Comparison of supercritical fluid extraction and ultrasound-assisted extraction of fatty acids from quince (Cydonia oblonga Miller) seed using response surface methodology and central composite design.

PubMed

Daneshvand, Behnaz; Ara, Katayoun Mahdavi; Raofie, Farhad

2012-08-24

Fatty acids of Cydonia oblonga Miller cultivated in Iran were obtained by supercritical (carbon dioxide) extraction and ultrasound-assisted extraction methods. The oils were analyzed by capillary gas chromatography using mass spectrometric detections. The compounds were identified according to their retention indices and mass spectra (EI, 70eV). The experimental parameters of SFE such as pressure, temperature, modifier volume, static and dynamic extraction time were optimized using a Central Composite Design (CCD) after a 2(5) factorial design. Pressure and dynamic extraction time had significant effect on the extraction yield, while the other factors (temperature, static extraction time and modifier volume) were not identified as significant factors under the selected conditions. The results of chemometrics analysis showed the highest yield for SFE (24.32%), which was obtained at a pressure of 353bar, temperature of 35°C, modifier (methanol) volume of 150μL, and static and dynamic extraction times of 10 and 60min, respectively. Ultrasound-assisted extraction (UAE) of Fatty acids from C. oblonga Miller was optimized, using a rotatable central composite design. The optimum conditions were as follows: solvent (n-hexane) volume, 22mL; extraction time, 30min; and extraction temperature, 55°C. This resulted in a maximum oil recovery of 19.5%. The extracts with higher yield from both methods were subjected to transesterification and GC-MS analysis. The results show that the oil obtained by SFE with the optimal operating conditions allowed a fatty acid composition similar to the oil obtained by UAE in optimum condition and no significant differences were found. The major components of oil extract were Linoleic, Palmitic, Oleic, Stearic and Eicosanoic acids. Copyright © 2012 Elsevier B.V. All rights reserved.

Root restriction: A tool for improving volume utilization efficiency in bioregenerative life-support systems

NASA Astrophysics Data System (ADS)

Graham, Thomas; Wheeler, Raymond

2016-06-01

The objective of this study was to evaluate root restriction as a tool to increase volume utilization efficiency in spaceflight crop production systems. Bell pepper plants (Capsicum annuum cv. California Wonder) were grown under restricted rooting volume conditions in controlled environment chambers. The rooting volume was restricted to 500 ml and 60 ml in a preliminary trial, and 1500 ml (large), 500 ml (medium), and 250 ml (small) for a full fruiting trial. To reduce the possible confounding effects of water and nutrient restrictions, care was taken to ensure an even and consistent soil moisture throughout the study, with plants being watered/fertilized several times daily with a low concentration soluble fertilizer solution. Root restriction resulted in a general reduction in biomass production, height, leaf area, and transpiration rate; however, the fruit production was not significantly reduced in the root restricted plants under the employed environmental and horticultural conditions. There was a 21% reduction in total height and a 23% reduction in overall crown diameter between the large and small pot size in the fruiting study. Data from the fruiting trial were used to estimate potential volume utilization efficiency improvements for edible biomass in a fixed production volume. For fixed lighting and rooting hardware situations, the majority of improvement from root restriction was in the reduction of canopy area per plant, while height reductions could also improve volume utilization efficiency in high stacked or vertical agricultural systems.

Large Root Cortical Cell Size Improves Drought Tolerance in Maize1[C][W][OPEN

PubMed Central

Chimungu, Joseph G.; Brown, Kathleen M.

2014-01-01

The objective of this study was to test the hypothesis that large cortical cell size (CCS) would improve drought tolerance by reducing root metabolic costs. Maize (Zea mays) lines contrasting in root CCS measured as cross-sectional area were grown under well-watered and water-stressed conditions in greenhouse mesocosms and in the field in the United States and Malawi. CCS varied among genotypes, ranging from 101 to 533 µm2. In mesocosms, large CCS reduced respiration per unit of root length by 59%. Under water stress in mesocosms, lines with large CCS had between 21% and 27% deeper rooting (depth above which 95% of total root length is located in the soil profile), 50% greater stomatal conductance, 59% greater leaf CO2 assimilation, and between 34% and 44% greater shoot biomass than lines with small CCS. Under water stress in the field, lines with large CCS had between 32% and 41% deeper rooting (depth above which 95% of total root length is located in the soil profile), 32% lighter stem water isotopic ratio of 18O to 16O signature, signifying deeper water capture, between 22% and 30% greater leaf relative water content, between 51% and 100% greater shoot biomass at flowering, and between 99% and 145% greater yield than lines with small cells. Our results are consistent with the hypothesis that large CCS improves drought tolerance by reducing the metabolic cost of soil exploration, enabling deeper soil exploration, greater water acquisition, and improved growth and yield under water stress. These results, coupled with the substantial genetic variation for CCS in diverse maize germplasm, suggest that CCS merits attention as a potential breeding target to improve the drought tolerance of maize and possibly other cereal crops. PMID:25293960

Root restriction: A tool for improving volume utilization efficiency in bioregenerative life-support systems.

PubMed

Graham, Thomas; Wheeler, Raymond

2016-06-01

The objective of this study was to evaluate root restriction as a tool to increase volume utilization efficiency in spaceflight crop production systems. Bell pepper plants (Capsicum annuum cv. California Wonder) were grown under restricted rooting volume conditions in controlled environment chambers. The rooting volume was restricted to 500ml and 60ml in a preliminary trial, and 1500ml (large), 500ml (medium), and 250ml (small) for a full fruiting trial. To reduce the possible confounding effects of water and nutrient restrictions, care was taken to ensure an even and consistent soil moisture throughout the study, with plants being watered/fertilized several times daily with a low concentration soluble fertilizer solution. Root restriction resulted in a general reduction in biomass production, height, leaf area, and transpiration rate; however, the fruit production was not significantly reduced in the root restricted plants under the employed environmental and horticultural conditions. There was a 21% reduction in total height and a 23% reduction in overall crown diameter between the large and small pot size in the fruiting study. Data from the fruiting trial were used to estimate potential volume utilization efficiency improvements for edible biomass in a fixed production volume. For fixed lighting and rooting hardware situations, the majority of improvement from root restriction was in the reduction of canopy area per plant, while height reductions could also improve volume utilization efficiency in high stacked or vertical agricultural systems. Copyright © 2016 The Committee on Space Research (COSPAR). All rights reserved.

Dark exposure of petunia cuttings strongly improves adventitious root formation and enhances carbohydrate availability during rooting in the light.

PubMed

Klopotek, Yvonne; Haensch, Klaus-Thomas; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

2010-05-01

The effect of temporary dark exposure on adventitious root formation (ARF) in Petuniaxhybrida 'Mitchell' cuttings was investigated. Histological and metabolic changes in the cuttings during the dark treatment and subsequent rooting in the light were recorded. Excised cuttings were exposed to the dark for seven days at 10 degrees C followed by a nine-day rooting period in perlite or were rooted immediately for 16 days in a climate chamber at 22/20 degrees C (day/night) and a photosynthetic photon flux density (PPFD) of 100micromolm(-2)s(-1). Dark exposure prior to rooting increased, accelerated and synchronized ARF. The rooting period was reduced from 16 days (non-treated cuttings) to 9 days (treated cuttings). Under optimum conditions, despite the reduced rooting period, dark-exposed cuttings produced a higher number and length of roots than non-treated cuttings. An increase in temperature to 20 degrees C during the dark treatment or extending the cold dark exposure to 14 days caused a similar enhancement of root development compared to non-treated cuttings. Root meristem formation had already started during the dark treatment and was enhanced during the subsequent rooting period. Levels of soluble sugars (glucose, fructose and sucrose) and starch in leaf and basal stem tissues significantly decreased during the seven days of dark exposure. This depletion was, however, compensated during rooting after 6 and 24h for soluble sugars in leaves and the basal stem, respectively, whereas the sucrose level in the basal stem was already increased at 6h. The association of higher carbohydrate levels with improved rooting in previously dark-exposed versus non-treated cuttings indicates that increased post-darkness carbohydrate availability and allocation towards the stem base contribute to ARF under the influence of dark treatment and provide energy for cell growth subject to a rising sink intensity in the base of the cutting. Copyright 2009 Elsevier GmbH. All rights reserved.

Maximizing root/rhizosphere efficiency to improve crop productivity and nutrient use efficiency in intensive agriculture of China.

PubMed

Shen, Jianbo; Li, Chunjian; Mi, Guohua; Li, Long; Yuan, Lixing; Jiang, Rongfeng; Zhang, Fusuo

2013-03-01

Root and rhizosphere research has been conducted for many decades, but the underlying strategy of root/rhizosphere processes and management in intensive cropping systems remain largely to be determined. Improved grain production to meet the food demand of an increasing population has been highly dependent on chemical fertilizer input based on the traditionally assumed notion of 'high input, high output', which results in overuse of fertilizers but ignores the biological potential of roots or rhizosphere for efficient mobilization and acquisition of soil nutrients. Root exploration in soil nutrient resources and root-induced rhizosphere processes plays an important role in controlling nutrient transformation, efficient nutrient acquisition and use, and thus crop productivity. The efficiency of root/rhizosphere in terms of improved nutrient mobilization, acquisition, and use can be fully exploited by: (1) manipulating root growth (i.e. root development and size, root system architecture, and distribution); (2) regulating rhizosphere processes (i.e. rhizosphere acidification, organic anion and acid phosphatase exudation, localized application of nutrients, rhizosphere interactions, and use of efficient crop genotypes); and (3) optimizing root zone management to synchronize root growth and soil nutrient supply with demand of nutrients in cropping systems. Experiments have shown that root/rhizosphere management is an effective approach to increase both nutrient use efficiency and crop productivity for sustainable crop production. The objectives of this paper are to summarize the principles of root/rhizosphere management and provide an overview of some successful case studies on how to exploit the biological potential of root system and rhizosphere processes to improve crop productivity and nutrient use efficiency.

Improved Root Normal Size Distributions for Liquid Atomization

DTIC Science & Technology

2015-11-01

Jackson, Primary Breakup of Round Aerated- Liquid Jets in Supersonic Crossflows, Atomization and Sprays, 16(6), 657-672, 2006 H. C. Simmons, The...Breakup in Liquid - Gas Mixing Layers, Atomization and Sprays, 1, 421-440, 1991 P.-K. Wu, L.-K. Tseng, and G. M. Faeth, Primary Breakup in Gas / Liquid ...Improved Root Normal Size Distributions for Liquid Atomization Distribution Statement A. Approved for public release; distribution is unlimited

Semiconductor laser irradiation improves root canal sealing during routine root canal therapy

PubMed Central

Hu, Xingxue; Wang, Dashan; Cui, Ting; Yao, Ruyong

2017-01-01

Objective To evaluate the effect of semiconductor laser irradiation on root canal sealing after routine root canal therapy (RCT). Methods Sixty freshly extracted single-rooted human teeth were randomly divided into six groups (n = 10). The anatomic crowns were sectioned at the cementoenamel junction and the remaining roots were prepared endodontically with conventional RCT methods. Groups A and B were irradiated with semiconductor laser at 1W for 20 seconds; Groups C and D were ultrasonically rinsed for 60 seconds as positive control groups; Groups E and F without treatment of root canal prior to RCT as negative control groups. Root canal sealing of Groups A, C and E were evaluated by measurements of apical microleakage. The teeth from Groups B, D and F were sectioned, and the micro-structures were examined with scanning electron microscopy (SEM). One way ANOVA and LSD-t test were used for statistical analysis (α = .05). Results The apical sealing of both the laser irradiated group and the ultrasonic irrigated group were significantly different from the control group (p<0.5). There was no significant difference between the laser irradiated group and the ultrasonic irrigated group (p>0.5). SEM observation showed that most of the dentinal tubules in the laser irradiation group melted, narrowed or closed, while most of the dentinal tubules in the ultrasonic irrigation group were filled with tooth paste. Conclusion The application of semiconductor laser prior to root canal obturation increases the apical sealing of the roots treated. PMID:28957407

Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability.

PubMed

Zhang, Haoqiang; Liu, Zhenkun; Chen, Hui; Tang, Ming

2016-01-01

Robinia pseudoacacia L. (black locust) is a widely planted tree species on Loess Plateau for revegetation. Due to its symbiosis forming capability with arbuscular mycorrhizal (AM) fungi, we explored the influence of arbuscular mycorrhizal fungi on plant biomass, root morphology, root tensile strength and soil aggregate stability in a pot experiment. We inoculated R. pseudoacacia with/without AM fungus (Rhizophagus irregularis or Glomus versiforme), and measured root colonization, plant growth, root morphological characters, root tensile force and tensile strength, and parameters for soil aggregate stability at twelve weeks after inoculation. AM fungi colonized more than 70% plant root, significantly improved plant growth. Meanwhile, AM fungi elevated root morphological parameters, root tensile force, root tensile strength, Glomalin-related soil protein (GRSP) content in soil, and parameters for soil aggregate stability such as water stable aggregate (WSA), mean weight diameter (MWD) and geometric mean diameter (GMD). Root length was highly correlated with WSA, MWD and GMD, while hyphae length was highly correlated with GRSP content. The improved R. pseudoacacia growth, root tensile strength and soil aggregate stability indicated that AM fungi could accelerate soil fixation and stabilization with R. pseudoacacia, and its function in revegetation on Loess Plateau deserves more attention.

Root Traits and Phenotyping Strategies for Plant Improvement

PubMed Central

Paez-Garcia, Ana; Motes, Christy M.; Scheible, Wolf-Rüdiger; Chen, Rujin; Blancaflor, Elison B.; Monteros, Maria J.

2015-01-01

Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics) and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs. PMID:27135332

Root Traits and Phenotyping Strategies for Plant Improvement.

PubMed

Paez-Garcia, Ana; Motes, Christy M; Scheible, Wolf-Rüdiger; Chen, Rujin; Blancaflor, Elison B; Monteros, Maria J

2015-06-15

Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics) and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs.

Root carboxylate exudation capacity under phosphorus stress does not improve grain yield in green gram.

PubMed

Pandey, Renu; Meena, Surendra Kumar; Krishnapriya, Vengavasi; Ahmad, Altaf; Kishora, Naval

2014-06-01

Genetic variability in carboxylate exudation capacity along with improved root traits was a key mechanism for P-efficient green gram genotype to cope with P-stress but it did not increase grain yield. This study evaluates genotypic variability in green gram for total root carbon exudation under low phosphorus (P) using (14)C and its relationship with root exuded carboxylates, growth and yield potential in contrasting genotypes. Forty-four genotypes grown hydroponically with low (2 μM) and sufficient (100 μM) P concentrations were exposed to (14)CO2 to screen for total root carbon exudation. Contrasting genotypes were employed to study carboxylate exudation and their performance in soil at two P levels. Based on relative (14)C exudation and biomass, genotypes were categorized. Carboxylic acids were measured in exudates and root apices of contrasting genotypes belonging to efficient and inefficient categories. Oxalic and citric acids were released into the medium under low-P. PDM-139 (efficient) was highly efficient in carboxylate exudation as compared to ML-818 (inefficient). In low soil P, the reduction in biomass was higher in ML-818 as compared to PDM-139. Total leaf area and photosynthetic rate averaged for genotypes increased by 71 and 41 %, respectively, with P fertilization. Significantly, higher root surface area and volume were observed in PDM-139 under low soil P. Though the grain yield was higher in ML-818, the total plant biomass was significantly higher in PDM-139 indicating improved P uptake and its efficient translation into biomass. The higher carboxylate exudation capacity and improved root traits in the later genotype might be the possible adaptive mechanisms to cope with P-stress. However, it is not necessary that higher root exudation would result in higher grain yield.

Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability

PubMed Central

Zhang, Haoqiang; Liu, Zhenkun; Chen, Hui; Tang, Ming

2016-01-01

Robinia pseudoacacia L. (black locust) is a widely planted tree species on Loess Plateau for revegetation. Due to its symbiosis forming capability with arbuscular mycorrhizal (AM) fungi, we explored the influence of arbuscular mycorrhizal fungi on plant biomass, root morphology, root tensile strength and soil aggregate stability in a pot experiment. We inoculated R. pseudoacacia with/without AM fungus (Rhizophagus irregularis or Glomus versiforme), and measured root colonization, plant growth, root morphological characters, root tensile force and tensile strength, and parameters for soil aggregate stability at twelve weeks after inoculation. AM fungi colonized more than 70% plant root, significantly improved plant growth. Meanwhile, AM fungi elevated root morphological parameters, root tensile force, root tensile strength, Glomalin-related soil protein (GRSP) content in soil, and parameters for soil aggregate stability such as water stable aggregate (WSA), mean weight diameter (MWD) and geometric mean diameter (GMD). Root length was highly correlated with WSA, MWD and GMD, while hyphae length was highly correlated with GRSP content. The improved R. pseudoacacia growth, root tensile strength and soil aggregate stability indicated that AM fungi could accelerate soil fixation and stabilization with R. pseudoacacia, and its function in revegetation on Loess Plateau deserves more attention. PMID:27064570

Overexpression of OsEXPA8, a Root-Specific Gene, Improves Rice Growth and Root System Architecture by Facilitating Cell Extension

PubMed Central

Ma, Nana; Wang, Ying; Qiu, Shichun; Kang, Zhenhui; Che, Shugang; Wang, Guixue; Huang, Junli

2013-01-01

Expansins are unique plant cell wall proteins that are involved in cell wall modifications underlying many plant developmental processes. In this work, we investigated the possible biological role of the root-specific α-expansin gene OsEXPA8 in rice growth and development by generating transgenic plants. Overexpression of OsEXPA8 in rice plants yielded pleiotropic phenotypes of improved root system architecture (longer primary roots, more lateral roots and root hairs), increased plant height, enhanced leaf number and enlarged leaf size. Further study indicated that the average cell length in both leaf and root vascular bundles was enhanced, and the cell growth in suspension cultures was increased, which revealed the cellular basis for OsEXPA8-mediated rice plant growth acceleration. Expansins are thought to be a key factor required for cell enlargement and wall loosening. Atomic force microscopy (AFM) technology revealed that average wall stiffness values for 35S::OsEXPA8 transgenic suspension-cultured cells decreased over six-fold compared to wild-type counterparts during different growth phases. Moreover, a prominent change in the wall polymer composition of suspension cells was observed, and Fourier-transform infrared (FTIR) spectra revealed a relative increase in the ratios of the polysaccharide/lignin content in cell wall compositions of OsEXPA8 overexpressors. These results support a role for expansins in cell expansion and plant growth. PMID:24124527

Integration and Improvement of Geophysical Root Biomass Measurements for Determining Carbon Credits

NASA Astrophysics Data System (ADS)

Boitet, J. I.

2013-12-01

Carbon trading schemes fundamentally rely on accurate subsurface carbon quantification in order for governing bodies to grant carbon credits inclusive of root biomass (What is Carbon Credit. 2013). Root biomass makes up a large chunk of the subsurface carbon and is difficult, labor intensive, and costly to measure. This paper stitches together the latest geophysical root measurement techniques into site-dependent recommendations for technique combinations and modifications that maximize large-scale root biomass measurement accuracy and efficiency. "Accuracy" is maximized when actual root biomass is closest to measured root biomass. "Efficiency" is maximized when time, labor, and cost of measurement is minimized. Several combinations have emerged which satisfy both criteria under different site conditions. Use of ground penetrating radar (GPR) and/or electrical resistivity tomography (ERT) allow for large tracts of land to be surveyed under appropriate conditions. Among other characteristics, GPR does best with detecting coarse roots in dry soil. ERT does best in detecting roots in moist soils, but is especially limited by electrode configuration (Mancuso, S. 2012). Integration of these two technologies into a baseline protocol based on site-specific characteristics, especially soil moisture and plants species heterogeneity, will drastically theoretically increase efficiency and accuracy of root biomass measurements. Modifications of current measurement protocols using these existing techniques will also theoretically lead to drastic improvements in both accuracy and efficiency. These modifications, such as efficient 3D imaging by adding an identical electrode array perpendicular to the first array used in the Pulled Array Continuous Electrical Profiling (PACEP) technique for ERT, should allow for more widespread application of these techniques for understanding root biomass. Where whole-site measurement is not feasible either due to financial, equipment, or

Reduced Root Cortical Cell File Number Improves Drought Tolerance in Maize1[C][W][OPEN

PubMed Central

Chimungu, Joseph G.; Brown, Kathleen M.

2014-01-01

We tested the hypothesis that reduced root cortical cell file number (CCFN) would improve drought tolerance in maize (Zea mays) by reducing the metabolic costs of soil exploration. Maize genotypes with contrasting CCFN were grown under well-watered and water-stressed conditions in greenhouse mesocosms and in the field in the United States and Malawi. CCFN ranged from six to 19 among maize genotypes. In mesocosms, reduced CCFN was correlated with 57% reduction of root respiration per unit of root length. Under water stress in the mesocosms, genotypes with reduced CCFN had between 15% and 60% deeper rooting, 78% greater stomatal conductance, 36% greater leaf CO2 assimilation, and between 52% to 139% greater shoot biomass than genotypes with many cell files. Under water stress in the field, genotypes with reduced CCFN had between 33% and 40% deeper rooting, 28% lighter stem water oxygen isotope enrichment (δ18O) signature signifying deeper water capture, between 10% and 35% greater leaf relative water content, between 35% and 70% greater shoot biomass at flowering, and between 33% and 114% greater yield than genotypes with many cell files. These results support the hypothesis that reduced CCFN improves drought tolerance by reducing the metabolic costs of soil exploration, enabling deeper soil exploration, greater water acquisition, and improved growth and yield under water stress. The large genetic variation for CCFN in maize germplasm suggests that CCFN merits attention as a breeding target to improve the drought tolerance of maize and possibly other cereal crops. PMID:25355868

Phenotyping: Using Machine Learning for Improved Pairwise Genotype Classification Based on Root Traits

PubMed Central

Zhao, Jiangsan; Bodner, Gernot; Rewald, Boris

2016-01-01

Phenotyping local crop cultivars is becoming more and more important, as they are an important genetic source for breeding – especially in regard to inherent root system architectures. Machine learning algorithms are promising tools to assist in the analysis of complex data sets; novel approaches are need to apply them on root phenotyping data of mature plants. A greenhouse experiment was conducted in large, sand-filled columns to differentiate 16 European Pisum sativum cultivars based on 36 manually derived root traits. Through combining random forest and support vector machine models, machine learning algorithms were successfully used for unbiased identification of most distinguishing root traits and subsequent pairwise cultivar differentiation. Up to 86% of pea cultivar pairs could be distinguished based on top five important root traits (Timp5) – Timp5 differed widely between cultivar pairs. Selecting top important root traits (Timp) provided a significant improved classification compared to using all available traits or randomly selected trait sets. The most frequent Timp of mature pea cultivars was total surface area of lateral roots originating from tap root segments at 0–5 cm depth. The high classification rate implies that culturing did not lead to a major loss of variability in root system architecture in the studied pea cultivars. Our results illustrate the potential of machine learning approaches for unbiased (root) trait selection and cultivar classification based on rather small, complex phenotypic data sets derived from pot experiments. Powerful statistical approaches are essential to make use of the increasing amount of (root) phenotyping information, integrating the complex trait sets describing crop cultivars. PMID:27999587

Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

USGS Publications Warehouse

McKee, K.L.

2001-01-01

1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

Ability of New Obturation Materials to Improve the Seal of the Root Canal System – A Review

PubMed Central

Zhang, Wei; Olsen, Mark; De-Deus, Gustavo; Eid, Ashraf A.; Chen, Ji-hua; Pashley, David H.; Tay, Franklin R.

2014-01-01

Objectives New obturation biomaterials have been introduced over the past decade to improve the seal of the root canal system. However, it is not clear whether they have really produced a three-dimensional impervious seal that is important for reducing diseases associated with root canal treatment. Methods A review of the literature was performed to identify models that have been employed for evaluating the seal of the root canal system. Results and Significance In-vitro and in-vivo models are not totally adept at quantifying the seal of root canals obturated with classic materials. Thus, one has to resort to clinical outcomes to examine whether there are real benefits associated with the use of recently-introduced materials for obturating root canals. However, there is no facile answer because endodontic treatment outcomes are influenced by a host of other predictors that are more likely to take precedence over the influence of obturation materials. From the perspective of clinical performance, classic root filling materials have stood the test of time. Because many of the recently-introduced materials are so new, there is not enough evidence yet to support their ability to improve clinical performance. This emphasizes the need to translate anecdotal information into clinically relevant research data on new biomaterials. PMID:24321349

Costus root granules improve ulcerative colitis through regulation of TGF-β mediation of the PI3K/AKT signaling pathway

PubMed Central

Wang, Xiaohong; Li, Dan; Zhang, Yong; Wu, Shuang; Tang, Fang

2018-01-01

Ulcerative colitis is a chronic nonspecific inflammatory disease that occurs in the colon and rectum. Costus root is a type of traditional Chinese medicine that exhibits antibacterial properties and serves an inhibitory role in the regeneration of gut bacteria. However, the molecular mechanisms underlying Costus root-mediated improvements in ulcerative colitis remain unclear. A complex formula of Costus root granules was created and investigated in the present study for its therapeutic effects in a rat model of ulcerative colitis. Ingredient dissolution into a traditional water decoction was used as a control. The potential mechanism mediated by Costus root granules was also analyzed in colonic epithelial cells isolated from the experimental rats. The results of the present study demonstrated that Costus root granule treatment inhibited inflammation in colonic tissue. Costus root granule treatment also suppressed the apoptosis of colonic epithelial cells isolated from the rat model of ulcerative colitis. Analyses of the underlying mechanisms of these effects indicated that the administration of Costus root granules increased transforming growth factor β expression, which activated the phosphoinositide 3-kinase/RAC-α serine/threonine-protein kinase signaling pathway in colonic epithelial cells. Notably, the administration of Costus root granules improved stomachache, diarrhea and hematochezia in and increased the body weight of, the ulcerative colitis rats. In conclusion, these results indicate that Costus root granules markedly ameliorate inflammation of the colonic epithelium, decrease the apoptosis of colonic epithelial cells and improve colonic function, which suggests that Costus root granules are an efficient agent for the treatment of ulcerative colitis. PMID:29731832

Characterization of Pearl Millet Root Architecture and Anatomy Reveals Three Types of Lateral Roots

PubMed Central

Passot, Sixtine; Gnacko, Fatoumata; Moukouanga, Daniel; Lucas, Mikaël; Guyomarc’h, Soazig; Ortega, Beatriz Moreno; Atkinson, Jonathan A.; Belko, Marème N.; Bennett, Malcolm J.; Gantet, Pascal; Wells, Darren M.; Guédon, Yann; Vigouroux, Yves; Verdeil, Jean-Luc; Muller, Bertrand; Laplaze, Laurent

2016-01-01

Pearl millet plays an important role for food security in arid regions of Africa and India. Nevertheless, it is considered an orphan crop as it lags far behind other cereals in terms of genetic improvement efforts. Breeding pearl millet varieties with improved root traits promises to deliver benefits in water and nutrient acquisition. Here, we characterize early pearl millet root system development using several different root phenotyping approaches that include rhizotrons and microCT. We report that early stage pearl millet root system development is characterized by a fast growing primary root that quickly colonizes deeper soil horizons. We also describe root anatomical studies that revealed three distinct types of lateral roots that form on both primary roots and crown roots. Finally, we detected significant variation for two root architectural traits, primary root lenght and lateral root density, in pearl millet inbred lines. This study provides the basis for subsequent genetic experiments to identify loci associated with interesting early root development traits in this important cereal. PMID:27379124

Root-endophytes improve the ecophysiological performance and production of an agricultural species under drought condition

PubMed Central

Molina-Montenegro, Marco A.; Oses, Rómulo; Torres-Díaz, Cristian; Atala, Cristian; Zurita-Silva, Andrés; Ruiz-Lara, Simón

2016-01-01

Throughout many regions of the world, climate change has limited the availability of water for irrigating crops. Indeed, current models of climate change predict that arid and semi-arid zones will be places where precipitation will drastically decrease. In this context, plant root-associated fungi appear as a new strategy to improve ecophysiological performance and yield of crops under abiotic stress. Thus, use of fungal endophytes from ecosystems currently subjected to severe drought conditions could improve the ecophysiological performance and quantum yield of crops exposed to drought. In this study, we evaluated how the inoculation of fungal endophytes isolated from Antarctic plants can improve the net photosynthesis, water use efficiency and production of fresh biomass in a lettuce cultivar, grown under different water availability regimes. In addition, we assessed if the presence of biochemical mechanisms and gene expression related with environmental tolerance are improved in presence of fungal endophytes. Overall, those individuals with presence of endophytes showed higher net photosynthesis and maintained higher water use efficiency in drought conditions, which was correlated with greater fresh and dry biomass production as well as greater root system development. In addition, presence of fungal endophytes was correlated with a higher proline concentration, lower peroxidation of lipids and up-/down-regulation of ion homeostasis. Our results suggest that presence of fungal endophytes could minimize the negative effect of drought by improving drought tolerance through biochemical mechanisms and improving nutritional status. Thus, root-endophytes might be a successful biotechnological tool to maintain high levels of ecophysiological performance and productivity in zones under drought. PMID:27613875

Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions.

PubMed

Uga, Yusaku; Sugimoto, Kazuhiko; Ogawa, Satoshi; Rane, Jagadish; Ishitani, Manabu; Hara, Naho; Kitomi, Yuka; Inukai, Yoshiaki; Ono, Kazuko; Kanno, Noriko; Inoue, Haruhiko; Takehisa, Hinako; Motoyama, Ritsuko; Nagamura, Yoshiaki; Wu, Jianzhong; Matsumoto, Takashi; Takai, Toshiyuki; Okuno, Kazutoshi; Yano, Masahiro

2013-09-01

The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops.

Building a better foundation: improving root-trait measurements to understand and model plant and ecosystem processes

DOE PAGES

McCormack, M. Luke; Guo, Dali; Iversen, Colleen M.; ...

2017-03-13

Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine roots and other plant organs is limited. Here we discuss three underappreciated areas where focused measurements of fine-root traits can make significant contributions to ecosystem science. These include assessment of spatiotemporal variation in fine-root traits, integration of mycorrhizal fungi into fine-root-trait frameworks, and the need for improved scaling of traits measured on individual rootsmore » to ecosystem-level processes. Progress in each of these areas is providing opportunities to revisit how below-ground processes are represented in terrestrial biosphere models. Targeted measurements of fine-root traits with clear linkages to ecosystem processes and plant responses to environmental change are strongly needed to reduce empirical and model uncertainties. Further identifying how and when suites of root and whole-plant traits are coordinated or decoupled will ultimately provide a powerful tool for modeling plant form and function at local and global scales.« less

Building a better foundation: improving root-trait measurements to understand and model plant and ecosystem processes

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

McCormack, M. Luke; Guo, Dali; Iversen, Colleen M.

Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine roots and other plant organs is limited. Here we discuss three underappreciated areas where focused measurements of fine-root traits can make significant contributions to ecosystem science. These include assessment of spatiotemporal variation in fine-root traits, integration of mycorrhizal fungi into fine-root-trait frameworks, and the need for improved scaling of traits measured on individual rootsmore » to ecosystem-level processes. Progress in each of these areas is providing opportunities to revisit how below-ground processes are represented in terrestrial biosphere models. Targeted measurements of fine-root traits with clear linkages to ecosystem processes and plant responses to environmental change are strongly needed to reduce empirical and model uncertainties. Further identifying how and when suites of root and whole-plant traits are coordinated or decoupled will ultimately provide a powerful tool for modeling plant form and function at local and global scales.« less

Root xylem plasticity to improve water use and yield in water-stressed soybean

PubMed Central

Prince, Silvas J.; Murphy, Mackensie; Durnell, Lorellin A.; Shannon, J. Grover

2017-01-01

Abstract We tested the hypothesis that increasing the number of metaxylem vessels would enhance the efficiency of water uptake in soybean (Glycine max) and decrease the yield gap in water-limited environments. A panel of 41 soybean accessions was evaluated in greenhouse, rainout shelter, and rain-fed field environments. The metaxylem number influenced the internal capture of CO2 and improved stomatal conductance, enhancing water uptake/use in soybeans exposed to stress during the reproductive stage. We determined that other root anatomical features, such as cortex cell area and the percentage of stele that comprised cortical cells, also affected seed yield under similar growth parameters. Seed yield was also impacted by pod retention rates under drought stress (24–80 pods/plant). We surmise that effective biomass allocation, that is, the transport of available photosynthates to floral structures at late reproductive growth stages (R6–R7), enables yield protection under drought stress. A mesocosm study of contrasting lines for yield under drought stress and root anatomical features revealed that increases in metaxylem number as an adaptation to drought in the high-yielding lines improved root hydraulic conductivity, which reduced the metabolic cost of exploring water in deeper soil strata and enhanced water transport. This allowed the maintenance of shoot physiological processes under water-limited conditions. PMID:28064176

Improved rooting of western white pine shoots from tissue cultures

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

Amerson, H.V.; Mott, R.L.

1982-01-01

Adventitious shoots of Pinus monticola obtained from embryonic tissue were exposed to 4 combinations of growth regulators (6-benzylaminopurine/NAA/IAA/IBA), either continuously for 6 weeks or by pulse treatment for 7 days, followed by 5 weeks culture without growth regulators. After 6 weeks of continuous exposure, rooting of shoots varied between 0 and 20%. Pulse treatment resulted in 40-64% rooting. In paired comparisons pulse treatments always provided better rooting percentages than did constant exposure treatments. Pulse treatments also produced longer (less than 2 mm) roots and more multiple roots.

Mixed artificial grasslands with more roots improved mine soil infiltration capacity

NASA Astrophysics Data System (ADS)

Wu, Gao-Lin; Yang, Zheng; Cui, Zeng; Liu, Yu; Fang, Nu-Fang; Shi, Zhi-Hua

2016-04-01

Soil water is one of the critical limiting factors in achieving sustainable revegetation. Soil infiltration capacity plays a vital role in determining the inputs from precipitation and enhancing water storage, which are important for the maintenance and survival of vegetation patches in arid and semi-arid areas. Our study investigated the effects of different artificial grasslands on soil physical properties and soil infiltration capacity. The artificial grasslands were Medicago sativa, Astragalus adsurgens, Agropyron mongolicum, Lespedeza davurica, Bromus inermis, Hedysarum scoparium, A. mongolicum + Artemisia desertorum, A. adsurgens + A. desertorum and M. sativa + B. inermis. The soil infiltration capacity index (SICI), which was based on the average infiltration rate of stage I (AIRSI) and the average infiltration rate of stage III (AIRS III), was higher (indicating that the infiltration capacity was greater) under the artificial grasslands than that of the bare soil. The SICI of the A. adsurgens + A. desertorum grassland had the highest value (1.48) and bare soil (-0.59) had the lowest value. It was evident that artificial grassland could improve soil infiltration capacity. We also used principal component analysis (PCA) to determine that the main factors that affected SICI were the soil water content at a depth of 20 cm (SWC20), the below-ground root biomasses at depths of 10 and 30 cm (BGB10, BGB30), the capillary porosity at a depth of 10 cm (CP10) and the non-capillary porosity at a depth of 20 cm (NCP20). Our study suggests that the use of Legume-poaceae mixtures and Legume-shrub mixtures to create grasslands provided an effective ecological restoration approach to improve soil infiltration properties due to their greater root biomasses. Furthermore, soil water content, below-ground root biomass, soil capillary porosity and soil non-capillary porosity were the main factors that affect the soil infiltration capacity.

Monitoring cotton root rot by synthetic Sentinel-2 NDVI time series using improved spatial and temporal data fusion

USDA-ARS?s Scientific Manuscript database

Airborne imagery has been successfully used for mapping cotton root rot within cotton fields toward the end of the growing season. To better understand the progression of cotton root rot within the season, time series monitoring is required. In this study, an improved spatial and temporal data fusio...

Clinical audit training improves undergraduates' performance in root canal therapy.

PubMed

Fong, J Y M; Tan, V J H; Lee, J R; Tong, Z G M; Foong, Y K; Tan, J M E; Parolia, A; Pau, A

2017-12-20

To evaluate the effectiveness of clinical audit-feedback cycle as an educational tool in improving the technical quality of root canal therapy (RCT) and compliance with record keeping performed by dental undergraduates. Clinical audit learning was introduced in Year 3 of a 5-year curriculum for dental undergraduates. During classroom activities, students were briefed on clinical audit, selected their audit topics in groups of 5 or 6 students, and prepared and presented their audit protocols. One chosen topic was RCT, in which 3 different cohorts of Year 3 students conducted retrospective audits of patients' records in 2012, 2014 and 2015 for their compliance with recommended record keeping criteria and their performance in RCT. Students were trained by and calibrated against an endodontist (κ ≥ 0.8). After each audit, the findings were reported in class, and recommendations were made for improvement in performance of RCT and record keeping. Students' compliance with published guidelines was presented and their RCT performances in each year were compared using the chi-square test. Overall compliance with of record keeping guidelines was 44.1% in 2012, 79.6% in 2014 and 94.6% in 2015 (P = .001). In the 2012 audit, acceptable extension, condensation and the absence of mishap were observed in 72.4, 75.7% and 91.5%; in the 2014 audit, 95.1%, 64.8% and 51.4%; and in 2015 audit, 96.4%, 82.1% and 92.8% of cases, respectively. In 2015, 76.8% of root canal fillings met all 3 technical quality criteria when compared to 48.6% in 2014 and 44.7% in 2012 (P = .001). Clinical audit-feedback cycle is an effective educational tool for improving dental undergraduates' compliance with record keeping and performance in the technical quality of RCT. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Vitamin e supplementation with rauwolfia vomitoria root bark extract improves hematological indices.

PubMed

Isaiah, Akpanabiatu Monday; Olawale, Otitoju; Effiong, Edet Emmanuel; Idongesit, Ndem Jessie; Fidelis, Uwah Anthony; Friday, Ufot Usenobong

2012-02-01

Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and impact significantly on hematology of albino Wistar rats. In this investigation we studied vitamin E supplementation with Rauwolfia vomitoria root bark extract on the hematology of experimental animals. Forty two rats weighing 200 - 230 g were randomly selected into six groups of seven animals each. Group 1 animals serve as controls; group 2 received vitamin E (10 IU/kg body weight). Groups 3 and 4 were given the extract (150 and 300 mg/kg body weight) respectively. Groups 5 and 6 were given vitamin E (10 IU/kg body weight), the extract (150 and 300 mg/kg body weight) respectively. The extract and the vitamin were administered daily by oral intubation. Blood samples analyzed for hematological indices. Decrease in white blood cell count (WBC) was observed, indicating improved immunity of animals. Extract at 150 and 300 mg/kg body weight with and without vitamin E affected hemoglobin and packed cell volume. Rauwolfia vomitoria with or without vitamin E improved animal's immunity and enhances their hematology. Interaction of vitamin E with the extract affects medicinal therapeutics of this plant.

Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

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

Ghimire, Bardan; Riley, William J.; Koven, Charles D.

In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis ratesmore » are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO 2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.« less

Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

DOE PAGES

Ghimire, Bardan; Riley, William J.; Koven, Charles D.; ...

2016-05-01

In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis ratesmore » are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO 2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.« less

Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

NASA Astrophysics Data System (ADS)

Ghimire, Bardan; Riley, William J.; Koven, Charles D.; Mu, Mingquan; Randerson, James T.

2016-06-01

In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis rates are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.

New insights to lateral rooting: Differential responses to heterogeneous nitrogen availability among maize root types

PubMed Central

Yu, Peng; White, Philip J; Li, Chunjian

2015-01-01

Historical domestication and the "Green revolution" have both contributed to the evolution of modern, high-performance crops. Together with increased irrigation and application of chemical fertilizers, these efforts have generated sufficient food for the growing global population. Root architecture, and in particular root branching, plays an important role in the acquisition of water and nutrients, plant performance, and crop yield. Better understanding of root growth and responses to the belowground environment could contribute to overcoming the challenges faced by agriculture today. Manipulating the abilities of crop root systems to explore and exploit the soil environment could enable plants to make the most of soil resources, increase stress tolerance and improve grain yields, while simultaneously reducing environmental degradation. In this article it is noted that the control of root branching, and the responses of root architecture to nitrate availability, differ between root types and between plant species. Since the control of root branching depends upon both plant species and root type, further work is urgently required to determine the appropriate genes to manipulate to improve resource acquisition by specific crops. PMID:26443081

New insights to lateral rooting: Differential responses to heterogeneous nitrogen availability among maize root types.

PubMed

Yu, Peng; White, Philip J; Li, Chunjian

2015-01-01

Historical domestication and the "Green revolution" have both contributed to the evolution of modern, high-performance crops. Together with increased irrigation and application of chemical fertilizers, these efforts have generated sufficient food for the growing global population. Root architecture, and in particular root branching, plays an important role in the acquisition of water and nutrients, plant performance, and crop yield. Better understanding of root growth and responses to the belowground environment could contribute to overcoming the challenges faced by agriculture today. Manipulating the abilities of crop root systems to explore and exploit the soil environment could enable plants to make the most of soil resources, increase stress tolerance and improve grain yields, while simultaneously reducing environmental degradation. In this article it is noted that the control of root branching, and the responses of root architecture to nitrate availability, differ between root types and between plant species. Since the control of root branching depends upon both plant species and root type, further work is urgently required to determine the appropriate genes to manipulate to improve resource acquisition by specific crops.

Improving student critical thinking skills through a root cause analysis pilot project.

PubMed

Tschannen, Dana; Aebersold, Michelle

2010-08-01

The Essentials of Baccalaureate Education for Professional Nursing Practice provides a framework for building the baccalaureate education for the twenty-first century. One of the exemplars included in the essentials toolkit includes student participation in an actual root cause analysis (RCA) or failure mode effects analysis. To align with this exemplar, faculty at the University of Michigan School of Nursing developed a pilot RCA project for the senior-level Leadership and Management course. While working collaboratively with faculty and unit liaisons at the University Health System, students completed an RCA on a nursing sensitive indicator (pain assessment or plan of care compliance). An overview of the pilot project, including the implementation process, is described. Each team of students identified root causes and recommendations for improvement on clinical and documentation practice within the context of the unit. Feedback from both the unit liaisons and the students confirmed the pilot's success.

Vitamin E Supplementation with Rauwolfia Vomitoria Root Bark Extract Improves Hematological Indices

PubMed Central

Isaiah, Akpanabiatu Monday; Olawale, Otitoju; Effiong, Edet Emmanuel; Idongesit, Ndem Jessie; Fidelis, Uwah Anthony; Friday, Ufot Usenobong

2012-01-01

Background: Vitamin supplementation in Rauwolfia vomitoria root bark extract administration may interact and impact significantly on hematology of albino Wistar rats. Aim: In this investigation we studied vitamin E supplementation with Rauwolfia vomitoria root bark extract on the hematology of experimental animals. Materials and Methods: Forty two rats weighing 200 – 230 g were randomly selected into six groups of seven animals each. Group 1 animals serve as controls; group 2 received vitamin E (10 IU/kg body weight). Groups 3 and 4 were given the extract (150 and 300 mg/kg body weight) respectively. Groups 5 and 6 were given vitamin E (10 IU/kg body weight), the extract (150 and 300 mg/kg body weight) respectively. The extract and the vitamin were administered daily by oral intubation. Blood samples analyzed for hematological indices. Results: Decrease in white blood cell count (WBC) was observed, indicating improved immunity of animals. Extract at 150 and 300 mg/kg body weight with and without vitamin E affected hemoglobin and packed cell volume. Conclusion: Rauwolfia vomitoria with or without vitamin E improved animal's immunity and enhances their hematology. Interaction of vitamin E with the extract affects medicinal therapeutics of this plant. PMID:22408754

Continuous chelation irrigation improves the adhesion of epoxy resin-based root canal sealer to root dentine.

PubMed

Neelakantan, P; Varughese, A A; Sharma, S; Subbarao, C V; Zehnder, M; De-Deus, G

2012-12-01

To test the impact of continuous chelation by NaOCl+ etidronic acid (HEBP) during instrumentation, and a final rinse of EDTA or NaOCl + HEBP on the dentine bond strength of an epoxy resin sealer (AH Plus). Single-rooted teeth (n = 100) were divided into five groups (n = 20) based on the irrigation protocol and their root canals instrumented using a rotary Ni-Ti system: 2.5% NaOCl during instrumentation followed by bi-distilled water (G1) or 17% EDTA (G2) as final rinse; 1 : 1 mixture of 5% NaOCl and 18% HEBP during instrumentation, and the same mixture (G3), 17% EDTA (G4) or bi-distilled water (G5) as final rinse. Canals were filled with AH Plus. Roots were sectioned, and push-out tests were performed in coronal, middle and apical root thirds. Results were analysed using analysis of variance (anova) and Bonferroni test for multiple comparisons. The alpha-type error was set at 0.05 for all the analyses. Push-out bond strength was highest in coronal and lowest in apical root thirds (P < 0.05). Groups that used NaOCl + HEBP irrigation during instrumentation had significantly higher bond strengths than groups following the NaOCl-EDTA irrigation in all root thirds (P < 0.05). The use of a strong chelator as final flush further increased bond strengths (G4, P < 0.05). The continuous chelation irrigation protocol optimizes the bond strength of an epoxy resin sealer to dentine. © 2012 International Endodontic Journal.

Compensatory Root Water Uptake of Overlapping Root Systems

NASA Astrophysics Data System (ADS)

Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

2015-12-01

Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

Effect of Root Moisture Content and Diameter on Root Tensile Properties.

PubMed

Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

2016-01-01

The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation.

Effect of Root Moisture Content and Diameter on Root Tensile Properties

PubMed Central

Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

2016-01-01

The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

Application of a single root-scale model to improve macroscopic modeling of root water uptake: focus on osmotic stress

NASA Astrophysics Data System (ADS)

Jorda, Helena; Perelman, Adi; Lazarovitch, Naftali; Vanderborght, Jan

2017-04-01

Root water uptake is a fundamental process in the hydrological cycle and it largely regulates the water balance in the soil vadose zone. Macroscopic stress functions are currently used to estimate the effect of salinity on root water uptake. These functions commonly assume stress to be a function of bulk salinity and of the plant sensitivity to osmotic stress expressed as the salinity at which transpiration is reduced by half or so called tolerance value. However, they fail to integrate additional relevant factors such as atmospheric conditions or root architectural traits. We conducted a comprehensive simulation study on a single root using a 3-D physically-based model that resolves flow and transport to individual root segments and that couples flow in the soil and root system. The effect of salt concentrations on root water uptake was accounted for by including osmotic water potential gradients between the solution at the soil root interface and the root xylem sap in the hydraulic gradient between the soil and root. A large set of factors were studied, namely, potential transpiration rate and dynamics, root length density (RLD), irrigation water quality and irrigation frequency, and leaching fraction. Results were fitted to the macroscopic function developed by van Genuchten and Hoffman (1984) and the dependency of osmotic stress and the fitted macroscopic parameters on the studied factors was evaluated. Osmotic stress was found to be highly dependent on RLD. Low RLDs result in a larger stress to the plant due to high evaporative demand per root length unit. In addition, osmotic stress was positively correlated to potential transpiration rate, and sinusoidal potential transpiration lead to larger stress than when imposed as a constant boundary condition. Macroscopic parameters are usually computed as single values for each crop and used for the entire growing season. However, our study shows that both tolerance value and shape parameter p from the van Genuchten

Root architecture impacts on root decomposition rates in switchgrass

NASA Astrophysics Data System (ADS)

de Graaff, M.; Schadt, C.; Garten, C. T.; Jastrow, J. D.; Phillips, J.; Wullschleger, S. D.

2010-12-01

of plants was -12‰, enabling us to differentiate between root-derived C and native SOM-C respiration. We found that the relative abundance of fine, medium and coarse roots were significantly different among cultivars. Root systems of Alamo, Kanlow and Cave-in-Rock were characterized by a large abundance of coarse-, relative to fine roots, whereas Carthage, Forestburg and Blackwell had a large abundance of fine, relative to coarse roots. Fine roots had a 28% lower C:N ratio than medium and coarse roots. These differences led to different root decomposition rates. We conclude that root architecture should be taken into account when predicting root decomposition rates; enhanced understanding of the mechanisms of root decomposition will improve model predictions of C input to soil organic matter.

Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids.

PubMed

Nichols, S N; Hofmann, R W; Williams, W M; van Koten, C

2016-05-20

Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC 1 ) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Two white clover cultivars, two T. uniflorum accessions and two BC 1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100-200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC 1 than 'Crusader'. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50-100 mm deep than the other entries, and more of its fine root mass at 400-500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400-500 mm than most entries, and a smaller decrease in root length density with depth. These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids

PubMed Central

Nichols, S. N.; Hofmann, R. W.; Williams, W. M.; van Koten, C.

2016-01-01

Background and aims Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC1) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Methods Two white clover cultivars, two T. uniflorum accessions and two BC1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Key Results Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100–200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC1 than ‘Crusader’. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50–100 mm deep than the other entries, and more of its fine root mass at 400–500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400–500 mm than most entries, and a smaller decrease in root length density with depth. Conclusions These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. PMID:27208735

Longleaf Pine Root System Development and Seedling Quality in Response to Copper Root Pruning and Cavity Size

Treesearch

Mary Anne Sword Sayer; Shi-Jean Susana Sung; James D. Haywood

2011-01-01

Cultural practices that modify root system structure in the plug of container-grown seedlings have the potential to improve root system function after planting. Our objective was to assess how copper root pruning affects the quality and root system development of longleaf pine seedlings grown in three cavity sizes in a greenhouse. Copper root pruning increased seedling...

Contrasting responses of root morphology and root-exuded organic acids to low phosphorus availability in three important food crops with divergent root traits.

PubMed

Wang, Yan-Liang; Almvik, Marit; Clarke, Nicholas; Eich-Greatorex, Susanne; Øgaard, Anne Falk; Krogstad, Tore; Lambers, Hans; Clarke, Jihong Liu

2015-08-17

Phosphorus (P) is an important element for crop productivity and is widely applied in fertilizers. Most P fertilizers applied to land are sorbed onto soil particles, so research on improving plant uptake of less easily available P is important. In the current study, we investigated the responses in root morphology and root-exuded organic acids (OAs) to low available P (1 μM P) and sufficient P (50 μM P) in barley, canola and micropropagated seedlings of potato-three important food crops with divergent root traits, using a hydroponic plant growth system. We hypothesized that the dicots canola and tuber-producing potato and the monocot barley would respond differently under various P availabilities. WinRHIZO and liquid chromatography triple quadrupole mass spectrometry results suggested that under low P availability, canola developed longer roots and exhibited the fastest root exudation rate for citric acid. Barley showed a reduction in root length and root surface area and an increase in root-exuded malic acid under low-P conditions. Potato exuded relatively small amounts of OAs under low P, while there was a marked increase in root tips. Based on the results, we conclude that different crops show divergent morphological and physiological responses to low P availability, having evolved specific traits of root morphology and root exudation that enhance their P-uptake capacity under low-P conditions. These results could underpin future efforts to improve P uptake of the three crops that are of importance for future sustainable crop production. Published by Oxford University Press on behalf of the Annals of Botany Company.

Matching roots to their environment

PubMed Central

White, Philip J.; George, Timothy S.; Gregory, Peter J.; Bengough, A. Glyn; Hallett, Paul D.; McKenzie, Blair M.

2013-01-01

Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future. PMID:23821619

Searching for plant root traits to improve soil cohesion and resist soil erosion

NASA Astrophysics Data System (ADS)

De Baets, Sarah; Smyth, Kevin; Denbigh, Tom; Weldon, Laura; Higgins, Ben; Matyjaszkiewicz, Antoni; Meersmans, Jeroen; Chenchiah, Isaac; Liverpool, Tannie; Quine, Tim; Grierson, Claire

2017-04-01

Soil erosion poses a serious threat to future food and environmental security. Soil erosion protection measures are therefore of great importance for soil conservation and food security. Plant roots have proven to be very effective in stabilizing the soil and protecting the soil against erosion. However, no clear insights are yet obtained into the root traits that are responsible for root-soil cohesion. This is important in order to better select the best species for soil protection. Research using Arabidopsis mutants has made great progress towards explaining how root systems are generated by growth, branching, and responses to gravity, producing mutants that affect root traits. In this study, the performance of selected Arabidopsis mutants is analyzed in three root-soil cohesion assays. Measurements of detachment, uprooting force and soil detachment are here combined with the microscopic analysis of root properties, such as the presence, length and density of root hairs in this case. We found that Arabidopsis seedlings with root hairs (wild type, wer myb23, rsl4) were more difficult to detach from gel media than hairless (cpc try) or short haired (rsl4, rhd2) roots. Hairy roots (wild type, wer myb23) on mature, non-reproductive rosettes were more difficult to uproot from compost or clay soil than hairless roots (cpc try). At high root densities, erosion rates from soils with hairless roots (cpc try) were as much as 10 times those seen from soils occupied by roots with hairs (wer myb23, wild type). We find therefore root hairs play a significant role in root-soil cohesion and in minimizing erosion. This framework and associated suite of experimental assays demonstrates its ability to measure the effect of any root phenotype on the effectiveness of plant roots in binding substrates and reducing erosion.

Synaptic plasticity and sensory-motor improvement following fibrin sealant dorsal root reimplantation and mononuclear cell therapy

PubMed Central

Benitez, Suzana U.; Barbizan, Roberta; Spejo, Aline B.; Ferreira, Rui S.; Barraviera, Benedito; Góes, Alfredo M.; de Oliveira, Alexandre L. R.

2014-01-01

Root lesions may affect both dorsal and ventral roots. However, due to the possibility of generating further inflammation and neuropathic pain, surgical procedures do not prioritize the repair of the afferent component. The loss of such sensorial input directly disturbs the spinal circuits thus affecting the functionality of the injuried limb. The present study evaluated the motor and sensory improvement following dorsal root reimplantation with fibrin sealant (FS) plus bone marrow mononuclear cells (MC) after dorsal rhizotomy. MC were used to enhance the repair process. We also analyzed changes in the glial response and synaptic circuits within the spinal cord. Female Lewis rats (6–8 weeks old) were divided in three groups: rhizotomy (RZ group), rhizotomy repaired with FS (RZ+FS group) and rhizotomy repaired with FS and MC (RZ+FS+MC group). The behavioral tests electronic von-Frey and Walking track test were carried out. For immunohistochemistry we used markers to detect different synapse profiles as well as glial reaction. The behavioral results showed a significant decrease in sensory and motor function after lesion. The reimplantation decreased glial reaction and improved synaptic plasticity of afferent inputs. Cell therapy further enhanced the rewiring process. In addition, both reimplanted groups presented twice as much motor control compared to the non-treated group. In conclusion, the reimplantation with FS and MC is efficient and may be considered an approach to improve sensory-motor recovery following dorsal rhizotomy. PMID:25249946

Root Gravitropism: Quantification, Challenges, and Solutions.

PubMed

Muller, Lukas; Bennett, Malcolm J; French, Andy; Wells, Darren M; Swarup, Ranjan

2018-01-01

Better understanding of root traits such as root angle and root gravitropism will be crucial for development of crops with improved resource use efficiency. This chapter describes a high-throughput, automated image analysis method to trace Arabidopsis (Arabidopsis thaliana) seedling roots grown on agar plates. The method combines a "particle-filtering algorithm with a graph-based method" to trace the center line of a root and can be adopted for the analysis of several root parameters such as length, curvature, and stimulus from original root traces.

QTL mapping of root traits in phosphorus-deficient soils reveals important genomic regions for improving NDVI and grain yield in barley.

PubMed

Gong, Xue; McDonald, Glenn

2017-09-01

Major QTLs for root rhizosheath size are not correlated with grain yield or yield response to phosphorus. Important QTLs were found to improve phosphorus efficiency. Root traits are important for phosphorus (P) acquisition, but they are often difficult to characterize and their breeding values are seldom assessed under field conditions. This has shed doubts on using seedling-based criteria of root traits to select and breed for P efficiency. Eight root traits were assessed under controlled conditions in a barley doubled-haploid population in soils differing in P levels. The population was also phenotyped for grain yield, normalized difference vegetation index (NDVI), grain P uptake and P utilization efficiency at maturity (PutE GY ) under field conditions. Several quantitative traits loci (QTLs) from the root screening and the field trials were co-incident. QTLs for root rhizosheath size and root diameter explained the highest phenotypic variation in comparison to QTLs for other root traits. Shared QTLs were found between root diameter and grain yield, and total root length and PutE GY . A common major QTL for rhizosheath size and NDVI was mapped to the HvMATE gene marker on chromosome 4H. Collocations between major QTLs for NDVI and grain yield were detected on chromosomes 6H and 7H. When results from BIP and MET were combined, QTLs detected for grain yield were also those QTLs found for NDVI. QTLs qGY5H, qGY6H and qGY7Hb on 7H were robust QTLs in improving P efficiency. A selection of multiple loci may be needed to optimize the breeding outcomes due to the QTL x Environment interaction. We suggest that rhizosheath size alone is not a reliable trait to predict P efficiency or grain yield.

Fine Mapping of QUICK ROOTING 1 and 2, Quantitative Trait Loci Increasing Root Length in Rice.

PubMed

Kitomi, Yuka; Nakao, Emari; Kawai, Sawako; Kanno, Noriko; Ando, Tsuyu; Fukuoka, Shuichi; Irie, Kenji; Uga, Yusaku

2018-02-02

The volume that the root system can occupy is associated with the efficiency of water and nutrient uptake from soil. Genetic improvement of root length, which is a limiting factor for root distribution, is necessary for increasing crop production. In this report, we describe identification of two quantitative trait loci (QTLs) for maximal root length, QUICK ROOTING 1 ( QRO1 ) on chromosome 2 and QRO2 on chromosome 6, in cultivated rice ( Oryza sativa L.). We measured the maximal root length in 26 lines carrying chromosome segments from the long-rooted upland rice cultivar Kinandang Patong in the genetic background of the short-rooted lowland cultivar IR64. Five lines had longer roots than IR64. By rough mapping of the target regions in BC 4 F 2 populations, we detected putative QTLs for maximal root length on chromosomes 2, 6, and 8. To fine-map these QTLs, we used BC 4 F 3 recombinant homozygous lines. QRO1 was mapped between markers RM5651 and RM6107, which delimit a 1.7-Mb interval on chromosome 2, and QRO2 was mapped between markers RM20495 and RM3430-1, which delimit an 884-kb interval on chromosome 6. Both QTLs may be promising gene resources for improving root system architecture in rice. Copyright © 2018 Kitomi et al.

Foraging strategies in trees of different root morphology: the role of root lifespan.

PubMed

Adams, Thomas S; McCormack, M Luke; Eissenstat, David M

2013-09-01

Resource exploitation of patches is influenced not simply by the rate of root production in the patches but also by the lifespan of the roots inhabiting the patches. We examined the effect of sustained localized nitrogen (N) fertilization on root lifespan in four tree species that varied widely in root morphology and presumed foraging strategy. The study was conducted in a 12-year-old common garden in central Pennsylvania using a combination of data from minirhizotron and root in-growth cores. The two fine-root tree species, Acer negundo L. and Populus tremuloides Michx., exhibited significant increases in root lifespan with local N fertilization; no significant responses were observed in the two coarse-root tree species, Sassafras albidum Nutt. and Liriodendron tulipifera L. Across species, coarse-root tree species had longer median root lifespan than fine-root tree species. Localized N fertilization did not significantly increase the N concentration or the respiration of the roots growing in the N-rich patch. Our results suggest that some plant species appear to regulate the lifespan of different portions of their root system to improve resource acquisition while other species do not. Our results are discussed in the context of different strategies of foraging of nutrient patches in species of different root morphology.

Root System Architecture and Abiotic Stress Tolerance: Current Knowledge in Root and Tuber Crops

PubMed Central

Khan, M. A.; Gemenet, Dorcus C.; Villordon, Arthur

2016-01-01

The challenge to produce more food for a rising global population on diminishing agricultural land is complicated by the effects of climate change on agricultural productivity. Although great progress has been made in crop improvement, so far most efforts have targeted above-ground traits. Roots are essential for plant adaptation and productivity, but are less studied due to the difficulty of observing them during the plant life cycle. Root system architecture (RSA), made up of structural features like root length, spread, number, and length of lateral roots, among others, exhibits great plasticity in response to environmental changes, and could be critical to developing crops with more efficient roots. Much of the research on root traits has thus far focused on the most common cereal crops and model plants. As cereal yields have reached their yield potential in some regions, understanding their root system may help overcome these plateaus. However, root and tuber crops (RTCs) such as potato, sweetpotato, cassava, and yam may hold more potential for providing food security in the future, and knowledge of their root system additionally focuses directly on the edible portion. Root-trait modeling for multiple stress scenarios, together with high-throughput phenotyping and genotyping techniques, robust databases, and data analytical pipelines, may provide a valuable base for a truly inclusive ‘green revolution.’ In the current review, we discuss RSA with special reference to RTCs, and how knowledge on genetics of RSA can be manipulated to improve their tolerance to abiotic stresses. PMID:27847508

An analysis of root cause identification and continuous quality improvement in public health H1N1 after-action reports.

PubMed

Singleton, Christa-Marie; Debastiani, Summer; Rose, Dale; Kahn, Emily B

2014-01-01

To identify the extent to which the Homeland Security Exercise and Evaluation Program's (HSEEP) After Action Report/Improvement Plan (AAR/IP) template was followed by public health entities and facilitated the identification of detailed corrective actions and continuous improvement. Data were drawn from the US H1N1 Public Health Emergency Response (PHER) federal grant awardees (n = 62). After action report/improvement plan text was examined to identify the presence of AAR/IP HSEEP elements and characterized as "minimally complete," "partially complete," or "complete." Corrective actions (CA) and recommendations within the IP focusing on performance deficits were coded as specific, measurable, and time-bound, and whether they were associated with a problem that met root cause criteria and whether the CA/recommendation was intended to address or fix the root cause. A total of 2619 CA/recommendations were identified. More than half (n = 1480, 57%) addressed root causes. Corrective actions/recommendations associated with complete AARs more frequently addressed root cause (58% vs 51%, χ = 9.1, P < 0.003) and were more specific (34% vs 23%, χ = 32.3, P < 0.0001), measurable (30% vs 18%, χ = 37.9, P < 0.0001), and time-bound (38% vs 15%, χ = 115.5, P < 0.0001) than partially complete AARs. The same pattern was not observed with completeness of IPs. Corrective actions and recommendations were similarly specific and measurable. Recommendations significantly addressed root cause more than CAs. Our analysis indicates a possible lack of awardee distinction between CA and recommendations in AARs. As HSEEP adapts to align with the 2011 National Preparedness Goal and National Preparedness System, future HSEEP documents should emphasize the importance of root cause analysis as a required element within AAR documents and templates in the exercise and real incident environment, as well as the need for specific and measurable CAs.

Traits and selection strategies to improve root systems and water uptake in water-limited wheat crops.

PubMed

Wasson, A P; Richards, R A; Chatrath, R; Misra, S C; Prasad, S V Sai; Rebetzke, G J; Kirkegaard, J A; Christopher, J; Watt, M

2012-05-01

resistances. Such a programme with field and laboratory evaluation at the outset will speed up delivery of varieties with improved root systems for higher yield.

Valve sparing aortic replacement - root remodeling.

PubMed

Lausberg, Henning F; Schäfers, Hans-Joachim

2006-01-01

Aortic root remodeling restores aortic root geometry and improves valve competence. We have used this technique whenever aorto-ventricular diameter is preserved. The operative technique is detained in this presentation. As a result of our 10-year experience with root remodeling we propose this operation as a reproducible option for patients with dilatation of the aortic root.

Indigenous species barcode database improves the identification of zooplankton

PubMed Central

Yang, Jianghua; Zhang, Wanwan; Sun, Jingying; Xie, Yuwei; Zhang, Yimin; Burton, G. Allen; Yu, Hongxia

2017-01-01

Incompleteness and inaccuracy of DNA barcode databases is considered an important hindrance to the use of metabarcoding in biodiversity analysis of zooplankton at the species-level. Species barcoding by Sanger sequencing is inefficient for organisms with small body sizes, such as zooplankton. Here mitochondrial cytochrome c oxidase I (COI) fragment barcodes from 910 freshwater zooplankton specimens (87 morphospecies) were recovered by a high-throughput sequencing platform, Ion Torrent PGM. Intraspecific divergence of most zooplanktons was < 5%, except Branchionus leydign (Rotifer, 14.3%), Trichocerca elongate (Rotifer, 11.5%), Lecane bulla (Rotifer, 15.9%), Synchaeta oblonga (Rotifer, 5.95%) and Schmackeria forbesi (Copepod, 6.5%). Metabarcoding data of 28 environmental samples from Lake Tai were annotated by both an indigenous database and NCBI Genbank database. The indigenous database improved the taxonomic assignment of metabarcoding of zooplankton. Most zooplankton (81%) with barcode sequences in the indigenous database were identified by metabarcoding monitoring. Furthermore, the frequency and distribution of zooplankton were also consistent between metabarcoding and morphology identification. Overall, the indigenous database improved the taxonomic assignment of zooplankton. PMID:28977035

Implementing Dynamic Root Optimization in Noah-MP for Simulating Phreatophytic Root Water Uptake

NASA Astrophysics Data System (ADS)

Wang, Ping; Niu, Guo-Yue; Fang, Yuan-Hao; Wu, Run-Jian; Yu, Jing-Jie; Yuan, Guo-Fu; Pozdniakov, Sergey P.; Scott, Russell L.

2018-03-01

Widely distributed in arid and semiarid regions, phreatophytic roots extend into the saturated zone and extract water directly from groundwater. In this paper, we implemented a vegetation optimality model of root dynamics (VOM-ROOT) in the Noah land surface model with multiparameterization options (Noah-MP LSM) to model the extraction of groundwater through phreatophytic roots at a riparian site with a hyperarid climate (with precipitation of 35 mm/yr) in northwestern China. VOM-ROOT numerically describes the natural optimization of the root profile in response to changes in subsurface water conditions. The coupled Noah-MP/VOM-ROOT model substantially improves the simulation of surface energy and water fluxes, particularly during the growing season, compared to the prescribed static root profile in the default Noah-MP. In the coupled model, more roots are required to grow into the saturated zone to meet transpiration demand when the groundwater level declines over the growing season. The modeling results indicate that at the study site, the modeled annual transpiration is 472 mm, accounting for 92.3% of the total evapotranspiration. Direct root water uptake from the capillary fringe and groundwater, which is supplied by lateral groundwater flow, accounts for approximately 84% of the total transpiration. This study demonstrates the importance of implementing a dynamic root scheme in a land surface model for adequately simulating phreatophytic root water uptake and the associated latent heat flux.

Resistance to compression of weakened roots subjected to different root reconstruction protocols

PubMed Central

ZOGHEIB, Lucas Villaça; SAAVEDRA, Guilherme de Siqueira Ferreira Anzaloni; CARDOSO, Paula Elaine; VALERA, Márcia Carneiro; de ARAÚJO, Maria Amélia Máximo

2011-01-01

Objective This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45º in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (α=0.05). Results Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol. PMID:22231002

Genomic regions responsible for seminal and crown root lengths identified by 2D & 3D root system image analysis.

PubMed

Uga, Yusaku; Assaranurak, Ithipong; Kitomi, Yuka; Larson, Brandon G; Craft, Eric J; Shaff, Jon E; McCouch, Susan R; Kochian, Leon V

2018-04-20

Genetic improvement of root system architecture is a promising approach for improved uptake of water and mineral nutrients distributed unevenly in the soil. To identify genomic regions associated with the length of different root types in rice, we quantified root system architecture in a set of 26 chromosome segment substitution lines derived from a cross between lowland indica rice, IR64, and upland tropical japonica rice, Kinandang Patong, (IK-CSSLs), using 2D & 3D root phenotyping platforms. Lengths of seminal and crown roots in the IK-CSSLs grown under hydroponic conditions were measured by 2D image analysis (RootReader2D). Twelve CSSLs showed significantly longer seminal root length than the recurrent parent IR64. Of these, 8 CSSLs also exhibited longer total length of the three longest crown roots compared to IR64. Three-dimensional image analysis (RootReader3D) for these CSSLs grown in gellan gum revealed that only one CSSL, SL1003, showed significantly longer total root length than IR64. To characterize the root morphology of SL1003 under soil conditions, SL1003 was grown in Turface, a soil-like growth media, and roots were quantified using RootReader3D. SL1003 had larger total root length and increased total crown root length than did IR64, although its seminal root length was similar to that of IR64. The larger TRL in SL1003 may be due to increased crown root length. SL1003 carries an introgression from Kinandang Patong on the long arm of chromosome 1 in the genetic background of IR64. We conclude that this region harbors a QTL controlling crown root elongation.

Preliminary Investigation of Several Root Designs for Cermet Turbine Blades in Turbojet Engine III : Curved-root Design

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin; Deutsch, George C; Morgan, William C

1955-01-01

Stresses om tje root fastenings of turbine blades were appreciably reduced by redesign of the root. The redesign consisted in curving the root to approximately conform to the camber of the airfoil and elimination of the blade platform. Full-scale jet-engine tests at rated speed using cermet blades of the design confirmed the improvement.

GiA Roots: software for the high throughput analysis of plant root system architecture.

PubMed

Galkovskyi, Taras; Mileyko, Yuriy; Bucksch, Alexander; Moore, Brad; Symonova, Olga; Price, Charles A; Topp, Christopher N; Iyer-Pascuzzi, Anjali S; Zurek, Paul R; Fang, Suqin; Harer, John; Benfey, Philip N; Weitz, Joshua S

2012-07-26

Characterizing root system architecture (RSA) is essential to understanding the development and function of vascular plants. Identifying RSA-associated genes also represents an underexplored opportunity for crop improvement. Software tools are needed to accelerate the pace at which quantitative traits of RSA are estimated from images of root networks. We have developed GiA Roots (General Image Analysis of Roots), a semi-automated software tool designed specifically for the high-throughput analysis of root system images. GiA Roots includes user-assisted algorithms to distinguish root from background and a fully automated pipeline that extracts dozens of root system phenotypes. Quantitative information on each phenotype, along with intermediate steps for full reproducibility, is returned to the end-user for downstream analysis. GiA Roots has a GUI front end and a command-line interface for interweaving the software into large-scale workflows. GiA Roots can also be extended to estimate novel phenotypes specified by the end-user. We demonstrate the use of GiA Roots on a set of 2393 images of rice roots representing 12 genotypes from the species Oryza sativa. We validate trait measurements against prior analyses of this image set that demonstrated that RSA traits are likely heritable and associated with genotypic differences. Moreover, we demonstrate that GiA Roots is extensible and an end-user can add functionality so that GiA Roots can estimate novel RSA traits. In summary, we show that the software can function as an efficient tool as part of a workflow to move from large numbers of root images to downstream analysis.

Quince (Cydonia oblonga Miller) peel polyphenols modulate LPS-induced inflammation in human THP-1-derived macrophages through NF-{kappa}B, p38MAPK and Akt inhibition

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

Essafi-Benkhadir, Khadija; Refai, Amira; Riahi, Ichrak

Highlights: Black-Right-Pointing-Pointer Quince peel polyphenols inhibit LPS-induced secretion of TNF-{alpha} and IL-8. Black-Right-Pointing-Pointer Quince peel polyphenols augment LPS-induced secretion of IL-10 and IL-6. Black-Right-Pointing-Pointer Quince peel polyphenols-mediated inhibition of LPS-induced secretion of TNF-{alpha} is partially mediated by IL-6. Black-Right-Pointing-Pointer The anti-inflammatory effects of quince polyphenols pass through NF-{kappa}B, p38MAPK and Akt inhibition. -- Abstract: Chronic inflammation is a hallmark of several pathologies, such as rheumatoid arthritis, gastritis, inflammatory bowel disease, atherosclerosis and cancer. A wide range of anti-inflammatory chemicals have been used to treat such diseases while presenting high toxicity and numerous side effects. Here, we report the anti-inflammatory effectmore » of a non-toxic, cost-effective natural agent, polyphenolic extract from the Tunisian quince Cydonia oblonga Miller. Lipopolysaccharide (LPS) treatment of human THP-1-derived macrophages induced the secretion of high levels of the pro-inflammatory cytokine TNF-{alpha} and the chemokine IL-8, which was inhibited by quince peel polyphenolic extract in a dose-dependent manner. Concomitantly, quince polyphenols enhanced the level of the anti-inflammatory cytokine IL-10 secreted by LPS-treated macrophages. We further demonstrated that the unexpected increase in IL-6 secretion that occurred when quince polyphenols were associated with LPS treatment was partially responsible for the polyphenols-mediated inhibition of TNF-{alpha} secretion. Biochemical analysis showed that quince polyphenols extract inhibited the LPS-mediated activation of three major cellular pro-inflammatory effectors, nuclear factor-kappa B (NF-{kappa}B), p38MAPK and Akt. Overall, our data indicate that quince peel polyphenolic extract induces a potent anti-inflammatory effect that may prove useful for the treatment of inflammatory diseases and that a quince

Fine-Root Production in an Amazon Rain Forest: Deep Roots are an Important Component of Net Primary Productivity

NASA Astrophysics Data System (ADS)

Norby, R.; Cordeiro, A. L.; Oblitas, E.; Valverde-Barrantes, O.; Quesada, C. A.

2017-12-01

Fine-root production is a significant component of net primary production (NPP), but it is the most difficult of the major components to measure. Data on fine-root production are especially sparse from tropical forests, and therefore the estimates of tropical forest NPP may not be accurate. Many estimates of fine-root production are based on observations in the top 15 or 30 cm of soil, with the implicit assumption that this approach will capture most of the root distribution. We measured fine-root production in a 30-m tall, old-growth, terra firme rain forest near Manaus, Brazil, which is the site for a free-air CO2 enrichment (FACE) experiment. Ten minirhizotrons were installed at a 45 degree angle to a depth of 1.1 meters; the tubes were installed 2 years before any measurements were made to allow the root systems to recover from disturbance. Images were collected biweekly, and measurements of root length per area of minirhizotron window were scaled up to grams of root per unit land area. Scaling up minirhizotron measurments is problematic, but our estimate of fine-root standing crop in the top 15 cm of soil (281 ± 37 g dry matter m-2) compares well with a direct measurement of fine roots in two nearby 15-cm soil cores (290 ± 37 g m-2). Although the largest fraction of the fine-root standing crop was in the upper soil horizons, 44% of the fine-root mass was deeper than 30 cm, and 17% was deeper than 60 cm. Annual fine-root production was 934 ± 234 g dry matter m-2 (453 ± 113 g C m-2), which was 35% of estimated NPP of the forest stand (1281 g C m-2). A previous estimate of NPP of the forest at this site was smaller (1010 g m-2), but that estimate relied on fine-root production measured elsewhere and only in the top 10 or 30 cm of soil; fine roots accounted for 21% of NPP in that analysis. Extending root observations deeper into the soil will improve estimates of the contribution of fine-root production to NPP, which will in turn improve estimates of ecosystem

Hydraulic conductivity of soil-grown lupine and maize unbranched roots and maize root-shoot junctions.

PubMed

Meunier, Félicien; Zarebanadkouki, Mohsen; Ahmed, Mutez A; Carminati, Andrea; Couvreur, Valentin; Javaux, Mathieu

2018-01-26

Improving or maintaining crop productivity under conditions of long term change of soil water availability and atmosphere demand for water is one the big challenges of this century. It requires a deep understanding of crop water acquisition properties, i.e. root system architecture and root hydraulic properties among other characteristics of the soil-plant-atmosphere continuum. A root pressure probe technique was used to measure the root hydraulic conductances of seven-week old maize and lupine plants grown in sandy soil. Unbranched root segments were excised in lateral, seminal, crown and brace roots of maize, and in lateral roots of lupine. Their total hydraulic conductance was quantified under steady-state hydrostatic gradient for progressively shorter segments. Furthermore, the axial conductance of proximal root regions removed at each step of root shortening was measured as well. Analytical solutions of the water flow equations in unbranched roots developed recently and relating root total conductance profiles to axial and radial conductivities were used to retrieve the root radial hydraulic conductivity profile along each root type, and quantify its uncertainty. Interestingly, the optimized root radial conductivities and measured axial conductances displayed significant differences across root types and species. However, the measured root total conductances did not differ significantly. As compared to measurements reported in the literature, our axial and radial conductivities concentrate in the lower range of herbaceous species hydraulic properties. In a final experiment, the hydraulic conductances of root junctions to maize stem were observed to highly depend on root type. Surprisingly maize brace root junctions were an order of magnitude more conductive than the other crown and seminal roots, suggesting potential regulation mechanism for root water uptake location and a potential role of the maize brace roots for water uptake more important than reported

Root gravitropism in maize and Arabidopsis

NASA Technical Reports Server (NTRS)

Evans, Michael L.

1993-01-01

Research during the period 1 March 1992 to 30 November 1993 focused on improvements in a video digitizer system designed to automate the recording of surface extension in plants responding to gravistimulation. The improvements included modification of software to allow detailed analysis of localized extension patterns in roots of Arabidopsis. We used the system to analyze the role of the postmitotic isodiametric growth zone (a region between the meristem and the elongation zone) in the response of maize roots to auxin, calcium, touch and gravity. We also used the system to analyze short-term auxin and gravitropic responses in mutants of Arabidopsis with reduced auxin sensitivity. In a related project, we studied the relationship between growth rate and surface electrical currents in roots by examining the effects of gravity and thigmostimulation on surface potentials in maize roots.

Coupling root architecture and pore network modeling - an attempt towards better understanding root-soil interactions

NASA Astrophysics Data System (ADS)

Leitner, Daniel; Bodner, Gernot; Raoof, Amir

2013-04-01

, but also improve the description of the rooting environment. Until now there have been no attempts to couple root architecture and pore network models. In our work we present a first attempt to join both types of models using the root architecture model of Leitner et al., (2010) and a pore network model presented by Raoof et al. (2010). The two main objectives of coupling both models are: (i) Representing the effect of root induced biopores on flow and transport processes: For this purpose a fixed root architecture created by the root model is superimposed as a secondary root induced pore network to the primary soil network, thus influencing the final pore topology in the network generation. (ii) Representing the influence of pre-existing pores on root branching: Using a given network of (rigid) pores, the root architecture model allocates its root axes into these preexisting pores as preferential growth paths with thereby shape the final root architecture. The main objective of our study is to reveal the potential of using a pore scale description of the plant growth medium for an improved representation of interaction processes at the interface of root and soil. References Raoof, A., Hassanizadeh, S.M. 2010. A New Method for Generating Pore-Network Models. Transp. Porous Med. 81, 391-407. Leitner, D, Klepsch, S., Bodner, G., Schnepf, S. 2010. A dynamic root system growth model based on L-Systems. Tropisms and coupling to nutrient uptake from soil. Plant Soil 332, 177-192.

The root economics spectrum: divergence of absorptive root strategies with root diameter

NASA Astrophysics Data System (ADS)

Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

2015-08-01

Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

Roots of polynomials by ratio of successive derivatives

NASA Technical Reports Server (NTRS)

Crouse, J. E.; Putt, C. W.

1972-01-01

An order of magnitude study of the ratios of successive polynomial derivatives yields information about the number of roots at an approached root point and the approximate location of a root point from a nearby point. The location approximation improves as a root is approached, so a powerful convergence procedure becomes available. These principles are developed into a computer program which finds the roots of polynomials with real number coefficients.

Prosthetic valve sparing aortic root replacement: an improved technique.

PubMed

Leacche, Marzia; Balaguer, Jorge M; Umakanthan, Ramanan; Byrne, John G

2008-10-01

We describe a modified surgical technique to treat patients with a previous history of isolated aortic valve replacement who now require aortic root replacement for an aneurysmal or dissected aorta. This technique consists of replacing the aortic root with a Dacron conduit, leaving intact the previously implanted prosthesis, and re-implanting the coronary arteries in the Dacron graft. Our technique differs from other techniques in that we do not leave behind any aortic tissue remnant and also in that we use a felt strip to obliterate any gap between the old sewing ring and the newly implanted graft. In our opinion, this promotes better hemostasis. We demonstrate that this technique is safe, feasible, and results in acceptable outcomes.

Relationships between root diameter, root length and root branching along lateral roots in adult, field-grown maize

PubMed Central

Wu, Qian; Pagès, Loïc; Wu, Jie

2016-01-01

Background and Aims Root diameter, especially apical diameter, plays an important role in root development and function. The variation in diameter between roots, and along roots, affects root structure and thus the root system’s overall foraging performance. However, the effect of diameter variation on root elongation, branching and topological connections has not been examined systematically in a population of high-order roots, nor along the roots, especially for mature plants grown in the field. Methods A method combining both excavation and analysis was applied to extract and quantify root architectural traits of adult, field-grown maize plants. The relationships between root diameter and other root architectural characteristics are analysed for two maize cultivars. Key Results The basal diameter of the lateral roots (orders 1–3) was highly variable. Basal diameter was partly determined by the diameter of the bearing segment. Basal diameter defined a potential root length, but the lengths of most roots fell far short of this. This was explained partly by differences in the pattern of diameter change along roots. Diameter tended to decrease along most roots, with the steepness of the gradient of decrease depending on basal diameter. The longest roots were those that maintained (or sometimes increased) their diameters during elongation. The branching density (cm–1) of laterals was also determined by the diameter of the bearing segment. However, the location of this bearing segment along the mother root was also involved – intermediate positions were associated with higher densities of laterals. Conclusions The method used here allows us to obtain very detailed records of the geometry and topology of a complex root system. Basal diameter and the pattern of diameter change along a root were associated with its final length. These relationships are especially useful in simulations of root elongation and branching in source–sink models. PMID:26744490

BIMLR: a method for constructing rooted phylogenetic networks from rooted phylogenetic trees.

PubMed

Wang, Juan; Guo, Maozu; Xing, Linlin; Che, Kai; Liu, Xiaoyan; Wang, Chunyu

2013-09-15

Rooted phylogenetic trees constructed from different datasets (e.g. from different genes) are often conflicting with one another, i.e. they cannot be integrated into a single phylogenetic tree. Phylogenetic networks have become an important tool in molecular evolution, and rooted phylogenetic networks are able to represent conflicting rooted phylogenetic trees. Hence, the development of appropriate methods to compute rooted phylogenetic networks from rooted phylogenetic trees has attracted considerable research interest of late. The CASS algorithm proposed by van Iersel et al. is able to construct much simpler networks than other available methods, but it is extremely slow, and the networks it constructs are dependent on the order of the input data. Here, we introduce an improved CASS algorithm, BIMLR. We show that BIMLR is faster than CASS and less dependent on the input data order. Moreover, BIMLR is able to construct much simpler networks than almost all other methods. BIMLR is available at http://nclab.hit.edu.cn/wangjuan/BIMLR/. © 2013 Elsevier B.V. All rights reserved.

Can Crops with Greater Rooting Systems Improve Nitrogen Retention and Mitigate Emissions of Nitrous Oxide?

NASA Astrophysics Data System (ADS)

Decock, Charlotte; Lee, Juhwan; Barthel, Matti; Mikita, Chris; Wilde, Benjamin; Verhoeven, Elizabeth; Hund, Andreas; Abiven, Samuel; Friedli, Cordula; Conen, Franz; Mohn, Joachim; Wolf, Benjamin; Six, Johan

2016-04-01

It has been suggested that crops with deeper root systems could improve agricultural sustainability, because scavenging of nitrogen (N) in the subsoil would increase overall N retention and use efficiency in the system. However, the effect of plant root depth and root architecture on N-leaching and emissions of the potent greenhouse N2O remains largely unknown. We aimed to assess the effect of plant rooting depth on N-cycling and N2O production and reduction within the plant-soil system and throughout the soil profile. We hypothesized that greater root depth and root biomass will (1) increase N use efficiency and decrease N losses in the form of N leaching and N2O emissions; (2) increase N retention by shifting the fate of NH4+ from more nitrification toward more plant uptake and microbial immobilization; and (3) increase the depth of maximum N2O production and decrease the ratio of N2O:(N2O+N2) in denitrification end-products. To test these hypotheses, 4 winter wheat cultivars were grown in lysimeters (1.5 m tall, 0.5 m diameter, 3 replications per cultivar) under greenhouse conditions. Each lysimeter was equipped with an automated flux chamber for the determination of N2O surface fluxes. At 7.5, 30, 60, 90 and 120 cm depth, sampling ports were installed for the determination of soil moisture contents, as well as the collection of soil pore air and soil pore water samples. We selected two older and two newer varieties from the Swiss winter wheat breeding program, spanning a 100-year breeding history. The selection was based on previous experiments indicating that the older varieties have deeper rooting systems than the newer varieties under well watered conditions. N2O fluxes were determined twice per day on a quantum cascade laser absorption spectrometer interfaced with the automated flux chambers. Once per week, we determined concentrations of mineral N in pore water and of CO2 and N2O in the pore air. For mineral N and N2O, also natural abundance isotope deltas

The Physiology of Adventitious Roots1

PubMed Central

Steffens, Bianka; Rasmussen, Amanda

2016-01-01

Adventitious roots are plant roots that form from any nonroot tissue and are produced both during normal development (crown roots on cereals and nodal roots on strawberry [Fragaria spp.]) and in response to stress conditions, such as flooding, nutrient deprivation, and wounding. They are important economically (for cuttings and food production), ecologically (environmental stress response), and for human existence (food production). To improve sustainable food production under environmentally extreme conditions, it is important to understand the adventitious root development of crops both in normal and stressed conditions. Therefore, understanding the regulation and physiology of adventitious root formation is critical for breeding programs. Recent work shows that different adventitious root types are regulated differently, and here, we propose clear definitions of these classes. We use three case studies to summarize the physiology of adventitious root development in response to flooding (case study 1), nutrient deficiency (case study 2), and wounding (case study 3). PMID:26697895

Automated Root Tracking with "Root System Analyzer"

NASA Astrophysics Data System (ADS)

Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

2015-04-01

Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

Root morphology and mycorrhizal type strongly influence root production in nutrient hot spots of mixed forests

DOE PAGES

Chen, Weile; Koide, Roger T.; Eissenstat, David M.

2017-04-26

Plants compete for nutrients using a range of strategies. We investigated nutrient foraging within nutrient hot-spots simultaneously available to plant species with diverse root traits. We hypothesized that there would be more root proliferation by thin-root species than by thick-root species, and that root proliferation by thin-root species would limit root proliferation by thick-root species. We conducted a root ingrowth experiment in a temperate forest in eastern USA where root systems of different tree species could interact. Tree species varied in the thickness of their absorptive roots, and were associated with either ectomycorrhizal (EM) or arbuscular mycorrhizal (AM) fungi. Thus,more » there were thin- and thick-root AM and thin- and thick-root EM plant functional groups. Half the ingrowth cores were amended with organic nutrients (dried green leaves). Relative root length abundance, the proportion of total root length in a given soil volume occupied by a particular plant functional group, was calculated for the original root population and ingrowth roots after 6 months. The shift in relative root length abundance from original to ingrowth roots was positive in thin-root species but negative in thick-root species (p < .001), especially in unamended patches (AM: +6% vs. -7%; EM: +8% vs. -9%). Being thin-rooted may thus allow a species to more rapidly recolonize soil after a disturbance, which may influence competition for nutrients. Moreover, we observed that nutrient additions amplified the shift in root length abundance of thin over thick roots in AM trees (+13% vs. -14%), but not in EM trees (+1% vs -3%). In contrast, phospholipid fatty acid biomarkers suggested that EM fungal hyphae strongly proliferated in nutrient hot-spots whereas AM fungal hyphae exhibited only modest proliferation. We found no evidence that when growing in the shared patch, the proliferation of thin roots inhibited the growth of thick roots. As a result, knowledge of root

Root morphology and mycorrhizal type strongly influence root production in nutrient hot spots of mixed forests

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

Chen, Weile; Koide, Roger T.; Eissenstat, David M.

Plants compete for nutrients using a range of strategies. We investigated nutrient foraging within nutrient hot-spots simultaneously available to plant species with diverse root traits. We hypothesized that there would be more root proliferation by thin-root species than by thick-root species, and that root proliferation by thin-root species would limit root proliferation by thick-root species. We conducted a root ingrowth experiment in a temperate forest in eastern USA where root systems of different tree species could interact. Tree species varied in the thickness of their absorptive roots, and were associated with either ectomycorrhizal (EM) or arbuscular mycorrhizal (AM) fungi. Thus,more » there were thin- and thick-root AM and thin- and thick-root EM plant functional groups. Half the ingrowth cores were amended with organic nutrients (dried green leaves). Relative root length abundance, the proportion of total root length in a given soil volume occupied by a particular plant functional group, was calculated for the original root population and ingrowth roots after 6 months. The shift in relative root length abundance from original to ingrowth roots was positive in thin-root species but negative in thick-root species (p < .001), especially in unamended patches (AM: +6% vs. -7%; EM: +8% vs. -9%). Being thin-rooted may thus allow a species to more rapidly recolonize soil after a disturbance, which may influence competition for nutrients. Moreover, we observed that nutrient additions amplified the shift in root length abundance of thin over thick roots in AM trees (+13% vs. -14%), but not in EM trees (+1% vs -3%). In contrast, phospholipid fatty acid biomarkers suggested that EM fungal hyphae strongly proliferated in nutrient hot-spots whereas AM fungal hyphae exhibited only modest proliferation. We found no evidence that when growing in the shared patch, the proliferation of thin roots inhibited the growth of thick roots. As a result, knowledge of root

Concerted transcription of auxin and carbohydrate homeostasis-related genes underlies improved adventitious rooting of microcuttings derived from far-red treated Eucalyptus globulus Labill mother plants.

PubMed

Ruedell, Carolina Michels; de Almeida, Márcia Rodrigues; Fett-Neto, Arthur Germano

2015-12-01

Economically important plant species, such as Eucalyptus globulus, are often rooting recalcitrant. We have previously shown that far-red light enrichment applied to E. globulus donor-plants improved microcutting rooting competence and increased rooting zone/shoot carbohydrate ratio. To better understand this developmental response, the relative expression profiles of genes involved in auxin signaling (ARF6, ARF8, AGO1), biosynthesis (YUC3) and transport (AUX1, PIN1, PIN2); sucrose cleavage (SUS1, CWINV1), transport (SUC5), hexose phosphorylation (HXK1, FLN1) and starch biosynthesis (SS3) were quantified during adventitious rooting of E. globulus microcuttings derived from donor plants exposed to far-red or white light. Expression of auxin transport-related genes increased in the first days of root induction. Far-red enrichment of donor plants induced ARF6, ARF8 and AGO1 in microcuttings. The first two gene products could activate GH3 and other rooting related genes, whereas AGO1 deregulation of the repressor ARF17 may relief rooting inhibition. Increased sink strength at the basal stem with sucrose unloading in root tissue mediated by SUC and subsequent hydrolysis by SUS1 were also supported by gene expression profile. Fructose phosphorylation and starch biosynthesis could also contribute to proper carbon allocation at the site of rooting, as evidenced by increased expression of related genes. These data are in good agreement with increased contents of hexoses and starch at the cutting base severed from far-red exposed donor plants. To sum up, pathways integrating auxin and carbohydrate metabolism were activated in microcuttings derived from donor plants exposed to far red light enrichment, thereby improving rooting response in E. globulus. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

ROOT 6 and beyond: TObject, C++14 and many cores

DOE PAGES

Bellenot, B.; Canal, Ph; Couet, O.; ...

2015-12-23

Following the release of version 6, ROOT has entered a new area of development. It will leverage the industrial strength compiler library shipping in ROOT 6 and its support of the C++11/14 standard, to significantly simplify and harden ROOT's interfaces and to clarify and substantially improve ROOT's support for multi-threaded environments. Furthermore, this talk will also recap the most important new features and enhancements in ROOT in general, focusing on those allowed by the improved interpreter and better compiler support, including I/O for smart pointers, easier type safe access to the content of TTrees and enhanced multi processor support.

Simulation of crop yield variability by improved root-soil-interaction modelling

NASA Astrophysics Data System (ADS)

Duan, X.; Gayler, S.; Priesack, E.

2009-04-01

Understanding the processes and factors that govern the within-field variability in crop yield has attached great importance due to applications in precision agriculture. Crop response to environment at field scale is a complex dynamic process involving the interactions of soil characteristics, weather conditions and crop management. The numerous static factors combined with temporal variations make it very difficult to identify and manage the variability pattern. Therefore, crop simulation models are considered to be useful tools in analyzing separately the effects of change in soil or weather conditions on the spatial variability, in order to identify the cause of yield variability and to quantify the spatial and temporal variation. However, tests showed that usual crop models such as CERES-Wheat and CERES-Maize were not able to quantify the observed within-field yield variability, while their performance on crop growth simulation under more homogeneous and mainly non-limiting conditions was sufficent to simulate average yields at the field-scale. On a study site in South Germany, within-field variability in crop growth has been documented since years. After detailed analysis and classification of the soil patterns, two site specific factors, the plant-available-water and the O2 deficiency, were considered as the main causes of the crop growth variability in this field. Based on our measurement of root distribution in the soil profile, we hypothesize that in our case the insufficiency of the applied crop models to simulate the yield variability can be due to the oversimplification of the involved root models which fail to be sensitive to different soil conditions. In this study, the root growth model described by Jones et al. (1991) was adapted by using data of root distributions in the field and linking the adapted root model to the CERES crop model. The ability of the new root model to increase the sensitivity of the CERES crop models to different enviromental

Imaging and modelling root water uptake

NASA Astrophysics Data System (ADS)

Zarebanadkouki, M.; Meunier, F.; Javaux, M.; Kaestner, A.; Carminati, A.

2017-12-01

Spatially resolved measurement and modelling of root water uptake is urgently needed to identify root traits that can improve capture of water from the soil. However, measuring water fluxes into roots of transpiring plants growing in soil remains challenging. Here, we describe an in-situ technique to measure local fluxes of water into roots. The technique consists of tracing the transport of deuterated water (D2O) in soil and roots using time series neutron radiography and tomography. A diffusion-convection model was used to model the transport of D2O in roots. The model includes root features such as the endodermis, xylem and the composite flow of water in the apoplastic and symplastic pathways. Diffusion permeability of root cells and of the endodermis were estimated by fitting the experiment during the night, when transpiration was negligible. The water fluxes at different position of the root system were obtained by fitting the experiments at daytime. The results showed that root water uptake was not uniform along root system and varied among different root types. The measured profiles of root water uptake into roots were used to estimate the radial and axial hydraulic of the roots. A three-dimensional model of root water uptake was used to fit the measured water fluxes by adjusting the root radial and axial hydraulic conductivities. We found that the estimated radial conductivities decreased with root age, while the axial conducances increased, and they are different among root types. The significance of this study is the development of a method to estimate 1) water uptake and 2) the radial and axial hydraulic conductivities of roots of transpiring plants growing in the soil.

Inhibition of strigolactones promotes adventitious root formation

PubMed Central

Beveridge, Christine A.; Geelen, Danny

2012-01-01

Roots that form from non-root tissues (adventitious roots) are crucial for cutting propagation in the forestry and horticulture industries. Strigolactone has been demonstrated to be an important regulator of these roots in both Arabidopsis and pea using strigolactone deficient mutants and exogenous hormone applications. Strigolactones are produced from a carotenoid precursor which can be blocked using the widely available but broad terpenoid biosynthesis blocker, fluridone. We demonstrate here that fluridone can be used to promote adventitious rooting in the model species Pisum sativum (pea). In addition, in the garden species Plumbago auriculata and Jasminium polyanthum fluridone was equally as successful at promoting roots as a commercial rooting compound containing NAA and IBA. Our findings demonstrate that inhibition of strigolactone signaling has the potential to be used to improve adventitious rooting in commercially relevant species. PMID:22580687

Cr(VI) and lindane removal by Streptomyces M7 is improved by maize root exudates.

PubMed

Simon Sola, María Z; Pérez Visñuk, Daiana; Benimeli, Claudia S; Polti, Marta Alejandra; Alvarez, Analia

2017-12-01

Environmental mixed pollution by both organic and inorganic compounds are detected worldwide. Phytoremediation techniques have been proposed as ecofriendly methods for cleaning up polluted sites. Several studies have demonstrated enhanced dissipation of contaminants at the root-soil interface through an increase in microbial activity caused by the release of plant root exudates (REs). The aim of this study was to evaluate the effectiveness for Cr(VI) and lindane removal by Streptomyces M7 cultured in a co-contaminated system in presence of maize REs. Our results showed when REs were added to the contaminated minimal medium (MM) as the only carbon source, microbial removal of Cr(VI) and lindane increased significantly in comparison to contaminant removal obtained in MM with glucose 1 g L -1 . The maximum removal of 91% of lindane and 49.5% of Cr(VI) were obtained in the co-contaminated system. Moreover, Streptomyces M7 showed plant growth promoting traits which could improve plant performance in contaminated soils. The results presented in this study provide evidence that maize REs improved growth of Streptomyces M7 when REs were used as a carbon source in comparison to glucose. Consequently, lindane and Cr(VI) removal was considerably enhanced making evident the phytoremediation potential of the actinobacteria-plant partnership. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Alveolar bone thickness and root length changes in the treatment of skeletal Class III patients facilitated by improved corticotomy: a cone-beam CT analysis].

PubMed

Wu, Jiaqi; Jiang, Jiuhui; Xu, Li; Liang, Cheng; Li, Cuiying; Xu, Xiao

2015-04-01

To evaluate the alveolar bone thickness and root length changes of anterior teeth with cone-beam computed tomography (CBCT). CBCT scans were taken for 12 skeletal Class III patients who accepted the improved corticotomy (IC) procedures during pre-surgical orthodontics. The CBCT data in T1 (the maxillary dental arch was aligned and leveled) and T2 (extraction space closure) were superimposed and the alveolar bone thickness at root apex level and root length measurements were done. From T1 to T2, the buccal alveolar bone thickness for the upper lateral incisors increased from (1.89±0.83) to (2.47±1.02) mm (P<0.05), and for central incisors and for canines from (2.32±0.71) to (2.68±1.48) mm and from (2.28±1.08) to (2.41±1.40) mm, respectively. According to Sharpe Grading System, the root resorption grade for 69 teeth of 72 was located in Grade 1, two teeth in Grade 2, one tooth in Grade 3. The improved corticotomy had the potential to increase the buccal alveolar bone thickness and the root resorption in most teeth was in Grade 1 according to Sharpe grading system.

Root structure-function relationships in 74 species: evidence of a root economics spectrum related to carbon economy.

PubMed

Roumet, Catherine; Birouste, Marine; Picon-Cochard, Catherine; Ghestem, Murielle; Osman, Normaniza; Vrignon-Brenas, Sylvain; Cao, Kun-Fang; Stokes, Alexia

2016-05-01

Although fine roots are important components of the global carbon cycle, there is limited understanding of root structure-function relationships among species. We determined whether root respiration rate and decomposability, two key processes driving carbon cycling but always studied separately, varied with root morphological and chemical traits, in a coordinated way that would demonstrate the existence of a root economics spectrum (RES). Twelve traits were measured on fine roots (diameter ≤ 2 mm) of 74 species (31 graminoids and 43 herbaceous and dwarf shrub eudicots) collected in three biomes. The findings of this study support the existence of a RES representing an axis of trait variation in which root respiration was positively correlated to nitrogen concentration and specific root length and negatively correlated to the root dry matter content, lignin : nitrogen ratio and the remaining mass after decomposition. This pattern of traits was highly consistent within graminoids but less consistent within eudicots, as a result of an uncoupling between decomposability and morphology, and of heterogeneity of individual roots of eudicots within the fine-root pool. The positive relationship found between root respiration and decomposability is essential for a better understanding of vegetation-soil feedbacks and for improving terrestrial biosphere models predicting the consequences of plant community changes for carbon cycling. © 2016 CNRS. New Phytologist © 2016 New Phytologist Trust.

Root cortical senescence decreases root respiration, nutrient content and radial water and nutrient transport in barley.

PubMed

Schneider, Hannah M; Wojciechowski, Tobias; Postma, Johannes A; Brown, Kathleen M; Lücke, Andreas; Zeisler, Viktoria; Schreiber, Lukas; Lynch, Jonathan P

2017-08-01

The functional implications of root cortical senescence (RCS) are poorly understood. We tested the hypotheses that RCS in barley (1) reduces the respiration and nutrient content of root tissue; (2) decreases radial water and nutrient transport; and (3) is accompanied by increased suberization to protect the stele. Genetic variation for RCS exists between modern germplasm and landraces. Nitrogen and phosphorus deficiency increased the rate of RCS. Maximal RCS, defined as the disappearance of the entire root cortex, reduced root nitrogen content by 66%, phosphorus content by 63% and respiration by 87% compared with root segments with no RCS. Roots with maximal RCS had 90, 92 and 84% less radial water, nitrate and phosphorus transport, respectively, compared with segments with no RCS. The onset of RCS coincided with 30% greater aliphatic suberin in the endodermis. These results support the hypothesis that RCS reduces root carbon and nutrient costs and may therefore have adaptive significance for soil resource acquisition. By reducing root respiration and nutrient content, RCS could permit greater root growth, soil resource acquisition and resource allocation to other plant processes. RCS merits investigation as a trait for improving the performance of barley, wheat, triticale and rye under edaphic stress. © 2017 John Wiley & Sons Ltd.

Endophytic Bacteria Isolated from Panax ginseng Improves Ginsenoside Accumulation in Adventitious Ginseng Root Culture.

PubMed

Song, Xiaolin; Wu, Hao; Yin, Zhenhao; Lian, Meilan; Yin, Chengri

2017-05-23

Ginsenoside is the most important secondary metabolite of ginseng. Natural sources of wild ginseng have been overexploited. Although root culture could reduce the length of the growth cycle of ginseng, the number of ginsenosides is fewer and their contents are lower in adventitious roots of ginseng than that in ginseng cultivated in the field. In this study, we investigated the effects of endophytic bacterial elicitors on biomass and ginsenoside production in adventitious roots cultures of Panax ginseng . Endophyte LB 5-3 as an elicitor could increase biomass and ginsenoside accumulation in ginseng adventitious root culture. After 6 days elicitation with a 10.0 mL of strain LB 5-3, the content of total ginsenoside was 2.026 mg g -1 which was four times more than that in unchallenged roots. The combination of methyl jasmonate and strain LB 5-3 had a negative effect on ginseng adventitious root growth and ginsenoside production. The genomic DNA of strain LB 5-3 was sequenced, and was found to be most closely related to Bacillus altitudinis (KX230132.1). The challenged ginseng adventitious root extracts exerted inhibitory effect against the HepG2 cells, which IC 50 value was 0.94 mg mL -1 .

Substituting root numbers for length: Improving the use of minirhizotrons to study fine root dynamics

Treesearch

Tracey L. Crocker; Ron L. Hendrick; Roger W. Ruess; Kurt S. Pregitzer; Andrew J. Burton; Michael F. Allen; Jianping Shan; Lawrence A. Morris

2003-01-01

Minirhizotrons provide a unique way to repeatedly measure the production and fate of individual root segments, while minimizing soil disturbance and the confounding of spatial-temporal variation. However, the time associated with processing videotaped minirhizotron images limits the amount of data that can be extracted in a reasonable amount of time. We found that this...

The improved Allium/Vicia root tip micronucleus assay for clastogenicity of environmental pollutants.

PubMed

Ma, T H; Xu, Z; Xu, C; McConnell, H; Rabago, E V; Arreola, G A; Zhang, H

1995-04-01

The meristematic mitotic cells of plant roots are appropriate and efficient cytogenetic materials for the detection of clastogenicity of environmental pollutants, especially for in situ monitoring of water contaminants. Among several cytological endpoints in these fast dividing cells, such as chromosome/chromatid aberrations, sister-chromatid exchanges and micronuclei, the most effective and simplest indicator of cytological damage is micronucleus formation. Although the Allium cepa and Vicia faba root meristem micronucleus assays (Allium/Vicia root MCN) have been used in clastogenicity studies about 12 times by various authors in the last 25 years, there is no report on the comparison of the efficiency of these two plant systems and in different cell populations (meristem and F1) of the root tip as well as under adequate recovery duration. In order to maximize the efficiency of these bioassays, the current study was designed to compare the Allium and the Vicia root MCN assays on the basis of chromosome length, peak sensitivity of the mitotic cells, and the regions of the root tip where the MCN are formed. The total length of the 2n complement of Allium chromosomes is 14.4 microns and the total length of the 2n complement of Vicia is 9.32 microns. The peak sensitivity determined by serial fixation at 12-h intervals after 100 R of X-irradiation is 44 h. The slope of the X-ray dose-response curve of Allium roots derived from the meristematic regions was lower than that derived from cells in the F1 region. Higher efficiency was also demonstrated when the MCN frequencies were scored from the F1 cells in both Allium and Vicia treated with formaldehyde (FA), mitomycin C (MMC), and maleic hydrazide (MH). The results indicated that scoring of MCN frequencies from the F1 cell region of the root tip was more efficient than scoring from the meristematic region. The X-ray linear regression dose-response curves were established in both Allium and Vicia cell systems and the

Root-soil relationships and terroir

NASA Astrophysics Data System (ADS)

Tomasi, Diego

2015-04-01

Soil features, along with climate, are among the most important determinants of a succesful grape production in a certain area. Most of the studies, so far, investigated the above-ground vine response to differente edaphic and climate condition, but it is clearly not sufficient to explain the vine whole behaviour. In fact, roots represent an important part of the terroir system (soil-plant-atmosphere-man), and their study can provide better comprehension of vine responses to different environments. The root density and distribution, the ability of deep-rooting and regenerating new roots are good indicators of root well-being, and represents the basis for an efficient physiological activity of the root system. Root deepening and distribution are strongly dependent and sensitive on soil type and soil properties, while root density is affected mostly by canopy size, rootstock and water availability. According to root well-being, soil management strategies should alleviate soil impediments, improving aeration and microbial activity. Moreover, agronomic practices can impact root system performance and influence the above-ground growth. It is well known, for example, that the root system size is largely diminished by high planting densities. Close vine spacings stimulate a more effective utilization of the available soil, water and nutrients, but if the competition for available soil becomes too high, it can repress vine growth, and compromise vineyard longevity, productivity and reaction to growing season weather. Development of resilient rootstocks, more efficient in terms of water and nutrient uptake and capable of dealing with climate and soil extremes (drought, high salinity) are primary goals fore future research. The use of these rootstocks will benefit a more sustainable use of the soil resources and the preservation and valorisation of the terroir.

Genome-wide association mapping and agronomic impact of cowpea root architecture.

PubMed

Burridge, James D; Schneider, Hannah M; Huynh, Bao-Lam; Roberts, Philip A; Bucksch, Alexander; Lynch, Jonathan P

2017-02-01

Genetic analysis of data produced by novel root phenotyping tools was used to establish relationships between cowpea root traits and performance indicators as well between root traits and Striga tolerance. Selection and breeding for better root phenotypes can improve acquisition of soil resources and hence crop production in marginal environments. We hypothesized that biologically relevant variation is measurable in cowpea root architecture. This study implemented manual phenotyping (shovelomics) and automated image phenotyping (DIRT) on a 189-entry diversity panel of cowpea to reveal biologically important variation and genome regions affecting root architecture phenes. Significant variation in root phenes was found and relatively high heritabilities were detected for root traits assessed manually (0.4 for nodulation and 0.8 for number of larger laterals) as well as repeatability traits phenotyped via DIRT (0.5 for a measure of root width and 0.3 for a measure of root tips). Genome-wide association study identified 11 significant quantitative trait loci (QTL) from manually scored root architecture traits and 21 QTL from root architecture traits phenotyped by DIRT image analysis. Subsequent comparisons of results from this root study with other field studies revealed QTL co-localizations between root traits and performance indicators including seed weight per plant, pod number, and Striga (Striga gesnerioides) tolerance. The data suggest selection for root phenotypes could be employed by breeding programs to improve production in multiple constraint environments.

Rhizosphere biophysics and root water uptake

NASA Astrophysics Data System (ADS)

Carminati, Andrea; Zarebanadkouki, Mohsen; Ahmed, Mutez A.; Passioura, John

2016-04-01

The flow of water into the roots and the (putative) presence of a large resistance at the root-soil interface have attracted the attention of plant and soil scientists for decades. Such resistance has been attributed to a partial contact between roots and soil, large gradients in soil matric potential around the roots, or accumulation of solutes at the root surface creating a negative osmotic potential. Our hypothesis is that roots are capable of altering the biophysical properties of the soil around the roots, the rhizosphere, facilitating root water uptake in dry soils. In particular, we expect that root hairs and mucilage optimally connect the roots to the soil maintaining the hydraulic continuity across the rhizosphere. Using a pressure chamber apparatus we measured the relation between transpiration rate and the water potential difference between soil and leaf xylem during drying cycles in barley mutants with and without root hairs. The samples were grown in well structured soils. At low soil moistures and high transpiration rates, large drops in water potential developed around the roots. These drops in water potential recovered very slowly, even after transpiration was severely decreased. The drops in water potential were much bigger in barley mutants without root hairs. These mutants failed to sustain high transpiration rates in dry conditions. To explain the nature of such drops in water potential across the rhizosphere we performed high resolution neutron tomography of the rhizosphere of the barleys with and without root hairs growing in the same soil described above. The tomograms suggested that the hydraulic contact between the soil structures was the highest resistance for the water flow in dry conditions. The tomograms also indicate that root hairs and mucilage improved the hydraulic contact between roots and soil structures. At high transpiration rates and low water contents, roots extracted water from the rhizosphere, while the bulk soil, due its

Drought-induced changes in root biomass largely result from altered root morphological traits: evidence from a synthesis of global field trials.

PubMed

Zhou, Guiyao; Zhou, Xuhui; Nie, Yuanyuan; Bai, Shahla Hosseini; Zhou, Lingyan; Shao, Junjiong; Cheng, Weisong; Wang, Jiawei; Hu, Fengqin; Fu, Yuling

2018-06-07

Extreme drought is likely to become more frequent and intense as a result of global climate change, which may significantly impact plant root traits and responses (i.e., morphology, production, turnover, and biomass). However, a comprehensive understanding of how drought affects root traits and responses remains elusive. Here, we synthesized data from 128 published studies under field conditions to examine the responses of 17 variables associated with root traits to drought. Our results showed that drought significantly decreased root length and root length density by 38.29% and 11.12%, respectively, but increased root diameter by 3.49%. However, drought significantly increased root: shoot mass ratio and root cortical aerenchyma by 13.54% and 90.7%, respectively. Our results suggest that drought significantly modified root morphological traits and increased root mortality, and the drought-induced decrease in root biomass was less than shoot biomass, causing higher root: shoot mass ratio. The cascading effects of drought on root traits and responses may need to be incorporated into terrestrial biosphere models to improve prediction of the climate-biosphere feedback. This article is protected by copyright. All rights reserved.

Root Cortical Senescence Improves Growth under Suboptimal Availability of N, P, and K1[OPEN

PubMed Central

Schneider, Hannah M.

2017-01-01

Root cortical senescence (RCS) in Triticeae reduces nutrient uptake, nutrient content, respiration, and radial hydraulic conductance of root tissue. We used the functional-structural model SimRoot to evaluate the functional implications of RCS in barley (Hordeum vulgare) under suboptimal nitrate, phosphorus, and potassium availability. The utility of RCS was evaluated using sensitivity analyses in contrasting nutrient regimes. At flowering (80 d), RCS increased simulated plant growth by up to 52%, 73%, and 41% in nitrate-, phosphorus-, and potassium-limiting conditions, respectively. Plants with RCS had reduced nutrient requirement of root tissue for optimal plant growth, reduced total cumulative cortical respiration, and increased total carbon reserves. Nutrient reallocation during RCS had a greater effect on simulated plant growth than reduced respiration or nutrient uptake. Under low nutrient availability, RCS had greater benefit in plants with fewer tillers. RCS had greater benefit in phenotypes with fewer lateral roots at low nitrate availability, but the opposite was true in low phosphorus or potassium availability. Additionally, RCS was quantified in field-grown barley in different nitrogen regimes. Field and virtual soil coring simulation results demonstrated that living cortical volume per root length (an indicator of RCS) decreased with depth in younger plants, while roots of older plants had very little living cortical volume per root length. RCS may be an adaptive trait for nutrient acquisition by reallocating nutrients from senescing tissue and secondarily by reducing root respiration. These simulated results suggest that RCS merits investigation as a breeding target for enhanced soil resource acquisition and edaphic stress tolerance. PMID:28667049

Root desiccation and drought stress responses of bareroot Quercus rubra seedlings treated with a hydrophilic polymer root dip

Treesearch

Kent G. Apostol; Douglass F. Jacobs; R. Kasten Dumroese

2009-01-01

Root hydrogel, a hydrophilic polymer, has been used to improve transplanting success of bareroot conifer seedlings through effects on water holding capacity. We examined mechanisms by which Terra-sorb Fine Hydrogel reduces damage that occurs when roots of 1-year old, dormant northern red oak (Quercus rubra L.) were subjected to shortterm (1, 3, and 5...

Root Transcriptomic Analysis Revealing the Importance of Energy Metabolism to the Development of Deep Roots in Rice (Oryza sativa L.).

PubMed

Lou, Qiaojun; Chen, Liang; Mei, Hanwei; Xu, Kai; Wei, Haibin; Feng, Fangjun; Li, Tiemei; Pang, Xiaomeng; Shi, Caiping; Luo, Lijun; Zhong, Yang

2017-01-01

Drought is the most serious abiotic stress limiting rice production, and deep root is the key contributor to drought avoidance. However, the genetic mechanism regulating the development of deep roots is largely unknown. In this study, the transcriptomes of 74 root samples from 37 rice varieties, representing the extreme genotypes of shallow or deep rooting, were surveyed by RNA-seq. The 13,242 differentially expressed genes (DEGs) between deep rooting and shallow rooting varieties (H vs. L) were enriched in the pathway of genetic information processing and metabolism, while the 1,052 DEGs between the deep roots and shallow roots from each of the plants (D vs. S) were significantly enriched in metabolic pathways especially energy metabolism. Ten quantitative trait transcripts (QTTs) were identified and some were involved in energy metabolism. Forty-nine candidate DEGs were confirmed by qRT-PCR and microarray. Through weighted gene co-expression network analysis (WGCNA), we found 18 hub genes. Surprisingly, all these hub genes expressed higher in deep roots than in shallow roots, furthermore half of them functioned in energy metabolism. We also estimated that the ATP production in the deep roots was faster than shallow roots. Our results provided a lot of reliable candidate genes to improve deep rooting, and firstly highlight the importance of energy metabolism to the development of deep roots.

Root Transcriptomic Analysis Revealing the Importance of Energy Metabolism to the Development of Deep Roots in Rice (Oryza sativa L.)

PubMed Central

Lou, Qiaojun; Chen, Liang; Mei, Hanwei; Xu, Kai; Wei, Haibin; Feng, Fangjun; Li, Tiemei; Pang, Xiaomeng; Shi, Caiping; Luo, Lijun; Zhong, Yang

2017-01-01

Drought is the most serious abiotic stress limiting rice production, and deep root is the key contributor to drought avoidance. However, the genetic mechanism regulating the development of deep roots is largely unknown. In this study, the transcriptomes of 74 root samples from 37 rice varieties, representing the extreme genotypes of shallow or deep rooting, were surveyed by RNA-seq. The 13,242 differentially expressed genes (DEGs) between deep rooting and shallow rooting varieties (H vs. L) were enriched in the pathway of genetic information processing and metabolism, while the 1,052 DEGs between the deep roots and shallow roots from each of the plants (D vs. S) were significantly enriched in metabolic pathways especially energy metabolism. Ten quantitative trait transcripts (QTTs) were identified and some were involved in energy metabolism. Forty-nine candidate DEGs were confirmed by qRT-PCR and microarray. Through weighted gene co-expression network analysis (WGCNA), we found 18 hub genes. Surprisingly, all these hub genes expressed higher in deep roots than in shallow roots, furthermore half of them functioned in energy metabolism. We also estimated that the ATP production in the deep roots was faster than shallow roots. Our results provided a lot of reliable candidate genes to improve deep rooting, and firstly highlight the importance of energy metabolism to the development of deep roots. PMID:28798764

Azadirachtin powder for control of root-knot nematodes in tomato

USDA-ARS?s Scientific Manuscript database

USDA ARS Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo St., Hilo, HI 96720. Root-knot nematodes cause root galling and yield reductions in many vegetable crops, including tomato. Three organic treatments to improve root growth and reduce nematode infestation were eval...

The effect of EDTA in attachment gain and root coverage.

PubMed

Kassab, Moawia M; Cohen, Robert E; Andreana, Sebastiano; Dentino, Andrew R

2006-06-01

Root surface biomodification using low pH agents such as citric acid and tetracycline has been proposed to enhance root coverage following connective tissue grafting. The authors hypothesized that root conditioning with neutral pH edetic acid would improve vertical recession depth, root surface coverage, pocket depth, and clinical attachment levels. Twenty teeth in 10 patients with Miller class I and II recession were treated with connective tissue grafting. The experimental sites received 24% edetic acid in sterile distilled water applied to the root surface for 2 minutes before grafting. Controls were pretreated with only sterile distilled water. Measurements were evaluated before surgery and 6 months after surgery. Analysis of variance was used to determine differences between experimental and control groups. We found significant postoperative improvements in vertical recession depth, root surface coverage, and clinical attachment levels in test and control groups, compared to postoperative data. Pocket depth differences were not significant (P<.01).

Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L.) and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress.

PubMed

Egamberdieva, Dilfuza; Wirth, Stephan J; Shurigin, Vyacheslav V; Hashem, Abeer; Abd Allah, Elsayed F

2017-01-01

Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non-rhizobial endophytic bacteria from the root nodules of chickpea ( Cicer arietinum L.), and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1 , Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H 2 O 2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani . This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress.

Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L.) and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress

PubMed Central

Egamberdieva, Dilfuza; Wirth, Stephan J.; Shurigin, Vyacheslav V.; Hashem, Abeer; Abd_Allah, Elsayed F.

2017-01-01

Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non–rhizobial endophytic bacteria from the root nodules of chickpea (Cicer arietinum L.), and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1, Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H2O2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani. This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress. PMID:29033922

Root rots

Treesearch

Kathryn Robbins; Philip M. Wargo

1989-01-01

Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

Synergy between root hydrotropic response and root biomass in maize (Zea mays L.) enhances drought avoidance.

PubMed

Eapen, Delfeena; Martínez-Guadarrama, Jesús; Hernández-Bruno, Oralia; Flores, Leonardo; Nieto-Sotelo, Jorge; Cassab, Gladys I

2017-12-01

Roots of higher plants change their growth direction in response to moisture, avoiding drought and gaining maximum advantage for development. This response is termed hydrotropism. There have been few studies of root hydrotropism in grasses, particularly in maize. Our goal was to test whether an enhanced hydrotropic response of maize roots correlates with a better adaptation to drought and partial/lateral irrigation in field studies. We developed a laboratory bioassay for testing hydrotropic response in primary roots of 47 maize elite DTMA (Drought Tolerant Maize for Africa) hybrids. After phenotyping these hybrids in the laboratory, selected lines were tested in the field. Three robust and three weak hybrids were evaluated employing three irrigation procedures: normal irrigation, partial lateral irrigation and drought. Hybrids with a robust hydrotropic response showed growth and developmental patterns, under drought and partial lateral irrigation, that differed from weak hydrotropic responders. A correlation between root crown biomass and grain yield in hybrids with robust hydrotropic response was detected. Hybrids with robust hydrotropic response showed earlier female flowering whereas several root system traits, such as projected root area, median width, maximum width, skeleton width, skeleton nodes, average tip diameter, rooting depth skeleton, thinner aboveground crown roots, as well as stem diameter, were considerably higher than in weak hydrotropic responders in the three irrigation procedures utilized. These results demonstrate the benefit of intensive phenotyping of hydrotropism in primary roots since maize plants that display a robust hydrotropic response grew better under drought and partial lateral irrigation, indicating that a selection for robust hydrotropism might be a promising breeding strategy to improve drought avoidance in maize. Copyright © 2017 Elsevier B.V. All rights reserved.

Root Zone Cooling and Exogenous Spermidine Root-Pretreatment Promoting Lactuca sativa L. Growth and Photosynthesis in the High-temperature Season

PubMed Central

Sun, Jin; Lu, Na; Xu, Hongjia; Maruo, Toru; Guo, Shirong

2016-01-01

Root zone high-temperature stress is a major factor limiting hydroponic plant growth during the high-temperature season. The effects of root zone cooling (RZC; at 25°C) and exogenous spermidine (Spd) root-pretreatment (SRP, 0.1 mM) on growth, leaf photosynthetic traits, and chlorophyll fluorescence characteristics of hydroponic Lactuca sativa L. grown in a high-temperature season (average temperature > 30°C) were examined. Both treatments significantly promoted plant growth and photosynthesis in the high-temperature season, but the mechanisms of photosynthesis improvement in the hydroponic grown lettuce plants were different between the RZC and SRP treatments. The former improved plant photosynthesis by increasing stoma conductance (Gs) to enhance CO2 supply, thus promoting photosynthetic electron transport activity and phosphorylation, which improved the level of the photochemical efficiency of photosystem II (PSII), rather than enhancing CO2 assimilation efficiency. The latter improved plant photosynthesis by enhancing CO2 assimilation efficiency, rather than stomatal regulation. Combination of RZC and SRP significantly improved PN of lettuce plants in a high-temperature season by both improvement of Gs to enhance CO2 supply and enhancement of CO2 assimilation. The enhancement of photosynthetic efficiency in both treatments was independent of altering light-harvesting or excessive energy dissipation. PMID:27047532

Root Zone Cooling and Exogenous Spermidine Root-Pretreatment Promoting Lactuca sativa L. Growth and Photosynthesis in the High-temperature Season.

PubMed

Sun, Jin; Lu, Na; Xu, Hongjia; Maruo, Toru; Guo, Shirong

2016-01-01

Root zone high-temperature stress is a major factor limiting hydroponic plant growth during the high-temperature season. The effects of root zone cooling (RZC; at 25°C) and exogenous spermidine (Spd) root-pretreatment (SRP, 0.1 mM) on growth, leaf photosynthetic traits, and chlorophyll fluorescence characteristics of hydroponic Lactuca sativa L. grown in a high-temperature season (average temperature > 30°C) were examined. Both treatments significantly promoted plant growth and photosynthesis in the high-temperature season, but the mechanisms of photosynthesis improvement in the hydroponic grown lettuce plants were different between the RZC and SRP treatments. The former improved plant photosynthesis by increasing stoma conductance (G s) to enhance CO2 supply, thus promoting photosynthetic electron transport activity and phosphorylation, which improved the level of the photochemical efficiency of photosystem II (PSII), rather than enhancing CO2 assimilation efficiency. The latter improved plant photosynthesis by enhancing CO2 assimilation efficiency, rather than stomatal regulation. Combination of RZC and SRP significantly improved P N of lettuce plants in a high-temperature season by both improvement of G s to enhance CO2 supply and enhancement of CO2 assimilation. The enhancement of photosynthetic efficiency in both treatments was independent of altering light-harvesting or excessive energy dissipation.

iRoot FM exerts an antibacterial effect on Porphyromonas endodontalis and improves the properties of stem cells from the apical papilla.

PubMed

Bi, J; Liu, Y; Liu, X M; Jiang, L M; Chen, X

2018-03-07

To investigate the antibacterial activity of a novel intracanal medicament, iRoot FM, against Porphyromonas endodontalis and its effects on the proliferation and osteo-/odontogenic differentiation of stem cells from apical papilla (SCAP). The agar diffusion test was used to compare the antimicrobial efficacy of iRoot FM with two traditional intracanal medicaments, calcium hydroxide [Ca(OH) 2 ] and triple antibiotic paste (TAP). The CCK-8 assay was used to assess the proliferation rate of SCAP when exposed to the three intracanal medicaments. The expression levels of ALP and DMP-1 and the capacity to form mineralized nodules were used to evaluate the osteo-/odontogenic differentiation of SCAP, as assessed by real-time PCR, Western blotting and alizarin red S staining. Data were statistically analysed with one-way analysis of variance (anova), and comparisons between each of two groups were analysed by the least significance difference method. P values less than 0.05 were considered statistically significant. The zone of inhibition against P. endodontalis produced by iRoot FM was 20.74 ± 4.35 mm, whilst the zones of inhibition of Ca(OH) 2 and TAP were 24.89 ± 3.84 mm and 34.51 ± 1.20 mm. The antibacterial capacity of iRoot FM was similar to that of Ca(OH) 2 (P > 0.05). SCAP, cultured in conditioned medium with iRoot FM, was associated with greater proliferation and osteo-/odontogenic differentiation capacity than those cultured in conditioned medium with Ca(OH) 2 and TAP (P < 0.05). Moreover, iRoot FM had no negative effects on the proliferation rate of SCAP. iRoot FM exhibited excellent antibacterial activity against P. endodontalis and could improve the proliferation and differentiation of SCAP. The findings provide evidence that iRoot FM has potential as an intracanal medicament for endodontic procedures in immature permanent teeth. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Use of plant residues for improving soil fertility, pod nutrients, root growth and pod weight of okra (Abelmoschus esculentum L).

PubMed

Moyin-Jesu, Emmanuel Ibukunoluwa

2007-08-01

The effect of wood ash, sawdust, ground cocoa husk, spent grain and rice bran upon root development, ash content, pod yield and nutrient status and soil fertility for okra (Abelmoschus esculentum L NHAe 47 variety) was studied. The five organic fertilizer treatments were compared to chemical fertilizer (400kg/ha/crop NPK 15-15-15) and unfertilized controls in four field experiments replicated four times in a randomized complete block design. The results showed that the application of 6tha(-1) of plant residues increased (P<0.05) the soil N, P, K, Ca, Mg, pH, and SOM; pod N, P, K, Ca, Mg and ash; root length; and pod yield of okra in all four experiments relative to the control treatment. For instance, spent grain treatment increased the okra pod yield by 99%, 33%, 50%, 49%, 65% and 67% compared to control, NPK, wood ash, cocoa husk, rice bran and sawdust treatments respectively. In the stepwise regression, out of the total R(2) value of 0.83 for the soil nutrients to the pod yield of okra; soil N accounted for 50% of the soil fertility improvement and yield of okra. Spent grain, wood ash and cocoa husk were the most effective in improving okra pod weight, pod nutrients, ash content, root length and soil fertility whereas the rice bran and sawdust were the least effective. This was because the spent grain, wood ash and cocoa husk had lower C/N ratio and higher nutrient composition than rice bran and sawdust, thus, the former enhanced an increase in pod nutrients, composition for better human dietary intake, increased the root length, pod weight of okra and improved soil fertility and plant nutrition crop. The significance of the increases in okra mineral nutrition concentration by plant residues is that consumers will consume more of these minerals in their meals and monetarily spend less for purchasing vitamins and mineral supplement drugs to meet health requirements. In addition, the increase in plant nutrition and soil fertility would help to reduce the high cost

Root adaptations to soils with low fertility and aluminium toxicity

PubMed Central

Rao, Idupulapati M.; Miles, John W.; Beebe, Stephen E.; Horst, Walter J.

2016-01-01

Background Plants depend on their root systems to acquire the water and nutrients necessary for their survival in nature, and for their yield and nutritional quality in agriculture. Root systems are complex and a variety of root phenes have been identified as contributors to adaptation to soils with low fertility and aluminium (Al) toxicity. Phenotypic characterization of root adaptations to infertile soils is enabling plant breeders to develop improved cultivars that not only yield more, but also contribute to yield stability and nutritional security in the face of climate variability. Scope In this review the adaptive responses of root systems to soils with low fertility and Al toxicity are described. After a brief introduction, the purpose and focus of the review are outlined. This is followed by a description of the adaptive responses of roots to low supply of mineral nutrients [with an emphasis on low availability of nitrogen (N) and phosphorus (P) and on toxic levels of Al]. We describe progress in developing germplasm adapted to soils with low fertility or Al toxicity using selected examples from ongoing breeding programmes on food (maize, common bean) and forage/feed (Brachiaria spp.) crops. A number of root architectural, morphological, anatomical and metabolic phenes contribute to the superior performance and yield on soils with low fertility and Al toxicity. Major advances have been made in identifying root phenes in improving adaptation to low N (maize), low P (common bean) or high Al [maize, common bean, species and hybrids of brachiariagrass, bulbous canarygrass (Phalaris aquatica) and lucerne (Medicago sativa)]. Conclusions Advanced root phenotyping tools will allow dissection of root responses into specific root phenes that will aid both conventional and molecular breeders to develop superior cultivars. These new cultivars will play a key role in sustainable intensification of crop–livestock systems, particularly in smallholder systems of the

Root system-based limits to agricultural productivity and efficiency: the farming systems context

PubMed Central

Thorup-Kristensen, Kristian; Kirkegaard, John

2016-01-01

Background There has been renewed global interest in both genetic and management strategies to improve root system function in order to improve agricultural productivity and minimize environmental damage. Improving root system capture of water and nutrients is an obvious strategy, yet few studies consider the important interactions between the genetic improvements proposed, and crop management at a system scale that will influence likely success. Scope To exemplify these interactions, the contrasting cereal-based farming systems of Denmark and Australia were used, where the improved uptake of water and nitrogen from deeper soil layers has been proposed to improve productivity and environmental outcomes in both systems. The analysis showed that water and nitrogen availability, especially in deeper layers (>1 m), was significantly affected by the preceding crops and management, and likely to interact strongly with deeper rooting as a specific trait of interest. Conclusions In the semi-arid Australian environment, grain yield impacts from storage and uptake of water from depth (>1 m) could be influenced to a stronger degree by preceding crop choice (0·42 t ha–1), pre-crop fallow management (0·65 t ha–1) and sowing date (0·63 t ha–1) than by current genetic differences in rooting depth (0·36 t ha–1). Matching of deep-rooted genotypes to management provided the greatest improvements related to deep water capture. In the wetter environment of Denmark, reduced leaching of N was the focus. Here the amount of N moving below the root zone was also influenced by previous crop choice or cover crop management (effects up to 85 kg N ha–1) and wheat crop sowing date (up to 45 kg ha–1), effects which over-ride the effects of differences in rooting depth among genotypes. These examples highlight the need to understand the farming system context and important G × E × M interactions in studies on proposed genetic improvements to root systems for improved

Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

NASA Technical Reports Server (NTRS)

Ng, Y. K.; Moore, R.

1985-01-01

The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

Methanolic Root Extract of Rauwolfia serpentina Benth Improves the Glycemic, Antiatherogenic, and Cardioprotective Indices in Alloxan-Induced Diabetic Mice.

PubMed

Azmi, Muhammad Bilal; Qureshi, Shamim A

2012-01-01

The aim of the study was to evaluate the phytochemistry and the effect of methanolic root extract (MREt) of Rauwolfia serpentina on alloxan-induced diabetic Wister male mice. Mice were divided in control (distilled water at 1 mL/kg) and alloxan-induced diabetic mice which subdivided into diabetic (distilled water at 1 mL/kg), negative (0.05% dimethyl sulfoxide at 1 mL/kg), positive (glibenclamide at 5 mg/kg) controls, and three test groups (MREt at 10, 30, and 60 mg/kg). All treatments were given orally for 14 days. Qualitatively MREt showed the presence of alkaloids, carbohydrates, flavonoids, glycosides, cardiac glycosides, phlobatannins, resins, saponins, steroids, tannins, and triterpenoids, while quantitatively extract was rich in total phenols. The flavonoids, saponins and alkaloids were also determined in root powder. MREt found effective in improving the body weights, glucose and insulin levels, insulin/glucose ratio, glycosylated and total hemoglobin in test groups as compared to diabetic control. Similarly, significantly decreased levels of total cholesterol, triglycerides, low-density lipoprotein (LDL-c), and very low-density lipoprotein (VLDL-c) cholesterols were found in test groups. Significant lipolysis with improved glycogenesis was also found in liver tissues of all test groups. ALT levels were found normal in all groups. Thus, MREt improves the glycemic, antiatherogenic, coronary risk, and cardioprotective indices in alloxan-induced diabetic mice.

Methanolic Root Extract of Rauwolfia serpentina Benth Improves the Glycemic, Antiatherogenic, and Cardioprotective Indices in Alloxan-Induced Diabetic Mice

PubMed Central

Azmi, Muhammad Bilal; Qureshi, Shamim A.

2012-01-01

The aim of the study was to evaluate the phytochemistry and the effect of methanolic root extract (MREt) of Rauwolfia serpentina on alloxan-induced diabetic Wister male mice. Mice were divided in control (distilled water at 1 mL/kg) and alloxan-induced diabetic mice which subdivided into diabetic (distilled water at 1 mL/kg), negative (0.05% dimethyl sulfoxide at 1 mL/kg), positive (glibenclamide at 5 mg/kg) controls, and three test groups (MREt at 10, 30, and 60 mg/kg). All treatments were given orally for 14 days. Qualitatively MREt showed the presence of alkaloids, carbohydrates, flavonoids, glycosides, cardiac glycosides, phlobatannins, resins, saponins, steroids, tannins, and triterpenoids, while quantitatively extract was rich in total phenols. The flavonoids, saponins and alkaloids were also determined in root powder. MREt found effective in improving the body weights, glucose and insulin levels, insulin/glucose ratio, glycosylated and total hemoglobin in test groups as compared to diabetic control. Similarly, significantly decreased levels of total cholesterol, triglycerides, low-density lipoprotein (LDL-c), and very low-density lipoprotein (VLDL-c) cholesterols were found in test groups. Significant lipolysis with improved glycogenesis was also found in liver tissues of all test groups. ALT levels were found normal in all groups. Thus, MREt improves the glycemic, antiatherogenic, coronary risk, and cardioprotective indices in alloxan-induced diabetic mice. PMID:23365565

Root decisions.

PubMed

Hodge, Angela

2009-06-01

Root systems have recognizable developmental plans when grown in solution or agar; however, these plans often must be modified to cope with the prevailing conditions in the soil environment such as the avoidance of obstacles and the exploitation of nutrient-rich patches or water zones. The modular structure of roots enables them to respond to their environment, and roots are very adaptive at modifying growth throughout the root system to concentrate their efforts in the areas that are the most profitable. Roots also form associations with microorganisms as a strategy to enhance resource capture. However, while the responses of roots in nutrient patches are well-recognized, overall 'rules of response' and variation in strategy among plant species that can be applied in a number of different environments are still lacking. Finally, there is increasing evidence that root-root interactions are much more sophisticated than previously thought, and the evidence for roots to identify self from non-self roots will be briefly discussed.

Variability of Root Traits in Spring Wheat Germplasm

PubMed Central

Narayanan, Sruthi; Mohan, Amita; Gill, Kulvinder S.; Prasad, P. V. Vara

2014-01-01

Root traits influence the amount of water and nutrient absorption, and are important for maintaining crop yield under drought conditions. The objectives of this research were to characterize variability of root traits among spring wheat genotypes and determine whether root traits are related to shoot traits (plant height, tiller number per plant, shoot dry weight, and coleoptile length), regions of origin, and market classes. Plants were grown in 150-cm columns for 61 days in a greenhouse under optimal growth conditions. Rooting depth, root dry weight, root: shoot ratio, and shoot traits were determined for 297 genotypes of the germplasm, Cultivated Wheat Collection (CWC). The remaining root traits such as total root length and surface area were measured for a subset of 30 genotypes selected based on rooting depth. Significant genetic variability was observed for root traits among spring wheat genotypes in CWC germplasm or its subset. Genotypes Sonora and Currawa were ranked high, and genotype Vandal was ranked low for most root traits. A positive relationship (R2≥0.35) was found between root and shoot dry weights within the CWC germplasm and between total root surface area and tiller number; total root surface area and shoot dry weight; and total root length and coleoptile length within the subset. No correlations were found between plant height and most root traits within the CWC germplasm or its subset. Region of origin had significant impact on rooting depth in the CWC germplasm. Wheat genotypes collected from Australia, Mediterranean, and west Asia had greater rooting depth than those from south Asia, Latin America, Mexico, and Canada. Soft wheat had greater rooting depth than hard wheat in the CWC germplasm. The genetic variability identified in this research for root traits can be exploited to improve drought tolerance and/or resource capture in wheat. PMID:24945438

Metabolic transition in mycorrhizal tomato roots

PubMed Central

Rivero, Javier; Gamir, Jordi; Aroca, Ricardo; Pozo, María J.; Flors, Víctor

2015-01-01

Beneficial plant–microorganism interactions are widespread in nature. Among them, the symbiosis between plant roots and arbuscular mycorrhizal fungi (AMF) is of major importance, commonly improving host nutrition and tolerance against environmental and biotic challenges. Metabolic changes were observed in a well-established symbiosis between tomato and two common AMF: Rhizophagus irregularis and Funneliformis mosseae. Principal component analysis of metabolites, determined by non-targeted liquid chromatography–mass spectrometry, showed a strong metabolic rearrangement in mycorrhizal roots. There was generally a negative impact of mycorrhizal symbiosis on amino acid content, mainly on those involved in the biosynthesis of phenylpropanoids. On the other hand, many intermediaries in amino acid and sugar metabolism and the oxylipin pathway were among the compounds accumulating more in mycorrhizal roots. The metabolic reprogramming also affected other pathways in the secondary metabolism, mainly phenyl alcohols (lignins and lignans) and vitamins. The results showed that source metabolites of these pathways decreased in mycorrhizal roots, whilst the products derived from α-linolenic and amino acids presented higher concentrations in AMF-colonized roots. Mycorrhization therefore increased the flux into those pathways. Venn-diagram analysis showed that there are many induced signals shared by both mycorrhizal interactions, pointing to general mycorrhiza-associated changes in the tomato metabolome. Moreover, fungus-specific fingerprints were also found, suggesting that specific molecular alterations may underlie the reported functional diversity of the symbiosis. Since most positively regulated pathways were related to stress response mechanisms, their potential contribution to improved host stress tolerance is discussed. PMID:26157423

Root hairs increase root exudation and rhizosphere extension

NASA Astrophysics Data System (ADS)

Holz, Maire; Zarebandanadkouki, Mohsen; Kuzyakov, Yakov; Carmintati, Andrea

2017-04-01

Plant roots employ various mechanisms to increase their access to limited soil resources. An example of such strategies is the production of root hairs. Root hairs extend the root surface and therefore increase the access to nutrients. Additionally, carbon release from root hairs might facilitate nutrient uptake by spreading of carbon in the rhizosphere and enhancing microbial activity. The aim of this study was to test: i) how root hairs change the allocation of carbon in the soil-plant system; ii) whether root hairs exude carbon into the soil and iii) how differences in C release between plants with and without root hairs affect rhizosphere extension. We grew barley plants with and without root hairs (wild type: WT, bald root barley: brb) in rhizoboxes filled with a sandy soil. Root elongation was monitored over time. After 4 weeks of growth, plants were labelled with 14CO2. A filter paper was placed on the soil surface before labelling and was removed after 36 h. 14C imaging of the soil surface and of the filter paper was used to quantify the allocation of 14C into the roots and the exudation of 14C, respectively. Plants were sampled destructively one day after labeling to quantify 14C in the plant-soil system. 14CO2 release from soil over time (17 d) was quantified by trapping CO2 in NaOH with an additional subset of plants. WT and brb plants had a similar aboveground biomass and allocated similar amounts of 14C into shoots (170 KBq for WT; 152 KBq for brb) and roots one day after labelling. Biomass of root, rhizosphere soil as well as root elongation were lower for brb compared to the wild type. WT plants transported more C from the shoots to the roots (22.8% for WT; 13.8% for brb) and from the root into the rhizosphere (8.8% for WT 3.5% for brb). Yet lower amounts of 14CO2 were released from soil over time for WT. Radial and longitudinal rhizosphere extension was increased for WT compared to brb (4.7 vs. 2.6 mm; 5.6 vs. 3.1 cm). The total exudation which was

Shaping an Optimal Soil by Root-Soil Interaction.

PubMed

Jin, Kemo; White, Philip J; Whalley, William R; Shen, Jianbo; Shi, Lei

2017-10-01

Crop production depends on the availability of water and mineral nutrients, and increased yields might be facilitated by a greater focus on roots-soil interactions. Soil properties affecting plant growth include drought, compaction, nutrient deficiency, mineral toxicity, salinity, and submergence. Plant roots respond to the soil environment both spatially and temporally by avoiding stressful soil environments and proliferating in more favorable environments. We observe that crops can be bred for specific root architectural and biochemical traits that facilitate soil exploration and resource acquisition, enabling greater crop yields. These root traits affect soil physical and chemical properties and might be utilized to improve the soil for subsequent crops. We argue that optimizing root-soil interactions is a prerequisite for future food security. Copyright © 2017 Elsevier Ltd. All rights reserved.

Root structural and functional dynamics in terrestrial biosphere models--evaluation and recommendations.

PubMed

Warren, Jeffrey M; Hanson, Paul J; Iversen, Colleen M; Kumar, Jitendra; Walker, Anthony P; Wullschleger, Stan D

2015-01-01

There is wide breadth of root function within ecosystems that should be considered when modeling the terrestrial biosphere. Root structure and function are closely associated with control of plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils, and control of biogeochemical cycles through interactions within the rhizosphere. Root function is extremely dynamic and dependent on internal plant signals, root traits and morphology, and the physical, chemical and biotic soil environment. While plant roots have significant structural and functional plasticity to changing environmental conditions, their dynamics are noticeably absent from the land component of process-based Earth system models used to simulate global biogeochemical cycling. Their dynamic representation in large-scale models should improve model veracity. Here, we describe current root inclusion in models across scales, ranging from mechanistic processes of single roots to parameterized root processes operating at the landscape scale. With this foundation we discuss how existing and future root functional knowledge, new data compilation efforts, and novel modeling platforms can be leveraged to enhance root functionality in large-scale terrestrial biosphere models by improving parameterization within models, and introducing new components such as dynamic root distribution and root functional traits linked to resource extraction. No claim to original US Government works. New Phytologist © 2014 New Phytologist Trust.

Transgenic hairy roots. recent trends and applications.

PubMed

Giri, A; Narasu, M L

2000-03-01

Agrobacterium rhizogenes causes hairy root disease in plants. The neoplastic roots produced by A. rhizogenes infection is characterized by high growth rate and genetic stability. These genetically transformed root cultures can produce higher levels of secondary metabolites or amounts comparable to that of intact plants. Hairy root cultures offer promise for production of valuable secondary metabolites in many plants. The main constraint for commercial exploitation of hairy root cultures is their scaling up, as there is a need for developing a specially designed bioreactor that permits the growth of interconnected tissues unevenly distributed throughout the vessel. Rheological characteristics of heterogeneous system should also be taken into consideration during mass scale culturing of hairy roots. Development of bioreactor models for hairy root cultures is still a recent phenomenon. It is also necessary to develop computer-aided models for different parameters such as oxygen consumption and excretion of product to the medium. Further, transformed roots are able to regenerate genetically stable plants as transgenics or clones. This property of rapid growth and high plantlet regeneration frequency allows clonal propagation of elite plants. In addition, the altered phenotype of hairy root regenerants (hairy root syndrome) is useful in plant breeding programs with plants of ornamental interest. In vitro transformation and regeneration from hairy roots facilitates application of biotechnology to tree species. The ability to manipulate trees at a cellular and molecular level shows great potential for clonal propagation and genetic improvement. Transgenic root system offers tremendous potential for introducing additional genes along with the Ri T-DNA genes for alteration of metabolic pathways and production of useful metabolites or compounds of interest. This article discusses various applications and perspectives of hairy root cultures and the recent progress achieved

Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

NASA Astrophysics Data System (ADS)

Salinas, A.; Zaharescu, D. G.

2015-12-01

A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops

Root adaptations to soils with low fertility and aluminium toxicity.

PubMed

Rao, Idupulapati M; Miles, John W; Beebe, Stephen E; Horst, Walter J

2016-06-01

Plants depend on their root systems to acquire the water and nutrients necessary for their survival in nature, and for their yield and nutritional quality in agriculture. Root systems are complex and a variety of root phenes have been identified as contributors to adaptation to soils with low fertility and aluminium (Al) toxicity. Phenotypic characterization of root adaptations to infertile soils is enabling plant breeders to develop improved cultivars that not only yield more, but also contribute to yield stability and nutritional security in the face of climate variability. In this review the adaptive responses of root systems to soils with low fertility and Al toxicity are described. After a brief introduction, the purpose and focus of the review are outlined. This is followed by a description of the adaptive responses of roots to low supply of mineral nutrients [with an emphasis on low availability of nitrogen (N) and phosphorus (P) and on toxic levels of Al]. We describe progress in developing germplasm adapted to soils with low fertility or Al toxicity using selected examples from ongoing breeding programmes on food (maize, common bean) and forage/feed (Brachiaria spp.) crops. A number of root architectural, morphological, anatomical and metabolic phenes contribute to the superior performance and yield on soils with low fertility and Al toxicity. Major advances have been made in identifying root phenes in improving adaptation to low N (maize), low P (common bean) or high Al [maize, common bean, species and hybrids of brachiariagrass, bulbous canarygrass (Phalaris aquatica) and lucerne (Medicago sativa)]. Advanced root phenotyping tools will allow dissection of root responses into specific root phenes that will aid both conventional and molecular breeders to develop superior cultivars. These new cultivars will play a key role in sustainable intensification of crop-livestock systems, particularly in smallholder systems of the tropics. Development of these new

Arbuscular Mycorrhiza Improves Substrate Hydraulic Conductivity in the Plant Available Moisture Range Under Root Growth Exclusion.

PubMed

Bitterlich, Michael; Franken, Philipp; Graefe, Jan

2018-01-01

Arbuscular mycorrhizal fungi (AMF) proliferate in soils and are known to affect soil structure. Although their contribution to structure is extensively investigated, the consequences of those processes for soil water extractability and transport has, so far, gained surprisingly little attention. Therefore we asked, whether AMF can affect water retention and unsaturated hydraulic conductivity under exclusion of root ingrowth, in order to minimize plant driven effects. We carried out experiments with tomato inoculated with Rhizoglomus irregulare in a soil substrate with sand and vermiculite that created variation in colonization by mixed pots with wild type (WT) plants and mycorrhiza resistant (RMC) mutants. Sampling cores were introduced and used to assess substrate moisture retention dynamics and modeling of substrate water retention and hydraulic conductivity. AMF reduced the saturated water content and total porosity, but maintained air filled porosity in soil spheres that excluded root ingrowth. The water content between field capacity and the permanent wilting point (6-1500 kPa) was only reduced in mycorrhizal substrates that contained at least one RMC mutant. Plant available water contents correlated positively with soil protein contents. Soil protein contents were highest in pots that possessed the strongest hyphal colonization, but not significantly affected. Substrate conductivity increased up to 50% in colonized substrates in the physiologically important water potential range between 6 and 10 kPa. The improvements in hydraulic conductivity are restricted to substrates where at least one WT plant was available for the fungus, indicating a necessity of a functional symbiosis for this effect. We conclude that functional mycorrhiza alleviates the resistance to water movement through the substrate in substrate areas outside of the root zone.

Colonization on Cucumber Root and Enhancement of Chlorimuron-ethyl Degradation in the Rhizosphere by Hansschlegelia zhihuaiae S113 and Root Exudates.

PubMed

Zhang, Hao; Chen, Feng; Zhao, Hua-Zhu; Lu, Jia-Sen; Zhao, Meng-Jun; Hong, Qing; Huang, Xing

2018-05-09

The colonization of Hansschlegelia zhihuaiae S113 and its degradation of the herbicide chlorimuron-ethyl in the cucumber rhizosphere was investigated. The results reveal that S113 colonized the cucumber roots (2.14 × 10 5 cells per gram of roots) and were able to survive in the rhizosphere (maintained for 20 d). The root exudates promoted colonization on roots and increased the degradation of chlorimuron-ethyl by S113. Five organic acids in cucumber-root exudates were detected and identified by HPLC. Citric acid and fumaric acid significantly stimulated S113 colonization on cucumber roots, with 18.4 and 15.5% increases, respectively, compared with the control. After irrigation with an S113 solution for 10 days, chlorimuron-ethyl could not be detected in the roots, seedlings, or rhizosphere soil, which allowed for improved cucumber growth. Therefore, the degradation mechanism of chlorimuron-ethyl residues by S113 in the rhizosphere could be applied in situ for the bioremediation of chlorimuron-ethyl contaminated soil to ensure crop safety.

Rooting gene trees without outgroups: EP rooting.

PubMed

Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

2012-01-01

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

RootJS: Node.js Bindings for ROOT 6

NASA Astrophysics Data System (ADS)

Beffart, Theo; Früh, Maximilian; Haas, Christoph; Rajgopal, Sachin; Schwabe, Jonas; Wolff, Christoph; Szuba, Marek

2017-10-01

We present rootJS, an interface making it possible to seamlessly integrate ROOT 6 into applications written for Node.js, the JavaScript runtime platform increasingly commonly used to create high-performance Web applications. ROOT features can be called both directly from Node.js code and by JIT-compiling C++ macros. All rootJS methods are invoked asynchronously and support callback functions, allowing non-blocking operation of Node.js applications using them. Last but not least, our bindings have been designed to platform-independent and should therefore work on all systems supporting both ROOT 6 and Node.js. Thanks to rootJS it is now possible to create ROOT-aware Web applications taking full advantage of the high performance and extensive capabilities of Node.js. Examples include platforms for the quality assurance of acquired, reconstructed or simulated data, book-keeping and e-log systems, and even Web browser-based data visualisation and analysis.

Permanent Improved High-Quality Draft Genome Sequence of Nocardia casuarinae Strain BMG51109, an Endophyte of Actinorhizal Root Nodules of Casuarina glauca

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

Ghodhbane-Gtari, Faten; Beauchemin, Nicholas; Louati, Moussa

Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG51109, isolated from Casuarina glauca root nodules. The improved high-quality draft genome sequence contains 8,787,999 bp with a 68.90% GC content and 7,307 predicted protein-coding genes.

Permanent Improved High-Quality Draft Genome Sequence of Nocardia casuarinae Strain BMG51109, an Endophyte of Actinorhizal Root Nodules of Casuarina glauca

DOE PAGES

Ghodhbane-Gtari, Faten; Beauchemin, Nicholas; Louati, Moussa; ...

2016-08-04

Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG51109, isolated from Casuarina glauca root nodules. The improved high-quality draft genome sequence contains 8,787,999 bp with a 68.90% GC content and 7,307 predicted protein-coding genes.

Rooting Gene Trees without Outgroups: EP Rooting

PubMed Central

Sinsheimer, Janet S.; Little, Roderick J. A.; Lake, James A.

2012-01-01

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167–181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301–316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60–76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489–493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763–766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255–260). PMID:22593551

Comparison of different assimilation methodologies of groundwater levels to improve predictions of root zone soil moisture with an integrated terrestrial system model

NASA Astrophysics Data System (ADS)

Zhang, Hongjuan; Kurtz, Wolfgang; Kollet, Stefan; Vereecken, Harry; Franssen, Harrie-Jan Hendricks

2018-01-01

The linkage between root zone soil moisture and groundwater is either neglected or simplified in most land surface models. The fully-coupled subsurface-land surface model TerrSysMP including variably saturated groundwater dynamics is used in this work. We test and compare five data assimilation methodologies for assimilating groundwater level data via the ensemble Kalman filter (EnKF) to improve root zone soil moisture estimation with TerrSysMP. Groundwater level data are assimilated in the form of pressure head or soil moisture (set equal to porosity in the saturated zone) to update state vectors. In the five assimilation methodologies, the state vector contains either (i) pressure head, or (ii) log-transformed pressure head, or (iii) soil moisture, or (iv) pressure head for the saturated zone only, or (v) a combination of pressure head and soil moisture, pressure head for the saturated zone and soil moisture for the unsaturated zone. These methodologies are evaluated in synthetic experiments which are performed for different climate conditions, soil types and plant functional types to simulate various root zone soil moisture distributions and groundwater levels. The results demonstrate that EnKF cannot properly handle strongly skewed pressure distributions which are caused by extreme negative pressure heads in the unsaturated zone during dry periods. This problem can only be alleviated by methodology (iii), (iv) and (v). The last approach gives the best results and avoids unphysical updates related to strongly skewed pressure heads in the unsaturated zone. If groundwater level data are assimilated by methodology (iii), EnKF fails to update the state vector containing the soil moisture values if for (almost) all the realizations the observation does not bring significant new information. Synthetic experiments for the joint assimilation of groundwater levels and surface soil moisture support methodology (v) and show great potential for improving the representation

Root Hairs

PubMed Central

Grierson, Claire; Nielsen, Erik; Ketelaarc, Tijs; Schiefelbein, John

2014-01-01

Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology. PMID:24982600

The unseen iceberg: Plant roots in arctic tundra

USGS Publications Warehouse

Iverson, Colleen M.; Sloan, Victoria L.; Sullivan, Patrick F.; Euskirchen, E.S.; McGuire, A. David; Norby, Richard J.; Walker, Anthony P.; Warren, Jeffrey M.; Wullschleger, Stan D.

2015-01-01

Plant roots play a critical role in ecosystem function in arctic tundra, but root dynamics in these ecosystems are poorly understood. To address this knowledge gap, we synthesized available literature on tundra roots, including their distribution, dynamics and contribution to ecosystem carbon and nutrient fluxes, and highlighted key aspects of their representation in terrestrial biosphere models. Across all tundra ecosystems, belowground plant biomass exceeded aboveground biomass, with the exception of polar desert tundra. Roots were shallowly distributed in the thin layer of soil that thaws annually, and were often found in surface organic soil horizons. Root traits – including distribution, chemistry, anatomy and resource partitioning – play an important role in controlling plant species competition, and therefore ecosystem carbon and nutrient fluxes, under changing climatic conditions, but have only been quantified for a small fraction of tundra plants. Further, the annual production and mortality of fine roots are key components of ecosystem processes in tundra, but extant data are sparse. Tundra root traits and dynamics should be the focus of future research efforts. Better representation of the dynamics and characteristics of tundra roots will improve the utility of models for the evaluation of the responses of tundra ecosystems to changing environmental conditions.

The unseen iceberg: plant roots in arctic tundra.

PubMed

Iversen, Colleen M; Sloan, Victoria L; Sullivan, Patrick F; Euskirchen, Eugenie S; McGuire, A David; Norby, Richard J; Walker, Anthony P; Warren, Jeffrey M; Wullschleger, Stan D

2015-01-01

Plant roots play a critical role in ecosystem function in arctic tundra, but root dynamics in these ecosystems are poorly understood. To address this knowledge gap, we synthesized available literature on tundra roots, including their distribution, dynamics and contribution to ecosystem carbon and nutrient fluxes, and highlighted key aspects of their representation in terrestrial biosphere models. Across all tundra ecosystems, belowground plant biomass exceeded aboveground biomass, with the exception of polar desert tundra. Roots were shallowly distributed in the thin layer of soil that thaws annually, and were often found in surface organic soil horizons. Root traits - including distribution, chemistry, anatomy and resource partitioning - play an important role in controlling plant species competition, and therefore ecosystem carbon and nutrient fluxes, under changing climatic conditions, but have only been quantified for a small fraction of tundra plants. Further, the annual production and mortality of fine roots are key components of ecosystem processes in tundra, but extant data are sparse. Tundra root traits and dynamics should be the focus of future research efforts. Better representation of the dynamics and characteristics of tundra roots will improve the utility of models for the evaluation of the responses of tundra ecosystems to changing environmental conditions. No claim to original US Government works New Phytologist © 2014 New Phytologist Trust.

Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster.

PubMed

Danjon, Frédéric; Caplan, Joshua S; Fortin, Mathieu; Meredieu, Céline

2013-01-01

Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

PubMed Central

Danjon, Frédéric; Caplan, Joshua S.; Fortin, Mathieu; Meredieu, Céline

2013-01-01

Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately. PMID

A global Fine-Root Ecology Database to address below-ground challenges in plant ecology

DOE PAGES

Iversen, Colleen M.; McCormack, M. Luke; Powell, A. Shafer; ...

2017-02-28

Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. And while fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of rootmore » traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. There has been a continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time.« less

A global Fine-Root Ecology Database to address below-ground challenges in plant ecology

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

Iversen, Colleen M.; McCormack, M. Luke; Powell, A. Shafer

Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. And while fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of rootmore » traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. There has been a continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time.« less

Improving root-zone soil properties for Trembling Aspen in a reconstructed mine-site soil

NASA Astrophysics Data System (ADS)

Dyck, M. F.; Sabbagh, P.; Bockstette, S.; Landhäusser, S.; Pinno, B.

2014-12-01

Surface mining activities have significantly depleted natural tree cover, especially trembling aspen (Populus tremuloides), in the Boreal Forest and Aspen Parkland Natural Regions of Alberta. The natural soil profile is usually destroyed during these mining activities and soil and landscape reconstruction is typically the first step in the reclamation process. However, the mine tailings and overburden materials used for these new soils often become compacted during the reconstruction process because they are subjected to high amounts of traffic with heavy equipment. Compacted soils generally have low porosity and low penetrability through increased soil strength, making it difficult for roots to elongate and explore the soil. Compaction also reduces infiltration capacity and drainage, which can cause excessive runoff and soil erosion. To improve the pore size distribution and water transmission, subsoil ripping was carried out in a test plot at Genesee Prairie Mine, Alberta. Within the site, six replicates with two treatments each, unripped (compacted) and ripped (decompacted), were established with 20-m buffers between them. The main objective of this research was to characterize the effects of subsoil ripping on soil physical properties and the longevity of those effects.as well as soil water dynamics during spring snowmelt. Results showed improved bulk density, pore size distribution and water infiltration in the soil as a result of the deep ripping, but these improvements appear to be temporary.

A split-root technique for measuring root water potential.

PubMed

Adeoye, K B; Rawlins, S L

1981-07-01

Water encounters various resistances in moving along a path of decreasing potential energy from the soil through the plant to the atmosphere. The reported relative magnitudes of these pathway resistances vary widely and often these results are conflicting. One reason for such inconsistency is the difficulty in measuring the potential drop across various segments of the soil-plant-atmosphere continuum. The measurement of water potentials at the soil-root interface and in the root xylem of a transpiring plant remains a challenging problem.In the divided root experiment reported here, the measured water potential of an enclosed, nonabsorbing branch of the root system of young corn (Bonanza) plants to infer the water potential of the remaining roots growing in soil was used. The selected root branch of the seedling was grown in a specially constructed Teflon test tube into which a screen-enclosed thermocouple psychrometer was inserted and sealed to monitor the root's water potential. The root and its surrounding atmosphere were assumed to be in vapor equilibrium.

A Split-Root Technique for Measuring Root Water Potential

PubMed Central

Adeoye, Kingsley B.; Rawlins, Stephen L.

1981-01-01

Water encounters various resistances in moving along a path of decreasing potential energy from the soil through the plant to the atmosphere. The reported relative magnitudes of these pathway resistances vary widely and often these results are conflicting. One reason for such inconsistency is the difficulty in measuring the potential drop across various segments of the soil-plant-atmosphere continuum. The measurement of water potentials at the soil-root interface and in the root xylem of a transpiring plant remains a challenging problem. In the divided root experiment reported here, the measured water potential of an enclosed, nonabsorbing branch of the root system of young corn (Bonanza) plants to infer the water potential of the remaining roots growing in soil was used. The selected root branch of the seedling was grown in a specially constructed Teflon test tube into which a screen-enclosed thermocouple psychrometer was inserted and sealed to monitor the root's water potential. The root and its surrounding atmosphere were assumed to be in vapor equilibrium. Images PMID:16661886

Polygalasaponin XXXII from Polygala tenuifolia root improves hippocampal-dependent learning and memory.

PubMed

Xue, Wei; Hu, Jin-feng; Yuan, Yu-he; Sun, Jian-dong; Li, Bo-yu; Zhang, Dong-ming; Li, Chuang-jun; Chen, Nai-hong

2009-09-01

The aim of this study was to investigate the cognition-enhancing activity and underlying mechanisms of a triterpenoid saponin (polygalasaponin XXXII, PGS32) isolated from the roots of Polygala tenuifolia Willd. The Morris water maze was used to evaluate the spatial learning and memory of mice. To detect the basic properties of synaptic transmission and long-term potentiation (LTP) in the dentate gyrus of rats, electrophysiological recordings were made of evoked potentials. Western blotting analysis and immunofluorescence assays were used to determine the phosphorylation of extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), synapsin I and the expression of brain derived neurotrophic factor (BDNF). When administered at 0.125, 0.5, or 2 mg/kg, PGS32 could significantly prevent scopolamine-induced cognitive impairments in mice. Intracerebroventricular (icv) administration of PGS32 greatly enhanced basic synaptic transmission in the dentate gyrus of rats and induced LTP. In primary hippocampal neurons, as well as in the hippocampus of maze-trained mice, PGS32 activated the mitogen-activated protein (MAP) kinase cascade by promoting phosphorylation of ERK, CREB and synapsin I. The expression of BDNF was also greatly enhanced in the hippocampus. Our findings suggest that PGS32 can improve hippocampus-dependent learning and memory, possibly through improvement of synaptic transmission, activation of the MAP kinase cascade and enhancement of the level of BDNF. Therefore, PGS32 shows promise as a potential cognition-enhancing therapeutic drug.

Polygalasaponin XXXII from Polygala tenuifolia root improves hippocampal-dependent learning and memory

PubMed Central

Xue, Wei; Hu, Jin-feng; Yuan, Yu-he; Sun, Jian-dong; Li, Bo-yu; Zhang, Dong-ming; Li, Chuang-jun; Chen, Nai-hong

2009-01-01

Aim: The aim of this study was to investigate the cognition-enhancing activity and underlying mechanisms of a triterpenoid saponin (polygalasaponin XXXII, PGS32) isolated from the roots of Polygala tenuifolia Willd. Methods: The Morris water maze was used to evaluate the spatial learning and memory of mice. To detect the basic properties of synaptic transmission and long-term potentiation (LTP) in the dentate gyrus of rats, electrophysiological recordings were made of evoked potentials. Western blotting analysis and immunofluorescence assays were used to determine the phosphorylation of extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), synapsin I and the expression of brain derived neurotrophic factor (BDNF). Results: When administered at 0.125, 0.5, or 2 mg/kg, PGS32 could significantly prevent scopolamine-induced cognitive impairments in mice. Intracerebroventricular (icv) administration of PGS32 greatly enhanced basic synaptic transmission in the dentate gyrus of rats and induced LTP. In primary hippocampal neurons, as well as in the hippocampus of maze-trained mice, PGS32 activated the mitogen-activated protein (MAP) kinase cascade by promoting phosphorylation of ERK, CREB and synapsin I. The expression of BDNF was also greatly enhanced in the hippocampus. Conclusion: Our findings suggest that PGS32 can improve hippocampus-dependent learning and memory, possibly through improvement of synaptic transmission, activation of the MAP kinase cascade and enhancement of the level of BDNF. Therefore, PGS32 shows promise as a potential cognition-enhancing therapeutic drug. PMID:19684611

A major QTL controlling deep rooting on rice chromosome 4.

PubMed

Uga, Yusaku; Yamamoto, Eiji; Kanno, Noriko; Kawai, Sawako; Mizubayashi, Tatsumi; Fukuoka, Shuichi

2013-10-24

Drought is the most serious abiotic stress that hinders rice production under rainfed conditions. Breeding for deep rooting is a promising strategy to improve the root system architecture in shallow-rooting rice cultivars to avoid drought stress. We analysed the quantitative trait loci (QTLs) for the ratio of deep rooting (RDR) in three F₂ mapping populations derived from crosses between each of three shallow-rooting varieties ('ARC5955', 'Pinulupot1', and 'Tupa729') and a deep-rooting variety, 'Kinandang Patong'. In total, we detected five RDR QTLs on chromosomes 2, 4, and 6. In all three populations, QTLs on chromosome 4 were found to be located at similar positions; they explained from 32.0% to 56.6% of the total RDR phenotypic variance. This suggests that one or more key genetic factors controlling the root growth angle in rice is located in this region of chromosome 4.

Hairy root culture in a liquid-dispersed bioreactor: characterization of spatial heterogeneity.

PubMed

Williams, G R; Doran, P M

2000-01-01

A liquid-dispersed reactor equipped with a vertical mesh cylinder for inoculum support was developed for culture of Atropa belladonna hairy roots. The working volume of the culture vessel was 4.4 L with an aspect ratio of 1.7. Medium was dispersed as a spray onto the top of the root bed, and the roots grew radially outward from the central mesh cylinder to the vessel wall. Significant benefits in terms of liquid drainage and reduced interstitial liquid holdup were obtained using a vertical rather than horizontal support structure for the biomass and by operating the reactor with cocurrent air and liquid flow. With root growth, a pattern of spatial heterogeneity developed in the vessel. Higher local biomass densities, lower volumes of interstitial liquid, lower sugar concentrations, and higher root atropine contents were found in the upper sections of the root bed compared with the lower sections, suggesting a greater level of metabolic activity toward the top of the reactor. Although gas-liquid oxygen transfer to the spray droplets was very rapid, there was evidence of significant oxygen limitations in the reactor. Substantial volumes of non-free-draining interstitial liquid accumulated in the root bed. Roots near the bottom of the vessel trapped up to 3-4 times their own weight in liquid, thus eliminating the advantages of improved contact with the gas phase offered by liquid-dispersed culture systems. Local nutrient and product concentrations in the non-free-draining liquid were significantly different from those in the bulk medium, indicating poor liquid mixing within the root bed. Oxygen enrichment of the gas phase improved neither growth nor atropine production, highlighting the greater importance of liquid-solid compared with gas-liquid oxygen transfer resistance. The absence of mechanical or pneumatic agitation and the tendency of the root bed to accumulate liquid and impede drainage were identified as the major limitations to reactor performance. Improved

Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; McClelen, C. E.

1989-01-01

Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

A global Fine-Root Ecology Database to address below-ground challenges in plant ecology.

PubMed

Iversen, Colleen M; McCormack, M Luke; Powell, A Shafer; Blackwood, Christopher B; Freschet, Grégoire T; Kattge, Jens; Roumet, Catherine; Stover, Daniel B; Soudzilovskaia, Nadejda A; Valverde-Barrantes, Oscar J; van Bodegom, Peter M; Violle, Cyrille

2017-07-01

Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time. © 2017 UT-Battelle LLC. New Phytologist © 2017 New Phytologist Trust.

Root anatomy, morphology, and longevity among root orders in Vaccinium corymbosum (Ericaceae).

PubMed

Valenzuela-Estrada, Luis R; Vera-Caraballo, Vivianette; Ruth, Leah E; Eissenstat, David M

2008-12-01

Understanding root processes at the whole-plant or ecosystem scales requires an accounting of the range of functions within a root system. Studying root traits based on their branching order can be a powerful approach to understanding this complex system. The current study examined the highly branched root system of the ericoid plant, Vaccinium corymbosum L. (highbush blueberry) by classifying its root orders with a modified version of the morphometric approach similar to that used in hydrology for stream classification. Root anatomy provided valuable insight into variation in root function across orders. The more permanent portion of the root system occurred in 4th- and higher-order roots. Roots in these orders had radial growth; the lowest specific root length, N:C ratios, and mycorrhizal colonization; the highest tissue density and vessel number; and the coarsest root diameter. The ephemeral portion of the root system was mainly in the first three root orders. First- and 2nd-order roots were nearly anatomically identical, with similar mycorrhizal colonization and diameter, and also, despite being extremely fine, median lifespans were not very short (115-120 d; estimated with minirhizotrons). Our research underscores the value of examining root traits by root order and its implications to understanding belowground processes.

Fine root morphological traits determine variation in root respiration of Quercus serrata.

PubMed

Makita, Naoki; Hirano, Yasuhiro; Dannoura, Masako; Kominami, Yuji; Mizoguchi, Takeo; Ishii, Hiroaki; Kanazawa, Yoichi

2009-04-01

Fine root respiration is a significant component of carbon cycling in forest ecosystems. Although fine roots differ functionally from coarse roots, these root types have been distinguished based on arbitrary diameter cut-offs (e.g., 2 or 5 mm). Fine root morphology is directly related to physiological function, but few attempts have been made to understand the relationships between morphology and respiration of fine roots. To examine relationships between respiration rates and morphological traits of fine roots (0.15-1.4 mm in diameter) of mature Quercus serrata Murr., we measured respiration of small fine root segments in the field with a portable closed static chamber system. We found a significant power relationship between mean root diameter and respiration rate. Respiration rates of roots<0.4 mm in mean diameter were high and variable, ranging from 3.8 to 11.3 nmol CO2 g(-1) s(-1), compared with those of larger diameter roots (0.4-1.4 mm), which ranged from 1.8 to 3.0 nmol CO2 g(-1) s(-1). Fine root respiration rate was positively correlated with specific root length (SRL) as well as with root nitrogen (N) concentration. For roots<0.4 mm in diameter, SRL had a wider range (11.3-80.4 m g(-1)) and was more strongly correlated with respiration rate than diameter. Our results indicate that a more detailed classification of fine roots<2.0 mm is needed to represent the heterogeneity of root respiration and to evaluate root biomass and root morphological traits.

Root system morphology of Oregon white oak on a glacial outwash soil.

Treesearch

Warren D. Devine; Constance A. Harrington

2005-01-01

Oregon white oak is reportedly a deeply rooted species, but its rooting habit on coarse-textured soils is undocumented. In the Puget Trough of western Washington, Oregon white oak grows in coarse-textured glacial outwash soils on lowland sites. Our objective was to quantify the gross root system morphology of Oregon white oak in these soils, thereby improving our...

A major QTL controlling deep rooting on rice chromosome 4

PubMed Central

Uga, Yusaku; Yamamoto, Eiji; Kanno, Noriko; Kawai, Sawako; Mizubayashi, Tatsumi; Fukuoka, Shuichi

2013-01-01

Drought is the most serious abiotic stress that hinders rice production under rainfed conditions. Breeding for deep rooting is a promising strategy to improve the root system architecture in shallow-rooting rice cultivars to avoid drought stress. We analysed the quantitative trait loci (QTLs) for the ratio of deep rooting (RDR) in three F2 mapping populations derived from crosses between each of three shallow-rooting varieties (‘ARC5955', ‘Pinulupot1', and ‘Tupa729') and a deep-rooting variety, ‘Kinandang Patong'. In total, we detected five RDR QTLs on chromosomes 2, 4, and 6. In all three populations, QTLs on chromosome 4 were found to be located at similar positions; they explained from 32.0% to 56.6% of the total RDR phenotypic variance. This suggests that one or more key genetic factors controlling the root growth angle in rice is located in this region of chromosome 4. PMID:24154623

Mixed nano/micro-sized calcium phosphate composite and EDTA root surface etching improve availability of graft material in intrabony defects: an in vivo scanning electron microscopy evaluation.

PubMed

Gamal, Ahmed Y; Iacono, Vincent J

2013-12-01

The use of nanoparticles of graft materials may lead to breakthrough applications for periodontal regeneration. However, due to their small particle size, nanoparticles may be eliminated from periodontal defects by phagocytosis. In an attempt to improve nanoparticle retention in periodontal defects, the present in vivo study uses scanning electron microscopy (SEM) to evaluate the potential of micrograft particles of β-tricalcium phosphate (β-TCP) to enhance the binding and retention of nanoparticles of hydroxyapatite (nHA) on EDTA-treated and non-treated root surfaces in periodontal defects after 14 days of healing. Sixty patients having at least two hopeless periodontally affected teeth designated for extraction were randomly divided into four treatment groups (15 patients per group). Patients in group 1 had selected periodontal intrabony defects grafted with nHA of particle size 10 to 100 nm. Patients in group 2 were treated in a similar manner but had the affected roots etched for 2 minutes with a neutral 24% EDTA gel before grafting of the associated vertical defects with nHA. Patients in group 3 had the selected intrabony defects grafted with a composite graft consisting of equal volumes of nHA and β-TCP (particle size 63 to 150 nm). Patients in group 4 were treated as in group 3 but the affected roots were etched with neutral 24% EDTA as in group 2. For each of the four groups, one tooth was extracted immediately, and the second tooth was extracted after 14 days of healing for SEM evaluation. Fourteen days after surgery, all group 1 samples were devoid of any nanoparticles adherent to the root surfaces. Group 2 showed root surface areas 44.7% covered by a single layer of clot-blended grafted particles 14 days following graft application. After 14 days, group 3 samples appeared to retain fibrin strands devoid of grafted particles. Immediately extracted root samples of group 4 had adherent graft particles that covered a considerable area of the root surfaces

Root gravitropism and root hair development constitute coupled developmental responses regulated by auxin homeostasis in the Arabidopsis root apex.

PubMed

Rigas, Stamatis; Ditengou, Franck Anicet; Ljung, Karin; Daras, Gerasimos; Tietz, Olaf; Palme, Klaus; Hatzopoulos, Polydefkis

2013-03-01

Active polar transport establishes directional auxin flow and the generation of local auxin gradients implicated in plant responses and development. Auxin modulates gravitropism at the root tip and root hair morphogenesis at the differentiation zone. Genetic and biochemical analyses provide evidence for defective basipetal auxin transport in trh1 roots. The trh1, pin2, axr2 and aux1 mutants, and transgenic plants overexpressing PIN1, all showing impaired gravity response and root hair development, revealed ectopic PIN1 localization. The auxin antagonist hypaphorine blocked root hair elongation and caused moderate agravitropic root growth, also leading to PIN1 mislocalization. These results suggest that auxin imbalance leads to proximal and distal developmental defects in Arabidopsis root apex, associated with agravitropic root growth and root hair phenotype, respectively, providing evidence that these two auxin-regulated processes are coupled. Cell-specific subcellular localization of TRH1-YFP in stele and epidermis supports TRH1 engagement in auxin transport, and hence impaired function in trh1 causes dual defects of auxin imbalance. The interplay between intrinsic cues determining root epidermal cell fate through the TTG/GL2 pathway and environmental cues including abiotic stresses modulates root hair morphogenesis. As a consequence of auxin imbalance in Arabidopsis root apex, ectopic PIN1 mislocalization could be a risk aversion mechanism to trigger root developmental responses ensuring root growth plasticity. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Use of Model-Based Nutrient Feeding for Improved Production of Artemisinin by Hairy Roots of Artemisia Annua in a Modified Stirred Tank Bioreactor.

PubMed

Patra, Nivedita; Srivastava, Ashok K

2015-09-01

Artemisinin has been indicated to be a potent drug for the cure of malaria. Batch growth and artemisinin production kinetics of hairy root cultures of Artemisia annua were studied under shake flask conditions which resulted in accumulation of 12.49 g/L biomass and 0.27 mg/g artemisinin. Using the kinetic data, a mathematical model was identified to understand and optimize the system behavior. The developed model was then extrapolated to design nutrient feeding strategies during fed-batch cultivation for enhanced production of artemisinin. In one of the fed-batch cultivation, sucrose (37 g/L) feeding was done at a constant feed rate of 0.1 L/day during 10-15 days, which led to improved artemisinin accumulation of 0.77 mg/g. The second strategy of fed-batch hairy root cultivation involved maintenance of pseudo-steady state sucrose concentration (20.8 g/L) during 10-15 days which resulted in artemisinin accumulation of 0.99 mg/g. Fed-batch cultivation (with the maintenance of pseudo-steady state of substrate) of Artemisia annua hairy roots was, thereafter, implemented in bioreactor cultivation, which featured artemisinin accumulation of 1.0 mg/g artemisinin in 16 days of cultivation. This is the highest reported artemisinin yield by hairy root cultivation in a bioreactor.

Seedling root targets

Treesearch

Diane L. Haase

2011-01-01

Roots are critical to seedling performance after outplanting. Although root quality is not as quick and simple to measure as shoot quality, target root characteristics should be included in any seedling quality assessment program. This paper provides a brief review of root characteristics most commonly targeted for operational seedling production. These are: root mass...

Maize and soybean root front velocity and maximum depth in the Iowa, USA

USDA-ARS?s Scientific Manuscript database

Quantitative measurements of root traits can improve our understanding of how crops respond to soil-weather conditions. However, such data are rare. Our objective was to quantify maximum root depth and root front velocity (RFV) for corn and soybean crops across a range of growing conditions in the M...

Posterior Meniscal Root Repairs: Outcomes of an Anatomic Transtibial Pull-Out Technique.

PubMed

LaPrade, Robert F; Matheny, Lauren M; Moulton, Samuel G; James, Evan W; Dean, Chase S

2017-03-01

Outcomes after transtibial pull-out repair for posterior meniscal root tears remain underreported, and factors that may affect outcomes are unknown. Purpose/Hypothesis: The purpose of this study was to compare patient-centered outcomes after transtibial pull-out repair for posterior root tears in patients <50 and ≥50 years of age. We hypothesized that improvement in function and activity level at minimum 2-year follow-up would be similar among patients <50 years of age compared with patients ≥50 years and among patients undergoing medial versus lateral root repairs. Cohort study; Level of evidence, 3. Inclusion criteria were patients aged 18 years or older who underwent anatomic transtibial pull-out repair of the medial or lateral posterior meniscus root by a single surgeon. All patients were identified from a data registry consisting of prospectively collected data in a consecutive series. Cohorts were analyzed by age (<50 years [n = 35] vs ≥50 years [n = 15]) and laterality (lateral [n = 15] vs medial [n = 35]). Patients completed a subjective questionnaire preoperatively and at minimum of 2 years postoperatively (Lysholm, Tegner, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], 12-Item Short Form Health Survey [SF-12], and patient satisfaction with outcome). Failure was defined as revision meniscal root repair or partial meniscectomy. The analysis included 50 knees in 49 patients (16 females, 33 males; mean age, 38.3 years; mean body mass index, 26.6). Of the 50 knees, 45 were available for analysis. Three of 45 (6.7%) required revision surgery. All failures were in patients <50 years old, and all failures underwent medial root repair. No significant difference in failure was found based on age ( P=.541) or laterality ( P = .544). For age cohorts, Lysholm and WOMAC scores demonstrated significant postoperative improvement. For laterality cohorts, all functional scores significantly improved postoperatively. No significant difference

Genotype-Specific Variation in the Structure of Root Fungal Communities Is Related to Chickpea Plant Productivity

PubMed Central

Hamel, Chantal; Gan, Yantai; Tar'an, Bunyamin; Knight, Joan Diane

2015-01-01

Increasing evidence supports the existence of variations in the association of plant roots with symbiotic fungi that can improve plant growth and inhibit pathogens. However, it is unclear whether intraspecific variations in the symbiosis exist among plant cultivars and if they can be used to improve crop productivity. In this study, we determined genotype-specific variations in the association of chickpea roots with soil fungal communities and evaluated the effect of root mycota on crop productivity. A 2-year field experiment was conducted in southwestern Saskatchewan, the central zone of the chickpea growing region of the Canadian prairie. The effects of 13 cultivars of chickpea, comprising a wide range of phenotypes and genotypes, were tested on the structure of root-associated fungal communities based on internal transcribed spacer (ITS) and 18S rRNA gene markers using 454 amplicon pyrosequencing. Chickpea cultivar significantly influenced the structure of the root fungal community. The magnitude of the effect varied with the genotypes evaluated, and effects were consistent across years. For example, the roots of CDC Corrine, CDC Cory, and CDC Anna hosted the highest fungal diversity and CDC Alma and CDC Xena the lowest. Fusarium sp. was dominant in chickpea roots but was less abundant in CDC Corrine than the other cultivars. A bioassay showed that certain of these fungal taxa, including Fusarium species, can reduce the productivity of chickpea, whereas Trichoderma harzianum can increase chickpea productivity. The large variation in the profile of chickpea root mycota, which included growth-promoting and -inhibiting species, supports the possibility of improving the productivity of chickpea by improving its root mycota in chickpea genetic improvement programs using traditional breeding techniques. PMID:25616789

Estimation of root zone storage capacity at the catchment scale using improved Mass Curve Technique

NASA Astrophysics Data System (ADS)

Zhao, Jie; Xu, Zongxue; Singh, Vijay P.

2016-09-01

The root zone storage capacity (Sr) greatly influences runoff generation, soil water movement, and vegetation growth and is hence an important variable for ecological and hydrological modelling. However, due to the great heterogeneity in soil texture and structure, there seems to be no effective approach to monitor or estimate Sr at the catchment scale presently. To fill the gap, in this study the Mass Curve Technique (MCT) was improved by incorporating a snowmelt module for the estimation of Sr at the catchment scale in different climatic regions. The "range of perturbation" method was also used to generate different scenarios for determining the sensitivity of the improved MCT-derived Sr to its influencing factors after the evaluation of plausibility of Sr derived from the improved MCT. Results can be showed as: (i) Sr estimates of different catchments varied greatly from ∼10 mm to ∼200 mm with the changes of climatic conditions and underlying surface characteristics. (ii) The improved MCT is a simple but powerful tool for the Sr estimation in different climatic regions of China, and incorporation of more catchments into Sr comparisons can further improve our knowledge on the variability of Sr. (iii) Variation of Sr values is an integrated consequence of variations in rainfall, snowmelt water and evapotranspiration. Sr values are most sensitive to variations in evapotranspiration of ecosystems. Besides, Sr values with a longer return period are more stable than those with a shorter return period when affected by fluctuations in its influencing factors.

Ammonium-induced loss of root gravitropism is related to auxin distribution and TRH1 function, and is uncoupled from the inhibition of root elongation in Arabidopsis.

PubMed

Zou, Na; Li, Baohai; Dong, Gangqiang; Kronzucker, Herbert J; Shi, Weiming

2012-06-01

Root gravitropism is affected by many environmental stresses, including salinity, drought, and nutrient deficiency. One significant environmental stress, excess ammonium (NH(4)(+)), is well documented to inhibit root elongation and lateral root formation, yet little is known about its effects on the direction of root growth. We show here that inhibition of root elongation upon elevation of external NH(4)(+) is accompanied by a loss in root gravitropism (agravitropism) in Arabidopsis. Addition of potassium (K(+)) to the treatment medium partially rescued the inhibition of root elongation by high NH(4)(+) but did not improve gravitropic root curvature. Expression analysis of the auxin-responsive reporter gene DR5::GUS revealed that NH(4)(+) treatment delayed the development of gravity-induced auxin gradients across the root cap but extended their duration once initiated. Moreover, the β-glucuronidase (GUS) signal intensity in root tip cells was significantly reduced under high NH(4)(+) treatment over time. The potassium carrier mutant trh1 displayed different patterns of root gravitropism and DR5::GUS signal intensity in root apex cells compared with the wild type in response to NH(4)(+). Together, the results demonstrate that the effects of NH(4)(+) on root gravitropism are related to delayed lateral auxin redistribution and the TRH1 pathway, and are largely independent of inhibitory effects on root elongation.

Is the Inherent Potential of Maize Roots Efficient for Soil Phosphorus Acquisition?

PubMed Central

Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

2014-01-01

Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg−1, and the threshold indicating a significant environmental risk was about 15 mg kg−1, which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg−1, indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots. PMID:24594677

Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

PubMed

Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

2014-01-01

Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1), and the threshold indicating a significant environmental risk was about 15 mg kg(-1), which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1), indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

Using a Root Cause Analysis Curriculum for Practice-Based Learning and Improvement in General Surgery Residency.

PubMed

Ramanathan, Rajesh; Duane, Therese M; Kaplan, Brian J; Farquhar, Doris; Kasirajan, Vigneshwar; Ferrada, Paula

2015-01-01

To describe and evaluate a root cause analysis (RCA)-based educational curriculum for quality improvement (QI) practice-based learning and implementation in general surgery residency. A QI curriculum was designed using RCA and spaced-learning approaches to education. The program included a didactic session about the RCA methodology. Resident teams comprising multiple postgraduate years then selected a personal complication, completed an RCA, and presented the findings to the Department of Surgery. Mixed methods consisting of quantitative assessment of performance and qualitative feedback about the program were used to assess the value, strengths, and limitations of the program. Urban tertiary academic medical center. General surgery residents, faculty, and medical students. An RCA was completed by 4 resident teams for the following 4 adverse outcomes: postoperative neck hematoma, suboptimal massive transfusion for trauma, venous thromboembolism, and decubitus ulcer complications. Quantitative peer assessment of their performance revealed proficiency in selecting an appropriate case, defining the central problem, identifying root causes, and proposing solutions. During the qualitative feedback assessment, residents noted value of the course, with the greatest limitation being time constraints and equal participation. An RCA-based curriculum can provide general surgery residents with QI exposure and training that they value. Barriers to successful implementation include time restrictions and equal participation from all involved members. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Aortic root dynamics and surgery: from craft to science.

PubMed

Cheng, Allen; Dagum, Paul; Miller, D Craig

2007-08-29

Since the fifteenth century beginning with Leonardo da Vinci's studies, the precise structure and functional dynamics of the aortic root throughout the cardiac cycle continues to elude investigators. The last five decades of experimental work have contributed substantially to our current understanding of aortic root dynamics. In this article, we review and summarize the relevant structural analyses, using radiopaque markers and sonomicrometric crystals, concerning aortic root three-dimensional deformations and describe aortic root dynamics in detail throughout the cardiac cycle. We then compare data between different studies and discuss the mechanisms responsible for the modes of aortic root deformation, including the haemodynamics, anatomical and temporal determinants of those deformations. These modes of aortic root deformation are closely coupled to maximize ejection, optimize transvalvular ejection haemodynamics and-perhaps most importantly-reduce stress on the aortic valve cusps by optimal diastolic load sharing and minimizing transvalvular turbulence throughout the cardiac cycle. This more comprehensive understanding of aortic root mechanics and physiology will contribute to improved medical and surgical treatment methods, enhanced therapeutic decision making and better post-intervention care of patients. With a better understanding of aortic root physiology, future research on aortic valve repair and replacement should take into account the integrated structural and functional asymmetry of aortic root dynamics to minimize stress on the aortic cusps in order to prevent premature structural valve deterioration.

Competing neighbors: light perception and root function.

PubMed

Gundel, Pedro E; Pierik, Ronald; Mommer, Liesje; Ballaré, Carlos L

2014-09-01

Plant responses to competition have often been described as passive consequences of reduced resource availability. However, plants have mechanisms to forage for favorable conditions and anticipate competition scenarios. Despite the progresses made in understanding the role of light signaling in modulating plant-plant interactions, little is known about how plants use and integrate information gathered by their photoreceptors aboveground to regulate performance belowground. Given that the phytochrome family of photoreceptors plays a key role in the acquisition of information about the proximity of neighbors and canopy cover, it is tempting to speculate that changes in the red:far-red (R:FR) ratio perceived by aboveground plant parts have important implications shaping plant behavior belowground. Exploring data from published experiments, we assess the neglected role of light signaling in the control of root function. The available evidence indicates that plant exposure to low R:FR ratios affects root growth and morphology, root exudate profiles, and interactions with beneficial soil microorganisms. Although dependent on species identity, signals perceived aboveground are likely to affect root-to-root interactions. Root systems could also be guided to deploy new growth predominantly in open areas by light signals perceived by the shoots. Studying interactions between above- and belowground plant-plant signaling is expected to improve our understanding of the mechanisms of plant competition.

Next Generation Image-Based Phenotyping of Root System Architecture

NASA Astrophysics Data System (ADS)

Davis, T. W.; Shaw, N. M.; Cheng, H.; Larson, B. G.; Craft, E. J.; Shaff, J. E.; Schneider, D. J.; Piñeros, M. A.; Kochian, L. V.

2016-12-01

The development of the Plant Root Imaging and Data Acquisition (PRIDA) hardware/software system enables researchers to collect digital images, along with all the relevant experimental details, of a range of hydroponically grown agricultural crop roots for 2D and 3D trait analysis. Previous efforts of image-based root phenotyping focused on young cereals, such as rice; however, there is a growing need to measure both older and larger root systems, such as those of maize and sorghum, to improve our understanding of the underlying genetics that control favorable rooting traits for plant breeding programs to combat the agricultural risks presented by climate change. Therefore, a larger imaging apparatus has been prototyped for capturing 3D root architecture with an adaptive control system and innovative plant root growth media that retains three-dimensional root architectural features. New publicly available multi-platform software has been released with considerations for both high throughput (e.g., 3D imaging of a single root system in under ten minutes) and high portability (e.g., support for the Raspberry Pi computer). The software features unified data collection, management, exploration and preservation for continued trait and genetics analysis of root system architecture. The new system makes data acquisition efficient and includes features that address the needs of researchers and technicians, such as reduced imaging time, semi-automated camera calibration with uncertainty characterization, and safe storage of the critical experimental data.

Impact of root growth and root hydraulic conductance on water availability of young walnut trees

NASA Astrophysics Data System (ADS)

Jerszurki, Daniela; Couvreur, Valentin; Hopmans, Jan W.; Silva, Lucas C. R.; Shackel, Kenneth A.; de Souza, Jorge L. M.

2015-04-01

Walnut (Juglans regia L.) is a tree species of high economic importance in the Central Valley of California. This crop has particularly high water requirements, which makes it highly dependent on irrigation. The context of decreasing water availability in the state calls for efficient water management practices, which requires improving our understanding of the relationship between water application and walnut water availability. In addition to the soil's hydraulic conductivity, two plant properties are thought to control the supply of water from the bulk soil to the canopy: (i) root distribution and (ii) plant hydraulic conductance. Even though these properties are clearly linked to crop water requirements, their quantitative relation remains unclear. The aim of this study is to quantitatively explain walnut water requirements under water deficit from continuous measurements of its water consumption, soil and stem water potential, root growth and root system hydraulic conductance. For that purpose, a greenhouse experiment was conducted for a two month period. Young walnut trees were planted in transparent cylindrical pots, equipped with: (i) rhizotron tubes, which allowed for non-invasive monitoring of root growth, (ii) pressure transducer tensiometers for soil water potential, (iii) psychrometers attached to non-transpiring leaves for stem water potential, and (iv) weighing scales for plant transpiration. Treatments consisted of different irrigation rates: 100%, 75% and 50% of potential crop evapotranspiration. Plant responses were compared to predictions from three simple process-based soil-plant-atmosphere models of water flow: (i) a hydraulic model of stomatal regulation based on stem water potential and vapor pressure deficit, (ii) a model of plant hydraulics predicting stem water potential from soil-root interfaces water potential, and (iii) a model of soil water depletion predicting the water potential drop between the bulk soil and soil-root interfaces

Root Tip Shape Governs Root Elongation Rate under Increased Soil Strength1[OPEN

PubMed Central

Kirchgessner, Norbert; Walter, Achim

2017-01-01

Increased soil strength due to soil compaction or soil drying is a major limitation to root growth and crop productivity. Roots need to exert higher penetration force, resulting in increased penetration stress when elongating in soils of greater strength. This study aimed to quantify how the genotypic diversity of root tip geometry and root diameter influences root elongation under different levels of soil strength and to determine the extent to which roots adjust to increased soil strength. Fourteen wheat (Triticum aestivum) varieties were grown in soil columns packed to three bulk densities representing low, moderate, and high soil strength. Under moderate and high soil strength, smaller root tip radius-to-length ratio was correlated with higher genotypic root elongation rate, whereas root diameter was not related to genotypic root elongation. Based on cavity expansion theory, it was found that smaller root tip radius-to-length ratio reduced penetration stress, thus enabling higher root elongation rates in soils with greater strength. Furthermore, it was observed that roots could only partially adjust to increased soil strength. Root thickening was bounded by a maximum diameter, and root tips did not become more acute in response to increased soil strength. The obtained results demonstrated that root tip geometry is a pivotal trait governing root penetration stress and root elongation rate in soils of greater strength. Hence, root tip shape needs to be taken into account when selecting for crop varieties that may tolerate high soil strength. PMID:28600344

Root Ideotype Influences Nitrogen Transport and Assimilation in Maize

PubMed Central

Dechorgnat, Julie; Francis, Karen L.; Dhugga, Kanwarpal S.; Rafalski, J. A.; Tyerman, Stephen D.; Kaiser, Brent N.

2018-01-01

Maize (Zea mays, L.) yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE), a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA) developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown) were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program. PMID:29740466

Correlation of root dentin thickness and length of roots in mesial roots of mandibular molars.

PubMed

Dwivedi, Shweta; Dwivedi, Chandra Dhar; Mittal, Neelam

2014-09-01

The purpose of this study was to analyze the relation of tooth length and distal wall thickness of mesial roots in mandibular molars at different locations (ie, 2 mm below the furcation and at the junction between the middle and apical third). Forty-five mandibular first molars were taken, and the length of each tooth was measured. Then, specimens were divided into three groups according to their length: group I-long (24.2 mm ± 1.8), group II-medium (21 mm ± 1.5) and group III-short (16.8 mm ± 1.8). mesial root of each marked at two levels - at 2 mm below the furcation as well as at junction of apical and middle third of roots. The minimum thickness of the distal root dentine associated with the buccal and lingual canals of the mesial roots was measured, The distance between the buccal and lingual canals and the depth of concavity in the distal surface of the mesial roots were also measured. Statistical analysis was performed by using analysis of variance and the Student-Newman-Keuls test. The minimum thickness of the distal wall of the mesiobuccal canal was significantly different (P < .001) between groups 1 (long) and 3 (short). Distal wall thickness of the mesiobuccal root and distal concavity of the mesial root of mandibular first molars were found to be thinner in longer teeth compared with shorter teeth. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The Importance of Juvenile Root Traits for Crop Yields

NASA Astrophysics Data System (ADS)

White, Philip; Adu, Michael; Broadley, Martin; Brown, Lawrie; Dupuy, Lionel; George, Timothy; Graham, Neil; Hammond, John; Hayden, Rory; Neugebauer, Konrad; Nightingale, Mark; Ramsay, Gavin; Thomas, Catherine; Thompson, Jacqueline; Wishart, Jane; Wright, Gladys

2014-05-01

Genetic variation in root system architecture (RSA) is an under-exploited breeding resource. This is partly a consequence of difficulties in the rapid and accurate assessment of subterranean root systems. However, although the characterisation of root systems of large plants in the field are both time-consuming and labour-intensive, high-throughput (HTP) screens of root systems of juvenile plants can be performed in the field, glasshouse or laboratory. It is hypothesised that improving the root systems of juvenile plants can accelerate access to water and essential mineral elements, leading to rapid crop establishment and, consequently, greater yields. This presentation will illustrate how aspects of the juvenile root systems of potato (Solanum tuberosum L.) and oilseed rape (OSR; Brassica napus L.) correlate with crop yields and examine the reasons for such correlations. It will first describe the significant positive relationships between early root system development, phosphorus acquisition, canopy establishment and eventual yield among potato genotypes. It will report the development of a glasshouse assay for root system architecture (RSA) of juvenile potato plants, the correlations between root system architectures measured in the glasshouse and field, and the relationships between aspects of the juvenile root system and crop yields under drought conditions. It will then describe the development of HTP systems for assaying RSA of OSR seedlings, the identification of genetic loci affecting RSA in OSR, the development of mathematical models describing resource acquisition by OSR, and the correlations between root traits recorded in the HTP systems and yields of OSR in the field.

Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots1[OPEN

PubMed Central

Durand, Mickaël; Porcheron, Benoît; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

2016-01-01

Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. 14CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. PMID:26802041

Surviving floods: leaf gas films improve O₂ and CO₂ exchange, root aeration, and growth of completely submerged rice.

PubMed

Pedersen, Ole; Rich, Sarah Meghan; Colmer, Timothy David

2009-04-01

When completely submerged, the leaves of some species retain a surface gas film. Leaf gas films on submerged plants have recently been termed 'plant plastrons', analogous with the plastrons of aquatic insects. In aquatic insects, surface gas layers (i.e. plastrons) enlarge the gas-water interface to promote O₂ uptake when under water; however, the function of leaf gas films has rarely been considered. The present study demonstrates that gas films on leaves of completely submerged rice facilitate entry of O₂ from floodwaters when in darkness and CO₂ entry when in light. O₂ microprofiles showed that the improved gas exchange was not caused by differences in diffusive boundary layers adjacent to submerged leaves with or without gas films; instead, reduced resistance to gas exchange was probably due to the enlarged water-gas interface (cf. aquatic insects). When gas films were removed artificially, underwater net photosynthesis declined to only 20% of the rate with gas films present, such that, after 7 days of complete submergence, tissue sugar levels declined, and both shoot and root growth were reduced. Internal aeration of roots in anoxic medium, when shoots were in aerobic floodwater in darkness or when in light, was improved considerably when leaf gas films were present. Thus, leaf gas films contribute to the submergence tolerance of rice, in addition to those traits already recognized, such as the shoot-elongation response, aerenchyma and metabolic adjustments to O₂ deficiency and oxidative stress. © 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd.

Root diversity in alpine plants: root length, tensile strength and plant age

NASA Astrophysics Data System (ADS)

Pohl, M.; Stroude, R.; Körner, C.; Buttler, A.; Rixen, C.

2009-04-01

A high diversity of plant species and functional groups is hypothesised to increase the diversity of root types and their subsequent effects for soil stability. However, even basic data on root characteristics of alpine plants are very scarce. Therefore, we determined important root characteristics of 13 plant species from different functional groups, i.e. grasses, herbs and shrubs. We excavated the whole root systems of 62 plants from a machine-graded ski slope at 2625 m a.s.l. and analysed the rooting depth, the horizontal root extension, root length and diameter. Single roots of plant species were tested for tensile strength. The age of herbs and shrubs was determined by growth-ring analysis. Root characteristics varied considerably between both plant species and functional groups. The rooting depth of different species ranged from 7.2 ± 0.97 cm to 20.5 ± 2.33 cm, but was significantly larger in the herb Geum reptans (70.8 ± 10.75 cm). The woody species Salix breviserrata reached the highest horizontal root extensions (96.8 ± 25.5 cm). Most plants had their longest roots in fine diameter classes (0.5

Meniscus root repair.

PubMed

Vyas, Dharmesh; Harner, Christopher D

2012-06-01

Root tears are a subset of meniscal injuries that result in significant knee joint pathology. Occurring on either the medial or lateral side, root tears are defined as radial tears or avulsions of the posterior horn attachment to bone. After a root tear, there is a significant increase in tibio-femoral contact pressure concomitant with altered knee joint kinematics. Previous cadaver studies from our institution have shown that root repair of the medial meniscus is successful in restoring joint biomechanics to within normal limits. Indications for operative management of meniscal root tears include (1) a symptomatic medial meniscus root tear with minimal arthritis and having failed non-operative treatment, and (2) a lateral root tear in associated with an ACL tear. In this review, we describe diagnosis, imaging, patient selection, and arthroscopic surgical technique of medial and lateral meniscus root injuries. In addition we highlight the pearls of repair technique, associated complications, post-operative rehabilitation regimen, and expected outcomes.

Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

PubMed Central

Chimungu, Joseph G.; Loades, Kenneth W.; Lynch, Jonathan P.

2015-01-01

The ability of roots to penetrate hard soil is important for crop productivity but specific root phenes contributing to this ability are poorly understood. Root penetrability and biomechanical properties are likely to vary in the root system dependent on anatomical structure. No information is available to date on the influence of root anatomical phenes on root penetrability and biomechanics. Root penetration ability was evaluated using a wax layer system. Root tensile and bending strength were evaluated in plant roots grown in the greenhouse and in the field. Root anatomical phenes were found to be better predictors of root penetrability than root diameter per se and associated with smaller distal cortical region cell size. Smaller outer cortical region cells play an important role in stabilizing the root against ovalization and reducing the risk of local buckling and collapse during penetration, thereby increasing root penetration of hard layers. The use of stele diameter was found to be a better predictor of root tensile strength than root diameter. Cortical thickness, cortical cell count, cortical cell wall area and distal cortical cell size were stronger predictors of root bend strength than root diameter. Our results indicate that root anatomical phenes are important predictors for root penetrability of high-strength layers and root biomechanical properties. PMID:25903914

Genetic and environmental factors affecting early rooting of six Populus genomic groups: implications for tree improvement

Treesearch

Ronald S., Jr. Zalesny

2006-01-01

Genetic and environmental factors affect the early rooting of Populus planted as unrooted hardwood cuttings. Populus genotypes of six genomic groups were tested in numerous studies for the quantitative genetics of rooting, along with effects of preplanting treatments and soil temperature. Genetics data (e.g. heritabilities,...

Light as stress factor to plant roots – case of root halotropism

PubMed Central

Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

2014-01-01

Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives. PMID:25566292

Petaminer: Using ROOT for efficient data storage in MySQL database

NASA Astrophysics Data System (ADS)

Cranshaw, J.; Malon, D.; Vaniachine, A.; Fine, V.; Lauret, J.; Hamill, P.

2010-04-01

High Energy and Nuclear Physics (HENP) experiments store Petabytes of event data and Terabytes of calibration data in ROOT files. The Petaminer project is developing a custom MySQL storage engine to enable the MySQL query processor to directly access experimental data stored in ROOT files. Our project is addressing the problem of efficient navigation to PetaBytes of HENP experimental data described with event-level TAG metadata, which is required by data intensive physics communities such as the LHC and RHIC experiments. Physicists need to be able to compose a metadata query and rapidly retrieve the set of matching events, where improved efficiency will facilitate the discovery process by permitting rapid iterations of data evaluation and retrieval. Our custom MySQL storage engine enables the MySQL query processor to directly access TAG data stored in ROOT TTrees. As ROOT TTrees are column-oriented, reading them directly provides improved performance over traditional row-oriented TAG databases. Leveraging the flexible and powerful SQL query language to access data stored in ROOT TTrees, the Petaminer approach enables rich MySQL index-building capabilities for further performance optimization.

Does mycorrhizal inoculation improve plant survival, aggregate stability, and fine root development on a coarse-grained soil in an alpine eco-engineering field experiment?

NASA Astrophysics Data System (ADS)

Bast, A.; Wilcke, W.; Graf, F.; Lüscher, P.; Gärtner, H.

2016-08-01

Steep vegetation-free talus slopes in high mountain environments are prone to superficial slope failures and surface erosion. Eco-engineering measures can reduce slope instabilities and thus contribute to risk mitigation. In a field experiment, we established mycorrhizal and nonmycorrhizal research plots and determined their biophysical contribution to small-scale soil fixation. Mycorrhizal inoculation impact on plant survival, aggregate stability, and fine root development was analyzed. Here we present plant survival (ntotal = 1248) and soil core (ntotal = 108) analyses of three consecutive years in the Swiss Alps. Soil cores were assayed for their aggregate stability coefficient (ASC), root length density (RLD), and mean root diameter (MRD). Inoculation improved plant survival significantly, but it delayed aggregate stabilization relative to the noninoculated site. Higher aggregate stability occurred only after three growing seasons. Then also RLD tended to be higher and MRD increased significantly at the mycorrhizal treated site. There was a positive correlation between RLD, ASC, and roots <0.5 mm, which had the strongest impact on soil aggregation. Our results revealed a temporal offset between inoculation effects tested in laboratory and field experiments. Consequently, we recommend to establish an intermediate to long-term field experimental monitoring before transferring laboratory results to the field.

Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin.

PubMed

Gaddala, Naresh; Veeramachineni, Chandrasekhar; Tummala, Muralidhar

2015-05-01

Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but not statistically significant than smear clear.

Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin

PubMed Central

Gaddala, Naresh; Veeramachineni, Chandrasekhar

2015-01-01

Background Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. Aim The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. Materials and Methods Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. Results Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. Conclusion Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but

Psoralen production in hairy roots and adventitious roots cultures of Psoralea coryfolia.

PubMed

Baskaran, P; Jayabalan, N

2009-07-01

Psoralea corylifolia is an endangered plant producing various compounds of medical importance. Adventitious roots and hairy roots were induced in cultures prepared from hypocotyl explants. Psoralen content was evaluated in both root types grown either in suspension cultures or on agar solidified medium. Psoralen content was approximately 3 mg g(-1) DW in suspension grown hairy roots being higher than in solid grown hairy roots and in solid and suspension-grown adventitious roots.

Comparing root architectural models

NASA Astrophysics Data System (ADS)

Schnepf, Andrea; Javaux, Mathieu; Vanderborght, Jan

2017-04-01

Plant roots play an important role in several soil processes (Gregory 2006). Root architecture development determines the sites in soil where roots provide input of carbon and energy and take up water and solutes. However, root architecture is difficult to determine experimentally when grown in opaque soil. Thus, root architectural models have been widely used and been further developed into functional-structural models that are able to simulate the fate of water and solutes in the soil-root system (Dunbabin et al. 2013). Still, a systematic comparison of the different root architectural models is missing. In this work, we focus on discrete root architecture models where roots are described by connected line segments. These models differ (a) in their model concepts, such as the description of distance between branches based on a prescribed distance (inter-nodal distance) or based on a prescribed time interval. Furthermore, these models differ (b) in the implementation of the same concept, such as the time step size, the spatial discretization along the root axes or the way stochasticity of parameters such as root growth direction, growth rate, branch spacing, branching angles are treated. Based on the example of two such different root models, the root growth module of R-SWMS and RootBox, we show the impact of these differences on simulated root architecture and aggregated information computed from this detailed simulation results, taking into account the stochastic nature of those models. References Dunbabin, V.M., Postma, J.A., Schnepf, A., Pagès, L., Javaux, M., Wu, L., Leitner, D., Chen, Y.L., Rengel, Z., Diggle, A.J. Modelling root-soil interactions using three-dimensional models of root growth, architecture and function (2013) Plant and Soil, 372 (1-2), pp. 93 - 124. Gregory (2006) Roots, rhizosphere and soil: the route to a better understanding of soil science? European Journal of Soil Science 57: 2-12.

Root hairs aid soil penetration by anchoring the root surface to pore walls

PubMed Central

Bengough, A. Glyn; Loades, Kenneth; McKenzie, Blair M.

2016-01-01

The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3–3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0–1.5g cm−3). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm−3 soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm−3 soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm−3). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm−3 soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

Factors affecting induction and development of in vitro rooting in apple rootstocks.

PubMed

Sharma, T; Modgil, M; Thakur, M

2007-09-01

Shoots of apple rootstocks raised in vitro were transferred to various rooting media to study the effect of different factors on root initiation and development. Various concentrations of indole-3-butyric acid (IBA) initiated rooting but maximum rooting percentage was found with 2.0 and 2.5 mg l(-1) of IBA in M7 and with 1.0 mg l(-1) of IBA in MM106. The drawback was that the roots were thick, short and with profuse callus. The presence of activated charcoal (AC) in the rooting medium improved the rooting quality but reduced the rooting percentage in both the rootstocks. In high auxin dip of 70, 80 and 90 mg l(-1) IBA for 2, 2 and 1 hr showed 75-85 per cent rooting in M7, but lacked reproducibility of the results. Whereas in MM106, 66 - 70 % rooting was achieved with 70 mg l(-1) of IBA dip for 3 h. Root induction in shoots in IBA containing liquid medium (LM) in dark for few days and root elongation in IBA--free medium in light proved most effective. On the other hand, continuous light treatment showed reduced rooting. Reduction of MS salts and sucrose in root elongation medium showed decreased rooting. Plantlets from two--stage rooting procedure showed more rapid growth and satisfactory survival during hardening of plants and on transfer to field.

Root canal irrigants

PubMed Central

Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

2010-01-01

Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

Hybrid Artificial Root Foraging Optimizer Based Multilevel Threshold for Image Segmentation

PubMed Central

Liu, Yang; Liu, Junfei

2016-01-01

This paper proposes a new plant-inspired optimization algorithm for multilevel threshold image segmentation, namely, hybrid artificial root foraging optimizer (HARFO), which essentially mimics the iterative root foraging behaviors. In this algorithm the new growth operators of branching, regrowing, and shrinkage are initially designed to optimize continuous space search by combining root-to-root communication and coevolution mechanism. With the auxin-regulated scheme, various root growth operators are guided systematically. With root-to-root communication, individuals exchange information in different efficient topologies, which essentially improve the exploration ability. With coevolution mechanism, the hierarchical spatial population driven by evolutionary pressure of multiple subpopulations is structured, which ensure that the diversity of root population is well maintained. The comparative results on a suit of benchmarks show the superiority of the proposed algorithm. Finally, the proposed HARFO algorithm is applied to handle the complex image segmentation problem based on multilevel threshold. Computational results of this approach on a set of tested images show the outperformance of the proposed algorithm in terms of optimization accuracy computation efficiency. PMID:27725826

Hybrid Artificial Root Foraging Optimizer Based Multilevel Threshold for Image Segmentation.

PubMed

Liu, Yang; Liu, Junfei; Tian, Liwei; Ma, Lianbo

2016-01-01

This paper proposes a new plant-inspired optimization algorithm for multilevel threshold image segmentation, namely, hybrid artificial root foraging optimizer (HARFO), which essentially mimics the iterative root foraging behaviors. In this algorithm the new growth operators of branching, regrowing, and shrinkage are initially designed to optimize continuous space search by combining root-to-root communication and coevolution mechanism. With the auxin-regulated scheme, various root growth operators are guided systematically. With root-to-root communication, individuals exchange information in different efficient topologies, which essentially improve the exploration ability. With coevolution mechanism, the hierarchical spatial population driven by evolutionary pressure of multiple subpopulations is structured, which ensure that the diversity of root population is well maintained. The comparative results on a suit of benchmarks show the superiority of the proposed algorithm. Finally, the proposed HARFO algorithm is applied to handle the complex image segmentation problem based on multilevel threshold. Computational results of this approach on a set of tested images show the outperformance of the proposed algorithm in terms of optimization accuracy computation efficiency.

Regulation of root morphogenesis in arbuscular mycorrhizae: what role do fungal exudates, phosphate, sugars and hormones play in lateral root formation?

PubMed Central

Fusconi, Anna

2014-01-01

Background Arbuscular mycorrhizae (AMs) form a widespread root–fungus symbiosis that improves plant phosphate (Pi) acquisition and modifies the physiology and development of host plants. Increased branching is recognized as a general feature of AM roots, and has been interpreted as a means of increasing suitable sites for colonization. Fungal exudates, which are involved in the dialogue between AM fungi and their host during the pre-colonization phase, play a well-documented role in lateral root (LR) formation. In addition, the increased Pi content of AM plants, in relation to Pi-starved controls, as well as changes in the delivery of carbohydrates to the roots and modulation of phytohormone concentration, transport and sensitivity, are probably involved in increasing root system branching. Scope This review discusses the possible causes of increased branching in AM plants. The differential root responses to Pi, sugars and hormones of potential AM host species are also highlighted and discussed in comparison with those of the non-host Arabidopsis thaliana. Conclusions Fungal exudates are probably the main compounds regulating AM root morphogenesis during the first colonization steps, while a complex network of interactions governs root development in established AMs. Colonization and high Pi act synergistically to increase root branching, and sugar transport towards the arbusculated cells may contribute to LR formation. In addition, AM colonization and high Pi generally increase auxin and cytokinin and decrease ethylene and strigolactone levels. With the exception of cytokinins, which seem to regulate mainly the root:shoot biomass ratio, these hormones play a leading role in governing root morphogenesis, with strigolactones and ethylene blocking LR formation in the non-colonized, Pi-starved plants, and auxin inducing them in colonized plants, or in plants grown under high Pi conditions. PMID:24227446

Fine-tuning of root elongation by ethylene: a tool to study dynamic structure–function relationships between root architecture and nitrate absorption

PubMed Central

Le Deunff, Erwan; Lecourt, Julien; Malagoli, Philippe

2016-01-01

Background Recently developed genetic and pharmacological approaches have been used to explore NO3−/ethylene signalling interactions and how the modifications in root architecture by pharmacological modulation of ethylene biosynthesis affect nitrate uptake. Key Results Structure–function studies combined with recent approaches to chemical genomics highlight the non-specificity of commonly used inhibitors of ethylene biosynthesis such as AVG (l-aminoethoxyvinylglycine). Indeed, AVG inhibits aminotransferases such as ACC synthase (ACS) and tryptophan aminotransferase (TAA) involved in ethylene and auxin biosynthesis but also some aminotransferases implied in nitrogen (N) metabolism. In this framework, it can be assumed that the products of nitrate assimilation and hormones may interact through a hub in carbon (C) and N metabolism to drive the root morphogenetic programme (RMP). Although ethylene/auxin interactions play a major role in cell division and elongation in root meristems, shaping of the root system depends also on energetic considerations. Based on this finding, the analysis is extended to nutrient ion–hormone interactions assuming a fractal or constructal model for root development. Conclusion Therefore, the tight control of root structure–function in the RMP may explain why over-expressing nitrate transporter genes to decouple structure–function relationships and improve nitrogen use efficiency (NUE) has been unsuccessful. PMID:27411681

X-ray computed tomography uncovers root-root interactions: quantifying spatial relationships between interacting root systems in three dimensions.

PubMed

Paya, Alexander M; Silverberg, Jesse L; Padgett, Jennifer; Bauerle, Taryn L

2015-01-01

Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D) using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen) and Picea mariana (black spruce) seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for 2 months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals) and paired seedlings (inter- or intra-specific), than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.

Root hairs aid soil penetration by anchoring the root surface to pore walls.

PubMed

Bengough, A Glyn; Loades, Kenneth; McKenzie, Blair M

2016-02-01

The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3-3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0-1.5g cm(-3)). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm(-3) soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm(-3) soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm(-3)). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm(-3) soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Measurements of water uptake of maize roots: the key function of lateral roots

NASA Astrophysics Data System (ADS)

Ahmed, M. A.; Zarebanadkouki, M.; Kroener, E.; Kaestner, A.; Carminati, A.

2014-12-01

Maize (Zea mays L.) is one of the most important crop worldwide. Despite its importance, there is limited information on the function of different root segments and root types of maize in extracting water from soils. Therefore, the aim of this study was to investigate locations of root water uptake in maize. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maizes were grown in aluminum containers (40×38×1 cm) filled with a sandy soil. When the plants were 16 days old, we injected D2O into selected soil regions containing primary, seminal and lateral roots. The experiments were performed during the day (transpiring plants) and night (not transpiring plants). The transport of D2O into roots was simulated using a new convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusional permeability and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Water uptake occurred primarily in lateral roots. Lateral roots had the highest diffusional permeability (9.4×10-7), which was around six times higher that the diffusional permeability of the old seminal segments (1.4×10-7), and two times higher than the diffusional permeability of the young seminal segments (4.7×10-7). The radial flow of D2O into the lateral (6.7×10-5 ) was much higher than in the young seminal roots (1.1×10-12). The radial flow of D2O into the old seminal was negligible. We concluded that the function of the primary and seminal roots was to collect water from the lateral roots and transport it to the shoot. A maize root system with lateral roots branching from deep primary and seminal roots would be

The protein expression landscape of the Arabidopsis root

PubMed Central

Petricka, Jalean J.; Schauer, Monica A.; Megraw, Molly; Breakfield, Natalie W.; Thompson, J. Will; Georgiev, Stoyan; Soderblom, Erik J.; Ohler, Uwe; Moseley, Martin Arthur; Grossniklaus, Ueli; Benfey, Philip N.

2012-01-01

Because proteins are the major functional components of cells, knowledge of their cellular localization is crucial to gaining an understanding of the biology of multicellular organisms. We have generated a protein expression map of the Arabidopsis root providing the identity and cell type-specific localization of nearly 2,000 proteins. Grouping proteins into functional categories revealed unique cellular functions and identified cell type-specific biomarkers. Cellular colocalization provided support for numerous protein–protein interactions. With a binary comparison, we found that RNA and protein expression profiles are weakly correlated. We then performed peak integration at cell type-specific resolution and found an improved correlation with transcriptome data using continuous values. We performed GeLC-MS/MS (in-gel tryptic digestion followed by liquid chromatography-tandem mass spectrometry) proteomic experiments on mutants with ectopic and no root hairs, providing complementary proteomic data. Finally, among our root hair-specific proteins we identified two unique regulators of root hair development. PMID:22447775

Depth and Diameter of the Parent Roots of Aspen Root Suckers

Treesearch

Robert E. Farmer

1962-01-01

Studies of the Populus tremuloides root system by Day (1944), Sandberg (1951) and Barnes (1959) have all shown lateral roots extending as much as 30 feet from tree base. These roots may branch extensively and sometimes exhibit an "undulating" growth habit. According to the above authors, suckers occur on the segments of these lateral roots...

Strontium ranelate improved tooth anchorage and reduced root resorption in orthodontic treatment of rats.

PubMed

Kirschneck, Christian; Wolf, Michael; Reicheneder, Claudia; Wahlmann, Ulrich; Proff, Peter; Roemer, Piero

2014-12-05

The anchorage mechanisms currently used in orthodontic treatment have various disadvantages. The objective of this study was to determine the applicability of the osteoporosis medication strontium ranelate in pharmacologically induced orthodontic tooth anchorage. In 48 male Wistar rats, a constant orthodontic force of 0.25 N was reciprocally applied to the upper first molar and the incisors by means of a Sentalloy(®) closed coil spring for two to four weeks. 50% of the animals received strontium ranelate at a daily oral dosage of 900 mg per kilogramme of body weight. Bioavailability was determined by blood analyses. The extent of tooth movement was measured both optometrically and cephalometrically (CBCT). Relative alveolar gene expression of osteoclastic markers and OPG-RANKL was assessed by qRT-PCR and root resorption area and osteoclastic activity were determined in TRAP-stained histologic sections of the alveolar process. Compared to controls, the animals treated with strontium ranelate showed up to 40% less tooth movement after four weeks of orthodontic treatment. Gene expression and histologic analyses showed significantly less osteoclastic activity and a significantly smaller root resorption area. Blood analyses confirmed sufficient bioavailability of strontium ranelate. Because of its pharmacologic effects on bone metabolism, strontium ranelate significantly reduced tooth movement and root resorption in orthodontic treatment of rats. Strontium ranelate may be a viable agent for inducing tooth anchorage and reducing undesired root resorption in orthodontic treatment. Patients under medication of strontium ranelate have to expect prolonged orthodontic treatment times. Copyright © 2014 Elsevier B.V. All rights reserved.

Trench Inserts as Long-term Barriers to Root Transmission for Control of Oak Wilt

Treesearch

A. Dan Wilson; D.G. Lester

2002-01-01

Physical and chemical barriers to root penetration and root grafting across trenches were evaluated for their effectiveness in improving trenches as barriers to root transmission of the oak wilt fungus in live oaks. Four trench insert materials were tested, including water-permeable Typar and Biobarrier, and water-impermeable Geomembranc of two thicknesses....

Sorghum root-system classification in contrasting P environments reveals three main rooting types and root-architecture-related marker-trait associations.

PubMed

Parra-Londono, Sebastian; Kavka, Mareike; Samans, Birgit; Snowdon, Rod; Wieckhorst, Silke; Uptmoor, Ralf

2018-02-12

Roots facilitate acquisition of macro- and micronutrients, which are crucial for plant productivity and anchorage in the soil. Phosphorus (P) is rapidly immobilized in the soil and hardly available for plants. Adaptation to P scarcity relies on changes in root morphology towards rooting systems well suited for topsoil foraging. Root-system architecture (RSA) defines the spatial organization of the network comprising primary, lateral and stem-derived roots and is important for adaptation to stress conditions. RSA phenotyping is a challenging task and essential for understanding root development. In this study, 19 traits describing RSA were analysed in a diversity panel comprising 194 sorghum genotypes, fingerprinted with a 90-k single-nucleotide polymorphism (SNP) array and grown under low and high P availability. Multivariate analysis was conducted and revealed three different RSA types: (1) a small root system; (2) a compact and bushy rooting type; and (3) an exploratory root system, which might benefit plant growth and development if water, nitrogen (N) or P availability is limited. While several genotypes displayed similar rooting types in different environments, others responded to P scarcity positively by developing more exploratory root systems, or negatively with root growth suppression. Genome-wide association studies revealed significant quantitative trait loci (P < 2.9 × 10-6) on chromosomes SBI-02, SBI-03, SBI-05 and SBI-09. Co-localization of significant and suggestive (P < 5.7 × 10-5) associations for several traits indicated hotspots controlling root-system development on chromosomes SBI-02 and SBI-03. Sorghum genotypes with a compact, bushy and shallow root system provide potential adaptation to P scarcity in the field by allowing thorough topsoil foraging, while genotypes with an exploratory root system may be advantageous if N or water is the limiting factor, although such genotypes showed highest P uptake levels under the artificial conditions

RootGraph: a graphic optimization tool for automated image analysis of plant roots

PubMed Central

Cai, Jinhai; Zeng, Zhanghui; Connor, Jason N.; Huang, Chun Yuan; Melino, Vanessa; Kumar, Pankaj; Miklavcic, Stanley J.

2015-01-01

This paper outlines a numerical scheme for accurate, detailed, and high-throughput image analysis of plant roots. In contrast to existing root image analysis tools that focus on root system-average traits, a novel, fully automated and robust approach for the detailed characterization of root traits, based on a graph optimization process is presented. The scheme, firstly, distinguishes primary roots from lateral roots and, secondly, quantifies a broad spectrum of root traits for each identified primary and lateral root. Thirdly, it associates lateral roots and their properties with the specific primary root from which the laterals emerge. The performance of this approach was evaluated through comparisons with other automated and semi-automated software solutions as well as against results based on manual measurements. The comparisons and subsequent application of the algorithm to an array of experimental data demonstrate that this method outperforms existing methods in terms of accuracy, robustness, and the ability to process root images under high-throughput conditions. PMID:26224880

GLO-Roots: An imaging platform enabling multidimensional characterization of soil-grown root systems

DOE PAGES

Rellan-Alvarez, Ruben; Lobet, Guillaume; Lindner, Heike; ...

2015-08-19

Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow themore » spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes.« less

Protein accumulation in leaves and roots associated with improved drought tolerance in creeping bentgrass expressing an ipt gene for cytokinin synthesis

PubMed Central

Merewitz, Emily B.; Gianfagna, Thomas; Huang, Bingru

2011-01-01

Cytokinins (CKs) may be involved in the regulation of plant adaptation to drought stress. The objectives of the study were to identify proteomic changes in leaves and roots in relation to improved drought tolerance in transgenic creeping bentgrass (Agrostis stolonifera) containing a senescence-activated promoter (SAG12) and the isopentyl transferase (ipt) transgene that increases endogenous CK content. Leaves of SAG12-ipt bentgrass exhibited less severe senescence under water stress, as demonstrated by maintaining lower electrolyte leakage and lipid peroxidation, and higher photochemical efficiency (Fv/Fm), compared with the null transformant (NT) plants. SAG12-ipt plants had higher root/shoot ratios and lower lipid peroxidation in leaves under water stress than the NT plants. The suppression of drought-induced leaf senescence and root dieback in the transgenic plants was associated with the maintenance of greater antioxidant enzyme activities (superoxide dismutase, peroxidase, and catalase). The SAG12-ipt and NT plants exhibited differential protein expression patterns under well-watered and drought conditions in both leaves and roots. Under equivalent leaf water deficit (47% relative water content), SAG12-ipt plants maintained higher abundance of proteins involved in (i) energy production within both photosynthesis and respiration [ribulose 1,5-bisphosphate carboxylase (RuBisCO) and glyceraldehyde phosphate dehydrogenase (GAPDH)]; (ii) amino acid synthesis (methionine and glutamine); (iii) protein synthesis and destination [chloroplastic elongation factor (EF-Tu) and protein disulphide isomerases (PDIs)]; and (iv) antioxidant defence system (catalase and peroxidase) than the NT plants. These results suggest that increased endogenous CKs under drought stress may directly or indirectly regulate protein abundance and enzymatic activities involved in the above-mentioned metabolic processes, thereby enhancing plant drought tolerance. PMID:21831843

Specialized 'dauciform' roots of Cyperaceae are structurally distinct, but functionally analogous with 'cluster' roots.

PubMed

Shane, Michael W; Cawthray, Gregory R; Cramer, Michael D; Kuo, John; Lambers, Hans

2006-10-01

When grown in nutrient solutions of extremely low [P] (roots, which are short and carrot shaped, and produce dense numbers of long root hairs. It has been suggested that dauciform roots of monocotyledonous sedges function to acquire P from nutrient-poor, P-fixing soils in a manner similar to that of cluster (proteoid) roots developed by some dicotyledonous species, but without evidence to substantiate this claim. To elucidate the ecophysiological role of dauciform roots, we assessed carboxylate exudation, internal carboxylate and P concentrations and O(2) uptake rates during dauciform root development. We showed that O(2) consumption was fastest [9 nmol O(2) g(-1) fresh mass (FM) s(-1)] and root [P] greatest (0.4 mg P g(-1) FM) when dauciform roots were young and rapidly developing. Citrate was the most abundant carboxylate in root tissues at all developmental stages, and was most concentrated (22.2 micromol citrate g(-1) FM) in young dauciform roots, decreasing by more than half in mature dauciform roots. Peak citrate-exudation rates (1.7 nmol citrate g(-1) FM s(-1)) occurred from mature dauciform roots, and were approximately an order of magnitude faster than those from roots of species without root clusters, and similar to those of mature proteoid (cluster) roots of Proteaceae. Both developing and mature dauciform roots had the capacity to acidify (but not alkalinize) the rhizosphere. Anatomical studies showed that epidermal cells in dauciform roots were greatly elongated in the transverse plane; epidermal cells of parent roots were unmodified. Although structurally distinct, the physiology of dauciform roots in sedges appears to be analogous to that of proteoid roots of Proteaceae and Fabaceae, and hence, dauciform roots would facilitate access to sorbed P and micronutrients from soils of low fertility.

Nitrogen fluxes at the root-soil interface show a mismatch of nitrogen fertilizer supply and sugarcane root uptake capacity

NASA Astrophysics Data System (ADS)

Inselsbacher, Erich; Schmidt, Susanne; Näsholm, Torgny; Robinson, Nicole; Guillou, Stéphane; Vinall, Kerry; Lakshmanan, Prakash; Brackin, Richard

2016-04-01

Nitrogen (N) uptake by agricultural crops is a key constituent of the global N cycle, as N captured by roots has a markedly different fate than N remaining in the soil. Global evidence indicates that only approximately 50% of applied N fertilizer is captured by crops, and the remainder can cause pollution via runoff and gaseous emissions. This inefficiency is of global concern, and requires innovation based on improved understanding of which N forms are available for and ultimately taken up by crops. However, current soil analysis methods based on destructive soil sampling provide little insight into delivery and acquisition of N forms by roots. Here, we present the results of a study in sugarcane fields receiving different fertilizer regimes comparing soil N supply rates with potential root N uptake rates. We applied microdialysis, a novel technique for in situ quantification of soil nutrient fluxes, to measure flux rates of inorganic N and amino acid N, and analyzed N uptake capacities of sugarcane roots using 15N labelled tracers. We found that in fertilized sugarcane soils, fluxes of inorganic N exceed the uptake capacities of sugarcane roots by several orders of magnitude. Contrary, fluxes of organic N closely matched roots' uptake capacity. These results indicate root uptake capacity constrains plant acquisition of inorganic N. This mismatch between soil N supply and root N uptake capacity is a likely key driver for low N efficiency in the studied crop system. Our results also suggest that the relative contribution of inorganic N for plant nutrition may be overestimated when relying on soil extracts as indicators for root-available N, and organic N may contribute more to crop N supply than is currently assumed. Overall, we show a new approach for examining in situ N relations in soil in context of crop N physiology, which provides a new avenue towards tailoring N fertilizer supply to match the specific uptake abilities and N demand of crops over the growth

Systematics of Juniperus section Juniperus based on leaf essential oils and random amplified polymorphic DNAs (RAPDs).

PubMed

Adams

2000-07-01

The composition of the leaf essential oils of all the species of Juniperus in sect. Juniperus (=sect. Oxycedrus) are reported and compared (J. brevifolia, J. cedrus, J. communis, J. c. var. saxatilis, J. c. var. oblonga, J. formosana, J. oxycedrus, J. o. subsp. badia, J. o. subsp. macrocarpa, J. o. subsp. transtagana, J. rigida, J. r. subsp. conferta, J. sibirica, J. taxifolia and J. t. var. lutchuensis). In addition, DNA fingerprinting by RAPDs was utilized. Based on these data, several taxa remained at the same taxonomic level: J. brevifolia, J. cedrus, J. communis, J. c. var. saxatilis, J. formosana, J. oxycedrus, J. rigida, J. r. var. conferta, and J. taxifolia. However, several taxa exhibited considerable differentiation that warranted their recognition at the specific level: J. oblonga M.-Bieb. (=J. communis var. oblonga), J. badia H. Gay (=J. oxycedrus subsp. badia), J. macrocarpa Sibth. and Sm. (=J. oxycedrus subsp. macrocarpa), J. navicularis Gand. (=J. oxycedrus subsp. transtagana), J. sibirica Brugsd. (=J. communis var. saxatilis in part), and J. lutchuensis Koidz. (= J. taxifolia var. lutchuensis).

Nonchamber, Root-Side, Inert-Gas Purging During Welding

NASA Technical Reports Server (NTRS)

Mcgee, William F.; Rybicki, Daniel J.

1995-01-01

Improved apparatus distributes inert gas to protect against oxidation on root side of weld during welding and after welding while joint remains hot. Simple and lightweight; readily moved along weld path in synchronism with torch. Because it concentrates inert gas where needed, consumes gas at relatively low rate, and not necessary to monitor oxygen content of protective atmosphere. Apparatus does not obscure view of root side of weld. Used for full-penetration plasma-arc welding of such reactive metals as aluminum/lithium alloys and titanium.

GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

PubMed Central

Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

2015-01-01

Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes. DOI: http://dx.doi.org/10.7554/eLife.07597.001 PMID:26287479

ROOT.NET: Using ROOT from .NET languages like C# and F#

NASA Astrophysics Data System (ADS)

Watts, G.

2012-12-01

ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F# (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

Can we manipulate root system architecture to control soil erosion?

NASA Astrophysics Data System (ADS)

Ola, A.; Dodd, I. C.; Quinton, J. N.

2015-09-01

Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above-ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to specifically manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We demonstrate the importance of root system architecture for the control of soil erosion. We also show that some plant species respond to nutrient-enriched patches by increasing lateral root proliferation. The erosional response to root proliferation will depend upon its location: at the soil surface dense mats of roots may reduce soil erodibility but block soil pores thereby limiting infiltration, enhancing runoff. Additionally, in nutrient-deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilizing nutrient placement at specific depths may represent a potentially new, easily implemented, management strategy on nutrient-poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

Identifying seedling root architectural traits associated with yield and yield components in wheat.

PubMed

Xie, Quan; Fernando, Kurukulasuriya M C; Mayes, Sean; Sparkes, Debbie L

2017-05-01

Plant roots growing underground are critical for soil resource acquisition, anchorage and plant-environment interactions. In wheat ( Triticum aestivum ), however, the target root traits to improve yield potential still remain largely unknown. This study aimed to identify traits of seedling root system architecture (RSA) associated with yield and yield components in 226 recombinant inbred lines (RILs) derived from a cross between the bread wheat Triticum aestivum 'Forno' (small, wide root system) and spelt Triticum spelta 'Oberkulmer' (large, narrow root system). A 'pouch and wick' high-throughput phenotyping pipeline was used to determine the RSA traits of 13-day-old RIL seedlings. Two field experiments and one glasshouse experiment were carried out to investigate the yield, yield components and phenology, followed by identification of quantitative trait loci (QTLs). There was substantial variation in RSA traits between genotypes. Seminal root number and total root length were both positively associated with grains m -2 , grains per spike, above-ground biomass m -2 and grain yield. More seminal roots and longer total root length were also associated with delayed maturity and extended grain filling, likely to be a consequence of more grains being defined before anthesis. Additionally, the maximum width of the root system displayed positive relationships with spikes m -2 , grains m -2 and grain yield. Ten RILs selected for the longest total roots exhibited the same effects on yield and phenology as described above, compared with the ten lines with the shortest total roots. Genetic analysis revealed 38 QTLs for the RSA, and QTL coincidence between the root and yield traits was frequently observed, indicating tightly linked genes or pleiotropy, which concurs with the results of phenotypic correlation analysis. Based on the results from the Forno × Oberkulmer population, it is proposed that vigorous early root growth, particularly more seminal roots and longer total

Global root zone storage capacity from satellite-based evaporation

NASA Astrophysics Data System (ADS)

Wang-Erlandsson, Lan; Bastiaanssen, Wim G. M.; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel B.; van Dijk, Albert I. J. M.; Guerschman, Juan P.; Keys, Patrick W.; Gordon, Line J.; Savenije, Hubert H. G.

2016-04-01

This study presents an "Earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale independent. In contrast to a traditional look-up table approach, our method captures the variability in root zone storage capacity within land cover types, including in rainforests where direct measurements of root depths otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM (Simple Terrestrial Evaporation to Atmosphere Model) improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. Our results suggest that several forest types are able to create a large storage to buffer for severe droughts (with a very long return period), in contrast to, for example, savannahs and woody savannahs (medium length return period), as well as grasslands, shrublands, and croplands (very short return period). The presented method to estimate root zone storage capacity eliminates the need for poor resolution soil and rooting depth data that form a limitation for achieving progress in the global land surface modelling community.

Improving the Health of Cambodian Americans: Grassroots Approaches and Root Causes.

PubMed

Lee, Juliet P; Kirkpatrick, Sean; Rojas-Cheatham, Ann; Sin, Talaya; Moore, Roland S; Tan, Sotheavy; Godoy, Shadia; Ercia, Angelo

2016-01-01

Cambodian Americans experience great disparities in health compared to other Americans, yet may be underserved by conventional healthcare systems. Community-based participatory research (CBPR) is a means to engage underserved communities in health research and programming. We describe results of our efforts to engage the Cambodian grassroots members as well as formal leaders in Oakland, California. In addition to a community advisory group, we convened a Community Work Group (CWG), composed of 10 grassroots community women of varying ages and backgrounds. The project aimed to leverage the lived experiences of these women and their understandings of health and wellness in identifying specific health issues and developing culturally resonant strategies. The CWG met weekly with staff facilitators using methods for collective analysis including theater, body mapping, and other expressive arts. The approach proved logistically challenging, but resulted in novel analyses and strategies. The group identified trauma, along with poor access to education, unemployment and underemployment, social isolation, and generation gap, together with community violence, as root causes of key behavioral health issues, namely, alcohol abuse, gambling, prescription drug misuse, and domestic violence. Strategies proposed and implemented by the group and project staff were a community garden, Cambodian New Year's celebrations, and a museum exhibit on the Cambodian refugee experiences. Grassroots community engagement can support projects in identifying social determinants of health and developing the capacities of community members to conduct research and actions to improve health.

Improving the Health of Cambodian Americans: Grassroots Approaches and Root Causes

PubMed Central

Lee, Juliet P.; Kirkpatrick, Sean; Rojas-Cheatham, Ann; Sin, Talaya; Moore, Roland S.; Tan, Sotheavy; Godoy, Shadia; Ercia, Angelo

2015-01-01

Background Cambodian Americans experience great disparities in health compared to other Americans, yet may be underserved by conventional healthcare systems. CBPR is a means to engage underserved communities in health research and programming. We describe results of our efforts to engage the Cambodian grassroots members as well as formal leaders in Oakland, CA. Objectives In addition to a community advisory group, we convened a Community Work Group (CWG), composed of ten grassroots community women of varying ages and backgrounds. The project aimed to leverage the lived experiences of these women and their understandings of health and wellness in identifying specific health issues and developing culturally resonant strategies. Methods The CWG met weekly with staff facilitators using methods for collective analysis including theater, body mapping, and other expressive arts. Results The approach proved logistically challenging, but resulted in novel analyses and strategies. The group identified trauma, along with poor access to education, un- and under-employment, social isolation, and generation gap, together with community violence, as root causes of key behavioral health issues, i.e. alcohol abuse, gambling, prescription drug misuse, and domestic violence. Strategies proposed and implemented by the group and project staff were a community garden, Cambodian New Year’s celebrations, and a museum exhibit on the Cambodian refugee experiences. Conclusions Grassroots community engagement can support projects in identifying social determinants of health and developing the capacities of community members to conduct research and actions to improve health. PMID:27018360

A new Approach for Quantifying Root-Reinforcement of Streambanks: the RipRoot Model

NASA Astrophysics Data System (ADS)

Pollen, N. L.; Simon, A.

2003-12-01

Riparian vegetation plays an important role in controlling geotechnical and fluvial processes acting along and within streambanks through the binding effects of roots. Quantification of this mechanical effect is therefore essential to accurately model streambank stability. Until now, most attempts to include the effects of root reinforcement by riparian vegetation have used root-cohesion values estimated using the Wu et al. (1979) equation, requiring the tensile strengths and diameters of the roots crossing the potential shear-plane. However, the Wu et al. equation is a static model that assumes that all roots break, and that they all break simultaneously. Field observations and laboratory experiments have shown that in reality the roots do not all break simultaneously, and that the breaking of roots during mass failure is in fact a dynamic process. Static models such as the Wu et al. equation are therefore likely to produce overestimations of cohesion due to roots. As a response to this concern, a dynamic root reinforcement model (RipRoot) was developed, based on the concepts of fiber bundle models (FBM's) used in materials science. Within the model the root-soil system is loaded incrementally resulting in progressive root breaking and redistribution of stresses from the broken roots to the remaining intact roots in the soil matrix. The redistribution and loading process continues until either all of the roots have broken, or equilibrium is reached where the root network supports the driving force imposed on the bank. The increase in bank cohesion using the static Wu et al. equation are 18% to 38% higher than RipRoot for riparian tree species, including Black Willow, Sandbar Willow, Cottonwood, River Birch and Eastern Sycamore, and 49% higher for Switch Grass. These variations in cohesion values can have a significant impact on streambank Factor of Safety (Fs) values calculated using the Simon et al. (2000) bank-stability model. For example, a 3m high silt

High-resolution quantification of root dynamics in split-nutrient rhizoslides reveals rapid and strong proliferation of maize roots in response to local high nitrogen

PubMed Central

in ‘t Zandt, Dina; Le Marié, Chantal; Kirchgessner, Norbert; Visser, Eric J.W.; Hund, Andreas

2015-01-01

The plant’s root system is highly plastic, and can respond to environmental stimuli such as high nitrogen (N) in patches. A root may respond to an N patch by selective placement of new lateral roots, and therewith increases root N uptake. This may be a desirable trait in breeding programmes, since it decreases NO3 - leaching and N2O emission. Roots of maize (Zea mays L.) were grown without N in split-nutrient rhizoslides. One side of the slides was exposed to high N after 15 d of root development, and root elongation was measured for another 15 d, described in a time course model and parameterized. The elongation rates of crown axile roots on the N-treated side of the plant followed a logistic increase to a maximum of 5.3cm d-1; 95% of the maximum were reached within 4 d. At the same time, on the untreated side, axile root elongation dropped linearly to 1.2cm d-1 within 6.4 d and stayed constant thereafter. Twice as many lateral roots were formed on the crown axis on the N side compared to the untreated side. Most strikingly, the elongation rates of laterals of the N side increased linearly with most of the roots reaching an asymptote ~8 d after start of the N treatment. By contrast, laterals on the side without N did not show any detectable elongation beyond the first day after their emergence. We conclude that split-nutrient rhizoslides have great potential to improve our knowledge about nitrogen responsiveness and selection for contrasting genotypes. PMID:26105997

Root and Root Canal Morphology of Human Third Molar Teeth.

PubMed

Mohammadi, Zahed; Jafarzadeh, Hamid; Shalavi, Sousan; Bandi, Shilpa; Patil, Shankargouda

2015-04-01

Successful root canal treatment depends on having comprehensive information regarding the root(s)/canal(s) anatomy. Dentists may have some complication in treatment of third molars because the difficulty in their access, their aberrant occlusal anatomy and different patterns of eruption. The aim of this review was to review and address the number of roots and root canals in third molars, prevalence of confluent canals in third molars, C-shaped canals, dilaceration and fusion in third molars, autotransplantation of third molars and endodontic treatment strategies for third molars.

Organization and function of the actin cytoskeleton in developing root cells.

PubMed

Blancaflor, Elison B; Wang, Yuh-Shuh; Motes, Christy M

2006-01-01

The actin cytoskeleton is a highly dynamic structure, which mediates various cellular functions in large part through accessory proteins that tilt the balance between monomeric G-actin and filamentous actin (F-actin) or by facilitating interactions between actin and the plasma membrane, microtubules, and other organelles. Roots have become an attractive model to study actin in plant development because of their simple anatomy and accessibility of some root cell types such as root hairs for microscopic analyses. Roots also exhibit a remarkable developmental plasticity and possess a delicate sensory system that is easily manipulated, so that one can design experiments addressing a range of important biological questions. Many facets of root development can be regulated by the diverse actin network found in the various root developmental regions. Various molecules impinge on this actin scaffold to define how a particular root cell type grows or responds to a specific environmental signal. Although advances in genomics are leading the way toward elucidating actin function in roots, more significant strides will be realized when such tools are combined with improved methodologies for accurately depicting how actin is organized in plant cells.

Effect of different root canal sealers on fracture strength of simulated immature roots.

PubMed

Ulusoy, Özgür İlke Atasoy; Nayır, Yelda; Darendeliler-Yaman, Sis

2011-10-01

The objective of this study was to compare the effects of different root canal sealers on fracture resistance of simulated immature teeth. One hundred eight roots were divided into 9 groups. The roots were instrumented except the negative controls. Four millimeters of mineral trioxide aggregate (MTA) barriers were placed apically. The roots were backfilled as follows: group 1, AH Plus+gutta-percha; group 2, EndoREZ+gutta-percha; group 3, EndoREZ+Resilon; group 4, Hybrid Root SEAL+gutta-percha; group 5, Hybrid Root SEAL+Resilon; group 6, iRootSP+gutta-percha; group 7, iRootSP+Resilon; group 8, No obturation other than MTA barrier; group 9, No instrumentation, no obturation. A compressive loading was applied at a speed of 1 mm/min. Data were compared with ANOVA and Duncan tests. Group 5 showed the highest resistance to fracture. The fracture values of group 3 were lower than those of the other experimental groups. Hybrid Root SEAL and iRootSP reinforce the simulated immature roots against fracture when used with either gutta-percha or Resilon. Copyright © 2011 Mosby, Inc. All rights reserved.

Lateral root initiation in Marsilea quadrifolia. I. Origin and histogensis of lateral roots

NASA Technical Reports Server (NTRS)

Lin, B. L.; Raghavan, V.

1991-01-01

In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a five-celled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types.

Improvement in Long-Term Memory following Chronic Administration of Eryngium planum Root Extract in Scopolamine Model: Behavioral and Molecular Study

PubMed Central

Ozarowski, Marcin; Thiem, Barbara; Mikolajczak, Przemyslaw L.; Piasecka, Anna; Kachlicki, Piotr; Szulc, Michal; Kaminska, Ewa; Kujawski, Radoslaw; Bartkowiak-Wieczorek, Joanna; Kujawska, Malgorzata; Jodynis-Liebert, Jadwiga; Budzianowski, Jaromir; Kędziora, Izabela; Seremak-Mrozikiewicz, Agnieszka; Czerny, Boguslaw; Bobkiewicz-Kozłowska, Teresa

2015-01-01

Eryngium planum L. (EP) is as a rare medicinal plant with a lot of potentials as pharmaceutical crops. The aim of our study was to assess the effect of subchronic (28-fold) administration of a 70% ethanol extract of EP roots (200 mg/kg, p.o.) on behavioral and cognitive responses in Wistar rats linked with acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and beta-secretase (BACE-1) mRNA levels and AChE and BuChE activities in the hippocampus and frontal cortex. On the last day of experiment, 30 min after the last dose of EP or Huperzine A (HU), scopolamine (SC) was given at a dose of 0.5 mg/kg b.w. intraperitoneally. The results of a passive avoidance test showed an improvement in long-term memory produced by the EP extract in both scopolamine-induced rats and control group. EP caused an insignificant inhibition of AChE and BuChE activities in the frontal cortex and the hippocampus. EP decreased mRNA AChE, BuChE, and BACE-1 levels, especially in the cortex. Our results suggest that the EP extract led to the improvement of the long-term memory in rats coupled with total saponin content. The mechanism of EP action is probably complicated, since HPLC-MS analysis showed 64 chemical compounds (phenolics, saponins) in the extract of EP roots. PMID:26483842

Metabolic Profile and Root Development of Hypericum perforatum L. In vitro Roots under Stress Conditions Due to Chitosan Treatment and Culture Time.

PubMed

Brasili, Elisa; Miccheli, Alfredo; Marini, Federico; Praticò, Giulia; Sciubba, Fabio; Di Cocco, Maria E; Cechinel, Valdir Filho; Tocci, Noemi; Valletta, Alessio; Pasqua, Gabriella

2016-01-01

The responses of Hypericum perforatum root cultures to chitosan elicitation had been investigated through (1)H-NMR-based metabolomics associated with morpho-anatomical analyses. The root metabolome was influenced by two factors, i.e., time of culture (associated with biomass growth and related "overcrowding stress") and chitosan elicitation. ANOVA simultaneous component analysis (ASCA) modeling showed that these factors act independently. In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed. Among the xanthones, brasilixanthone B has been identified for the first time in chitosan-elicited root cultures of H. perforatum. Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels. The histological analysis of chitosan-treated roots revealed a marked swelling of the root apex, mainly due to the hypertrophy of the first two sub-epidermal cell layers. In addition, periclinal divisions in hypertrophic cortical cells, resulting in an increase of cortical layers, were frequently observed. Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation. The obtained results improve the knowledge of the root responses to biotic stress and provide useful information to optimize the biotechnological production of plant compounds of industrial interest.

Metabolic Profile and Root Development of Hypericum perforatum L. In vitro Roots under Stress Conditions Due to Chitosan Treatment and Culture Time

PubMed Central

Brasili, Elisa; Miccheli, Alfredo; Marini, Federico; Praticò, Giulia; Sciubba, Fabio; Di Cocco, Maria E.; Cechinel, Valdir Filho; Tocci, Noemi; Valletta, Alessio; Pasqua, Gabriella

2016-01-01

The responses of Hypericum perforatum root cultures to chitosan elicitation had been investigated through 1H-NMR-based metabolomics associated with morpho-anatomical analyses. The root metabolome was influenced by two factors, i.e., time of culture (associated with biomass growth and related “overcrowding stress”) and chitosan elicitation. ANOVA simultaneous component analysis (ASCA) modeling showed that these factors act independently. In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed. Among the xanthones, brasilixanthone B has been identified for the first time in chitosan-elicited root cultures of H. perforatum. Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels. The histological analysis of chitosan-treated roots revealed a marked swelling of the root apex, mainly due to the hypertrophy of the first two sub-epidermal cell layers. In addition, periclinal divisions in hypertrophic cortical cells, resulting in an increase of cortical layers, were frequently observed. Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation. The obtained results improve the knowledge of the root responses to biotic stress and provide useful information to optimize the biotechnological production of plant compounds of industrial interest. PMID:27148330

Three-rooted premolar analyzed by high-resolution and cone beam CT.

PubMed

Marca, Caroline; Dummer, Paul M H; Bryant, Susan; Vier-Pelisser, Fabiana Vieira; Só, Marcus Vinicius Reis; Fontanella, Vania; Dutra, Vinicius D'avila; de Figueiredo, José Antonio Poli

2013-07-01

The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (μCT) and cone beam computed tomography (CBCT). Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using μCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using μCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. Images using μCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the μCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional μCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. Although variation was similar in the roots and canals under study, CBCT produced poorer image details than μCT. Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.

Eight-year results of aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis.

PubMed

Kon, Neal D; Riley, Robert D; Adair, Sandy M; Kitzman, Dalane W; Cordell, A Robert

2002-06-01

Stentless porcine aortic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation, and perhaps improved durability. One hundred four patients were operated on from September 17, 1992, to October 31, 1997, as part of a multicenter worldwide investigation of the Medtronic Freestyle stentless porcine bioprosthesis. All patients received a total aortic root replacement. The patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography. Operative mortality was 3.9%. No patient experienced structural valve deterioration, nonstructural deterioration, perivalvular leak, or unacceptable hemodynamic performance. At 8 years, survival was 59.8%. Freedom from thromboembolic complications was 83.3%. Freedom from postoperative endocarditis was 96.9%. Freedom from reoperation was 100%. Mean systolic gradients did not change over the time period studied. They were 6.4 +/- 3.8 mm Hg at 1 year and 6.7 +/- 2.6 mm Hg at 8 years. Correspondingly, effective orifice area was 1.9 +/- 0.7 cm2 at 1 year and 1.8 +/- 0.8 cm2 at 8 years. The incidence of any aortic insufficiency also did not change over the length of follow-up. At 1 year, 98% of patients had no or trivial aortic insufficiency and 2% had mild aortic insufficiency. At 8 years, 100% of patients evaluated were free of any aortic insufficiency. The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root or aortic valve for aortic valve and aortic root pathology. Total root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Results up to 8 years show excellent survival and no signs of degeneration. Further follow-up is still needed to determine valve durability.

Highly concentrated EDTA gel improves cleaning efficiency of root canal preparation in vitro.

PubMed

Putzer, P; Hoy, L; Günay, H

2008-12-01

Debris and smear layer, as a product of mechanical root canal instrumentation, reduce the effectiveness of pharmacological substances to prevent post-treatment diseases and impair direct contact of filling materials with a clean dentinal surface. The aim of this in vitro study was to investigate the presence and localization of debris and smear layer via scanning electron microscope analysis after standardized root canal preparation with different chelating agents. Dentin surfaces received treatment with: (1) 15% ethylenediaminetetraacetic acid (EDTA), (2) 18.6% EDTA (3) and 24% EDTA or without any demineralizing chemicals as control. Forty vertically split human premolars were sputtered and divided into coronal, middle, and apical sections, followed by a randomized, blinded score evaluation using five scores. Pairwise comparisons of all treatment groups against a control group have been performed by Mann-Whitney U test and the Kruskal-Wallis test. Debris grades showed no significant difference between the three regions of the root canals, except for 18.6% EDTA in the central third. Smear layer and smear plug removal was concentration-dependent. Removal of the smear layer in the three areas showed that there was a statistically significant difference between all parts when using 18.6% and 24% EDTA concentrations compared with the control. The best smear layer removal in the apical region was observed using a 24% EDTA gel as chelating agent and lubricant. The usage of EDTA gel >/=18.6% presented a better cleaning regime when compared to the control group.

Molecular Physiology of Root System Architecture in Model Grasses

NASA Astrophysics Data System (ADS)

Hixson, K.; Ahkami, A. H.; Anderton, C.; Veličković, D.; Myers, G. L.; Chrisler, W.; Lindenmaier, R.; Fang, Y.; Yabusaki, S.; Rosnow, J. J.; Farris, Y.; Khan, N. E.; Bernstein, H. C.; Jansson, C.

2017-12-01

) and leaf node axile root (LNR) during developmental stages of root formation. The root exudates also will be quantified and preliminary data will be used to engineer our microbial consortium to improve plant growth.

Quest for Continual Growth Takes Root

ERIC Educational Resources Information Center

Surdey, Mary M.; Hashey, Jane M.

2006-01-01

In this article, the authors describe how the quest for continual growth has taken its root at Vestal Central School district. Located at the heart of upstate New York, educators at Vestal Central School district have created a spirit of "kaizen," a Japanese word meaning the relentless quest for continual improvement and higher-quality…

Global root zone storage capacity from satellite-based evaporation data

NASA Astrophysics Data System (ADS)

Wang-Erlandsson, Lan; Bastiaanssen, Wim; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel; van Dijk, Albert; Guerschman, Juan; Keys, Patrick; Gordon, Line; Savenije, Hubert

2016-04-01

We present an "earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale-independent. In contrast to traditional look-up table approaches, our method captures the variability in root zone storage capacity within land cover type, including in rainforests where direct measurements of root depth otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. We find that evergreen forests are able to create a large storage to buffer for extreme droughts (with a return period of up to 60 years), in contrast to short vegetation and crops (which seem to adapt to a drought return period of about 2 years). The presented method to estimate root zone storage capacity eliminates the need for soils and rooting depth information, which could be a game-changer in global land surface modelling.

Role of Root Hairs and Lateral Roots in Silicon Uptake by Rice

PubMed Central

Ma, Jian Feng; Goto, Shoko; Tamai, Kazunori; Ichii, Masahiko

2001-01-01

The rice plant (Oryza sativa L. cv Oochikara) is known to be a Si accumulator, but the mechanism responsible for the high uptake of Si by the roots is not well understood. We investigated the role of root hairs and lateral roots in the Si uptake using two mutants of rice, one defective in the formation of root hairs (RH2) and another in that of lateral roots (RM109). Uptake experiments with nutrient solution during both a short term (up to 12 h) and relatively long term (26 d) showed that there was no significant difference in Si uptake between RH2 and the wild type (WT), whereas the Si uptake of RM109 was much less than that of WT. The number of silica bodies formed on the third leaf in RH2 was similar to that in WT, but the number of silica bodies in RM109 was only 40% of that in WT, when grown in soil amended with Si under flooded conditions. There was also no difference in the shoot Si concentration between WT and RH2 when grown in soil under upland conditions. Using a multi-compartment transport box, the Si uptake at the root tip (0–1 cm, without lateral roots and root hairs) was found to be similar in WT, RH2, and RM109. However, the Si uptake in the mature zone (1–4 cm from root tip) was significantly lower in RM109 than in WT, whereas no difference was found in Si uptake between WT and RH2. All these results clearly indicate that lateral roots contribute to the Si uptake in rice plant, whereas root hairs do not. Analysis of F2 populations between RM109 and WT showed that Si uptake was correlated with the presence of lateral roots and that the gene controlling formation of lateral roots and Si uptake is a dominant gene. PMID:11743120

Can we manipulate root system architecture to control soil erosion?

NASA Astrophysics Data System (ADS)

Ola, A.; Dodd, I. C.; Quinton, J. N.

2015-03-01

Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We clearly demonstrate the importance of root system architecture for the control of soil erosion. We also demonstrate that some plant species respond to nutrient enriched patches by increasing lateral root proliferation. The soil response to root proliferation will depend upon its location: at the soil surface dense mats of roots may block soil pores thereby limiting infiltration, enhancing runoff and thus erosion; whereas at depth local increases in shear strength may reinforce soils against structural failure at the shear plane. Additionally, in nutrient deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilising nutrient placement at depth may represent a potentially new, easily implemented, management strategy on nutrient poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

Computer-aided design of the human aortic root.

PubMed

Ovcharenko, E A; Klyshnikov, K U; Vlad, A R; Sizova, I N; Kokov, A N; Nushtaev, D V; Yuzhalin, A E; Zhuravleva, I U

2014-11-01

The development of computer-based 3D models of the aortic root is one of the most important problems in constructing the prostheses for transcatheter aortic valve implantation. In the current study, we analyzed data from 117 patients with and without aortic valve disease and computed tomography data from 20 patients without aortic valvular diseases in order to estimate the average values of the diameter of the aortic annulus and other aortic root parameters. Based on these data, we developed a 3D model of human aortic root with unique geometry. Furthermore, in this study we show that by applying different material properties to the aortic annulus zone in our model, we can significantly improve the quality of the results of finite element analysis. To summarize, here we present four 3D models of human aortic root with unique geometry based on computational analysis of ECHO and CT data. We suggest that our models can be utilized for the development of better prostheses for transcatheter aortic valve implantation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Measuring and Modeling Root Distribution and Root Reinforcement in Forested Slopes for Slope Stability Calculations

NASA Astrophysics Data System (ADS)

Cohen, D.; Giadrossich, F.; Schwarz, M.; Vergani, C.

2016-12-01

Roots provide mechanical anchorage and reinforcement of soils on slopes. Roots also modify soil hydrological properties (soil moisture content, pore-water pressure, preferential flow paths) via subsurface flow path associated with root architecture, root density, and root-size distribution. Interactions of root-soil mechanical and hydrological processes are an important control of shallow landslide initiation during rainfall events and slope stability. Knowledge of root-distribution and root strength are key components to estimate slope stability in vegetated slopes and for the management of protection forest in steep mountainous area. We present data that show the importance of measuring root strength directly in the field and present methods for these measurements. These data indicate that the tensile force mobilized in roots depends on root elongation (a function of soil displacement), root size, and on whether roots break in tension of slip out of the soil. Measurements indicate that large lateral roots that cross tension cracks at the scarp are important for slope stability calculations owing to their large tensional resistance. These roots are often overlooked and when included, their strength is overestimated because extrapolated from measurements on small roots. We present planned field experiments that will measure directly the force held by roots of different sizes during the triggering of a shallow landslide by rainfall. These field data are then used in a model of root reinforcement based on fiber-bundle concepts that span different spacial scales, from a single root to the stand scale, and different time scales, from timber harvest to root decay. This model computes the strength of root bundles in tension and in compression and their effect on soil strength. Up-scaled to the stand the model yields the distribution of root reinforcement as a function of tree density, distance from tree, tree species and age with the objective of providing quantitative

Storage root of cassava: Morphological types, anatomy, formation, growth, development and harvest time

USDA-ARS?s Scientific Manuscript database

Cassava (Manihot esculenta, Crantz) is considered a starchy root crop that provides staple food for millions of people in tropical and subtropical regions of the world. Research efforts are directed towards genetic breeding and cultivation of cassava to improve cassava storage root starch production...

Root Water Uptake and Tracer Transport in a Lupin Root System: Integration of Magnetic Resonance Images and the Numerical Model RSWMS

NASA Astrophysics Data System (ADS)

Pohlmeier, Andreas; Vanderborght, Jan; Haber-Pohlmeier, Sabina; Wienke, Sandra; Vereecken, Harry; Javaux, Mathieu

2010-05-01

Combination of experimental studies with detailed deterministic models help understand root water uptake processes. Recently, Javaux et al. developed the RSWMS model by integration of Doussańs root model into the well established SWMS code[1], which simulates water and solute transport in unsaturated soil [2, 3]. In order to confront RSWMS modeling results to experimental data, we used Magnetic Resonance Imaging (MRI) technique to monitor root water uptake in situ. Non-invasive 3-D imaging of root system architecture, water content distributions and tracer transport by MR were performed and compared with numerical model calculations. Two MRI experiments were performed and modeled: i) water uptake during drought stress and ii) transport of a locally injected tracer (Gd-DTPA) to the soil-root system driven by root water uptake. Firstly, the high resolution MRI image (0.23x0.23x0.5mm) of the root system was transferred into a continuous root system skeleton by a combination of thresholding, region-growing filtering and final manual 3D redrawing of the root strands. Secondly, the two experimental scenarios were simulated by RSWMS with a resolution of about 3mm. For scenario i) the numerical simulations could reproduce the general trend that is the strong water depletion from the top layer of the soil. However, the creation of depletion zones in the vicinity of the roots could not be simulated, due to a poor initial evaluation of the soil hydraulic properties, which equilibrates instantaneously larger differences in water content. The determination of unsaturated conductivities at low water content was needed to improve the model calculations. For scenario ii) simulations confirmed the solute transport towards the roots by advection. 1. Simunek, J., T. Vogel, and M.T. van Genuchten, The SWMS_2D Code for Simulating Water Flow and Solute Transport in Two-Dimensional Variably Saturated Media. Version 1.21. 1994, U.S. Salinity Laboratory, USDA, ARS: Riverside, California

Cadmium translocation by contractile roots differs from that in regular, non-contractile roots

PubMed Central

Lux, Alexander; Lackovič, Andrej; Van Staden, Johannes; Lišková, Desana; Kohanová, Jana; Martinka, Michal

2015-01-01

Background and Aims Contractile roots are known and studied mainly in connection with the process of shrinkage of their basal parts, which acts to pull the shoot of the plant deeper into the ground. Previous studies have shown that the specific structure of these roots results in more intensive water uptake at the base, which is in contrast to regular root types. The purpose of this study was to find out whether the basal parts of contractile roots are also more active in translocation of cadmium to the shoot. Methods Plants of the South African ornamental species Tritonia gladiolaris were cultivated in vitro for 2 months, at which point they possessed well-developed contractile roots. They were then transferred to Petri dishes with horizontally separated compartments of agar containing 50 µmol Cd(NO3)2 in the region of the root base or the root apex. Seedlings of 4-d-old maize (Zea mays) plants, which do not possess contractile roots, were also transferred to similar Petri dishes. The concentrations of Cd in the leaves of the plants were compared after 10 d of cultivation. Anatomical analyses of Tritonia roots were performed using appropriately stained freehand cross-sections. Key Results The process of contraction required specific anatomical adaptation of the root base in Tritonia, with less lignified and less suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics were accompanied by more intensive translocation of Cd ions from the basal part of contractile roots to the leaves than from the apical–subapical root parts. The opposite effects were seen in the non-contractile roots of maize, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part. Conclusions The specific characteristics of contractile roots may have a significant impact on the uptake of ions, including toxic metals from the soil surface layers. This may be important for plant

Corky root rot

USDA-ARS?s Scientific Manuscript database

Corky root rot (corchosis) was first reported in Argentina in 1985, but the disease was presumably present long before that. The disease occurs in most alfalfa-growing areas of Argentina but is more common in older stands. In space-planted alfalfa trials scored for root problems, corky root rot was ...

Armillaria root rot

USDA-ARS?s Scientific Manuscript database

First described on grapevines in California in the 1880s, Armillaria root rot occurs in all major grape-growing regions of the state. The causal fungus, Armillaria mellea, infects woody grapevine roots and the base of the trunk (the root collar), resulting in a slow decline and eventual death of the...

Plant growth-promoting rhizobacteria and root system functioning

PubMed Central

Vacheron, Jordan; Desbrosses, Guilhem; Bouffaud, Marie-Lara; Touraine, Bruno; Moënne-Loccoz, Yvan; Muller, Daniel; Legendre, Laurent; Wisniewski-Dyé, Florence; Prigent-Combaret, Claire

2013-01-01

The rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth. Among the latter, plant growth-promoting rhizobacteria (PGPR) colonize roots of monocots and dicots, and enhance plant growth by direct and indirect mechanisms. Modification of root system architecture by PGPR implicates the production of phytohormones and other signals that lead, mostly, to enhanced lateral root branching and development of root hairs. PGPR also modify root functioning, improve plant nutrition and influence the physiology of the whole plant. Recent results provided first clues as to how PGPR signals could trigger these plant responses. Whether local and/or systemic, the plant molecular pathways involved remain often unknown. From an ecological point of view, it emerged that PGPR form coherent functional groups, whose rhizosphere ecology is influenced by a myriad of abiotic and biotic factors in natural and agricultural soils, and these factors can in turn modulate PGPR effects on roots. In this paper, we address novel knowledge and gaps on PGPR modes of action and signals, and highlight recent progress on the links between plant morphological and physiological effects induced by PGPR. We also show the importance of taking into account the size, diversity, and gene expression patterns of PGPR assemblages in the rhizosphere to better understand their impact on plant growth and functioning. Integrating mechanistic and ecological knowledge on PGPR populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture. PMID:24062756

Abscisic Acid Regulates Auxin Homeostasis in Rice Root Tips to Promote Root Hair Elongation

PubMed Central

Wang, Tao; Li, Chengxiang; Wu, Zhihua; Jia, Yancui; Wang, Hong; Sun, Shiyong; Mao, Chuanzao; Wang, Xuelu

2017-01-01

Abscisic acid (ABA) plays an essential role in root hair elongation in plants, but the regulatory mechanism remains to be elucidated. In this study, we found that exogenous ABA can promote rice root hair elongation. Transgenic rice overexpressing SAPK10 (Stress/ABA-activated protein kinase 10) had longer root hairs; rice plants overexpressing OsABIL2 (OsABI-Like 2) had attenuated ABA signaling and shorter root hairs, suggesting that the effect of ABA on root hair elongation depends on the conserved PYR/PP2C/SnRK2 ABA signaling module. Treatment of the DR5-GUS and OsPIN-GUS lines with ABA and an auxin efflux inhibitor showed that ABA-induced root hair elongation depends on polar auxin transport. To examine the transcriptional response to ABA, we divided rice root tips into three regions: short root hair, long root hair and root tip zones; and conducted RNA-seq analysis with or without ABA treatment. Examination of genes involved in auxin transport, biosynthesis and metabolism indicated that ABA promotes auxin biosynthesis and polar auxin transport in the root tip, which may lead to auxin accumulation in the long root hair zone. Our findings shed light on how ABA regulates root hair elongation through crosstalk with auxin biosynthesis and transport to orchestrate plant development. PMID:28702040

Modelling increased soil cohesion by plant roots with EUROSEM

NASA Astrophysics Data System (ADS)

de Baets, S.; Poesen, J.; Torri, D.; Salvador, M. P.

2009-04-01

Soil cohesion is an important variable to model soil detachment by runoff (Morgan et al., 1998a). As soil particles are not loose, soil detachment by runoff will be limited by the cohesion of the soil material. It is generally recognized that plant roots contribute to the overall cohesion of the soil. Determination of this increased cohesion and soil roughness however is complicated and measurements of shear strength and soil reinforcement by plant roots are very time- and labour consuming. A model approach offers an alternative for the assessment of soil cohesion provided by plant roots However, few erosion models account for the effects of the below-ground biomass in their calculation of erosion rates. Therefore, the main objectives of this study is to develop an approach to improve an existing soil erosion model (EUROSEM) accounting for the erosion-reducing effects of roots. The approach for incorporating the root effects into this model is based on a comparison of measured soil detachment rates for bare and for root-permeated topsoil samples with predicted erosion rates under the same flow conditions using the erosion equation of EUROSEM. Through backwards calculation, transport capacity efficiencies and corresponding soil cohesion values can be assessed for bare and root-permeated topsoils respectively. The results are promising and show that grass roots provide a larger increase in soil cohesion as compared with tap-rooted species and that the increase in soil cohesion is not significantly different under wet and dry soil conditions, either for fibrous root systems or for tap root systems. Relationships are established between measured root density values and the corresponding calculated soil cohesion values, reflecting the effects of roots on the resistance of the topsoil to concentrated flow incision. These relationships enable one to incorporate the root effect into the soil erosion model EUROSEM, through adapting the soil cohesion input value. A scenario

Brassinolide Increases Potato Root Growth In Vitro in a Dose-Dependent Way and Alleviates Salinity Stress

PubMed Central

Xia, Shitou; Su, Yi; Wang, Huiqun; Luo, Weigui; Su, Shengying

2016-01-01

Brassinosteroids (BRs) are steroidal phytohormones that regulate various physiological processes, such as root development and stress tolerance. In the present study, we showed that brassinolide (BL) affects potato root in vitro growth in a dose-dependent manner. Low BL concentrations (0.1 and 0.01 μg/L) promoted root elongation and lateral root development, whereas high BL concentrations (1–100 μg/L) inhibited root elongation. There was a significant (P < 0.05) positive correlation between root activity and BL concentrations within a range from 0.01 to 100 μg/L, with the peak activity of 8.238 mg TTC·g−1 FW·h−1 at a BL concentration of 100 μg/L. Furthermore, plants treated with 50 μg/L BL showed enhanced salt stress tolerance through in vitro growth. Under this scenario, BL treatment enhanced the proline content and antioxidant enzymes' (superoxide dismutase, peroxidase, and catalase) activity and reduced malondialdehyde content in potato shoots. Application of BL maintain K+ and Na+ homeostasis by improving tissue K+/Na+ ratio. Therefore, we suggested that the effects of BL on root development from stem fragments explants as well as on primary root development are dose-dependent and that BL application alleviates salt stress on potato by improving root activity, root/shoot ratio, and antioxidative capacity in shoots and maintaining K+/Na+ homeostasis in potato shoots and roots. PMID:27803931

[Effects nutrients on the seedlings root hair development and root growth of Poncirus trifoliata under hydroponics condition].

PubMed

Cao, Xiu; Xia, Ren-Xue; Zhang, De-Jian; Shu, Bo

2013-06-01

Ahydroponics experiment was conducted to study the effects of nutrients (N, P, K, Ca, Mg, Fe, and Mn) deficiency on the length of primary root, the number of lateral roots, and the root hair density, length, and diameter on the primary root and lateral roots of Poncirus trifoliata seedlings. Under the deficiency of each test nutrient, root hair could generate, but was mainly concentrated on the root base and fewer on the root tip. The root hair density on lateral roots was significantly larger than that on primary root, but the root hair length was in adverse. The deficiency of each test nutrient had greater effects on the growth and development of root hairs, with the root hair density on primary root varied from 55.0 to 174.3 mm(-2). As compared with the control, Ca deficiency induced the significant increase of root hair density and length on primary root, P deficiency promoted the root hair density and length on the base and middle part of primary root and on the lateral roots significantly, Fe deficiency increased the root hair density but decreased the root hair length on the tip of primary root significantly, K deficiency significantly decreased the root hair density, length, and diameter on primary root and lateral roots, whereas Mg deficiency increased the root hair length of primary root significantly. In all treatments of nutrient deficiency, the primary root had the similar growth rate, but, with the exceptions of N and Mg deficiency, the lateral roots exhibited shedding and regeneration.

RootScan: Software for high-throughput analysis of root anatomical traits

USDA-ARS?s Scientific Manuscript database

RootScan is a program for semi-automated image analysis of anatomical phenes in root cross-sections. RootScan uses pixel value thresholds to separate the cross-section from its background and to visually dissect it into tissue regions. Area measurements and object counts are performed within various...

Getting to the roots of it: Genetic and hormonal control of root architecture

PubMed Central

Jung, Janelle K. H.; McCouch, Susan

2013-01-01

Root system architecture (RSA) – the spatial configuration of a root system – is an important developmental and agronomic trait, with implications for overall plant architecture, growth rate and yield, abiotic stress resistance, nutrient uptake, and developmental plasticity in response to environmental changes. Root architecture is modulated by intrinsic, hormone-mediated pathways, intersecting with pathways that perceive and respond to external, environmental signals. The recent development of several non-invasive 2D and 3D root imaging systems has enhanced our ability to accurately observe and quantify architectural traits on complex whole-root systems. Coupled with the powerful marker-based genotyping and sequencing platforms currently available, these root phenotyping technologies lend themselves to large-scale genome-wide association studies, and can speed the identification and characterization of the genes and pathways involved in root system development. This capability provides the foundation for examining the contribution of root architectural traits to the performance of crop varieties in diverse environments. This review focuses on our current understanding of the genes and pathways involved in determining RSA in response to both intrinsic and extrinsic (environmental) response pathways, and provides a brief overview of the latest root system phenotyping technologies and their potential impact on elucidating the genetic control of root development in plants. PMID:23785372

Cyanogen Metabolism in Cassava Roots: Impact on Protein Synthesis and Root Development.

PubMed

Zidenga, Tawanda; Siritunga, Dimuth; Sayre, Richard T

2017-01-01

Cassava ( Manihot esculenta Crantz), a staple crop for millions of sub-Saharan Africans, contains high levels of cyanogenic glycosides which protect it against herbivory. However, cyanogens have also been proposed to play a role in nitrogen transport from leaves to roots. Consistent with this hypothesis, analyses of the distribution and activities of enzymes involved in cyanide metabolism provides evidence for cyanide assimilation, derived from linamarin, into amino acids in cassava roots. Both β-cyanoalanine synthase (CAS) and nitrilase (NIT), two enzymes involved in cyanide assimilation to produce asparagine, were observed to have higher activities in roots compared to leaves, consistent with their proposed role in reduced nitrogen assimilation. In addition, rhodanese activity was not detected in cassava roots, indicating that this competing means for cyanide metabolism was not a factor in cyanide detoxification. In contrast, leaves had sufficient rhodanese activity to compete with cyanide assimilation into amino acids. Using transgenic low cyanogen plants, it was shown that reducing root cyanogen levels is associated with elevated root nitrate reductase activity, presumably to compensate for the loss of reduced nitrogen from cyanogens. Finally, we overexpressed Arabidopsis CAS and NIT4 genes in cassava roots to study the feasibility of enhancing root cyanide assimilation into protein. Optimal overexpression of CAS and NIT4 resulted in up to a 50% increase in root total amino acids and a 9% increase in root protein accumulation. However, plant growth and morphology was altered in plants overexpressing these enzymes, demonstrating a complex interaction between cyanide metabolism and hormonal regulation of plant growth.

Cyanogen Metabolism in Cassava Roots: Impact on Protein Synthesis and Root Development

PubMed Central

Zidenga, Tawanda; Siritunga, Dimuth; Sayre, Richard T.

2017-01-01

Cassava (Manihot esculenta Crantz), a staple crop for millions of sub-Saharan Africans, contains high levels of cyanogenic glycosides which protect it against herbivory. However, cyanogens have also been proposed to play a role in nitrogen transport from leaves to roots. Consistent with this hypothesis, analyses of the distribution and activities of enzymes involved in cyanide metabolism provides evidence for cyanide assimilation, derived from linamarin, into amino acids in cassava roots. Both β-cyanoalanine synthase (CAS) and nitrilase (NIT), two enzymes involved in cyanide assimilation to produce asparagine, were observed to have higher activities in roots compared to leaves, consistent with their proposed role in reduced nitrogen assimilation. In addition, rhodanese activity was not detected in cassava roots, indicating that this competing means for cyanide metabolism was not a factor in cyanide detoxification. In contrast, leaves had sufficient rhodanese activity to compete with cyanide assimilation into amino acids. Using transgenic low cyanogen plants, it was shown that reducing root cyanogen levels is associated with elevated root nitrate reductase activity, presumably to compensate for the loss of reduced nitrogen from cyanogens. Finally, we overexpressed Arabidopsis CAS and NIT4 genes in cassava roots to study the feasibility of enhancing root cyanide assimilation into protein. Optimal overexpression of CAS and NIT4 resulted in up to a 50% increase in root total amino acids and a 9% increase in root protein accumulation. However, plant growth and morphology was altered in plants overexpressing these enzymes, demonstrating a complex interaction between cyanide metabolism and hormonal regulation of plant growth. PMID:28286506

Cassava root membrane proteome reveals activities during storage root maturation.

PubMed

Naconsie, Maliwan; Lertpanyasampatha, Manassawe; Viboonjun, Unchera; Netrphan, Supatcharee; Kuwano, Masayoshi; Ogasawara, Naotake; Narangajavana, Jarunya

2016-01-01

Cassava (Manihot esculenta Crantz) is one of the most important crops of Thailand. Its storage roots are used as food, feed, starch production, and be the important source for biofuel and biodegradable plastic production. Despite the importance of cassava storage roots, little is known about the mechanisms involved in their formation. This present study has focused on comparison of the expression profiles of cassava root proteome at various developmental stages using two-dimensional gel electrophoresis and LC-MS/MS. Based on an anatomical study using Toluidine Blue, the secondary growth was confirmed to be essential during the development of cassava storage root. To investigate biochemical processes occurring during storage root maturation, soluble and membrane proteins were isolated from storage roots harvested from 3-, 6-, 9-, and 12-month-old cassava plants. The proteins with differential expression pattern were analysed and identified to be associated with 8 functional groups: protein folding and degradation, energy, metabolism, secondary metabolism, stress response, transport facilitation, cytoskeleton, and unclassified function. The expression profiling of membrane proteins revealed the proteins involved in protein folding and degradation, energy, and cell structure were highly expressed during early stages of development. Integration of these data along with the information available in genome and transcriptome databases is critical to expand knowledge obtained solely from the field of proteomics. Possible role of identified proteins were discussed in relation with the activities during storage root maturation in cassava.

Root system markup language: toward a unified root architecture description language.

PubMed

Lobet, Guillaume; Pound, Michael P; Diener, Julien; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Javaux, Mathieu; Leitner, Daniel; Meunier, Félicien; Nacry, Philippe; Pridmore, Tony P; Schnepf, Andrea

2015-03-01

The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. © 2015 American Society of Plant Biologists. All Rights Reserved.

Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions.

PubMed

Choudhary, Dnyanraj; Bhattacharyya, Sauvik; Bose, Sekhar

2017-11-02

Cognitive decline is often associated with the aging process. Ashwagandha (Withania somnifera (L.) Dunal) has long been used in the traditional Ayurvedic system of medicine to enhance memory and improve cognition. This pilot study was designed to evaluate the efficacy and safety of ashwagandha (Withania somnifera (L.) Dunal) in improving memory and cognitive functioning in adults with mild cognitive impairment (MCI). A prospective, randomized, double-blind, placebo-controlled study was conducted in 50 adults. Subjects were treated with either ashwagandha-root extract (300 mg twice daily) or placebo for eight weeks. After eight weeks of study, the ashwagandha treatment group demonstrated significant improvements compared with the placebo group in both immediate and general memory, as evidenced by Wechsler Memory Scale III subtest scores for logical memory I (p = 0.007), verbal paired associates I (p = 0.042), faces I (p = 0.020), family pictures I (p = 0.006), logical memory II (p = 0.006), verbal paired associates II (p = 0.031), faces II (p = 0.014), and family pictures II (p = 0.006). The treatment group also demonstrated significantly greater improvement in executive function, sustained attention, and information-processing speed as indicated by scores on the Eriksen Flanker task (p = 0.002), Wisconsin Card Sort test (p = 0.014), Trail-Making test part A (p = 0.006), and the Mackworth Clock test (p = 0.009). Ashwagandha may be effective in enhancing both immediate and general memory in people with MCI as well as improving executive function, attention, and information processing speed.

Auxin fluxes in the root apex co-regulate gravitropism and lateral root initiation.

PubMed

Lucas, M; Godin, C; Jay-Allemand, C; Laplaze, L

2008-01-01

Root architecture plays an important role in water and nutrient acquisition and in the ability of the plant to adapt to the soil. Lateral root development is the main determinant of the shape of the root system and is controlled by external factors such as nutrient concentration. Here it is shown that lateral root initiation and root gravitropism, two processes that are regulated by auxin, are co-regulated in Arabidopsis. A mathematical model was generated that can predict the effects of gravistimulations on lateral root initiation density and suggests that lateral root initiation is controlled by an inhibitory fields mechanism. Moreover, gene transactivation experiments suggest a mechanism involving a single auxin transport route for both responses. Finally, co-regulation may offer a selective advantage by optimizing soil exploration as supported by a simple quantitative analysis.

Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species

PubMed Central

2013-01-01

Background Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. Results We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. Conclusion Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield. PMID:24083555

Phene Synergism between Root Hair Length and Basal Root Growth Angle for Phosphorus Acquisition1[OPEN

PubMed Central

Miguel, Magalhaes Amade

2015-01-01

Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here. PMID:25699587

Data Inquiry for School Improvement: Root Cause Analysis. Q&A with Roni Silverstein. REL Mid-Atlantic Webinar

ERIC Educational Resources Information Center

Silverstein, Roni

2014-01-01

Root cause analysis is a powerful method schools use to analyze data to solve problems; it aims to identify and correct the root causes of problems or events, rather than simply addressing their symptoms. Veteran practitioner, Roni Silverstein, presented the value of this process and practical ways to use it in your school or district. This…

Comparison of intracanal EndoSequence Root Repair Material and ProRoot MTA to induce pH changes in simulated root resorption defects over 4 weeks in matched pairs of human teeth.

PubMed

Hansen, Stephen W; Marshall, J Gordon; Sedgley, Christine M

2011-04-01

Intracanal mineral trioxide aggregate (MTA) may provide an alternative to calcium hydroxide in the treatment of external inflammatory root resorption. This in vitro study using human matched pairs of teeth compared white ProRoot MTA (WMTA; (Dentsply Tulsa Dental Specialties, Tulsa, OK) and an alternative material with purportedly improved handling properties, EndoSequence Root Repair Material (ES; Brasseler USA, Savannah, GA), by measuring pH in simulated root surface resorptive defects after intracanal placement. The null hypothesis tested was that there is no difference between WMTA and ES. Bilaterally matched pairs (n = 24) of extracted, human, single-rooted teeth were instrumented to apical size 50/.06, and root surface cavities were prepared at 5 mm and 2 mm from the apex. Root canals of experimental matched pairs (n = 20) were filled with WMTA or ES; control pairs (n = 4) were filled with calcium hydroxide (positive control [POS]) or saline (negative control [NEG]). Teeth were sealed coronally and apically and immersed in saline. The pH in root surface cavities was measured at 20 minutes, 3 hours, 24 hours, 1 week, 2 weeks, 3 weeks, and 4 weeks. The pH at 5 mm when compared with the 2-mm level was significantly higher for the WMTA, ES, and POS groups (P < .05, paired t tests); therefore, each level was analyzed separately. At both the 2-mm and 5-mm levels, significant pH changes occurred over time in the WMTA, ES (both P < .0001, repeated-measures analysis of variance), and POS (P < .0001, Friedman test) groups and not in the NEG group (mean pH = 7.32 ± 0.04, P > .05). There were no differences between WMTA and ES at 20 minutes and 3 hours at both levels or at 24 hours at 5mm. The pH of WMTA was higher than ES by 24 hours at the 2-mm level (8.79 vs 8.56, P < .05, paired t test) and after 1 week at the 5-mm level (8.91 vs 8.05, P < .0001) and was thereafter always significantly higher in WMTA compared with ES (P < .0001). The null hypothesis was rejected

Transcriptome Profiling of Watermelon Root in Response to Short-Term Osmotic Stress

PubMed Central

Yang, Yongchao; Mo, Yanling; Yang, Xiaozheng; Zhang, Haifei; Wang, Yongqi; Li, Hao; Wei, Chunhua; Zhang, Xian

2016-01-01

Osmotic stress adversely affects the growth, fruit quality and yield of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai). Increasing the tolerance of watermelon to osmotic stress caused by factors such as high salt and water deficit is an effective way to improve crop survival in osmotic stress environments. Roots are important organs in water absorption and are involved in the initial response to osmosis stress; however, few studies have examined the underlying mechanism of tolerance to osmotic stress in watermelon roots. For better understanding of this mechanism, the inbred watermelon accession M08, which exhibits relatively high tolerance to water deficits, was treated with 20% polyethylene glycol (PEG) 6000. The root samples were harvested at 6 h after PEG treatment and untreated samples were used as controls. Transcriptome analyses were carried out by Illumina RNA sequencing. A total of 5246 differentially expressed genes were identified. Gene ontology enrichment and biochemical pathway analyses of these 5246 genes showed that short-term osmotic stress affected osmotic adjustment, signal transduction, hormone responses, cell division, cell cycle and ribosome, and M08 may repress root growth to adapt osmotic stress. The results of this study describe the watermelon root transcriptome under osmotic stress and propose new insight into watermelon root responses to osmotic stress at the transcriptome level. Accordingly, these results allow us to better understand the molecular mechanisms of watermelon in response to drought stress and will facilitate watermelon breeding projects to improve drought tolerance. PMID:27861528

Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

NASA Astrophysics Data System (ADS)

Ahmed, Mutez Ali; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

2016-04-01

Roots play a key role in water acquisition and are a significant component of plant adaptation to different environmental conditions. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of root water uptake in mature maize. We used neutron radiography to image the spatial distribution of maize roots and trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers filled with a sandy soil that was kept homogeneously wet throughout the experiment. When the plants were five weeks-old, we injected D2O into selected soil regions. The transport of D2O was simulated using a diffusion-convection numerical model. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The model was initially developed and tested with two weeks-old maize (Ahmed et. al. 2015), for which we found that water was mainly taken up by lateral roots and the water uptake of the seminal roots was negligible. Here, we used this method to measure root water uptake in a mature maize root system. The root architecture of five weeks-old maize consisted of primary and seminal roots with long laterals and crown (nodal) roots that emerged from the above ground part of the plant two weeks after planting. The crown roots were thicker than the seminal roots and had fewer and shorter laterals. Surprisingly, we found that the water was mainly taken up by the crown roots and their laterals, while the lateral roots of seminal roots, which were the main location of water uptake of younger plants, stopped to take up water. Interestingly, we also found that in contrast to the seminal roots, the crown roots were able to take up water also from their distal segments. We conclude that for the two weeks

Strigolactones Effects on Root Growth

NASA Astrophysics Data System (ADS)

Koltai, Hinanit

2012-07-01

Strigolactones (SLs) were defined as a new group of plant hormones that suppress lateral shoot branching. Our previous studies suggested SLs to be regulators of root development. SLs were shown to alter root architecture by regulating lateral root formation and to affect root hair elongation in Arabidopsis. Another important effect of SLs on root growth was shown to be associated with root directional growth. Supplementation of SLs to roots led to alterations in root directional growth, whereas associated mutants showed asymmetrical root growth, which was influenced by environmental factors. The regulation by SLs of root development was shown to be conducted via a cross talk of SLs with other plant hormones, including auxin. SLs were shown to regulate auxin transport, and to interfere with the activity of auxin-efflux carriers. Therefore, it might be that SLs are regulators of root directional growth as a result of their ability to regulated auxin transport. However, other evidences suggest a localized effect of SLs on cell division, which may not necessarily be associated with auxin efflux. These and other, recent hypothesis as to the SLs mode of action and the associated root perception and response to environmental factors will be discussed.

Mini-incubators improve the adventitious rooting performance of Corymbia and Eucalyptus microcuttings according to the environment in which they are conditioned.

PubMed

Brondani, Gilvano E; Oliveira, Leandro S DE; Konzen, Enéas R; Silva, André L L DA; Costa, Jefferson L

2017-10-16

We addressed a major challenge in the in vitro clonal propagation of Corymbia citriodora, Eucalyptus urophylla and E. benthamii by using an ex vitro adventitious rooting strategy in a mini-incubator. Mini-incubators were placed in four environments for rooting. A shade house with no fogging system and a greenhouse with no ventilation but with a fogging environment had the best performance in terms of rooting, root growth and survival of microcuttings. Daily recording of the temperature within each mini-incubator in each environment allowed the verification of negative correlations between the maximum average temperature and the survival, adventitious rooting and root growth. The ideal maximum air temperature for the efficient production of clonal plants was 28.4°C (± 5.5°C), and the minimum was 20.3°C (± 6.2°C). E. benthamii was more sensitive to higher temperatures than C. citriodora and E. urophylla. Nevertheless, placing mini-incubators in the shade house with no fogging system resulted in a stable and uniform performance among the three species, with 100.0% survival and 81.4% rooting. Histological sections of the adventitious roots revealed connection with the stem vascular cambium. Therefore, our experimental system demonstrated the potential of mini-incubators coupled with the proper environment to optimize the adventitious rooting performance of microcuttings.

Plant roots use a patterning mechanism to position lateral root branches toward available water.

PubMed

Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

2014-06-24

The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

Air lateral root pruning affects longleaf pine seedling root system morphology

Treesearch

Shi-Jean Susana Sung; Dave Haywood

2016-01-01

Longleaf pine (Pinus palustris) seedlings were cultured with air lateral root pruning (side-vented containers, VT) or without (solid-walled containers, SW). Seedling root system morphology and growth were assessed before planting and 8 and 14 months after planting. Although VT seedlings had greater root collar diameter than the SW before planting,...

Relationships between root respiration rate and root morphology, chemistry and anatomy in Larix gmelinii and Fraxinus mandshurica.

PubMed

Jia, Shuxia; McLaughlin, Neil B; Gu, Jiacun; Li, Xingpeng; Wang, Zhengquan

2013-06-01

Tree roots are highly heterogeneous in form and function. Previous studies revealed that fine root respiration was related to root morphology, tissue nitrogen (N) concentration and temperature, and varied with both soil depth and season. The underlying mechanisms governing the relationship between root respiration and root morphology, chemistry and anatomy along the root branch order have not been addressed. Here, we examined these relationships of the first- to fifth-order roots for near surface roots (0-10 cm) of 22-year-old larch (Larix gmelinii L.) and ash (Fraxinus mandshurica L.) plantations. Root respiration rate at 18 °C was measured by gas phase O2 electrodes across the first five branching order roots (the distal roots numbered as first order) at three times of the year. Root parameters of root diameter, specific root length (SRL), tissue N concentration, total non-structural carbohydrates (starch and soluble sugar) concentration (TNC), cortical thickness and stele diameter were also measured concurrently. With increasing root order, root diameter, TNC and the ratio of root TNC to tissue N concentration increased, while the SRL, tissue N concentration and cortical proportion decreased. Root respiration rate also monotonically decreased with increasing root order in both species. Cortical tissue (including exodermis, cortical parenchyma and endodermis) was present in the first three order roots, and cross sections of the cortex for the first-order root accounted for 68% (larch) and 86% (ash) of the total cross section of the root. Root respiration was closely related to root traits such as diameter, SRL, tissue N concentration, root TNC : tissue N ratio and stele-to-root diameter proportion among the first five orders, which explained up to 81-94% of variation in the rate of root respiration for larch and up to 83-93% for ash. These results suggest that the systematic variations of root respiration rate within tree fine root system are possibly due to the

Involvement of Arabidopsis thaliana phospholipase Dzeta2 in root hydrotropism through the suppression of root gravitropism.

PubMed

Taniguchi, Yukimi Y; Taniguchi, Masatoshi; Tsuge, Tomohiko; Oka, Atsuhiro; Aoyama, Takashi

2010-01-01

Root hydrotropism is the phenomenon of directional root growth toward moisture under water-deficient conditions. Although physiological and genetic studies have revealed the involvement of the root cap in the sensing of moisture gradients, and those of auxin and abscisic acid (ABA) in the signal transduction for asymmetric root elongation, the overall mechanism of root hydrotropism is still unclear. We found that the promoter activity of the Arabidopsis phospholipase Dzeta2 gene (PLDzeta2) was localized to epidermal cells in the distal root elongation zone and lateral root cap cells adjacent to them, and that exogenous ABA enhanced the activity and extended its area to the entire root cap. Although pldzeta2 mutant root caps did not exhibit a morphological phenotype in either the absence or presence of exogenous ABA, the inhibitory effect of ABA on gravitropism, which was significant in wild-type roots, was not observed in pldzeta2 mutant roots. In root hydrotropism experiments, pldzeta2 mutations significantly retarded or disturbed root hydrotropic responses. A drought condition similar to that used in a hydrotropism experiment enhanced the PLDzeta2 promoter activity in the root cap, as did exogenous ABA. These results suggest that PLDzeta2 responds to drought through ABA signaling in the root cap and accelerates root hydrotropism through the suppression of root gravitropism.

Root developmental adaptation to phosphate starvation: better safe than sorry.

PubMed

Péret, Benjamin; Clément, Mathilde; Nussaume, Laurent; Desnos, Thierry

2011-08-01

Phosphorus is a crucial component of major organic molecules such as nucleic acids, ATP and membrane phospholipids. It is present in soils in the form of inorganic phosphate (Pi), which has low availability and poor mobility. To cope with Pi limitations, plants have evolved complex adaptive responses that include morphological and physiological modifications. This review describes how the model plant Arabidopsis thaliana adapts its root system architecture to phosphate deficiency through inhibition of primary root growth, increase in lateral root formation and growth and production of root hairs, which all promote topsoil foraging. A better understanding of plant adaptation to low phosphate will open the way to increased phosphorus use efficiency by crops. Such an improvement is needed in order to adjust how we manage limited phosphorus stocks and to reduce the disastrous environmental effects of phosphate fertilizers overuse. Copyright © 2011 Elsevier Ltd. All rights reserved.

Functional Manipulation of Root Endophyte Populations for Feedstock Improvement- Final Report

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

Dangl, Jeffery L.

This study provides a systemic analysis of the influence of the abiotic environment on the assembly of plant microbiomes. We show that under controlled conditions, community assembly cues are robust and predictable across multiple abiotic gradients. Plant colonization patterns are largely driven by phylogeny, and colonization phenotypes are ubiquitous across different specimens of the same phylogenetic class. Subsets of the full synthetic community were shown to induce different root morphologies, and the morphology observed with the full community is an outcome of epistasis between two functional guilds.

Inhibition of auxin movement from the shoot into the root inhibits lateral root development in Arabidopsis

NASA Technical Reports Server (NTRS)

Reed, R. C.; Brady, S. R.; Muday, G. K.

1998-01-01

In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

A role for the root cap in root branching revealed by the non-auxin probe naxillin.

PubMed

De Rybel, Bert; Audenaert, Dominique; Xuan, Wei; Overvoorde, Paul; Strader, Lucia C; Kepinski, Stefan; Hoye, Rebecca; Brisbois, Ronald; Parizot, Boris; Vanneste, Steffen; Liu, Xing; Gilday, Alison; Graham, Ian A; Nguyen, Long; Jansen, Leentje; Njo, Maria Fransiska; Inzé, Dirk; Bartel, Bonnie; Beeckman, Tom

2012-09-01

The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture.

A role for the root cap in root branching revealed by the non-auxin probe naxillin

PubMed Central

De Rybel, Bert; Audenaert, Dominique; Xuan, Wei; Overvoorde, Paul; Strader, Lucia C; Kepinski, Stefan; Hoye, Rebecca; Brisbois, Ronald; Parizot, Boris; Vanneste, Steffen; Liu, Xing; Gilday, Alison; Graham, Ian A; Nguyen, Long; Jansen, Leentje; Njo, Maria Fransiska; Inzé, Dirk; Bartel, Bonnie; Beeckman, Tom

2013-01-01

The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture. PMID:22885787

Root Traits, Nodulation and Root Distribution in Soil for Five Wild Lentil Species and Lens culinaris (Medik.) Grown under Well-Watered Conditions.

PubMed

Gorim, Linda Y; Vandenberg, Albert

2017-01-01

The efficient use of resources such as water and nutrients by plants is increasingly important as the world population food demand continues to grow. With the increased production of lentil in the temperate zones of North America, improvement in yield needs to be maintained. The use of wild lentil genotypes as sources of genetic diversity for introgression into cultivated lentil is an important breeding strategy, but little is known about their root systems. We evaluated the root systems of five wild lentil species and Lens culinaris under fully watered conditions. Plants were grown in 60 cm tubes containing equal volumes of soil collected from the reconstructed A, B, and C horizons. Significant differences were observed for root traits and fine root distribution between and within species and the proportion of root biomass partitioned into each soil layer was unique for each genotype. We also observed variability in nodule number and nodule shape within and between genotypes. Some genotypes more efficiently used water for either biomass or seed production. The allocation of resources to seed production also varied between genotypes. These observations could have impact on the design of future lentil breeding in the context of strategies for managing changes in rainfall amount and distribution for lentil production ecosystems.

Low Light Availability Alters Root Exudation and Reduces Putative Beneficial Microorganisms in Seagrass Roots

PubMed Central

Martin, Belinda C.; Gleeson, Deirdre; Statton, John; Siebers, Andre R.; Grierson, Pauline; Ryan, Megan H.; Kendrick, Gary A.

2018-01-01

Seagrass roots host a diverse microbiome that is critical for plant growth and health. Composition of microbial communities can be regulated in part by root exudates, but the specifics of these interactions in seagrass rhizospheres are still largely unknown. As light availability controls primary productivity, reduced light may impact root exudation and consequently the composition of the root microbiome. Hence, we analyzed the influence of light availability on root exudation and community structure of the root microbiome of three co-occurring seagrass species, Halophila ovalis, Halodule uninervis and Cymodocea serrulata. Plants were grown under four light treatments in mesocosms for 2 weeks; control (100% surface irradiance (SI), medium (40% SI), low (20% SI) and fluctuating light (10 days 20% and 4 days 100%). 16S rDNA amplicon sequencing revealed that microbial diversity, composition and predicted function were strongly influenced by the presence of seagrass roots, such that root microbiomes were unique to each seagrass species. Reduced light availability altered seagrass root exudation, as characterized using fluorescence spectroscopy, and altered the composition of seagrass root microbiomes with a reduction in abundance of potentially beneficial microorganisms. Overall, this study highlights the potential for above-ground light reduction to invoke a cascade of changes from alterations in root exudation to a reduction in putative beneficial microorganisms and, ultimately, confirms the importance of the seagrass root environment – a critical, but often overlooked space. PMID:29375529

Negative gravitropism in plant roots.

PubMed

Ge, Liangfa; Chen, Rujin

2016-10-17

Plants are capable of orienting their root growth towards gravity in a process termed gravitropism, which is necessary for roots to grow into soil, for water and nutrient acquisition and to anchor plants. Here we show that root gravitropism depends on the novel protein, NEGATIVE GRAVITROPIC RESPONSE OF ROOTS (NGR). In both Medicago truncatula and Arabidopsis thaliana, loss of NGR reverses the direction of root gravitropism, resulting in roots growing upward.

Morphology of Er:YAG-laser-treated root surfaces

NASA Astrophysics Data System (ADS)

Keller, Ulrich; Stock, Karl; Hibst, Raimund

1997-12-01

From previous studies it could be demonstrated that an efficient ablation of dental calculus is possible using an Er:YAG laser with a special contact fiber tip. After improving of the design and the efficiency of light transmission of the contact tip laser treated tooth root surfaces were investigated due to morphological changes in comparison to conventional root scaling and planing. Surface modifications were observed histologically under the light microscope and by means of a Scanning Electron Microscope. During laser treatment the intrapulpal temperature increase was measured. The results show that the improved contact tip a microstructured surface can be generated, which shows no signs of thermal effects even when a laser pulse repetition rate of 15 Hz was used. Temperature increase was limited to 4 K at a repetition rate of 10 Hz and to 5.5 K at a repetition rate of 15 Hz.

Root gravitropism

NASA Technical Reports Server (NTRS)

Masson, P. H.

1995-01-01

When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Improving Sexual Function in Women: A Pilot Study.

PubMed

Dongre, Swati; Langade, Deepak; Bhattacharyya, Sauvik

2015-01-01

Many women experience sexual dysfunction where there are orgasm disorders and sexual difficulties. Ashwagandha (Withania somnifera) is a herb known to improve the body's physical and psychological condition. The purpose of the study was to determine the efficacy and safety of a high-concentration ashwagandha root extract (HCARE) supplementation for improving sexual function in healthy females. In this pilot study, 50 study subjects were randomized to either (i) HCARE-treated group or (ii) placebo- (starch-) treated group. The subjects consumed either HCARE or placebo capsules of 300mg twice daily for 8 weeks. Sexual function was assessed using two psychometric scales, the Female Sexual Function Index (FSFI) Questionnaire and the Female Sexual Distress Scale (FSDS), and by the number of total and successful sexual encounters. The analysis indicates that treatment with HCARE leads to significantly higher improvement, relative to placebo, in the FSFI Total score (p < 0.001), FSFI domain score for "arousal" (p < 0.001), "lubrication" (p < 0.001), "orgasm" (p = 0.004), and "satisfaction" (p < 0.001), and also FSDS score (p < 0.001) and the number of successful sexual encounters (p < 0.001) at the end of the treatment. This study demonstrated that oral administration of HCARE may improve sexual function in healthy women. The present study is registered in the Clinical Trial Registry, Government of India, with a number CTRI/2015/07/006045.

A new anatomically based nomenclature for the roots and root canals-part 1: maxillary molars.

PubMed

Kottoor, Jojo; Albuquerque, Denzil Valerian; Velmurugan, Natanasabapathy

2012-01-01

Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

Fine root mercury heterogeneity: metabolism of lower-order roots as an effective route for mercury removal.

PubMed

Wang, Jun-Jian; Guo, Ying-Ying; Guo, Da-Li; Yin, Sen-Lu; Kong, De-Liang; Liu, Yang-Sheng; Zeng, Hui

2012-01-17

Fine roots are critical components for plant mercury (Hg) uptake and removal, but the patterns of Hg distribution and turnover within the heterogeneous fine root components and their potential limiting factors are poorly understood. Based on root branching structure, we studied the total Hg (THg) and its cellular partitioning in fine roots in 6 Chinese subtropical trees species and the impacts of root morphological and stoichiometric traits on Hg partitioning. The THg concentration generally decreased with increasing root order, and was higher in cortex than in stele. This concentration significantly correlated with root length, diameter, specific root length, specific root area, and nitrogen concentration, whereas its cytosolic fraction (accounting for <10% of THg) correlated with root carbon and sulfur concentrations. The estimated Hg return flux from dead fine roots outweighed that from leaf litter, and ephemeral first-order roots that constituted 7.2-22.3% of total fine root biomass may have contributed most to this flux (39-71%, depending on tree species and environmental substrate). Our results highlight the high capacity of Hg stabilization and Hg return by lower-order roots and demonstrate that turnover of lower-order roots may be an effective strategy of detoxification in perennial tree species.

Responses of grapevine rootstocks to drought through altered root system architecture and root transcriptomic regulations.

PubMed

Yıldırım, Kubilay; Yağcı, Adem; Sucu, Seda; Tunç, Sümeyye

2018-06-01

Roots are the major interface between the plant and various stress factors in the soil environment. Alteration of root system architecture (RSA) (root length, spread, number and length of lateral roots) in response to environmental changes is known to be an important strategy for plant adaptation and productivity. In light of ongoing climate changes and global warming predictions, the breeding of drought-tolerant grapevine cultivars is becoming a crucial factor for developing a sustainable viticulture. Root-trait modeling of grapevine rootstock for drought stress scenarios, together with high-throughput phenotyping and genotyping techniques, may provide a valuable background for breeding studies in viticulture. Here, tree grafted grapevine rootstocks (110R, 5BB and 41B) having differential RSA regulations and drought tolerance were investigated to define their drought dependent root characteristics. Root area, root length, ramification and number of root tips reduced less in 110R grafted grapevines compared to 5BB and 41B grafted ones during drought treatment. Root relative water content as well as total carbohydrate and nitrogen content were found to be much higher in the roots of 110R than it was in the roots of other rootstocks under drought. Microarray-based root transcriptome profiling was also conducted on the roots of these rootstocks to identify their gene regulation network behind drought-dependent RSA alterations. Transcriptome analysis revealed totally 2795, 1196 and 1612 differentially expressed transcripts at the severe drought for the roots of 110R, 5BB and 41B, respectively. According to this transcriptomic data, effective root elongation and enlargement performance of 110R were suggested to depend on three transcriptomic regulations. First one is the drought-dependent induction in sugar and protein transporters genes (SWEET and NRT1/PTR) in the roots of 110R to facilitate carbohydrate and nitrogen accumulation. In the roots of the same rootstock

[Effects and mechanisms of plant roots on slope reinforcement and soil erosion resistance: a research review].

PubMed

Xiong, Yan-Mei; Xia, Han-Ping; Li, Zhi-An; Cai, Xi-An

2007-04-01

Plant roots play an important role in resisting the shallow landslip and topsoil erosion of slopes by raising soil shear strength. Among the models in interpreting the mechanisms of slope reinforcement by plant roots, Wu-Waldron model is a widely accepted one. In this model, the reinforced soil strength by plant roots is positively proportional to average root tensile strength and root area ratio, the two most important factors in evaluating slope reinforcement effect of plant roots. It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them. The increase of soil erosion resistance by plant roots was mainly through the actions of fiber roots less than 1 mm in diameter, while fiber roots enhanced the soil stability to resist water dispersion via increasing the number and diameter of soil water-stable aggregates. Fine roots could also improve soil permeability effectively to decrease runoff and weaken soil erosion.

DRO1 influences root system architecture in Arabidopsis and Prunus species.

PubMed

Guseman, Jessica M; Webb, Kevin; Srinivasan, Chinnathambi; Dardick, Chris

2017-03-01

Roots provide essential uptake of water and nutrients from the soil, as well as anchorage and stability for the whole plant. Root orientation, or angle, is an important component of the overall architecture and depth of the root system; however, little is known about the genetic control of this trait. Recent reports in Oryza sativa (rice) identified a role for DEEPER ROOTING 1 (DRO1) in influencing the orientation of the root system, leading to positive changes in grain yields under water-limited conditions. Here we found that DRO1 and DRO1-related genes are present across diverse plant phyla, and fall within the IGT gene family. The IGT family also includes TAC1 and LAZY1, which are known to affect the orientation of lateral shoots. Consistent with a potential role in root development, DRO1 homologs in Arabidopsis and peach showed root-specific expression. Promoter-reporter constructs revealed that AtDRO1 is predominantly expressed in both the root vasculature and root tips, in a distinct developmental pattern. Mutation of AtDRO1 led to more horizontal lateral root angles. Overexpression of AtDRO1 under a constitutive promoter resulted in steeper lateral root angles, as well as shoot phenotypes including upward leaf curling, shortened siliques and narrow lateral branch angles. A conserved C-terminal EAR-like motif found in IGT genes was required for these ectopic phenotypes. Overexpression of PpeDRO1 in Prunus domestica (plum) led to deeper-rooting phenotypes. Collectively, these data indicate a potential application for DRO1-related genes to alter root architecture for drought avoidance and improved resource use. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Effect of topical alendronate on root resorption of dried replanted dog teeth.

PubMed

Levin, L; Bryson, E C; Caplan, D; Trope, M

2001-06-01

Alendronate (ALN) is a third generation bisphosphonate with demonstrated osteoclast inhibitory activity that may slow down the resorptive process after severe traumatic injuries. Eighty-two premolar roots of five mongrel dogs were endodontically treated and restored, extracted and treated as follows: 70 roots were bench dried for either 40 or 60 min. Thirty-eight of these roots were then soaked for 5 min in a 1 mM solution of ALN in Hanks' Balanced Salt Solution (HBSS) and replanted. Thirty-two roots were soaked for 5 min in HBSS and replanted. In the remaining 12 roots which were not exposed to the bench drying procedure, a 0.5 mM deep lingual mid-root cemental defect was made. Six of these roots were soaked in a 1 mM solution of ALN in HBSS for 5 min and replanted. The other six roots were soaked for 5 min in HBSS and replanted. Historical negative and positive controls were used from similarly treated teeth in our previous studies. After 4 months the dogs were killed and the roots prepared for histological evaluation. Five-microm-thick cross-sections of the root and surrounding tissue taken every 70 microm were evaluated for healing according to the criteria of Andreasen. In the 12 roots with cemental defects, healing with cementum of the damaged root surface was evaluated. In addition, residual root mass was also measured to determine the extent of root structure loss for each soaking method. Cemental healing took place in all 12 artificially damaged roots, indicating that these soaking media did not inhibit cementogenesis. The alendronate-soaked roots had statistically significantly more healing than the roots soaked in HBSS without alendronate. This improvement in healing was seen in all dogs except one and in all teeth except the first premolar. Soaking in alendronate also resulted in significantly less loss in root mass due to resorption compared to those teeth soaked in HBSS without alendronate.

Association analysis of single nucleotide polymorphisms in candidate genes with root traits in maize (Zea mays L.) seedlings.

PubMed

Kumar, Bharath; Abdel-Ghani, Adel H; Pace, Jordon; Reyes-Matamoros, Jenaro; Hochholdinger, Frank; Lübberstedt, Thomas

2014-07-01

Several genes involved in maize root development have been isolated. Identification of SNPs associated with root traits would enable the selection of maize lines with better root architecture that might help to improve N uptake, and consequently plant growth particularly under N deficient conditions. In the present study, an association study (AS) panel consisting of 74 maize inbred lines was screened for seedling root traits in 6, 10, and 14-day-old seedlings. Allele re-sequencing of candidate root genes Rtcl, Rth3, Rum1, and Rul1 was also carried out in the same AS panel lines. All four candidate genes displayed different levels of nucleotide diversity, haplotype diversity and linkage disequilibrium. Gene based association analyses were carried out between individual polymorphisms in candidate genes, and root traits measured in 6, 10, and 14-day-old maize seedlings. Association analyses revealed several polymorphisms within the Rtcl, Rth3, Rum1, and Rul1 genes associated with seedling root traits. Several nucleotide polymorphisms in Rtcl, Rth3, Rum1, and Rul1 were significantly (P<0.05) associated with seedling root traits in maize suggesting that all four tested genes are involved in the maize root development. Thus considerable allelic variation present in these root genes can be exploited for improving maize root characteristics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effects of peach tree root system morphology and transpiration on leaf nitrogen and phosphorus

USDA-ARS?s Scientific Manuscript database

Adequate mineral nutrition is critical for high fruit quality and sustained yield of fruit trees. It is likely that nutritional competence of a fruit tree depends on several physiological and morphological traits that affect nutrient uptake. Fruit trees with improved root systems (own-rooted or as ...

Volatile signalling by sesquiterpenes from ectomycorrhizal fungi reprogrammes root architecture

PubMed Central

Ditengou, Franck A.; Müller, Anna; Rosenkranz, Maaria; Felten, Judith; Lasok, Hanna; van Doorn, Maja Miloradovic; Legué, Valerie; Palme, Klaus; Schnitzler, Jörg-Peter; Polle, Andrea

2015-01-01

The mutualistic association of roots with ectomycorrhizal fungi promotes plant health and is a hallmark of boreal and temperate forests worldwide. In the pre-colonization phase, before direct contact, lateral root (LR) production is massively stimulated, yet little is known about the signals exchanged during this step. Here, we identify sesquiterpenes (SQTs) as biologically active agents emitted by Laccaria bicolor while interacting with Populus or Arabidopsis. We show that inhibition of fungal SQT production by lovastatin strongly reduces LR proliferation and that (–)-thujopsene, a low-abundance SQT, is sufficient to stimulate LR formation in the absence of the fungus. Further, we show that the ectomycorrhizal ascomycote, Cenococcum geophilum, which cannot synthesize SQTs, does not promote LRs. We propose that the LR-promoting SQT signal creates a win-win situation by enhancing the root surface area for plant nutrient uptake and by improving fungal access to plant-derived carbon via root exudates. PMID:25703994

Reduction in nerve root compression by the nucleus pulposus after Feng's Spinal Manipulation☆

PubMed Central

Feng, Yu; Gao, Yan; Yang, Wendong; Feng, Tianyou

2013-01-01

Ninety-four patients with lumbar intervertebral disc herniation were enrolled in this study. Of these, 48 were treated with Feng's Spinal Manipulation, hot fomentation, and bed rest (treatment group). The remaining 46 patients were treated with hot fomentation and bed rest only (control group). After 3 weeks of treatment, clinical parameters including the angle of straight-leg raising, visual analogue scale pain score, and Japanese Orthopaedic Association score for low back pain were improved. The treatment group had significantly better improvement in scores than the control group. Magnetic resonance myelography three-dimensional reconstruction imaging of the vertebral canal demonstrated that filling of the compressed nerve root sleeve with cerebrospinal fluid increased significantly in the treatment group. The diameter of the nerve root sleeve was significantly larger in the treatment group than in the control group. However, the sagittal diameter index of the herniated nucleus pulposus and the angle between the nerve root sleeve and the thecal sac did not change significantly in either the treatment or control groups. The effectiveness of Feng's Spinal Manipulation for the treatment of symptoms associated with lumbar intervertebral disc herniation may be attributable to the relief of nerve root compression, without affecting the herniated nucleus pulposus or changing the morphology or position of the nerve root. PMID:25206408

Discrete square root smoothing.

NASA Technical Reports Server (NTRS)

Kaminski, P. G.; Bryson, A. E., Jr.

1972-01-01

The basic techniques applied in the square root least squares and square root filtering solutions are applied to the smoothing problem. Both conventional and square root solutions are obtained by computing the filtered solutions, then modifying the results to include the effect of all measurements. A comparison of computation requirements indicates that the square root information smoother (SRIS) is more efficient than conventional solutions in a large class of fixed interval smoothing problems.

Estimate of fine root production including the impact of decomposed roots in a Bornean tropical rainforest

NASA Astrophysics Data System (ADS)

Katayama, Ayumi; Khoon Koh, Lip; Kume, Tomonori; Makita, Naoki; Matsumoto, Kazuho; Ohashi, Mizue

2016-04-01

Considerable carbon is allocated belowground and used for respiration and production of roots. It is reported that approximately 40 % of GPP is allocated belowground in a Bornean tropical rainforest, which is much higher than those in Neotropical rainforests. This may be caused by high root production in this forest. Ingrowth core is a popular method for estimating fine root production, but recent study by Osawa et al. (2012) showed potential underestimates of this method because of the lack of consideration of the impact of decomposed roots. It is important to estimate fine root production with consideration for the decomposed roots, especially in tropics where decomposition rate is higher than other regions. Therefore, objective of this study is to estimate fine root production with consideration of decomposed roots using ingrowth cores and root litter-bag in the tropical rainforest. The study was conducted in Lambir Hills National Park in Borneo. Ingrowth cores and litter bags for fine roots were buried in March 2013. Eighteen ingrowth cores and 27 litter bags were collected in May, September 2013, March 2014 and March 2015, respectively. Fine root production was comparable to aboveground biomass increment and litterfall amount, and accounted only 10% of GPP in this study site, suggesting most of the carbon allocated to belowground might be used for other purposes. Fine root production was comparable to those in Neotropics. Decomposed roots accounted for 18% of fine root production. This result suggests that no consideration of decomposed fine roots may cause underestimate of fine root production.

Genome-wide microarray analysis of tomato roots showed defined responses to iron deficiency

PubMed Central

2012-01-01

Background Plants react to iron deficiency stress adopting different kind of adaptive responses. Tomato, a Strategy I plant, improves iron uptake through acidification of rhizosphere, reduction of Fe3+ to Fe2+ and transport of Fe2+ into the cells. Large-scale transcriptional analyses of roots under iron deficiency are only available for a very limited number of plant species with particular emphasis for Arabidopsis thaliana. Regarding tomato, an interesting model species for Strategy I plants and an economically important crop, physiological responses to Fe-deficiency have been thoroughly described and molecular analyses have provided evidence for genes involved in iron uptake mechanisms and their regulation. However, no detailed transcriptome analysis has been described so far. Results A genome-wide transcriptional analysis, performed with a chip that allows to monitor the expression of more than 25,000 tomato transcripts, identified 97 differentially expressed transcripts by comparing roots of Fe-deficient and Fe-sufficient tomato plants. These transcripts are related to the physiological responses of tomato roots to the nutrient stress resulting in an improved iron uptake, including regulatory aspects, translocation, root morphological modification and adaptation in primary metabolic pathways, such as glycolysis and TCA cycle. Other genes play a role in flavonoid biosynthesis and hormonal metabolism. Conclusions The transcriptional characterization confirmed the presence of the previously described mechanisms to adapt to iron starvation in tomato, but also allowed to identify other genes potentially playing a role in this process, thus opening new research perspectives to improve the knowledge on the tomato root response to the nutrient deficiency. PMID:22433273

Seasonal changes of whole root system conductance by a drought-tolerant grape root system.

PubMed

Alsina, Maria Mar; Smart, David R; Bauerle, Taryn; de Herralde, Felicidad; Biel, Carme; Stockert, Christine; Negron, Claudia; Save, Robert

2011-01-01

The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (A(L):A(R)). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (A(R)) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (g(s)) and whole root system hydraulic conductance (k(r)) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψ(L)) for Merlot grafted onto the 1103P root system (-0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (-1.06±0.03 MPa) during spring, but dropped by approximately -0.4 MPa from spring to autumn, and were significantly lower by -0.15 MPa (-1.43±0.02 MPa) than for Merlot on 101-14Mgt (at -1.28±0.02 MPa). Surprisingly, g(s) of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35-20 mmol vine(-1) s(-1) during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (k(r)) increased from 0.004 to 0.009 kg MPa(-1) s(-1) during that same time period. The changes in k(r) could not be explained by xylem anatomy or conductivity changes of individual root

Responses of Heterodera glycines and Meloidogyne incognita infective juveniles to root tissues, root exudates, and root extracts from three plant species

USDA-ARS?s Scientific Manuscript database

The infective juvenile (J2) stage of endoparasitic plant nematodes uses plant chemical signals, released from roots, to localize and infect hosts. We examined the behaviors of soybean cyst nematode (Heterodera glycines) and root-knot nematode (Meloidogyne incognita) J2s in the presence of root signa...

A SPATIAL ANALYSIS OF THE FINE ROOT BIOMASS FROM STAND DATA IN THE PACIFIC NORTHWEST

EPA Science Inventory

High spatial variability of fine roots in natural forest stands makes accurate estimates of stand-level fine root biomass difficult and expensive to obtain by standard coring methods. This study uses aboveground tree metrics and spatial relationships to improve core-based estima...

An index for plant water deficit based on root-weighted soil water content

NASA Astrophysics Data System (ADS)

Shi, Jianchu; Li, Sen; Zuo, Qiang; Ben-Gal, Alon

2015-03-01

Governed by atmospheric demand, soil water conditions and plant characteristics, plant water status is dynamic, complex, and fundamental to efficient agricultural water management. To explore a centralized signal for the evaluation of plant water status based on soil water status, two greenhouse experiments investigating the effect of the relative distribution between soil water and roots on wheat and rice were conducted. Due to the significant offset between the distributions of soil water and roots, wheat receiving subsurface irrigation suffered more from drought than wheat under surface irrigation, even when the arithmetic averaged soil water content (SWC) in the root zone was higher. A significant relationship was found between the plant water deficit index (PWDI) and the root-weighted (rather than the arithmetic) average SWC over root zone. The traditional soil-based approach for the estimation of PWDI was improved by replacing the arithmetic averaged SWC with the root-weighted SWC to take the effect of the relative distribution between soil water and roots into consideration. These results should be beneficial for scheduling irrigation, as well as for evaluating plant water consumption and root density profile.

Tooth Eruption without Roots

PubMed Central

2013-01-01

Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the difficulties in studying late stages of tooth development and tooth movement and the lack of good model systems. Transgenic mice with eruption problems and short or no roots can be used as a powerful model for further deciphering of the cellular, molecular, and genetic mechanisms underlying root formation and tooth eruption. Better understanding of these processes can provide hints on delivering more efficient dental therapies in the future. PMID:23345536

Allometry of root branching and its relationship to root morphological and functional traits in three range grasses.

PubMed

Arredondo, J Tulio; Johnson, Douglas A

2011-11-01

The study of proportional relationships between size, shape, and function of part of or the whole organism is traditionally known as allometry. Examination of correlative changes in the size of interbranch distances (IBDs) at different root orders may help to identify root branching rules. Root morphological and functional characteristics in three range grasses {bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Löve], crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.×A. cristatum (L.) Gaert.], and cheatgrass (Bromus tectorum L.)} were examined in response to a soil nutrient gradient. Interbranch distances along the main root axis and the first-order laterals as well as other morphological and allocation root traits were determined. A model of nutrient diffusivity parameterized with root length and root diameter for the three grasses was used to estimate root functional properties (exploitation efficiency and exploitation potential). The results showed a significant negative allometric relationship between the main root axis and first-order lateral IBD (P ≤ 0.05), but only for bluebunch wheatgrass. The main root axis IBD was positively related to the number and length of roots, estimated exploitation efficiency of second-order roots, and specific root length, and was negatively related to estimated exploitation potential of first-order roots. Conversely, crested wheatgrass and cheatgrass, which rely mainly on root proliferation responses, exhibited fewer allometric relationships. Thus, the results suggested that species such as bluebunch wheatgrass, which display slow root growth and architectural root plasticity rather than opportunistic root proliferation and rapid growth, exhibit correlative allometry between the main axis IBD and morphological, allocation, and functional traits of roots.

Differential effects of fine root morphology on water dynamics in the root-soil interface

NASA Astrophysics Data System (ADS)

DeCarlo, K. F.; Bilheux, H.; Warren, J.

2017-12-01

Soil water uptake form plants, particularly in the rhizosphere, is a poorly understood question in the plant and soil sciences. Our study analyzed the role of belowground plant morphology on soil structural and water dynamics of 5 different plant species (juniper, grape, maize, poplar, maple), grown in sandy soils. Of these, the poplar system was extended to capture drying dynamics. Neutron radiography was used to characterize in-situ dynamics of the soil-water-plant system. A joint map of root morphology and soil moisture was created for the plant systems using digital image processing, where soil pixels were connected to associated root structures via minimum distance transforms. Results show interspecies emergent behavior - a sigmoidal relationship was observed between root diameter and bulk/rhizosphere soil water content difference. Extending this as a proxy for extent of rhizosphere development with root age, we observed a logistic growth pattern for the rhizosphere: minimal development in the early stages is superceded by rapid onset of rhizosphere formation, which then stabilizes/decays with the likely root suberization. Dynamics analysis of water content differences between the root/rhizosphere, and rhizosphere/bulk soil interface highlight the persistently higher water content in the root at all water content and root size ranges. At the rhizosphere/bulk soil interface, we observe a shift in soil water dynamics by root size: in super fine roots, we observe that water content is primarily lower in the rhizosphere under wetter conditions, which then gradually increases to a relatively higher water content under drier conditions. This shifts to a persistently higher rhizosphere water content relative to bulk soil in both wet/dry conditions with increased root size, suggesting that, by size, the finest root structures may contribute the most to total soil water uptake in plants.

Dermatomal somatosensory evoked potential demonstration of nerve root decompression after VAX-D therapy.

PubMed

Naguszewski, W K; Naguszewski, R K; Gose, E E

2001-10-01

Reductions in low back pain and referred leg pain associated with a diagnosis of herniated disc, degenerative disc disease or facet syndrome have previously been reported after treatment with a VAX-D table, which intermittently distracts the spine. The object of this study was to use dermatomal somatosensory evoked potentials (DSSEPs) to demonstrate lumbar root decompression following VAX-D therapy. Seven consecutive patients with a diagnosis of low back pain and unilateral or bilateral L5 or S1 radiculopathy were studied at our center. Disc herniation at the L5-S1 level was documented by MRI or CT in all patients. All patients were studied bilaterally by DSSEPs at L5 and S1 before and after VAX-D therapy. All patients had at least 50% improvement in radicular symptoms and low back pain and three of them experienced complete resolution of all symptoms. The average pain reduction was 77%. The number of treatment sessions varied from 12 to 35. DSSEPs were considered to show improvement if triphasic characteristics returned or a 50% or greater increase in the P1-P2 amplitude was seen. All patients showed improvement in DSSEPs after VAX-D therapy either ipsilateral or contralateral to the symptomatic leg. Two patients showed deterioration in DSSEPs in the symptomatic leg despite clinically significant improvement in pain and radicular symptoms. Overall, 28 nerve roots were studied before and after VAX-D therapy. Seventeen nerve root responses were improved, eight remained unchanged and three deteriorated. The significance of DSSEP improvement contralateral to the symptomatic leg is emphasized. Direct compression of a nerve root by a disc herniation is probably not the sole explanation for referred leg pain.

Root-zone temperature and water availability affect early root growth of planted longleaf pine

Treesearch

M.A. Sword

1995-01-01

Longleaf pine seedlings from three seed sources were exposed to three root-zone temperatures and three levels of water availability for 28 days. Root growth declined as temperature and water availability decreased. Root growth differed by seed source. Results suggest that subtle changes in the regeneration environment may influence early root growth of longleaf pine...

Reduced gravitropic sensitivity in roots of a starch-deficient mutant of Nicotiana sylvestris

NASA Technical Reports Server (NTRS)

Kiss, J. Z.; Sack, F. D.

1989-01-01

Gravitropism was studied in seedlings of Nicotiana sylvestris Speg. et Comes wild-type (WT) and mutant NS 458 which has a defective plastid phosphoglucomutase (EC 2.7.5.1.). Starch was greatly reduced in NS 458 compared to the WT, but small amounts of starch were detected in rootcap columella cells in NS 458 by light and electron microscopy. The roots of WT are more sensitive to gravity than mutant NS 458 roots since: (1) in mutant roots, curvature was reduced and delayed in the time course of curvature; (2) curvature of mutant roots was 24-56% that of WT roots over the range of induction periods tested; (3) in intermittent-stimulation experiments, curvature of mutant roots was 37% or less than that of WT roots in all treatments tested. The perception time, determined by intermittent-stimulation experiments, was < or = 5 s for WT roots and 30-60 s for mutant roots. The growth rates for WT and NS 458 roots were essentially equal. These results and our previous results with WT and starchless mutant Arabidopsis roots (Kiss et al. 1989, Planta 177, 198-206) support the conclusions that a full complement of starch is necessary for full gravitropic sensitivity and that amyloplasts function in gravity perception. Since a presumed relatively small increase in plastid buoyant mass (N. sylvestris mutant versus Arabidopsis mutant) significantly improves the orientation of the N. sylvestris mutant roots, we suggest that plastids are the likeliest candidates to be triggering gravity perception in roots of both mutants.

Composite Cucurbita pepo plants with transgenic roots as a tool to study root development

PubMed Central

Ilina, Elena L.; Logachov, Anton A.; Laplaze, Laurent; Demchenko, Nikolay P.; Pawlowski, Katharina; Demchenko, Kirill N.

2012-01-01

Background and Aims In most plant species, initiation of lateral root primordia occurs above the elongation zone. However, in cucurbits and some other species, lateral root primordia initiation and development takes place in the apical meristem of the parental root. Composite transgenic plants obtained by Agrobacterium rhizogenes-mediated transformation are known as a suitable model to study root development. The aim of the present study was to establish this transformation technique for squash. Methods The auxin-responsive promoter DR5 was cloned into the binary vectors pKGW-RR-MGW and pMDC162-GFP. Incorporation of 5-ethynyl-2′-deoxyuridine (EdU) was used to evaluate the presence of DNA-synthesizing cells in the hypocotyl of squash seedlings to find out whether they were suitable for infection. Two A. rhizogenes strains, R1000 and MSU440, were used. Roots containing the respective constructs were selected based on DsRED1 or green fluorescent protein (GFP) fluorescence, and DR5::Egfp-gusA or DR5::gusA insertion, respectively, was verified by PCR. Distribution of the response to auxin was visualized by GFP fluorescence or β-glucuronidase (GUS) activity staining and confirmed by immunolocalization of GFP and GUS proteins, respectively. Key Results Based on the distribution of EdU-labelled cells, it was determined that 6-day-old squash seedlings were suited for inoculation by A. rhizogenes since their root pericycle and the adjacent layers contain enough proliferating cells. Agrobacterium rhizogenes R1000 proved to be the most virulent strain on squash seedlings. Squash roots containing the respective constructs did not exhibit the hairy root phenotype and were morphologically and structurally similar to wild-type roots. Conclusions The auxin response pattern in the root apex of squash resembled that in arabidopsis roots. Composite squash plants obtained by A. rhizogenes-mediated transformation are a good tool for the investigation of root apical meristem

CLE-like (CLEL) peptides control the pattern of root growth and lateral root development in Arabidopsis.

PubMed

Meng, Ling; Buchanan, Bob B; Feldman, Lewis J; Luan, Sheng

2012-01-31

CLE peptides, named for the CLV3/ESR-related peptide family, participate in intercellular-signaling pathways. Here we investigated members of the CLE-like (CLEL) gene family that encode peptide precursors recently designated as root growth factors [Matsuzaki Y et al. (2010) Science 329:1065-1067]. CLEL precursors share a similar domain structure with CLE precursors (i.e., they contain a putative N-terminal signal peptide and a C-terminal conserved 13-amino-acid CLEL motif with a variable middle portion). Our evidence shows that, unlike root growth factor, CLEL peptides are (i) unmodified and (ii) function in the regulation of the direction of root growth and lateral root development. Overexpression of several CLEL genes in Arabidopsis resulted in either long roots or long and wavy roots that also showed altered lateral root patterning. Exogenous application of unmodified synthetic 13-amino-acid peptides derived from two CLEL motifs resulted in similar phenotypic changes in roots of wild-type plants. In CLEL peptide-induced long roots, the root apical meristem (RAM) was enlarged and consisted of an increased number of cells, compared with wild-type root apical meristems. The wavy-root phenotype appeared to be independent of other responses of the roots to the environment (e.g., gravitropism, phototropism, and thigmotropism). Results also showed that the inhibition of lateral initiation by CLEL overexpression was not overcome by the application of auxin. These findings establish CLEL as a peptide family with previously unrecognized regulatory functions controlling the pattern of root growth and lateral root development in plants.

Hairy root biotechnology of Rauwolfia serpentina: a potent approach for the production of pharmaceutically important terpenoid indole alkaloids.

PubMed

Mehrotra, Shakti; Goel, Manoj K; Srivastava, Vikas; Rahman, Laiq Ur

2015-02-01

Hairy root cultures of Rauwolfia serpentina induced by Agrobacterium rhizogenes have been investigated extensively for the production of terpenoid indole alkaloids. Various biotechnological developments, such as scaling up in bioreactors, pathway engineering etc., have been explored to improve their metabolite production potential. These hairy roots are competent for regenerating into complete plants and show survival and unaltered biosynthetic potential during storage at low temperature. This review provides a comprehensive account of the hairy root cultures of R. serpentina, their biosynthetic potential and various biotechnological methods used to explore the production of pharmaceutically important terpenoid indole alkaloids. The review also indicates how biotechnological endeavors might improve the future progress of research for production of alkaloids using Rauwolfia hairy roots.

The interactive impact of root branch order and soil genetic horizon on root respiration and nitrogen concentration.

PubMed

Trocha, Lidia K; Bulaj, Bartosz; Kutczynska, Paulina; Mucha, Joanna; Rutkowski, Pawel; Zadworny, Marcin

2017-08-01

In general, respiration (RS) is highly correlated with nitrogen concentration (N) in plant organs, including roots, which exhibit a positive N-RS relationship. Less is known, however, about the relationship between N and RS in roots of different branch orders within an individual tree along a vertical soil profile; this is especially true in trees with contrasting life strategies, such as pioneer Scots pine (Pinus sylvestris L.) vs mid-successional sessile oak (Quercus petraea Liebl.). In the present research, the impact of root branch order, as represented by those with absorptive vs transporting ability, and soil genetic horizon on root N, RS and the N-RS relationship was examined. Mean RS and total N concentration differed significantly among root branch orders and was significantly higher in absorptive roots than in transporting roots. The soil genetic horizon differentially affected root RS in Scots pine vs sessile oak. The genetic horizon mostly affected RS in absorptive roots of Scots pine and transporting roots in sessile oak. Root N was the highest in absorptive roots and most affected by soil genetic horizon in both tree species. Root N was not correlated with soil N, although N levels were higher in roots growing in fertile soil genetic horizons. Overall, RS in different root branch orders was positively correlated with N in both species. The N-RS relationship in roots, pooled by soil genetic horizon, was significant in both species, but was only significant in sessile oak when roots were pooled by root branch order. In both tree species, a significant interaction was found between the soil genetic horizon and root branch order with root function; however, species-specific responses were found. Both root N, which was unaffected by soil N, and the positive N-RS relationship consistently observed in different genetic horizons suggest that root function prevails over environmental factors, such as soil genetic horizon. © The Author 2017. Published by

Effects of partial root-zone irrigation on hydraulic conductivity in the soil–root system of maize plants

PubMed Central

Hu, Tiantian; Kang, Shaozhong; Li, Fusheng; Zhang, Jianhua

2011-01-01

Effects of partial root-zone irrigation (PRI) on the hydraulic conductivity in the soil–root system (Lsr) in different root zones were investigated using a pot experiment. Maize plants were raised in split-root containers and irrigated on both halves of the container (conventional irrigation, CI), on one side only (fixed PRI, FPRI), or alternately on one of two sides (alternate PRI, APRI). Results show that crop water consumption was significantly correlated with Lsr in both the whole and irrigated root zones for all three irrigation methods but not with Lsr in the non-irrigated root zone of FPRI. The total Lsr in the irrigated root zone of two PRIs was increased by 49.0–92.0% compared with that in a half root zone of CI, suggesting that PRI has a significant compensatory effect of root water uptake. For CI, the contribution of Lsr in a half root zone to Lsr in the whole root zone was ∼50%. For FPRI, the Lsr in the irrigated root zone was close to that of the whole root zone. As for APRI, the Lsr in the irrigated root zone was greater than that of the non-irrigated root zone. In comparison, the Lsr in the non-irrigated root zone of APRI was much higher than that in the dried zone of FPRI. The Lsr in both the whole and irrigated root zones was linearly correlated with soil moisture in the irrigated root zone for all three irrigation methods. For the two PRI treatments, total water uptake by plants was largely determined by the soil water in the irrigated root zone. Nevertheless, the non-irrigated root zone under APRI also contributed to part of the total crop water uptake, but the continuously non-irrigated root zone under FPRI gradually ceased to contribute to crop water uptake, suggesting that it is the APRI that can make use of all the root system for water uptake, resulting in higher water use efficiency. PMID:21527627

The key players of the primary root growth and development also function in lateral roots in Arabidopsis.

PubMed

Tian, Huiyu; Jia, Yuebin; Niu, Tiantian; Yu, Qianqian; Ding, Zhaojun

2014-05-01

The core regulators which are required for primary root growth and development also function in lateral root development or lateral root stem cell niche maintenance. The primary root systems and the lateral root systems are the two important root systems which are vital to the survival of plants. Though the molecular mechanism of the growth and development of both the primary root systems and the lateral root systems have been extensively studied individually in Arabidopsis, there are not so much evidence to show that if both root systems share common regulatory mechanisms. AP2 family transcription factors such as PLT1 (PLETHORA1) and PLT2, GRAS family transcription factors such as SCR (SCARECROW) and SHR (SHORT ROOT) and WUSCHEL-RELATED HOMEOBOX transcription factor WOX5 have been extensively studied and found to be essential for primary root growth and development. In this study, through the expression pattern analysis and mutant examinations, we found that these core regulators also function in lateral root development or lateral root stem cell niche maintenance.

Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Improving Sexual Function in Women: A Pilot Study

PubMed Central

Dongre, Swati

2015-01-01

Background. Many women experience sexual dysfunction where there are orgasm disorders and sexual difficulties. Ashwagandha (Withania somnifera) is a herb known to improve the body's physical and psychological condition. Objective. The purpose of the study was to determine the efficacy and safety of a high-concentration ashwagandha root extract (HCARE) supplementation for improving sexual function in healthy females. Methods. In this pilot study, 50 study subjects were randomized to either (i) HCARE-treated group or (ii) placebo- (starch-) treated group. The subjects consumed either HCARE or placebo capsules of 300mg twice daily for 8 weeks. Sexual function was assessed using two psychometric scales, the Female Sexual Function Index (FSFI) Questionnaire and the Female Sexual Distress Scale (FSDS), and by the number of total and successful sexual encounters. Results. The analysis indicates that treatment with HCARE leads to significantly higher improvement, relative to placebo, in the FSFI Total score (p < 0.001), FSFI domain score for “arousal” (p < 0.001), “lubrication” (p < 0.001), “orgasm” (p = 0.004), and “satisfaction” (p < 0.001), and also FSDS score (p < 0.001) and the number of successful sexual encounters (p < 0.001) at the end of the treatment. Conclusions. This study demonstrated that oral administration of HCARE may improve sexual function in healthy women. The present study is registered in the Clinical Trial Registry, Government of India, with a number CTRI/2015/07/006045. PMID:26504795

Increased symplasmic permeability in barley root epidermal cells correlates with defects in root hair development

PubMed Central

Marzec, M; Muszynska, A; Melzer, M; Sas-Nowosielska, H; Kurczynska, E U; Wick, S

2014-01-01

It is well known that the process of plant cell differentiation depends on the symplasmic isolation of cells. Before starting the differentiation programme, the individual cell or group of cells should restrict symplasmic communication with neighbouring cells. We tested the symplasmic communication between epidermal cells in the different root zones of parental barley plants Hordeum vulgare L., cv. ‘Karat’ with normal root hair development, and two root hairless mutants (rhl1.a and rhl1.b). The results clearly show that symplasmic communication was limited during root hair differentiation in the parental variety, whereas in both root hairless mutants epidermal cells were still symplasmically connected in the corresponding root zone. This paper is the first report on the role of symplasmic isolation in barley root cell differentiation, and additionally shows that a disturbance in the restriction of symplasmic communication is present in root hairless mutants. PMID:23927737

Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields.

PubMed

Arai-Sanoh, Yumiko; Takai, Toshiyuki; Yoshinaga, Satoshi; Nakano, Hiroshi; Kojima, Mikiko; Sakakibara, Hitoshi; Kondo, Motohiko; Uga, Yusaku

2014-07-03

To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study.

Root System Markup Language: Toward a Unified Root Architecture Description Language1[OPEN

PubMed Central

Pound, Michael P.; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Leitner, Daniel; Meunier, Félicien; Pridmore, Tony P.; Schnepf, Andrea

2015-01-01

The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. PMID:25614065

New theories of root growth modelling

NASA Astrophysics Data System (ADS)

Landl, Magdalena; Schnepf, Andrea; Vanderborght, Jan; Huber, Katrin; Javaux, Mathieu; Bengough, A. Glyn; Vereecken, Harry

2016-04-01

In dynamic root architecture models, root growth is represented by moving root tips whose line trajectory results in the creation of new root segments. Typically, the direction of root growth is calculated as the vector sum of various direction-affecting components. However, in our simulations this did not reproduce experimental observations of root growth in structured soil. We therefore developed a new approach to predict the root growth direction. In this approach we distinguish between, firstly, driving forces for root growth, i.e. the force exerted by the root which points in the direction of the previous root segment and gravitropism, and, secondly, the soil mechanical resistance to root growth or penetration resistance. The latter can be anisotropic, i.e. depending on the direction of growth, which leads to a difference between the direction of the driving force and the direction of the root tip movement. Anisotropy of penetration resistance can be caused either by microscale differences in soil structure or by macroscale features, including macropores. Anisotropy at the microscale is neglected in our model. To allow for this, we include a normally distributed random deflection angle α to the force which points in the direction of the previous root segment with zero mean and a standard deviation σ. The standard deviation σ is scaled, so that the deflection from the original root tip location does not depend on the spatial resolution of the root system model. Similarly to the water flow equation, the direction of the root tip movement corresponds to the water flux vector while the driving forces are related to the water potential gradient. The analogue of the hydraulic conductivity tensor is the root penetrability tensor. It is determined by the inverse of soil penetration resistance and describes the ease with which a root can penetrate the soil. By adapting the three dimensional soil and root water uptake model R-SWMS (Javaux et al., 2008) in this way

Different Phylogenetic and Environmental Controls of First-order Root Morphological and Chemical Traits

NASA Astrophysics Data System (ADS)

Wang, R.; Wang, Q.; Zhao, N.; Yu, G.; He, N.

2017-12-01

with individual species-level trait, community-aggregated root traits could be used to improve our ability to predict how the distribution of vegetation will change in response to a changing climate.

Superior Root Hair Formation Confers Root Efficiency in Some, But Not All, Rice Genotypes upon P Deficiency.

PubMed

Nestler, Josefine; Wissuwa, Matthias

2016-01-01

Root hairs are a low-cost way to extend root surface area (RSA), water and nutrient acquisition. This study investigated to what extend variation exists for root hair formation in rice in dependence of genotype, phosphorus (P) supply, growth medium, and root type. In general, genotypic variation was found for three root hair properties: root hair length, density, and longevity. In low P nutrient solution more than twofold genotypic difference was detected for root hair length while only onefold variation was found in low P soil. These differences were mostly due to the ability of some genotypes to increase root hair length in response to P deficiency. In addition, we were able to show that a higher proportion of root hairs remain viable even in mature, field-grown plants under low P conditions. All investigated root hair parameters exhibited high correlations across root types which were always higher in the low P conditions compared to the high P controls. Therefore we hypothesize that a low P response leads to a systemic signal in the entire root system. The genotype DJ123 consistently had the longest root hairs under low P conditions and we estimated that, across the field-grown root system, root hairs increased the total RSA by 31% in this genotype. This would explain why DJ123 is considered to be very root efficient in P uptake and suggests that DJ123 should be utilized as a donor in breeding for enhanced P uptake. Surprisingly, another root and P efficient genotype seemed not to rely on root hair growth upon P deficiency and therefore must contain different methods of low P adaptation. Genotypic ranking of root hair properties did change substantially with growth condition highlighting the need to phenotype plants in soil-based conditions or at least to validate results obtained in solution-based growth conditions.

Root-soil air gap and resistance to water flow at the soil-root interface of Robinia pseudoacacia.

PubMed

Liu, X P; Zhang, W J; Wang, X Y; Cai, Y J; Chang, J G

2015-12-01

During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Improved soybean root association of N-starved Bradyrhizobium japonicum.

PubMed

López-García, S L; Vázquez, T E; Favelukes, G; Lodeiro, A R

2001-12-01

In this study, we addressed the effects of N limitation in Bradyrhizobium japonicum for its association with soybean roots. The wild-type strain LP 3001 grew for six generations with a growth rate of 1.2 day(-1) in a minimal medium with 28 mM mannitol as the carbon source and with the N source [(NH(4))(2)SO(4)] limited to only 20 microM. Under these conditions, the glutamine synthetase (GS) activity was five to six times higher than in similar cultures grown with 1 or 0.1 mM (NH(4))(2)SO(4). The NtrBC-inducible GSII form of this enzyme accounted for 60% of the specific activity in N-starved rhizobia, being negligible in the other two cultures. The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures. In agreement with the accumulation of CPS in N-starved cultures, soybean lectin (SBL) binding as well as stimulation of rhizobial adsorption to soybean roots by SBL pretreatment were higher. The last effect was evident only in cultures that had not entered stationary phase. We also studied nodC gene induction in relation to N starvation. In the chromosomal nodC::lacZ fusion Bj110-573, nodC gene expression was induced by genistein 2.7-fold more in N-starved young cultures than in nonstarved ones. In stationary-phase cultures, nodC gene expression was similarly induced in N-limited cultures, but induction was negligible in cultures limited by another nutrient. Nodulation profiles obtained with strain LP 3001 grown under N starvation indicated that these cultures nodulated faster. In addition, as culture age increased, the nodulation efficiency decreased for two reasons: fewer nodules were formed, and nodulation was delayed. However, their relative importance was different according to the nutrient condition: in older cultures the overall decrease in the number of nodules

Implementing dynamic root optimization in Noah-MP for simulating phreatophytic root water uptake

USDA-ARS?s Scientific Manuscript database

Plants are known to adjust their root systems to adapt to changing subsurface water conditions. However, most current land surface models (LSMs) use a prescribed, static root profile, which cuts off the interactions between soil moisture and root dynamics. In this paper, we implemented an optimality...

Evaluation of technical quality and periapical health of root-filled teeth by using cone-beam CT

PubMed Central

Bilge Gülsüm, NUR; Evren, OK; ALTUNSOY, Mustafa; AĞLARCI, Osman Sami; ÇOLAK, Mehmet; GÜNGÖR, Enes

2014-01-01

Objective This study aimed to assess the quality of root fillings, coronal restorations, complications of all root-filled teeth and their association with apical periodontitis (AP) detected by cone-beam computed tomography (CBCT) images from an adult Turkish subpopulation. Material and Methods The sample for this study consisted of 242 patients (aging from 15 to 72 years) with 522 endodontically treated teeth that were assessed for technical quality of the root canal filling and periapical status of the teeth. Additionally, the apical status of each root-filled tooth was assessed according to the gender, dental arch, tooth type and age classification, undetected canals, instrument fracture, root fracture, apical resorption, apical lesion, furcation lesion and type and quality of the coronal structure. Statistical analysis was performed using percentages and chi-square test. Results The success rate of the root canal treatment was of 54.4%. The success rates of adequate and inadequate root canal treatment were not significantly different (p>0.05). Apical periodontitis was found in 228 (45.6%) teeth treated for root canals. Higher prevalence of AP was found in patients aging from 20 to 29 years [64 (27%) teeth] and in anterior (canines and incisors) teeth [97 (41%) teeth]. Conclusions The technical quality of root canal filling performed by dental practitioners in a Turkish subpopulation was consistent with a high prevalence of AP. The probable reasons for this failure are multifactorial, and there may be a need for improved undergraduate education and postgraduate courses to improve the clinical skills of dental practitioners in endodontics. PMID:25591019

High-throughput two-dimensional root system phenotyping platform facilitates genetic analysis of root growth and development.

PubMed

Clark, Randy T; Famoso, Adam N; Zhao, Keyan; Shaff, Jon E; Craft, Eric J; Bustamante, Carlos D; McCouch, Susan R; Aneshansley, Daniel J; Kochian, Leon V

2013-02-01

High-throughput phenotyping of root systems requires a combination of specialized techniques and adaptable plant growth, root imaging and software tools. A custom phenotyping platform was designed to capture images of whole root systems, and novel software tools were developed to process and analyse these images. The platform and its components are adaptable to a wide range root phenotyping studies using diverse growth systems (hydroponics, paper pouches, gel and soil) involving several plant species, including, but not limited to, rice, maize, sorghum, tomato and Arabidopsis. The RootReader2D software tool is free and publicly available and was designed with both user-guided and automated features that increase flexibility and enhance efficiency when measuring root growth traits from specific roots or entire root systems during large-scale phenotyping studies. To demonstrate the unique capabilities and high-throughput capacity of this phenotyping platform for studying root systems, genome-wide association studies on rice (Oryza sativa) and maize (Zea mays) root growth were performed and root traits related to aluminium (Al) tolerance were analysed on the parents of the maize nested association mapping (NAM) population. © 2012 Blackwell Publishing Ltd.

Root Cause Analysis and Subsequent Intervention to Improve First Dose Antibiotic Turnaround Time for Hospitalized Pediatric Patients

PubMed Central

Dee, Abigail A.; Kelly, Brian; Hampp, Christian

2010-01-01

OBJECTIVE Antibiotic timing is used as a quality standard for hospital accreditation and is an important quality measure. The study aim was to identify barriers in the process of first dose antibiotic administration on the pediatric floors at a tertiary healthcare center and carry out and test an intervention to improve turnaround time to less than one hour. METHODS We conducted a quasi-experimental pre-post study of hospitalized pediatric patients up to 18 years of age initiated on intravenous antibiotics. Every order for a first dose intravenous antibiotic was assessed on all pediatric floors (10/2008). Orders that did not meet the overall turnaround time goal of ≤ 1 hour were identified. A root cause analysis (RCA) was performed to identify reasons for delayed antibiotic administration. Barriers identified in the RCA were used to develop interventions (03/2009) to improve compliance, and the proportion of orders that met the goal was compared pre- (10/2008–02/2009) and post-intervention (04/2009–05/2009). RESULTS During the pre-intervention assessment period, 32 out of 46 total physician orders for a first dose intravenous antibiotic did not meet the one-hour overall turnaround goal. A main reason for delay was failure to label antibiotic orders as first dose. We designed an intervention that included antibiotic audits and individualized feedback to prescribers. The mean ± SD time from the written physician order to drug administration was 228 ± 58 minutes; timing improved to 55 ± 4 minutes after the intervention. The proportion of antibiotics administered within one hour improved from 42.2% to 63% (p=0.0015). CONCLUSIONS We identified system barriers associated with delayed antibiotic administration. Antibiotic timing was improved after continued surveillance and individualized feedback to providers. PMID:22477810

A rapid, controlled-environment seedling root screen for wheat correlates well with rooting depths at vegetative, but not reproductive, stages at two field sites

PubMed Central

Watt, M.; Moosavi, S.; Cunningham, S. C.; Kirkegaard, J. A.; Rebetzke, G. J.; Richards, R. A.

2013-01-01

Background and Aims Root length and depth determine capture of water and nutrients by plants, and are targets for crop improvement. Here we assess a controlled-environment wheat seedling screen to determine speed, repeatability and relatedness to performance of young and adult plants in the field. Methods Recombinant inbred lines (RILs) and diverse genotypes were grown in rolled, moist germination paper in growth cabinets, and primary root number and length were measured when leaf 1 or 2 were fully expanded. For comparison, plants were grown in the field and root systems were harvested at the two-leaf stage with either a shovel or a soil core. From about the four-leaf stage, roots were extracted with a steel coring tube only, placed directly over the plant and pushed to the required depth with a hydraulic ram attached to a tractor. Key Results In growth cabinets, repeatability was greatest (r = 0·8, P < 0·01) when the paper was maintained moist and seed weight, pathogens and germination times were controlled. Scanned total root length (slow) was strongly correlated (r = 0·7, P < 0·01) with length of the two longest seminal axile roots measured with a ruler (fast), such that 100–200 genotypes were measured per day. Correlation to field-grown roots at two sites at two leaves was positive and significant within the RILs and cultivars (r = 0·6, P = 0·01), and at one of the two sites at the five-leaf stage within the RILs (r = 0·8, P = 0·05). Measurements made in the field with a shovel or extracted soil cores were fast (5 min per core) and had significant positive correlations to scanner measurements after root washing and cleaning (>2 h per core). Field measurements at two- and five-leaf stages did not correlate with root depth at flowering. Conclusions The seedling screen was fast, repeatable and reliable for selecting lines with greater total root length in the young vegetative phase in the field. Lack of significant correlation with reproductive stage

Endoscopic root canal treatment.

PubMed

Moshonov, Joshua; Michaeli, Eli; Nahlieli, Oded

2009-10-01

To describe an innovative endoscopic technique for root canal treatment. Root canal treatment was performed on 12 patients (15 teeth), using a newly developed endoscope (Sialotechnology), which combines an endoscope, irrigation, and a surgical microinstrument channel. Endoscopic root canal treatment of all 15 teeth was successful with complete resolution of all symptoms (6-month follow-up). The novel endoscope used in this study accurately identified all microstructures and simplified root canal treatment. The endoscope may be considered for use not only for preoperative observation and diagnosis but also for active endodontic treatment.

Root production method system

Treesearch

Wayne Lovelace

2002-01-01

The RPM system (Root Production Method) is a multistep production system of container tree production that places primary emphasis on the root system because the root system ultimately determines the tree's survival and performance in its outplanted environment. This particular container production system has been developed to facilitate volume production, in a...

Challenges to estimating whole forest root biomass with ground penetrating radar

NASA Astrophysics Data System (ADS)

Butnor, J. R.

2016-12-01

Over the past two decades, substantial technical advances have been made in detecting tree roots with ground penetrating radar (GPR). Under favorable soil dielectric conditions, root location, depth, diameter and mass estimates are possible in the field. With careful notation of survey lines, three dimensional reconstructions of root architecture may also be achieved. The technique has been very useful for quantifying lateral root biomass in silvicultural studies, but is not yet a standalone technique for estimating root biomass in forests. The purpose of this presentation is to highlight the limitations of GPR in the field to stimulate discussion on how to overcome these challenges. Under field conditions, surface-based antennas with frequencies of 400 to 1500 MHz cannot detect fine roots (<2 mm diameter), vertical taproots, below-stump mass, decayed roots or separate roots by species. Higher frequency antennas designed for concrete inspection are available, but penetration through forest soils would be marginal. Over half of the root mass in many Pinus species is in the taproot which is undetectable in part or whole by GPR. This presents challenges to stand-level quantification as whole classes of biomass and structures are not reliably detected. Lack of automation of data processing and interpretation steps currently makes data analysis arduous and in some cases subject to interpretation by an expert user. Forests have a high degree of heterogeneity in surface conditions (e.g., holes, soil moisture, stems, woody and herbaceous plants) that may prevent antennas from coupling with the surface to propagate EM waves and receive reflections. What is the potential for open source data analysis programs to be developed and shared? How will new digital, multi-frequency antennas improve resolution? Can air launched antennas be developed that have both the depth penetration and resolution to detect roots? Are purpose-designed bore hole antenna needed for imaging taproots?

Root-derived auxin contributes to the phosphorus-deficiency-induced cluster-root formation in white lupin (Lupinus albus).

PubMed

Meng, Zhi Bin; You, Xue Di; Suo, Dong; Chen, Yun Long; Tang, Caixian; Yang, Jian Li; Zheng, Shao Jian

2013-08-01

Formation of cluster roots is a typical morphological response to phosphorus (P) deficiency in white lupin (Lupinus albus), but its physiological and molecular mechanisms are still unclear. We investigated the role of auxin in the initiation of cluster roots by distinguishing the sources of auxin, measuring the longitudinal distribution patterns of free indole-3-acetic acid (IAA) along the root and the related gene expressions responsible for polar auxin transport (PAT) in different developmental stages of cluster roots. We found that removal of shoot apex or primary root apex and application of auxin-influx or -efflux transport inhibitors, 3-chloro-4-hydroxyphenylacetic acid, N-1-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid, to the stem did not affect the number of cluster roots and the free-IAA concentration in the roots of P-deficient plants, but when these inhibitors were applied directly to the growth media, the cluster-root formation was greatly suppressed, suggesting the fundamental role of root-derived IAA in cluster-root formation. The concentration of free IAA in the roots was higher in P-deficient plants than in P-adequate ones, and the highest in the lateral-root apex and the lowest in the mature cluster roots. Meanwhile the expression patterns of LaAUX1, LaPIN1 and LaPIN3 transcripts related to PAT was consistent with concentrations of free IAA along the lateral root, indicating the contribution of IAA redistribution in the cluster-root development. We proposed that root-derived IAA plays a direct and important role in the P-deficiency-induced formation of cluster roots. Copyright © Physiologia Plantarum 2012.

Effect of education intervention on the quality and long-term outcomes of root canal treatment in general practice.

PubMed

Koch, M; Wolf, E; Tegelberg, Å; Petersson, K

2015-07-01

To compare the technical quality and long-term outcomes of root canal treatment by general practitioners of a Swedish Public Dental Service, before and after an endodontic education including Ni-Ti rotary technique (NiTiR). A random sample was compiled, comprising one root filled tooth from each of 830 patients, treated by 69 general practitioners participating in the education: 414 teeth root filled in 2002, pre-education, using primarily stainless steel instrumentation and filling by lateral compaction, and 416 teeth root filled post-education (2005), using mainly NiTiR and single-cone obturation. Follow-up radiographs taken in 2009 were evaluated alongside immediate post-filling radiographs from 2002 to 2005. The density and length of the root fillings were registered. Periapical status was assessed by the Periapical Index (PAI), using two definitions of disease: apical periodontitis (AP) (PAI 3 + 4 + 5) and definite AP (PAI 4 + 5). Tooth survival was registered. Root fillings pre- and post-education were compared using chi-square and Fisher's exact tests. Crude extraction rates per 100 years were calculated for comparison of tooth survival. Explanatory variables (type of tooth, root filling quality, periapical status, marginal bone loss, type and quality of coronal restoration) in relation to the dependent variable (AP at follow-up) were analysed by multivariable logistic regression. Follow-up data were available for 229 (55%) of teeth treated pre- and 288 (69%) treated post-education: both tooth survival (P < 0.001) and root filling quality were significantly higher (P < 0.001) in the latter. However, there was no corresponding improvement in periapical status. Both pre- and post-education, root fillings with definite AP on completion of treatment had significantly higher odds of AP or definite AP at follow-up. For teeth treated post-education, inadequate root filling quality was significantly associated with AP at follow-up. Despite a higher tooth survival

[Effects of Ca2+ on nitric oxide-induced adventitious rooting in cucumber under drought stress].

PubMed

Li, Chun Lan; Niu, Li Juan; Hu, Lin Li; Liao, Wei Biao; Chen, Yue

2017-11-01

Cucumber (Cucumis sativus L. 'Xinchun 4') was used to explore the relationship between nitric oxide (NO) and calcium (Ca 2+ ) during adventitious rooting under drought stress. Rooting parameters, endogenous Ca 2+ fluorescent intensity and the antioxidant enzymes activity (SOD, CAT and APX) in cucumber explants under drought stress were investigated. The results showed that treatment with 200 μmol·L -1 CaCl 2 and 0.05% PEG significantly improved the number and length of adventitious root in cucumber explants under drought stress, while the application of Ca 2+ chelating agent (EGTA) and channel inhibitor (BAPTA/AM) significantly decreased NO-induced number and length of adventitious root under drought stress. Under drought stress, the fluorescence intensity of Ca 2+ in hypocotyls treated with NO and CaCl 2 was improved, however, the Ca 2+ fluorescence intensity in the hypocotyls treated with NO scavenger (cPTIO) was significantly lower than that in the hypocotyls treated with NO. Under drought stress, the activities of antioxidant enzymes in the cucumber explants were significantly promoted by the treatments with NO and CaCl 2 , however, Ca 2+ chelating agent and channel inhibitor significantly decreased the activity of antioxidant enzymes induced by NO. In conclusion, Ca 2+ might be involved in the process of NO-adjusted antioxidant enzymes activity during adventitious rooting under drought stress, which alleviated the negative effects of drought on the adventitious rooting and promoted the formation of adventitious roots.

Induced jasmonate signaling leads to contrasting effects on root damage and herbivore performance.

PubMed

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-03-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. © 2015 American Society of Plant Biologists. All Rights Reserved.

Physical root-soil interactions

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Legué, Valérie; Bogeat-Triboulot, Marie-Béatrice

2017-12-01

Plant root system development is highly modulated by the physical properties of the soil and especially by its mechanical resistance to penetration. The interplay between the mechanical stresses exerted by the soil and root growth is of particular interest for many communities, in agronomy and soil science as well as in biomechanics and plant morphogenesis. In contrast to aerial organs, roots apices must exert a growth pressure to penetrate strong soils and reorient their growth trajectory to cope with obstacles like stones or hardpans or to follow the tortuous paths of the soil porosity. In this review, we present the main macroscopic investigations of soil-root physical interactions in the field and combine them with simple mechanistic modeling derived from model experiments at the scale of the individual root apex.

Physical root-soil interactions.

PubMed

Kolb, Evelyne; Legué, Valérie; Bogeat-Triboulot, Marie-Béatrice

2017-11-16

Plant root system development is highly modulated by the physical properties of the soil and especially by its mechanical resistance to penetration. The interplay between the mechanical stresses exerted by the soil and root growth is of particular interest for many communities, in agronomy and soil science as well as in biomechanics and plant morphogenesis. In contrast to aerial organs, roots apices must exert a growth pressure to penetrate strong soils and reorient their growth trajectory to cope with obstacles like stones or hardpans or to follow the tortuous paths of the soil porosity. In this review, we present the main macroscopic investigations of soil-root physical interactions in the field and combine them with simple mechanistic modeling derived from model experiments at the scale of the individual root apex.

Root Hydraulics and Root Sap Flow in a Panamanian Low-Land Tropical Forest

NASA Astrophysics Data System (ADS)

Bretfeld, M.; Ewers, B. E.; Hall, J. S.; Ogden, F. L.; Beverly, D.; Speckman, H. N.

2017-12-01

In the tropics, trees are subjected to increasingly frequent and severe droughts driven by climate change. Given the hydrological benefits associated with tropical forests, such as reduced peak runoff during high precipitation events and increased base flow during drought periods ("sponge-effect"), the underlying plant-hydrological processes at the soil-plant interface have become the focus of recent research efforts. In Panama, the 2015/16 El Niño-Southern Oscillation (ENSO) event ranks amongst the driest and hottest periods on record, thus providing an excellent opportunity to study the effects of drought on tropical forests. Starting in 2015, we instrumented 76 trees with heat-ratio sap flow sensors in regrowing secondary forest (8-, 25-, and 80-year old stands) in the 15 km2 Agua Salud study area, located in central Panama. Of those trees, 16 individuals were instrumented with additional sap flow sensors on three roots each. Data were logged every 30 minutes and soil moisture was measured at 10, 30, 50, and 100 cm depth. Meteorological data were taken from a nearby met-station. Rooting depth and root density were assessed in eight 2×2×2 m soil pits. In April 2017, we measured hydraulic conductance and vulnerability to cavitation of eight species using the centrifuge technique. Trees in 8-year old forest limited transpiration during the drought whereas no such limitation was evident in trees of the 80-year old forest. Root sap flow data show seasonal shifts in water uptake between individual roots of a given tree, with sap flow decreasing in some roots while simultaneously increasing in other roots during the wet-dry season transition. Roots followed a typical log distribution along the profile, with overall root densities of 46, 43, and 52 roots m-2 in the 8-, 25-, and 80-yo stand, respectively. Roots were found up to 200 cm depth in all forests, with roots >5 cm occurring at lower depths (>125 cm) only in 25- and 80-year old forests. Maximum hydraulic

The "Green" Root Beer Laboratory

ERIC Educational Resources Information Center

Clary, Renee; Wandersee, James

2010-01-01

No, your students will not be drinking green root beer for St. Patrick's Day--this "green" root beer laboratory promotes environmental awareness in the science classroom, and provides a venue for some very sound science content! While many science classrooms incorporate root beer-brewing activities, the root beer lab presented in this article has…

Analysis of gene expression profiles for cell wall modifying proteins and ACC synthases in soybean cyst nematode colonized roots, adventitious rooting hypocotyls, root tips, flooded roots, and IBA and ACC treatment roots

USDA-ARS?s Scientific Manuscript database

We hypothesized that soybean cyst nematode (SCN) co-opts a part or all of one or more innate developmental process in soybean to establish its feeding structure, syncytium, in soybean roots. The syncytium in soybean roots is formed in a predominantly lateral direction within the vascular bundle by ...

TGeoCad: an Interface between ROOT and CAD Systems

NASA Astrophysics Data System (ADS)

Luzzi, C.; Carminati, F.

2014-06-01

In the simulation of High Energy Physics experiment a very high precision in the description of the detector geometry is essential to achieve the required performances. The physicists in charge of Monte Carlo Simulation of the detector need to collaborate efficiently with the engineers working at the mechanical design of the detector. Often, this collaboration is made hard by the usage of different and incompatible software. ROOT is an object-oriented C++ framework used by physicists for storing, analyzing and simulating data produced by the high-energy physics experiments while CAD (Computer-Aided Design) software is used for mechanical design in the engineering field. The necessity to improve the level of communication between physicists and engineers led to the implementation of an interface between the ROOT geometrical modeler used by the virtual Monte Carlo simulation software and the CAD systems. In this paper we describe the design and implementation of the TGeoCad Interface that has been developed to enable the use of ROOT geometrical models in several CAD systems. To achieve this goal, the ROOT geometry description is converted into STEP file format (ISO 10303), which can be imported and used by many CAD systems.

Comparative Transcriptome Analysis of Latex Reveals Molecular Mechanisms Underlying Increased Rubber Yield in Hevea brasiliensis Self-Rooting Juvenile Clones

PubMed Central

Li, Hui-Liang; Guo, Dong; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

Rubber tree (Hevea brasiliensis) self-rooting juvenile clones (JCs) are promising planting materials for rubber production. In a comparative trial between self-rooting JCs and donor clones (DCs), self-rooting JCs exhibited better performance in rubber yield. To study the molecular mechanism associated with higher rubber yield in self-rooting JCs, we sequenced and comparatively analyzed the latex of rubber tree self-rooting JCs and DCs at the transcriptome level. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from the library of self-rooting JCs and DCs, respectively, by using Illumina HiSeq 2000 sequencing technology. De novo assemblies yielded 54689 unigenes from the library of self-rooting JCs and DCs. Among 54689 genes, 1716 genes were identified as differentially expressed between self-rooting JCs and DCs via comparative transcript profiling. Functional analysis showed that the genes related to the mass of categories were differentially enriched between the two clones. Several genes involved in carbohydrate metabolism, hormone metabolism and reactive oxygen species scavenging were up-regulated in self-rooting JCs, suggesting that the self-rooting JCs provide sufficient molecular basis for the increased rubber yielding, especially in the aspects of improved latex metabolisms and latex flow. Some genes encoding epigenetic modification enzymes were also differentially expressed between self-rooting JCs and DCs. Epigenetic modifications may lead to gene differential expression between self-rooting JCs and DCs. These data will provide new cues to understand the molecular mechanism underlying the improved rubber yield of H. brasiliensis self-rooting clones. PMID:27555864

Comparative Transcriptome Analysis of Latex Reveals Molecular Mechanisms Underlying Increased Rubber Yield in Hevea brasiliensis Self-Rooting Juvenile Clones.

PubMed

Li, Hui-Liang; Guo, Dong; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

Rubber tree (Hevea brasiliensis) self-rooting juvenile clones (JCs) are promising planting materials for rubber production. In a comparative trial between self-rooting JCs and donor clones (DCs), self-rooting JCs exhibited better performance in rubber yield. To study the molecular mechanism associated with higher rubber yield in self-rooting JCs, we sequenced and comparatively analyzed the latex of rubber tree self-rooting JCs and DCs at the transcriptome level. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from the library of self-rooting JCs and DCs, respectively, by using Illumina HiSeq 2000 sequencing technology. De novo assemblies yielded 54689 unigenes from the library of self-rooting JCs and DCs. Among 54689 genes, 1716 genes were identified as differentially expressed between self-rooting JCs and DCs via comparative transcript profiling. Functional analysis showed that the genes related to the mass of categories were differentially enriched between the two clones. Several genes involved in carbohydrate metabolism, hormone metabolism and reactive oxygen species scavenging were up-regulated in self-rooting JCs, suggesting that the self-rooting JCs provide sufficient molecular basis for the increased rubber yielding, especially in the aspects of improved latex metabolisms and latex flow. Some genes encoding epigenetic modification enzymes were also differentially expressed between self-rooting JCs and DCs. Epigenetic modifications may lead to gene differential expression between self-rooting JCs and DCs. These data will provide new cues to understand the molecular mechanism underlying the improved rubber yield of H. brasiliensis self-rooting clones.

Molecular Mechanisms of Root Gravitropism.

PubMed