The Experts below are selected from a list of 257304 Experts worldwide ranked by ideXlab platform
Alexia Stokes - One of the best experts on this subject based on the ideXlab platform.
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rhizosphere bacteria are more strongly related to Plant Root traits than fungi in temperate montane forests insights from closed and open forest patches along an elevational gradient
Plant and Soil, 2020Co-Authors: Luis Merinomartin, Robert I. Griffiths, Hyun S. Gweon, Anna Oliver, Yves Bissonnais, Clement Furgetbretagnon, Zhun Mao, Alexia StokesAbstract:Heterogeneous canopies in temperate montane forests affect microclimate and soil characteristics, with important effects on soil microbial communities and related processes. Here, we studied the interactions between Plant Root traits and soil bacterial and fungal communities in closed forest and open gaps in a mixed forest along an elevational gradient in the French Alps (1400, 1700 and 2000 m). Samples were separated into three fractions (Plant Root, rhizosphere and bulk soil), to further investigate the influence of Plant zones on microbial communities. Bacterial (16S) and fungal (ITS) biodiversity was determined using high throughput sequencing, along with standard measures of soil, litter and Root traits. We found that (i) microbial community diversity was higher in gaps than in closed forest because of increased Root trait diversity and density; (ii) open versus closed forest patches affected phylogenetic dispersion despite differences in elevations with phylogenetic clustering in closed forest; (iii) the interaction between Root traits and microbial communities was stronger for rhizosphere and Root fractions than for bulk soil and (iv) bacterial community composition was better explained by Root traits than for fungi. Our findings highlight the importance of open gaps versus closed forest patches and associated Root traits affecting microbial community structure, particularly for bacterial assemblages that exhibited a stronger interaction with Root traits than for fungi.
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Rhizosphere bacteria are more strongly related to Plant Root traits than fungi in temperate montane forests: insights from closed and open forest patches along an elevational gradient
Plant and Soil, 2020Co-Authors: Luis Merino-martín, Robert I. Griffiths, Hyun S. Gweon, Clément Furget-bretagnon, Anna Oliver, Yves Bissonnais, Alexia StokesAbstract:Aims Heterogeneous canopies in temperate montane forests affect microclimate and soil characteristics, with important effects on soil microbial communities and related processes. Here, we studied the interactions between Plant Root traits and soil bacterial and fungal communities in closed forest and open gaps in a mixed forest along an elevational gradient in the French Alps (1400, 1700 and 2000 m). Methods Samples were separated into three fractions (Plant Root, rhizosphere and bulk soil), to further investigate the influence of Plant zones on microbial communities. Bacterial (16S) and fungal (ITS) biodiversity was determined using high throughput sequencing, along with standard measures of soil, litter and Root traits. Results We found that (i) microbial community diversity was higher in gaps than in closed forest because of increased Root trait diversity and density; (ii) open versus closed forest patches affected phylogenetic dispersion despite differences in elevations with phylogenetic clustering in closed forest; (iii) the interaction between Root traits and microbial communities was stronger for rhizosphere and Root fractions than for bulk soil and (iv) bacterial community composition was better explained by Root traits than for fungi. Conclusions Our findings highlight the importance of open gaps versus closed forest patches and associated Root traits affecting microbial community structure, particularly for bacterial assemblages that exhibited a stronger interaction with Root traits than for fungi.
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using three dimensional Plant Root architecture in models of shallow slope stability
Annals of Botany, 2007Co-Authors: Frederic Danjon, David H Barker, Michael Drexhage, Alexia StokesAbstract:Background: The contribution of vegetation to shallow-slope stability is of major importance in landslide-prone regions. However, existing slope stability models use only limited Plant Root architectural parameters. This study aims to provide a chain of tools useful for determining the contribution of tree Roots to soil reinforcement. Methods: Three-dimensional digitizing in situ was used to obtain accurate Root system architecture data for mature Quercus alba in two forest stands. These data were used as input to tools developed, which analyse the spatial position of Roots, topology and geometry. The contribution of Roots to soil reinforcement was determined by calculating additional soil cohesion using the limit equilibrium model, and the factor of safety (FOS) using an existing slope stability model, Slip4Ex. Key Results: Existing models may incorrectly estimate the additional soil cohesion provided by Roots, as the spatial position of Roots crossing the potential slip surface is usually not taken into account. However, most soil reinforcement by Roots occurs close to the tree stem and is negligible at a distance >1·0 m from the tree, and therefore global values of FOS for a slope do not take into account local slippage along the slope. Conclusions: Within a forest stand on a landslide-prone slope, soil fixation by Roots can be minimal between uniform rows of trees, leading to local soil slippage. Therefore, staggered rows of trees would improve overall slope stability, as trees would arrest the downward movement of soil. The chain of tools consisting of both software (free for non-commercial use) and functions available from the first author will enable a more accurate description and use of Root architectural parameters in standard slope stability analyses.
Johnathan J Dalzell - One of the best experts on this subject based on the ideXlab platform.
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ethylene response factor erf genes modulate Plant Root exudate composition and the attraction of Plant parasitic nematodes
International Journal for Parasitology, 2019Co-Authors: Steven Dyer, Ryan Weir, Xavier Cheseto, Baldwyn Torto, Johnathan J DalzellAbstract:Abstract Plant Root exudates are compositionally diverse, plastic and adaptive. Ethylene signalling influences the attraction of Plant parasitic nematodes (PPNs), presumably through the modulation of Root exudate composition. Understanding this pathway could lead to new sources of crop parasite resistance. Here we used Virus-Induced Gene Silencing (VIGS) to knock down the expression of two Ethylene Response Factor (ERF) genes, ERF-E2 and ERF-E3, in tomato. Root exudates were significantly more attractive to the PPNs Meloidogyne incognita and Globodera pallida following knockdown of ERF-E2, which had no impact on the attraction of Meloidogyne javanica. Knockdown of ERF-E3 had no impact on the attraction of Meloidogyne or Globodera spp. Gas Chromatography Mass Spectrometry (GC-MS) analysis revealed major changes in Root exudate composition relative to controls. However, these changes did not alter the attraction of rhizosphere microbes Bacillus subtilis or Agrobacterium tumefaciens. This study further supports the potential of engineering Plant Root exudate for parasite control, through the modulation of Plant genes.
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ethylene response factor erf genes modulate Plant Root exudate composition and the attraction of Plant parasitic nematodes
bioRxiv, 2019Co-Authors: Steven Dyer, Ryan Weir, Xavier Cheseto, Baldwyn Torto, Johnathan J DalzellAbstract:Plant Root exudates are compositionally diverse, plastic and adaptive. Ethylene signalling influences the attraction of Plant parasitic nematodes (PPNs), presumably through the modulation of Root exudate composition. Understanding this pathway could lead to new sources of crop parasite resistance. Here we have used Virus-Induced Gene Silencing (VIGS) to knockdown the expression of two ETHYLENE RESPONSE FACTOR (ERF) genes, ERF-E2 and ERF-E3 in tomato. Root exudates are significantly more attractive to the PPNs Meloidogyne incognita, and Globodera pallida following knockdown of ERF-E2, which has no impact on the attraction of Meloidogyne javanica. Knockdown of ERF-E3 has no impact on the attraction of Meloidogyne or Globodera spp. GC-MS analysis revealed major changes in Root exudate composition relative to controls. However, these changes do not alter the attraction of rhizosphere microbes Bacillus subtilis or Agrobacterium tumefaciens. This study further supports the potential of engineering Plant Root exudate for parasite control, through the modulation of Plant genes.nnnnO_TBL View this table:norg.highwire.dtl.DTLVardef@15fea9dorg.highwire.dtl.DTLVardef@241221org.highwire.dtl.DTLVardef@224609org.highwire.dtl.DTLVardef@24315corg.highwire.dtl.DTLVardef@24953e_HPS_FORMAT_FIGEXP M_TBL C_TBL
Angela Hodge - One of the best experts on this subject based on the ideXlab platform.
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Plant Root growth, architecture and function
Plant and Soil, 2009Co-Authors: Angela Hodge, Francisco Merchan, Claude Doussan, Graziella Berta, Martin CrespiAbstract:Without Roots there would be no rhizosphere and no rhizodeposition to fuel microbial activity. Although micro-organisms may view Roots merely as a source of carbon supply this belies the fascinating complexity and diversity of Root systems that occurs despite their common function. Here, we examine the physiological and genetic determinants of Root growth and the complex, yet varied and flexible, Root architecture that results. The main functions of Root systems are also explored including how Roots cope with nutrient acquisition from the heterogeneous soil environment and their ability to form mutualistic associations with key soil micro-organisms (such as nitrogen fixing bacteria and mycorrhizal fungi) to aid them in their quest for nutrients. Finally, some key biotic and abiotic constraints on Root development and function in the soil environment are examined and some of the adaptations Roots have evolved to counter such stresses discussed.
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the plastic Plant Root responses to heterogeneous supplies of nutrients
New Phytologist, 2004Co-Authors: Angela HodgeAbstract:Contents I. Introduction 000 II. Morphological responses 000 III. Root demography 000 IV. Physiological plasticity 000 V. Root plasticity in patches in competition and symbiosis with microorganisms 000 VI. Influence of patch attributes 000 VII. Control of Root proliferation 000 VIII. Conclusions 000 Acknowledgements 000 References 000 Summary When Roots encounter a nutrient-rich zone or patch they often proliferate within it. Roots experiencing nutrient-rich patches can also enhance their physiological ion-uptake capacities compared with Roots of the same Plant outside the patch zone. These plastic responses by the Root system have been proposed as the major mechanism by which Plants cope with the naturally occurring heterogeneous supplies of nutrients in soil. Various attempts to predict how contrasting species will respond to patches have been made based on specific Root length (SRL), Root demography and biomass allocation within the patch zone. No one criterion has proved definitive. Actually demonstrating that Root proliferation is beneficial to the Plant, especially in terms of nitrogen capture from patches, has also proved troublesome. Yet by growing Plants under more realistic conditions, such as in interspecific Plant competition, and with a complex organic patch, a direct benefit can be demonstrated. Thus, as highlighted in this review, the environmental context in which the Root response is expressed is as important as the magnitude of the response itself.
Thierry Dutoit - One of the best experts on this subject based on the ideXlab platform.
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Plant Root traits affecting the resistance of soils to concentrated flow erosion
Earth Surface Processes and Landforms, 2012Co-Authors: Melanie Burylo, Freddy Rey, Nicolle Mathys, Thierry DutoitAbstract:The effect of Plant species on erosion processes may be decisive for long-term soil protection in degraded ecosystems. The identification of functional effect traits that predict species ability for erosion control would be of great interest for ecological restoration purposes. Flume experiments were carried out to investigate the effect of the Root systems of three species having contrasted ecological requirements from eroded marly lands of the French Southern Alps [i.e. Robinia pseudo acacia (tree), Pinus nigra austriaca (tree) and Achnatherum calamagrostis (grass)], on concentrated flow erosion rates. Ten functional traits, describing Plant morphological and biomechanical features, were measured on each tested sample. Analyses were performed to identify traits that determine Plant Root effects on erosion control. Erosion rates were lowest for samples of Robinia pseudo acacia, intermediate in Achnatherum calamagrostis and highest in Pinus nigra austriaca. The three species also differed strongly in their traits. Principal components analysis showed that the erosion-reducing potential of Plant species was negatively correlated to Root diameter and positively correlated to the percentage of fine Roots. The results highlighted the role of small flexible Roots in Root reinforcement processes, and suggested the importance of high Root surface and higher tensile strength for soil stabilization. By combining flume experiment to Plant functional traits measurements, we identified Root system features influencing Plant species performance for soil protection against concentrated flow erosion. Plant functional traits related to species efficiency for erosion control represent useful tools to improve the diagnosis of land vulnerability to erosion, Plant community resistance and the prediction of ecosystem functioning after ecological restoration. Copyright © 2012 John Wiley & Sons, Ltd.
Jean Poesen - One of the best experts on this subject based on the ideXlab platform.
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the importance of Plant Root characteristics in controlling concentrated flow erosion rates
Earth Surface Processes and Landforms, 2003Co-Authors: Gwendolyn Gyssels, Jean PoesenAbstract:While it has been demonstrated in numerous studies that the aboveground characteristics of the vegetation are of particular importance with respect to soil erosion control, this study argues the importance of separating the influence of vegetation on soil erosion rates into two parts: the impact of leaves and stems (aboveground biomass) and the influence of Roots (belowground biomass). Although both Plant parameters form inseparable constituents of the total Plant organism, most studies attribute the impact of vegetation on soil erosion rates mainly to the characteristics of the aboveground biomass. This triggers the question whether the belowground biomass is of no or negligible importance with respect to soil erosion by concentrated flow. This study tried to answer this question by comparing cross-sectional areas of concentrated flow channels (rills and ephemeral gullies) in the Belgian Loess Belt for different cereal and grass Plant densities. The results of these measurements highlighted the fact that both an increase in shoot density as well as an increase in Root density resulted in an exponential decrease of concentrated flow erosion rates. Since protection of the soil surface in the early Plant growth stages is crucial with respect to the reduction of water erosion rates, increasing the Plant Root density in the topsoil could be a viable erosion control strategy. Copyright © 2003 John Wiley & Sons, Ltd.
