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David M Eissenstat - One of the best experts on this subject based on the ideXlab platform.
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on characterizing Root Function in perennial horticultural crops
American Journal of Botany, 2020Co-Authors: Emily K Lavely, Weile Chen, Aysha K Peterson, Annie E Klodd, Astrid Volder, Richard P Marini, David M EissenstatAbstract:PREMISE: While Root-order approaches to fine-Root classification have shown wide utility among wild plants, they have seen limited use for perennial crop plants. Moreover, inadequate characterization of fine Roots across species of domesticated perennial crops has led to a knowledge gap in the understanding of evolutionary and Functional patterns associated with different fine-Root orders. METHODS: We examined fine-Root traits of common horticultural fruit and nut crops: Malus ×domestica, Prunus persica, Vitus vinifera, Prunus dulcis, and Citrus ×clementina. Additional Roots were sampled from 33 common perennial horticultural crops, native to tropical, subtropical, and temperate regions, to examine variation in 1st- and 2nd-order absorptive Roots. RESULTS: First-order Roots of grape and 1st- and 2nd-order Roots of apple and peach were consistently thin, nonwoody, mycorrhizal, and had high N:C ratios. In contrast, 4th- and 5th-order Roots of grape and 5th-order Roots of apple and peach were woody, nonmycorrhizal, had low N:C ratios, and were thicker than lower-order Roots. Among the 33 horticultural species, diameter of 1st- and 2nd-order Roots varied about 15-fold, ranging from 0.04 to 0.60 mm and 0.05 to 0.89 mm respectively. This variation generally was phylogenetically conserved across plant lineages. CONCLUSIONS: Collectively, our research shows that Root-order characterization has considerably more utility than an arbitrary diameter cutoff for identifying Roots of different Functions in perennial horticultural crops. In addition, much of the variation in Root diameter among species can be predicted by evolutionary relationships.
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reliance on shallow soil water in a mixed hardwood forest in central pennsylvania
Tree Physiology, 2016Co-Authors: Katie P Gaines, Weile Chen, Jane W Stanley, Frederick C Meinzer, Katherine A Mcculloh, David R Woodruff, Thomas S Adams, David M EissenstatAbstract:We investigated depth of water uptake of trees on shale-derived soils in order to assess the importance of Roots over a meter deep as a driver of water use in a central Pennsylvania catchment. This information is not only needed to improve basic understanding of water use in these forests but also to improve descriptions of Root Function at depth in hydrologic process models. The study took place at the Susquehanna Shale Hills Critical Zone Observatory in central Pennsylvania. We asked two main questions: (i) Do trees in a mixed-hardwood, humid temperate forest in a central Pennsylvania catchment rely on deep Roots for water during dry portions of the growing season? (ii) What is the role of tree genus, size, soil depth and hillslope position on the depth of water extraction by trees? Based on multiple lines of evidence, including stable isotope natural abundance, sap flux and soil moisture depletion patterns with depth, the majority of water uptake during the dry part of the growing season occurred, on average, at less than ∼60 cm soil depth throughout the catchment. While there were some trends in depth of water uptake related to genus, tree size and soil depth, water uptake was more uniformly shallow than we expected. Our results suggest that these types of forests may rely considerably on water sources that are quite shallow, even in the drier parts of the growing season.
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decomposition of the finest Root branching orders linking belowground dynamics to fine Root Function and structure
Ecological Monographs, 2011Co-Authors: Marc Goebel, Bartosz Bulaj, Marcin Zadworny, Sarah E Hobbie, Douglas D Archibald, Jacek Oleksyn, Peter B Reich, David M EissenstatAbstract:Root turnover is fastest in the finest Roots of the Root system (first Root order). Additionally, tissue chemistry varies among even the finest Root orders and between white Roots and older, pigmented Roots. Yet the effects of pigmentation and order on Root decomposition have rarely been examined. We separated the first four Root orders (all <1 mm) of four temperate tree species into three classes: white first- and second-order Roots; pigmented first- and second-order Roots; and pigmented third- and fourth-order Roots. Roots were enclosed in litterbags and buried under their own and under a common species canopy in a 34-year-old common garden in Poland. When comparing decomposition of different Root orders over 36 months, pigmented third- and fourth-order Roots with a higher C:N ratio decomposed more rapidly, losing 20–40% of their mass, than pigmented first- and second-order Roots, which lost no more than 20%. When comparing decomposition of Roots of different levels of pigmentation within the same Root ...
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biological and environmental factors controlling Root dynamics and Function effects of Root ageing and soil moisture
Australian Journal of Grape and Wine Research, 2010Co-Authors: Louise H Comas, Taryn L Bauerle, David M EissenstatAbstract:Understanding factors controlling Root dynamics and Functioning can lead to more efficient and profitable vineyard management. However, our current understanding of Root dynamics and their regulation by plant and environmental factors is limited, particularly under field conditions. This paper presents current understanding of grape Root dynamics, highlighting studies using minirhizotron cameras, which directly assess Root dynamics, and experiments on Roots of known age, which link Root phenology and Function. Data summarised here show timing of grape Root production varies widely among different regions, as well as among Rootstocks and canopy management systems in the same region. Timing of production can be responsive to differences in soil moisture. Lifespan of grape Roots, however, appears less affected by soil moisture because of nocturnal hydraulic redistribution. Root Function, such as capacity for P and N uptake, declines rapidly with Root age. Differences in timing and spatial distribution of Root production can effect above-ground growth and vineyard water-use efficiency. Improving our understanding of when Roots grow and are Functionally active in agricultural systems can lead to improved water and fertiliser applications, and more precise vineyard management. Because both environmental and biological factors affect Root dynamics, simple predictions of timing of Root production or standing populations with shoot development are unlikely to be achieved. However, with multi-year data on Root dynamics, and environmental and biological factors, regionally specific models of Root populations and their Functioning may be possible to develop.
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Root anatomy morphology and longevity among Root orders in vaccinium corymbosum ericaceae
American Journal of Botany, 2008Co-Authors: Luis R Valenzuelaestrada, Vivianette Veracaraballo, Leah E Ruth, David M EissenstatAbstract: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.
Gunter Neumann - One of the best experts on this subject based on the ideXlab platform.
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the regulatory network of cluster Root Function and development in phosphate deficient white lupin lupinus albus identified by transcriptome sequencing
Physiologia Plantarum, 2014Co-Authors: Zhengrui Wang, Daniel Straub, Huaiyu Yang, Angelika Kania, Jianbo Shen, Uwe Ludewig, Gunter NeumannAbstract:: Lupinus albus serves as model plant for Root-induced mobilization of sparingly soluble soil phosphates via the formation of cluster-Roots (CRs) that mediate secretion of protons, citrate, phenolics and acid phosphatases (APases). This study employed next-generation sequencing to investigate the molecular mechanisms behind these complex adaptive responses at the transcriptome level. We compared different stages of CR development, including pre-emergent (PE), juvenile (JU) and the mature (MA) stages. The results confirmed that the primary metabolism underwent significant modifications during CR maturation, promoting the biosynthesis of organic acids, as had been deduced from physiological studies. Citrate catabolism was downregulated, associated with citrate accumulation in MA clusters. Upregulation of the phenylpropanoid pathway reflected the accumulation of phenolics. Specific transcript expression of ALMT and MATE transporter genes correlated with the exudation of citrate and flavonoids. The expression of transcripts related to nucleotide degradation and APases in MA clusters coincided with the re-mobilization and hydrolysis of organic phosphate resources. Most interestingly, hormone-related gene expression suggested a central role of ethylene during CR maturation. This was associated with the upregulation of the iron (Fe)-deficiency regulated network that mediates ethylene-induced expression of Fe-deficiency responses in other species. Finally, transcripts related to abscisic acid and jasmonic acid were upregulated in MA clusters, while auxin- and brassinosteroid-related genes and cytokinin receptors were most strongly expressed during CR initiation. Key regulations proposed by the RNA-seq data were confirmed by quantitative real-time polymerase chain reaction (RT-qPCR) and some physiological analyses. A model for the gene network regulating CR development and Function is presented.
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physiological aspects of cluster Root Function and development in phosphorus deficient white lupin lupinus albus l
Annals of Botany, 2000Co-Authors: Gunter Neumann, Agnes Massonneau, Nicolas B Langlade, Barbara Dinkelaker, Christine Hengeler, Volker Romheld, Enrico MartinoiaAbstract:Abstract Cluster Root formation in white lupin ( Lupinus albus L.) is induced mainly by phosphorus (P) starvation, and seems to be regulated by the endogenous P status of the plant. Increased formation of cluster Roots, when indole acetic acid is supplied to the growth medium of P sufficient plants, and inhibitory effects of kinetin application suggest the involvement of endogenous phytohormones (auxins and cytokinins), which may act in an antagonistic manner in the P-starvation response. Phosphorus deficiency-induced adaptations of white lupin, involved in P acquisition and mobilization of sparingly available P sources, are predominantly confined to the cluster Roots, and moreover to distinct stages during their development. Increased accumulation and exudation of citrate and a concomitant release of protons were found to be mainly restricted to mature Root clusters after prolonged culture (3–4 weeks) under P-deficient conditions. Inhibition of citrate exudation by exogenous application of anion channel antagonists such as ethacrynic- and anthracene-9-carboxylic acids may indicate involvement of an anion channel. Phosphorus deficiency-induced accumulation and subsequent exudation of citric acid seems to be a consequence of both enhanced biosynthesis and reduced turnover of citric acid in the cluster Root tissue, indicated by enhanced expression of sucrose synthase, fructokinase, phosphoglucomutase, phosphoenol-pyruvate carboxylase, but reduced activity of aconitase and slower Root respiration. The release of acid phosphatase and of phenolic compounds (isoflavonoids) as well as the induction of a putative high-affinity P uptake system was more highly expressed in juvenile, mature and even senescent cluster regions than in apical zones of non-proteoid Roots. An AFLP-cDNA library for cluster Root-specific gene expression was constructed to assist in the identification of further genes involved in cluster Root development.
Enrico Martinoia - One of the best experts on this subject based on the ideXlab platform.
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physiological aspects of cluster Root Function and development in phosphorus deficient white lupin lupinus albus l
Annals of Botany, 2000Co-Authors: Gunter Neumann, Agnes Massonneau, Nicolas B Langlade, Barbara Dinkelaker, Christine Hengeler, Volker Romheld, Enrico MartinoiaAbstract:Abstract Cluster Root formation in white lupin ( Lupinus albus L.) is induced mainly by phosphorus (P) starvation, and seems to be regulated by the endogenous P status of the plant. Increased formation of cluster Roots, when indole acetic acid is supplied to the growth medium of P sufficient plants, and inhibitory effects of kinetin application suggest the involvement of endogenous phytohormones (auxins and cytokinins), which may act in an antagonistic manner in the P-starvation response. Phosphorus deficiency-induced adaptations of white lupin, involved in P acquisition and mobilization of sparingly available P sources, are predominantly confined to the cluster Roots, and moreover to distinct stages during their development. Increased accumulation and exudation of citrate and a concomitant release of protons were found to be mainly restricted to mature Root clusters after prolonged culture (3–4 weeks) under P-deficient conditions. Inhibition of citrate exudation by exogenous application of anion channel antagonists such as ethacrynic- and anthracene-9-carboxylic acids may indicate involvement of an anion channel. Phosphorus deficiency-induced accumulation and subsequent exudation of citric acid seems to be a consequence of both enhanced biosynthesis and reduced turnover of citric acid in the cluster Root tissue, indicated by enhanced expression of sucrose synthase, fructokinase, phosphoglucomutase, phosphoenol-pyruvate carboxylase, but reduced activity of aconitase and slower Root respiration. The release of acid phosphatase and of phenolic compounds (isoflavonoids) as well as the induction of a putative high-affinity P uptake system was more highly expressed in juvenile, mature and even senescent cluster regions than in apical zones of non-proteoid Roots. An AFLP-cDNA library for cluster Root-specific gene expression was constructed to assist in the identification of further genes involved in cluster Root development.
J Draper - One of the best experts on this subject based on the ideXlab platform.
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floating point division and square Root using a taylor series expansion algorithm
Microelectronics Journal, 2009Co-Authors: Taekjun Kwon, J DraperAbstract:Hardware support for floating-point (FP) arithmetic is a mandatory feature of modern microprocessor design. Although division and square Root are relatively infrequent operations in traditional general-purpose applications, they are indispensable and becoming increasingly important in many modern applications. Therefore, overall performance can be greatly affected by the algorithms and the implementations used for designing FP-Div and FP-Sqrt units. In this paper, a single-precision fused floating-point multiply/divide/square Root unit based on Taylor-series expansion algorithm is proposed. We extended an existing multiply/divide fused unit to incorporate the square Root Function with little area and latency overhead since Taylor's theorem enables us to compute approximations for many well-known Functions with very similar forms. The implementation results of the proposed fused unit based on standard cell methodology in IBM 90nm technology exhibits that the incorporation of square Root Function to an existing multiply/divide unit requires only a modest 18% area increase and the same low latency for divide and square Root operation can be achieved (12 cycles). The proposed arithmetic unit exhibits a reasonably good area-performance balance.
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floating point division and square Root implementation using a taylor series expansion algorithm
International Conference on Electronics Circuits and Systems, 2008Co-Authors: Taekjun Kwon, J Sondeen, J DraperAbstract:Hardware support for floating-point (FP) arithmetic is an essential feature of modern microprocessor design. Although division and square Root are relatively infrequent operations in traditional general-purpose applications, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating-point multiply/divide/square Root unit based on Taylor-series expansion algorithm is presented. The implementation results of the proposed fused unit based on standard cell methodology in IBM 90 nm technology exhibits that the incorporation of square Root Function to an existing multiply/divide unit requires only a modest 23% area increase and the same low latency for divide and square Root operation can be achieved (12 cycles). The proposed arithmetic unit also exhibits a reasonably good area-performance balance.
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floating point division and square Root implementation using a taylor series expansion algorithm with reduced look up tables
Midwest Symposium on Circuits and Systems, 2008Co-Authors: Taekjun Kwon, J DraperAbstract:Hardware support for floating-point (FP) arithmetic is an essential feature of modern microprocessor design. Although division and square Root are relatively infrequent operations in traditional general-purpose applications, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating-point multiply/divide/square Root unit using the Taylor-series expansion algorithm with reduced lookup tables is presented. The implementation results of the proposed fused unit based on standard cell methodology in IBM 90 nm technology exhibits that the incorporation of square Root Function to an existing multiply/divide unit requires only a modest 20% area increase and the same low latency for divide and square Root operation can be achieved (12 cycles). The proposed arithmetic unit also exhibits a reasonably good area-performance balance.
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floating point division and square Root using a taylor series expansion algorithm
Midwest Symposium on Circuits and Systems, 2007Co-Authors: Taekjun Kwon, J Sondeen, J DraperAbstract:Hardware support for floating-point (FP) arithmetic is a mandatory feature of modern microprocessor design. Although division and square Root are relatively infrequent operations in traditional general-purpose applications, they are indispensable and becoming increasingly important in many modern applications. Therefore, overall performance can be greatly affected by the algorithms and the implementations used for designing FP-div and FP-sqrt units. In this paper, a fused floating-point multiply/divide/square Root unit based on Taylor-series expansion algorithm is proposed. We extended an existing multiply/divide fused unit to incorporate the square Root Function with little area and latency overhead since Taylor's theorem enables us to compute approximations for many well-known Functions with very similar forms. The proposed arithmetic unit exhibits a reasonably good area- performance balance.
Björn Rydevik - One of the best experts on this subject based on the ideXlab platform.
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Acute thermal nerve Root injury
European Spine Journal, 1994Co-Authors: Shinichi Konno, Kjell Olmarker, Claes Nordborg, Gunnar Byröd, Björn Strömqvist, Björn RydevikAbstract:Bone cement is sometimes used for vertebral body reconstruction following tumor removal. During such procedures, the polymerization of the methyl-metacrylate in the bone cement generates heat. Such temperature increase might cause damage to the nerve Roots within the spinal canal. In the present study, pig cauda equina nerve Roots were subjected to controlled temperature increases by means of a heat-generating probe. A temperature of 40°C applied for 5 min did not cause any changes in nerve Root Function. However, 70°C resulted in a complete block of nerve Root Function within 5 min. Histological nerve fiber damage was seen after exposure to 60°C and 70°C. The present study provides basic knowledge of heat-resistance properties of spinal nerve Roots that might be directly applicable as guidelines for safety margins during surgical spine reconstruction procedures using bone cement.
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effects of acute graded compression on spinal nerve Root Function and structure an experimental study of the pig cauda equina
Spine, 1991Co-Authors: Björn Rydevik, Robert A Pedowitz, Alan R Hargens, Michael R Swenson, Robert R Myers, Steven R GarfinAbstract:A well-controlled experimental model for analysis of compression-induced Functional changes of the porcine cauda equina is presented. The model allows for electrophysiologic investigation of a variety of neurophysiologic changes induced by nerve Root deformation. At an acute pressure threshold of 50-75 mm Hg, changes in both afferent and efferent conduction are induced. With higher compression pressure, a differential recovery in afferent and efferent conduction is seen.
