Furthermore, the creation of new developmental systems appears to be necessary for rhizome development. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Climbing plants in a temperate rainforest understorey: searching for high light or coping with deep shade?

PubMed

Valladares, Fernando; Gianoli, Ernesto; Saldaña, Alfredo

2011-08-01

While the climbing habit allows vines to reach well-lit canopy areas with a minimum investment in support biomass, many of them have to survive under the dim understorey light during certain stages of their life cycle. But, if the growth/survival trade-off widely reported for trees hold for climbing plants, they cannot maximize both light-interception efficiency and shade avoidance (i.e. escaping from the understorey). The seven most important woody climbers occurring in a Chilean temperate evergreen rainforest were studied with the hypothesis that light-capture efficiency of climbers would be positively associated with their abundance in the understorey. Species abundance in the understorey was quantified from their relative frequency and density in field plots, the light environment was quantified by hemispherical photography, the photosynthetic response to light was measured with portable gas-exchange analyser, and the whole shoot light-interception efficiency and carbon gain was estimated with the 3-D computer model Y-plant. Species differed in specific leaf area, leaf mass fraction, above ground leaf area ratio, light-interception efficiency and potential carbon gain. Abundance of species in the understorey was related to whole shoot features but not to leaf level features such as specific leaf area. Potential carbon gain was inversely related to light-interception efficiency. Mutual shading among leaves within a shoot was very low (<20 %). The abundance of climbing plants in this southern rainforest understorey was directly related to their capacity to intercept light efficiently but not to their potential carbon gain. The most abundant climbers in this ecosystem match well with a shade-tolerance syndrome in contrast to the pioneer-like nature of climbers observed in tropical studies. The climbers studied seem to sacrifice high-light searching for coping with the dim understorey light.

Phosphate Solubilization Potential and Phosphatase Activity Of Rhizospheric Trichoderma Spp.

PubMed Central

Anil, Kapri; Lakshmi, Tewari

2010-01-01

Trichoderma sp., a well known biological control agent against several phytopathogens, was tested for its phosphate (P) solubilizing potential. Fourteen strains of Trichoderma sp. were isolated from the forest tree rhizospheres of pinus, deodar, bamboo, guava and oak on Trichoderma selective medium. The isolates were tested for their in-vitro P-solubilizing potential using National Botanical Research Institute Phosphate (NBRIP) broth containing tricalcium phosphate (TCP) as the sole P source, and compared with a standard culture of T. harzianum. All the cultures were found to solubilize TCP but with varying potential. The isolate DRT-1 showed maximum amount of soluble phosphate (404.07 εg.ml-1), followed by the standard culture of T. harzianum (386.42 εg.ml-1) after 96 h of incubation at 30±10C. Extra-cellular acid and alkaline phosphatases of the fungus were induced only in the presence of insoluble phosphorus source (TCP). High extra-cellular alkaline phosphatase activity was recorded for the isolate DRT-1 (14.50 U.ml-1) followed by the standard culture (13.41 U.ml-1) at 72h. The cultures showed much lesser acid phosphatase activities. Under glasshouse conditions, Trichoderma sp. inoculation increased chickpea (Cicer arietinum) growth parameters including shoot length, root length, fresh and dry weight of shoot as well as roots, in P-deficient soil containing only bound phosphate (TCP). Shoot weight was increased by 23% and 33% by inoculation with the isolate DRT-1 in the soil amended with 100 and 200 mg TCP kg-1 soil, respectively, after 60 d of sowing. The study explores high P-solubilizing potential of Trichoderma sp., which can be exploited for the solubilization of fixed phosphates present in the soil, thereby enhancing soil fertility and plant growth. PMID:24031556

Conservative Decrease in Water Potential in Existing Leaves during New Leaf Expansion in Temperate and Tropical Evergreen Quercus Species

PubMed Central

Saito, Takami; Naiola, B. Paul; Terashima, Ichiro

2007-01-01

Background and Aims This study aimed at clarifying how the water potential gradient (ΔΨ) is maintained in the shoots of evergreen trees with expanding leaves, whose leaf water potentials at the turgor loss point (Ψtlp) are generally high. Materials The water relations were examined in current-year expanding (CEX) and 1-year-old (OLD) leaves on the same shoots in temperate (Osaka, Japan) and tropical (Bogor, Indonesia) areas. A temperate evergreen species, Quercus glauca growing in both sites, was compared with a temperate deciduous species, Q. serrata, in Osaka, and two tropical evergreen species, Q. gemelliflora and Q. subsericea, in Bogor. Key Results (1) In Osaka, the midday leaf water potential (Ψmidday) was slightly higher in OLD (−0·5 MPa) than in CEX leaves (−0·6 MPa), whereas Ψtlp was significantly lower in OLD (−2·9 MPa) than in CEX leaves (−1·0 MPa). In Bogor, Ψmidday was also higher in OLD leaves (−1·0 MPa) despite the low Ψtlp (−1·9 MPa), although stomatal conductance was not always low in OLD leaves. In the branch bearing CEX and OLD leaves, most of the hydraulic resistance (86 %) exists in the current-year branch, leading to differences in water supply between CEX and OLD leaves. The removal of buds just before breaking did not affect the high Ψmidday in OLD leaves after 1 month. Ψmidday in OLD leaves thus appears to be independent of that in CEX leaves. Conclusions The moderate decrease in Ψmidday in OLD leaves would contribute to maintenance of ΔΨ in the shoots during leaf expansion. PMID:17855379

Mechanisms of induced susceptibility to Diplodia tip blight in drought-stressed Austrian pine.

PubMed

Sherwood, Patrick; Villari, Caterina; Capretti, Paolo; Bonello, Pierluigi

2015-05-01

Plants experiencing drought stress are frequently more susceptible to pathogens, likely via alterations in physiology that create favorable conditions for pathogens. Common plant responses to drought include the production of reactive oxygen species (ROS) and the accumulation of free amino acids (AAs), particularly proline. These same phenomena also frequently occur during pathogenic attack. Therefore, drought-induced perturbations in AA and ROS metabolism could potentially contribute to the observed enhanced susceptibility. Furthermore, nitrogen (N) availability can influence AA accumulation and affect plant resistance, but its contributions to drought-induced susceptibility are largely unexplored. Here we show that drought induces accumulation of hydrogen peroxide (H2O2) in Austrian pine (Pinus nigra Arnold) shoots, but that shoot infection by the blight and canker pathogen Diplodia sapinea (Fr.) Fuckel leads to large reductions in H2O2 levels in droughted plants. In in vitro assays, H2O2 was toxic to D. sapinea, and the fungus responded to this oxidative stress by increasing catalase and peroxidase activities, resulting in substantial H2O2 degradation. Proline increased in response to drought and infection when examined independently, but unlike all other AAs, proline further increased in infected shoots of droughted trees. In the same tissues, the proline precursor, glutamate, decreased significantly. Proline was found to protect D. sapinea from H2O2 damage, while also serving as a preferred N source in vitro. Fertilization increased constitutive and drought-induced levels of some AAs, but did not affect plant resistance. A new model integrating interactions of proline and H2O2 metabolism with drought and fungal infection of plants is proposed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Host Genetics and Environment Drive Divergent Responses of Two Resource Sharing Gall-Formers on Norway Spruce: A Common Garden Analysis.

PubMed

Axelsson, E Petter; Iason, Glenn R; Julkunen-Tiitto, Riitta; Whitham, Thomas G

2015-01-01

A central issue in the field of community genetics is the expectation that trait variation among genotypes play a defining role in structuring associated species and in forming community phenotypes. Quantifying the existence of such community phenotypes in two common garden environments also has important consequences for our understanding of gene-by-environment interactions at the community level. The existence of community phenotypes has not been evaluated in the crowns of boreal forest trees. In this study we address the influence of tree genetics on needle chemistry and genetic x environment interactions on two gall-inducing adelgid aphids (Adelges spp. and Sacchiphantes spp.) that share the same elongating bud/shoot niche. We examine the hypothesis that the canopies of different genotypes of Norway spruce (Picea abies L.) support different community phenotypes. Three patterns emerged. First, the two gallers show clear differences in their response to host genetics and environment. Whereas genetics significantly affected the abundance of Adelges spp. galls, Sacchiphantes spp. was predominately affected by the environment suggesting that the genetic influence is stronger in Adelges spp. Second, the among family variation in genetically controlled resistance was large, i.e. fullsib families differed as much as 10 fold in susceptibility towards Adelges spp. (0.57 to 6.2 galls/branch). Also, the distribution of chemical profiles was continuous, showing both overlap as well as examples of significant differences among fullsib families. Third, despite the predicted effects of host chemistry on galls, principal component analyses using 31 different phenolic substances showed only limited association with galls and a similarity test showed that trees with similar phenolic chemical characteristics, did not host more similar communities of gallers. Nonetheless, the large genetic variation in trait expression and clear differences in how community members respond to host genetics supports our hypothesis that the canopies of Norway spruce differ in their community phenotypes.

Biolistic transformation of Carrizo citrange (Citrus sinensis Osb. × Poncirus trifoliata L. Raf.).

PubMed

Wu, Hao; Acanda, Yosvanis; Jia, Hongge; Wang, Nian; Zale, Janice

2016-09-01

The development of transgenic citrus plants by the biolistic method. A protocol for the biolistic transformation of epicotyl explants and transgenic shoot regeneration of immature citrange rootstock, cv. Carrizo (Citrus sinensis Osb. × Poncirus trifoliata L. Raf.) and plant regeneration is described. Immature epicotyl explants were bombarded with a vector containing the nptII selectable marker and the gfp reporter. The number of independent, stably transformed tissues/total number of explants, recorded by monitoring GFP fluorescence 4 weeks after bombardment was substantial at 18.4 %, and some fluorescing tissues regenerated into shoots. Fluorescing GFP, putative transgenic shoots were micro-grafted onto immature Carrizo rootstocks in vitro, confirmed by PCR amplification of nptII and gfp coding regions, followed by secondary grafting onto older rootstocks grown in soil. Southern blot analysis indicated that all the fluorescing shoots were transgenic. Multiple and single copies of nptII integrations were confirmed in five regenerated transgenic lines. There is potential to develop a higher throughput biolistics transformation system by optimizing the tissue culture medium to improve shoot regeneration and narrowing the window for plant sampling. This system will be appropriate for transformation with minimal cassettes.