1
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Colombi T, Pandey BK, Chawade A, Bennett MJ, Mooney SJ, Keller T. Root plasticity versus elasticity - when are responses acclimative? TRENDS IN PLANT SCIENCE 2024:S1360-1385(24)00018-9. [PMID: 38355326 DOI: 10.1016/j.tplants.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/27/2023] [Accepted: 01/23/2024] [Indexed: 02/16/2024]
Abstract
Spatiotemporal soil heterogeneity and the resulting edaphic stress cycles can be decisive for crop growth. However, our understanding of the acclimative value of root responses to heterogeneous soil conditions remains limited. We outline a framework to evaluate the acclimative value of root responses that distinguishes between stress responses that are persistent and reversible upon stress release, termed 'plasticity' and 'elasticity', respectively. Using energy balances, we provide theoretical evidence that the advantage of plasticity over elasticity increases with the number of edaphic stress cycles and if responses lead to comparatively high energy gains. Our framework provides a conceptual basis for assessing the acclimative value of root responses to soil heterogeneity and can catalyse research on crop adaptations to heterogeneous belowground environments.
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Affiliation(s)
- Tino Colombi
- Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 75007, Uppsala, Sweden.
| | - Bipin K Pandey
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Aakash Chawade
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Sundsvägen 10, 23456 Alnarp, Sweden
| | - Malcolm J Bennett
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Sacha J Mooney
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Thomas Keller
- Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 75007, Uppsala, Sweden; Department of Agroecology and Environment, Agroscope, Reckenholzstrasse 191, CH-8046, Zürich, Switzerland
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2
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Song B, Razavi BS, Pena R. Contrasting distribution of enzyme activities in the rhizosphere of European beech and Norway spruce. FRONTIERS IN PLANT SCIENCE 2022; 13:987112. [PMID: 36466222 PMCID: PMC9709443 DOI: 10.3389/fpls.2022.987112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/26/2022] [Indexed: 06/17/2023]
Abstract
Recent policies and silvicultural management call for forest regeneration that involve the selection of tree species able to cope with low soil nutrient availability in forest ecosystems. Understanding the impact of different tree species on the rhizosphere processes (e.g., enzyme activities) involved in nutrient mobilisation is critical in selecting suitable species to adapt forests to environmental change. Here, we visualised and investigated the rhizosphere distribution of enzyme activities (cellobiohydrolase, leucine-aminopeptidase, and acid phosphomonoesterase) using zymography. We related the distribution of enzyme activities to the seedling root morphological traits of European beech (Fagus sylvatica) and Norway spruce (Picea abies), the two most cultivated temperate tree species that employ contrasting strategies in soil nutrient acquisition. We found that spruce showed a higher morphological heterogeneity along the roots than beech, resulting in a more robust relationship between rhizoplane-associated enzyme activities and the longitudinal distance from the root apex. The rhizoplane enzyme activities decreased in spruce and increased in beech with the distance from the root apex over a power-law equation. Spruce revealed broader rhizosphere extents of all three enzymes, but only acid phosphomonoesterase activity was higher compared with beech. This latter result was determined by a larger root system found in beech compared with spruce that enhanced cellobiohydrolase and leucine-aminopeptidase activities. The root hair zone and hair lengths were significant variables determining the distribution of enzyme activities in the rhizosphere. Our findings indicate that spruce has a more substantial influence on rhizosphere enzyme production and diffusion than beech, enabling spruce to better mobilise nutrients from organic sources in heterogeneous forest soils.
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Affiliation(s)
- Bin Song
- School of Geography and Ocean Science, Nanjing University, Nanjing, China
- Forest Botany and Tree Physiology, University of Göttingen, Göttingen, Germany
| | - Bahar S. Razavi
- Department of Soil and Plant Microbiome, Institute of Phytopathology, University of Kiel, Kiel, Germany
- Department of Agriculture Soil Science, University of Göttingen, Göttingen, Germany
| | - Rodica Pena
- Forest Botany and Tree Physiology, University of Göttingen, Göttingen, Germany
- Department of Sustainable Land Management, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
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3
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Boursiac Y, Pradal C, Bauget F, Lucas M, Delivorias S, Godin C, Maurel C. Phenotyping and modeling of root hydraulic architecture reveal critical determinants of axial water transport. PLANT PHYSIOLOGY 2022; 190:1289-1306. [PMID: 35708646 PMCID: PMC9516777 DOI: 10.1093/plphys/kiac281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/15/2022] [Indexed: 05/26/2023]
Abstract
Water uptake by roots is a key adaptation of plants to aerial life. Water uptake depends on root system architecture (RSA) and tissue hydraulic properties that, together, shape the root hydraulic architecture. This work investigates how the interplay between conductivities along radial (e.g. aquaporins) and axial (e.g. xylem vessels) pathways determines the water transport properties of highly branched RSAs as found in adult Arabidopsis (Arabidopsis thaliana) plants. A hydraulic model named HydroRoot was developed, based on multi-scale tree graph representations of RSAs. Root water flow was measured by the pressure chamber technique after successive cuts of a same root system from the tip toward the base. HydroRoot model inversion in corresponding RSAs allowed us to concomitantly determine radial and axial conductivities, providing evidence that the latter is often overestimated by classical evaluation based on the Hagen-Poiseuille law. Organizing principles of Arabidopsis primary and lateral root growth and branching were determined and used to apply the HydroRoot model to an extended set of simulated RSAs. Sensitivity analyses revealed that water transport can be co-limited by radial and axial conductances throughout the whole RSA. The number of roots that can be sectioned (intercepted) at a given distance from the base was defined as an accessible and informative indicator of RSA. The overall set of experimental and theoretical procedures was applied to plants mutated in ESKIMO1 and previously shown to have xylem collapse. This approach will be instrumental to dissect the root water transport phenotype of plants with intricate alterations in root growth or transport functions.
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Affiliation(s)
| | | | | | | | - Stathis Delivorias
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier 34060, France
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Boursiac Y, Protto V, Rishmawi L, Maurel C. Experimental and conceptual approaches to root water transport. PLANT AND SOIL 2022; 478:349-370. [PMID: 36277078 PMCID: PMC9579117 DOI: 10.1007/s11104-022-05427-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/03/2022] [Indexed: 05/05/2023]
Abstract
BACKGROUND Root water transport, which critically contributes to the plant water status and thereby plant productivity, has been the object of extensive experimental and theoretical studies. However, root systems represent an intricate assembly of cells in complex architectures, including many tissues at distinct developmental stages. Our comprehension of where and how molecular actors integrate their function in order to provide the root with its hydraulic properties is therefore still limited. SCOPE Based on current literature and prospective discussions, this review addresses how root water transport can be experimentally measured, what is known about the underlying molecular actors, and how elementary water transport processes are scaled up in numerical/mathematical models. CONCLUSIONS The theoretical framework and experimental procedures on root water transport that are in use today have been established a few decades ago. However, recent years have seen the appearance of new techniques and models with enhanced resolution, down to a portion of root or to the tissue level. These advances pave the way for a better comprehension of the dynamics of water uptake by roots in the soil.
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Affiliation(s)
- Yann Boursiac
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, 34060 Montpellier, France
| | - Virginia Protto
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, 34060 Montpellier, France
| | - Louai Rishmawi
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, 34060 Montpellier, France
| | - Christophe Maurel
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, 34060 Montpellier, France
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5
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Sugiyama A. Flavonoids and saponins in plant rhizospheres: roles, dynamics, and the potential for agriculture. Biosci Biotechnol Biochem 2021; 85:1919-1931. [PMID: 34113972 DOI: 10.1093/bbb/zbab106] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 06/04/2021] [Indexed: 01/13/2023]
Abstract
Plants are in constant interaction with a myriad of soil microorganisms in the rhizosphere, an area of soil in close contact with plant roots. Recent research has highlighted the importance of plant-specialized metabolites (PSMs) in shaping and modulating the rhizosphere microbiota; however, the molecular mechanisms underlying the establishment and function of the microbiota mostly remain unaddressed. Flavonoids and saponins are a group of PSMs whose biosynthetic pathways have largely been revealed. Although these PSMs are abundantly secreted into the rhizosphere and exert various functions, the secretion mechanisms have not been clarified. This review summarizes the roles of flavonoids and saponins in the rhizosphere with a special focus on interactions between plants and the rhizosphere microbiota. Furthermore, this review introduces recent advancements in the dynamics of these metabolites in the rhizosphere and indicates potential applications of PSMs for crop production and discusses perspectives in this emerging research field.
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Affiliation(s)
- Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Japan
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Maurel C, Nacry P. Root architecture and hydraulics converge for acclimation to changing water availability. NATURE PLANTS 2020; 6:744-749. [PMID: 32601421 DOI: 10.1038/s41477-020-0684-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/29/2020] [Indexed: 05/16/2023]
Abstract
Because of intense transpiration and growth, the needs of plants for water can be immense. Yet water in the soil is most often heterogeneous if not scarce due to more and more frequent and intense drought episodes. The converse context, flooding, is often associated with marked oxygen deficiency and can also challenge the plant water status. Under our feet, roots achieve an incredible challenge to meet the water demand of the plant's aerial parts under such dramatically different environmental conditions. For this, they continuously explore the soil, building a highly complex, branched architecture. On shorter time scales, roots keep adjusting their water transport capacity (their so-called hydraulics) locally or globally. While the mechanisms that directly underlie root growth and development as well as tissue hydraulics are being uncovered, the signalling mechanisms that govern their local and systemic adjustments as a function of water availability remain largely unknown. A comprehensive understanding of root architecture and hydraulics as a whole (in other terms, root hydraulic architecture) is needed to apprehend the strategies used by plants to optimize water uptake and possibly improve crops regarding this crucial trait.
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Affiliation(s)
- Christophe Maurel
- Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France.
| | - Philippe Nacry
- Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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7
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Okutani F, Hamamoto S, Aoki Y, Nakayasu M, Nihei N, Nishimura T, Yazaki K, Sugiyama A. Rhizosphere modelling reveals spatiotemporal distribution of daidzein shaping soybean rhizosphere bacterial community. PLANT, CELL & ENVIRONMENT 2020; 43:1036-1046. [PMID: 31875335 DOI: 10.1111/pce.13708] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/16/2019] [Indexed: 05/21/2023]
Abstract
Plant roots nurture a wide variety of microbes via exudation of metabolites, shaping the rhizosphere's microbial community. Despite the importance of plant specialized metabolites in the assemblage and function of microbial communities in the rhizosphere, little is known of how far the effects of these metabolites extend through the soil. We employed a fluid model to simulate the spatiotemporal distribution of daidzein, an isoflavone secreted from soybean roots, and validated using soybeans grown in a rhizobox. We then analysed how daidzein affects bacterial communities using soils artificially treated with daidzein. Simulation of daidzein distribution showed that it was only present within a few millimetres of root surfaces. After 14 days in a rhizobox, daidzein was only present within 2 mm of root surfaces. Soils with different concentrations of daidzein showed different community composition, with reduced α-diversity in daidzein-treated soils. Bacterial communities of daidzein-treated soils were closer to those of the soybean rhizosphere than those of bulk soils. This study highlighted the limited distribution of daidzein within a few millimetres of root surfaces and demonstrated a novel role of daidzein in assembling bacterial communities in the rhizosphere by acting as more of a repellant than an attractant.
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Affiliation(s)
- Fuki Okutani
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Shoichiro Hamamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuichi Aoki
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Masaru Nakayasu
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Naoto Nihei
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Taku Nishimura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazufumi Yazaki
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
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Schneider HM, Postma JA, Kochs J, Pflugfelder D, Lynch JP, van Dusschoten D. Spatio-Temporal Variation in Water Uptake in Seminal and Nodal Root Systems of Barley Plants Grown in Soil. FRONTIERS IN PLANT SCIENCE 2020; 11:1247. [PMID: 32903494 PMCID: PMC7438553 DOI: 10.3389/fpls.2020.01247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/29/2020] [Indexed: 05/11/2023]
Abstract
The spatial and temporal dynamics of root water uptake in nodal and seminal roots are poorly understood, especially in relation to root system development and aging. Here we non-destructively quantify 1) root water uptake and 2) root length of nodal and seminal roots of barley in three dimensions during 43 days of growth. We developed a concentric split root system to hydraulically and physically isolate the seminal and nodal root systems. Using magnetic resonance imaging (MRI), roots were visualized, root length was determined, and soil water depletion in both compartments was measured. From 19 days after germination and onwards, the nodal root system had greater water uptake compared to the seminal root system due to both greater root length and greater root conductivity. At 29 days after germination onwards, the average age of the seminal and nodal root systems was similar and no differences were observed in water uptake per root length between seminal and nodal root systems, indicating the importance of embryonic root systems for seedling establishment and nodal root systems in more mature plants. Since nodal roots perform the majority of water uptake at 29 days after germination and onwards, nodal root phenes merit consideration as a selection target to improve water capture in barley and possibly other crops.
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Affiliation(s)
- Hannah M. Schneider
- Forschungszentrum Jülich, IBG-2, Jülich, Germany
- Department of Plant Science, The Pennsylvania State University, University Park, PA, United States
| | | | | | | | - Jonathan P. Lynch
- Department of Plant Science, The Pennsylvania State University, University Park, PA, United States
| | - Dagmar van Dusschoten
- Forschungszentrum Jülich, IBG-2, Jülich, Germany
- *Correspondence: Dagmar van Dusschoten,
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9
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Caroline Silva Lopes E, Pereira Rodrigues W, Ruas Fraga K, Machado Filho JA, Rangel da Silva J, Menezes de Assis-Gomes M, Moura Assis Figueiredo FAM, Gresshoff PM, Campostrini E. Hypernodulating soybean mutant line nod4 lacking 'Autoregulation of Nodulation' (AON) has limited root-to-shoot water transport capacity. ANNALS OF BOTANY 2019; 124:979-991. [PMID: 30955042 PMCID: PMC6881229 DOI: 10.1093/aob/mcz040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/01/2019] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS Although hypernodulating phenotype mutants of legumes, such as soybean, possess a high leaf N content, the large number of root nodules decreases carbohydrate availability for plant growth and seed yield. In addition, under conditions of high air vapour pressure deficit (VPD), hypernodulating plants show a limited capacity to replace water losses through transpiration, resulting in stomatal closure, and therefore decreased net photosynthetic rates. Here, we used hypernodulating (nod4) (282.33 ± 28.56 nodules per plant) and non-nodulating (nod139) (0 nodules per plant) soybean mutant lines to determine explicitly whether a large number of nodules reduces root hydraulic capacity, resulting in decreased stomatal conductance and net photosynthetic rates under high air VPD conditions. METHODS Plants were either inoculated or not inoculated with Bradyrhizobium diazoefficiens (strain BR 85, SEMIA 5080) to induce nitrogen-fixing root nodules (where possible). Absolute root conductance and root conductivity, plant growth, leaf water potential, gas exchange, chlorophyll a fluorescence, leaf 'greenness' [Soil Plant Analysis Development (SPAD) reading] and nitrogen content were measured 37 days after sowing. KEY RESULTS Besides the reduced growth of hypernodulating soybean mutant nod4, such plants showed decreased root capacity to supply leaf water demand as a consequence of their reduced root dry mass and root volume, which resulted in limited absolute root conductance and root conductivity normalized by leaf area. Thereby, reduced leaf water potential at 1300 h was observed, which contributed to depression of photosynthesis at midday associated with both stomatal and non-stomatal limitations. CONCLUSIONS Hypernodulated plants were more vulnerable to VPD increases due to their limited root-to-shoot water transport capacity. However, greater CO2 uptake caused by the high N content can be partly compensated by the stomatal limitation imposed by increased VPD conditions.
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Affiliation(s)
- Emile Caroline Silva Lopes
- Setor de Fisiologia Vegetal, Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, CEP, Ilhéus, Bahia, Braz il
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Weverton Pereira Rodrigues
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Katherine Ruas Fraga
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - José Altino Machado Filho
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
- Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural, Vitória, ES, Brazil
| | - Jefferson Rangel da Silva
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Cordeirópolis, São Paulo, Brazil
| | - Mara Menezes de Assis-Gomes
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | | | - Peter M Gresshoff
- Integrative Legume Research Group, The University of Queensland, St. Lucia, Brisbane, QLD, Australia
| | - Eliemar Campostrini
- Setor de Fisiologia Vegetal, LMGV, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
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10
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Root water uptake and its pathways across the root: quantification at the cellular scale. Sci Rep 2019; 9:12979. [PMID: 31506538 PMCID: PMC6737181 DOI: 10.1038/s41598-019-49528-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/27/2019] [Indexed: 11/09/2022] Open
Abstract
The pathways of water across root tissues and their relative contribution to plant water uptake remain debated. This is mainly due to technical challenges in measuring water flux non-invasively at the cellular scale under realistic conditions. We developed a new method to quantify water fluxes inside roots growing in soils. The method combines spatiotemporal quantification of deuterated water distribution imaged by rapid neutron tomography with an inverse simulation of water transport across root tissues. Using this non-invasive technique, we estimated for the first time the in-situ radial water fluxes [m s−1] in apoplastic and cell-to-cell pathways. The water flux in the apoplast of twelve days-old lupins (Lupinus albus L. cv. Feodora) was seventeen times faster than in the cell-to-cell pathway. Hence, the overall contribution of the apoplast in water flow [m3 s−1] across the cortex is, despite its small volume of 5%, as large as 57 ± 8% (Mean ± SD for n = 3) of the total water flow. This method is suitable to non-invasively measure the response of cellular scale root hydraulics and water fluxes to varying soil and climate conditions.
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11
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Koch A, Meunier F, Vanderborght J, Garré S, Pohlmeier A, Javaux M. Functional-structural root-system model validation using a soil MRI experiment. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2797-2809. [PMID: 30799498 PMCID: PMC6509106 DOI: 10.1093/jxb/erz060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/05/2019] [Indexed: 05/04/2023]
Abstract
For the first time, a functional-structural root-system model is validated by combining a tracer experiment monitored with magnetic resonance imaging and three-dimensional modeling of water and solute transport.
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Affiliation(s)
- Axelle Koch
- Earth and Life Institute – Environmental Sciences, UCLouvain, Louvain-la-Neuve, Belgium
| | - Félicien Meunier
- Earth and Life Institute – Environmental Sciences, UCLouvain, Louvain-la-Neuve, Belgium
- Computational and Applied Vegetation Ecology Lab, Ghent University, Ghent, Belgium
| | - Jan Vanderborght
- Institute of Bio- and Geosciences, IBG-3 Agrosphere, Forschungszentrum Jülich GmbH, Jülich, Germany
- Earth and Environmental Sciences, KU Leuven, Celestijnenlaan, Leuven, Belgium
| | - Sarah Garré
- Gembloux Agro-Bio Tech, Université de Liège, Passage des déportés, Gembloux, Belgium
| | - Andreas Pohlmeier
- Institute of Bio- and Geosciences, IBG-3 Agrosphere, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Mathieu Javaux
- Earth and Life Institute – Environmental Sciences, UCLouvain, Louvain-la-Neuve, Belgium
- Institute of Bio- and Geosciences, IBG-3 Agrosphere, Forschungszentrum Jülich GmbH, Jülich, Germany
- Correspondence:
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12
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Passot S, Couvreur V, Meunier F, Draye X, Javaux M, Leitner D, Pagès L, Schnepf A, Vanderborght J, Lobet G. Connecting the dots between computational tools to analyse soil-root water relations. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2345-2357. [PMID: 30329081 DOI: 10.1093/jxb/ery361] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/10/2018] [Indexed: 05/20/2023]
Abstract
In recent years, many computational tools, such as image analysis, data management, process-based simulation, and upscaling tools, have been developed to help quantify and understand water flow in the soil-root system, at multiple scales (tissue, organ, plant, and population). Several of these tools work together or at least are compatible. However, for the uninformed researcher, they might seem disconnected, forming an unclear and disorganized succession of tools. In this article, we show how different studies can be further developed by connecting them to analyse soil-root water relations in a comprehensive and structured network. This 'explicit network of soil-root computational tools' informs readers about existing tools and helps them understand how their data (past and future) might fit within the network. We also demonstrate the novel possibilities of scale-consistent parameterizations made possible by the network with a set of case studies from the literature. Finally, we discuss existing gaps in the network and how we can move forward to fill them.
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Affiliation(s)
- Sixtine Passot
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Valentin Couvreur
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Félicien Meunier
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Computational and Applied Vegetation Ecology lab, Ghent University, Gent, Belgium
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Xavier Draye
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Mathieu Javaux
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Agrosphere, IBG3, Forschungszentrum Jülich, GmbH Jülich, Germany
| | | | | | - Andrea Schnepf
- Agrosphere, IBG3, Forschungszentrum Jülich, GmbH Jülich, Germany
| | - Jan Vanderborght
- Agrosphere, IBG3, Forschungszentrum Jülich, GmbH Jülich, Germany
| | - Guillaume Lobet
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Agrosphere, IBG3, Forschungszentrum Jülich, GmbH Jülich, Germany
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13
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Ahmed MA, Zarebanadkouki M, Meunier F, Javaux M, Kaestner A, Carminati A. Root type matters: measurement of water uptake by seminal, crown, and lateral roots in maize. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1199-1206. [PMID: 29304205 PMCID: PMC6019006 DOI: 10.1093/jxb/erx439] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 11/11/2017] [Indexed: 05/20/2023]
Abstract
The ability of plants to take up water from the soil depends on both the root architecture and the distribution and evolution of the hydraulic conductivities among root types and along the root length. The mature maize (Zea mays L.) root system is composed of primary, seminal, and crown roots together with their respective laterals. Our understanding of root water uptake of maize is largely based on measurements of primary and seminal roots. Crown roots might have a different ability to extract water from the soil, but their hydraulic function remains unknown. The aim of this study was to measure the location of water uptake in mature maize and investigate differences between seminal, crown, and lateral roots. Neutron radiography and injections of deuterated water were used to visualize the root architecture and water transport in 5-week-old maize root systems. Water was mainly taken up by crown roots. Seminal roots and their laterals, which were the main location of water uptake in younger plants, made a minor contribution to water uptake. In contrast to younger seminal roots, crown roots were also able to take up water from their most distal segments. The greater uptake of crown roots compared with seminal roots is explained by their higher axial conductivity in the proximal parts and by the fact that they are connected to the shoot above the seminal roots, which favors the propagation of xylem tension along the crown roots. The deeper water uptake of crown roots is explained by their shorter and fewer laterals, which decreases the dissipation of water potential along the roots.
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Affiliation(s)
- Mutez Ali Ahmed
- Division of Soil Hydrology, University of Goettingen, Göttingen, Germany
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Correspondence:
| | | | - Félicien Meunier
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Mathieu Javaux
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Anders Kaestner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland
| | - Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
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Ndour A, Vadez V, Pradal C, Lucas M. Virtual Plants Need Water Too: Functional-Structural Root System Models in the Context of Drought Tolerance Breeding. FRONTIERS IN PLANT SCIENCE 2017; 8:1577. [PMID: 29018456 PMCID: PMC5622977 DOI: 10.3389/fpls.2017.01577] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/29/2017] [Indexed: 05/04/2023]
Abstract
Developing a sustainable agricultural model is one of the great challenges of the coming years. The agricultural practices inherited from the Green Revolution of the 1960s show their limits today, and new paradigms need to be explored to counter rising issues such as the multiplication of climate-change related drought episodes. Two such new paradigms are the use of functional-structural plant models to complement and rationalize breeding approaches and a renewed focus on root systems as untapped sources of plant amelioration. Since the late 1980s, numerous functional and structural models of root systems were developed and used to investigate the properties of root systems in soil or lab-conditions. In this review, we focus on the conception and use of such root models in the broader context of research on root-driven drought tolerance, on the basis of root system architecture (RSA) phenotyping. Such models result from the integration of architectural, physiological and environmental data. Here, we consider the different phenotyping techniques allowing for root architectural and physiological study and their limits. We discuss how QTL and breeding studies support the manipulation of RSA as a way to improve drought resistance. We then go over the integration of the generated data within architectural models, how those architectural models can be coupled with functional hydraulic models, and how functional parameters can be measured to feed those models. We then consider the assessment and validation of those hydraulic models through confrontation of simulations to experimentations. Finally, we discuss the up and coming challenges facing root systems functional-structural modeling approaches in the context of breeding.
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Affiliation(s)
- Adama Ndour
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés Aux Stress Environnementaux (LAPSE), Dakar, Senegal
- Laboratoire Commun de Microbiologie (IRD-ISRA-UCAD), Dakar, Senegal
- CERES, IRD, Université de Montpellier, UMR DIADE, Montpellier, France
- Département Maths/Informatique, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal
| | - Vincent Vadez
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India
| | - Christophe Pradal
- UMR AGAP, Univiversité de Montpellier, CIRAD, INRA, Inria, Montpellier SupAgro, Montpellier, France
| | - Mikaël Lucas
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés Aux Stress Environnementaux (LAPSE), Dakar, Senegal
- Laboratoire Commun de Microbiologie (IRD-ISRA-UCAD), Dakar, Senegal
- CERES, IRD, Université de Montpellier, UMR DIADE, Montpellier, France
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Zarebanadkouki M, Meunier F, Couvreur V, Cesar J, Javaux M, Carminati A. Estimation of the hydraulic conductivities of lupine roots by inverse modelling of high-resolution measurements of root water uptake. ANNALS OF BOTANY 2016; 118:853-864. [PMID: 27539602 PMCID: PMC5055639 DOI: 10.1093/aob/mcw154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/10/2016] [Indexed: 05/04/2023]
Abstract
Background and Aims Radial and axial hydraulic conductivities are key parameters for proper understanding and modelling of root water uptake. Despite their importance, there is limited experimental information on how the radial and axial hydraulic conductivities vary along roots growing in soil. Here, a new approach was introduced to estimate inversely the profile of hydraulic conductivities along the roots of transpiring plants growing in soil. Methods A three-dimensional model of root water uptake was used to reproduce the measured profile of root water uptake along roots of lupine plant grown in soil. The profile of fluxes was measured using a neutron radiography technique combined with injection of deuterated water as tracer. The aim was to estimate inversely the profiles of the radial and axial hydraulic conductivities along the roots. Key Results The profile of hydraulic conductivities along the taproot and the lateral roots of lupines was calculated using three flexible scenarios. For all scenarios, it was found that the radial hydraulic conductivity increases towards the root tips, while the axial conductivity decreases. Additionally, it was found that in soil with uniform water content: (1) lateral roots were the main location of root water uptake; (2) water uptake by laterals decreased towards the root tips due to the dissipation of water potential along the root; and (3) water uptake by the taproot was higher in the distal segments and was negligible in the proximal parts, which had a low radial conductivity. Conclusions The proposed approach allows the estimation of the root hydraulic properties of plants growing in soil. This information can be used in an advanced model of water uptake to predict the water uptake of different root types or different root architectures under varying soil conditions.
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Affiliation(s)
- Mohsen Zarebanadkouki
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
- *For correspondence. E-mail
| | - Félicien Meunier
- Université catholique de Louvain, Earth and Life Institute-Environnemental Sciences, Louvain-la Neuve, Belgium
| | - Valentin Couvreur
- Université catholique de Louvain, Earth and Life Institute-Agronomy, Louvain-la Neuve, Belgium
| | - Jimenez Cesar
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
| | - Mathieu Javaux
- Université catholique de Louvain, Earth and Life Institute-Environnemental Sciences, Louvain-la Neuve, Belgium
- University of California Davis, Department of Land, Air and Water Resources, Davis, CA, USA
- Forschungszentrum Juelich GmbH, IBG-3: Agrosphere, Juelich, Germany
| | - Andrea Carminati
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
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Carminati A, Zarebanadkouki M, Kroener E, Ahmed MA, Holz M. Biophysical rhizosphere processes affecting root water uptake. ANNALS OF BOTANY 2016; 118:561-571. [PMID: 27345032 PMCID: PMC5055629 DOI: 10.1093/aob/mcw113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/29/2016] [Accepted: 04/08/2016] [Indexed: 05/09/2023]
Abstract
Background Recent advances in imaging techniques now make it possible to visualize the biogeochemical and physical environment around the roots, the rhizosphere. Detailed images of pore space geometry and water content dynamics around roots have demonstrated the heterogeneity of the rhizosphere compared with the soil far from the roots. These findings have inspired new models of root water uptake which aim to describe such small-scale heterogeneity. However, the question remains of how far these image-based findings have really advanced our understanding of how roots extract water from soils. Scope The rhizosphere processes affecting root water uptake are reviewed. Special attention is dedicated to the role of mucilage exuded by roots. Mucilage increases the soil moisture at negative water potentials and it keeps the rhizosphere wet when plants take up water, possibly maintaining the hydraulic connection between roots and soil. However, mucilage becomes viscous and hydrophobic upon severe drying and it limits the water fluxes across the rhizosphere during the rewetting phase. The role of mucilage in maintaining the hydraulic contact between the root surface and the surrounding soil, thereby softening the drops in water potential around the roots in dry soils, remains to be demonstrated. Conclusion Despite detailed images of water content, water fluxes and soil structure in the rhizosphere, a general understanding of how the rhizosphere affects root water uptake is still lacking. The missing elements of the puzzle are the gradient in water potential around roots. Measurements of the xylem water potential at varying soil water potentials and transpiration rates supported by numerical models of root water uptake would allow the estimation of the water potential across the rhizosphere. Such measurements are crucial to comprehend how water enters the roots.
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Affiliation(s)
- A. Carminati
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - M. Zarebanadkouki
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - E. Kroener
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - M. A. Ahmed
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
- Department of Agricultural Engineering, Faculty of Agriculture, University of Khartoum, Khartoum North, 13314 Shambat, Sudan
| | - M. Holz
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
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York LM, Carminati A, Mooney SJ, Ritz K, Bennett MJ. The holistic rhizosphere: integrating zones, processes, and semantics in the soil influenced by roots. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3629-43. [PMID: 26980751 DOI: 10.1093/jxb/erw108] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Despite often being conceptualized as a thin layer of soil around roots, the rhizosphere is actually a dynamic system of interacting processes. Hiltner originally defined the rhizosphere as the soil influenced by plant roots. However, soil physicists, chemists, microbiologists, and plant physiologists have studied the rhizosphere independently, and therefore conceptualized the rhizosphere in different ways and using contrasting terminology. Rather than research-specific conceptions of the rhizosphere, the authors propose a holistic rhizosphere encapsulating the following components: microbial community gradients, macroorganisms, mucigel, volumes of soil structure modification, and depletion or accumulation zones of nutrients, water, root exudates, volatiles, and gases. These rhizosphere components are the result of dynamic processes and understanding the integration of these processes will be necessary for future contributions to rhizosphere science based upon interdisciplinary collaborations. In this review, current knowledge of the rhizosphere is synthesized using this holistic perspective with a focus on integrating traditionally separated rhizosphere studies. The temporal dynamics of rhizosphere activities will also be considered, from annual fine root turnover to diurnal fluctuations of water and nutrient uptake. The latest empirical and computational methods are discussed in the context of rhizosphere integration. Clarification of rhizosphere semantics, a holistic model of the rhizosphere, examples of integration of rhizosphere studies across disciplines, and review of the latest rhizosphere methods will empower rhizosphere scientists from different disciplines to engage in the interdisciplinary collaborations needed to break new ground in truly understanding the rhizosphere and to apply this knowledge for practical guidance.
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Affiliation(s)
- Larry M York
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD, UK
| | - Andrea Carminati
- Division of Soil Hydrology, Georg-August University of Göttingen, 37077 Göttingen, Germany
| | - Sacha J Mooney
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD, UK
| | - Karl Ritz
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD, UK
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD, UK
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Topp CN, Bray AL, Ellis NA, Liu Z. How can we harness quantitative genetic variation in crop root systems for agricultural improvement? JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:213-25. [PMID: 26911925 DOI: 10.1111/jipb.12470] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/21/2016] [Indexed: 05/20/2023]
Abstract
Root systems are a black box obscuring a comprehensive understanding of plant function, from the ecosystem scale down to the individual. In particular, a lack of knowledge about the genetic mechanisms and environmental effects that condition root system growth hinders our ability to develop the next generation of crop plants for improved agricultural productivity and sustainability. We discuss how the methods and metrics we use to quantify root systems can affect our ability to understand them, how we can bridge knowledge gaps and accelerate the derivation of structure-function relationships for roots, and why a detailed mechanistic understanding of root growth and function will be important for future agricultural gains.
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Affiliation(s)
| | - Adam L Bray
- Donald Danforth Plant Science Center, Saint Louis, Missouri 63132, USA
| | - Nathanael A Ellis
- Donald Danforth Plant Science Center, Saint Louis, Missouri 63132, USA
| | - Zhengbin Liu
- Donald Danforth Plant Science Center, Saint Louis, Missouri 63132, USA
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