Water uptake by plant roots: an integration of views

Steudle, Ernst

doi:10.1007/978-94-017-2858-4_9

Cited by 174 publications

(296 citation statements)

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“…The decrease in expression was substantial and of similar magnitude to the parallel decrease in root Lp as determined through exudation experiments, where osmotic forces drive water flow along the cell to cell path including PIP AQPs (Steudle, 2000) Together, these data suggest that the decrease in root Lp in rice plants following removal of the entire shoot and transpiring surface involved regulation of plasma membrane-localized AQPs, at least at the level of gene transcript abundance. Similarly, Ahamed et al (2012) observed for rice that the expression of most PIP AQPs in roots decreased in response to shoot removal, though analyses were carried out 1 d following shoot removal.…”

Section: Rice Root Pip Aqp Expression In Response To Shoot Removalsupporting

confidence: 58%

“…This contribution varies with species, time of day and environmental conditions (e.g. Frensch and Steudle, 1989;Zhu and Steudle, 1991;Steudle and Peterson, 1998;Steudle, 2000;Bramley et al, 2009;Fricke, 2010, 2011;Aroca et al, 2012). There is increasing evidence which points to a role for AQPs in also regulating the root hydraulic response to rather sudden changes in shoot transpirational water loss or to 'catastrophic' events such as injury and removal of the shoot (Levin et al, 2009;Almeida-Rodriguez et al, 2011;Sakurai-Ishikawa et al, 2011;Vandeleur et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Rapid changes in root hydraulic conductivity and aquaporin expression in rice (Oryza sativaL.) in response to shoot removal – xylem tension as a possible signal

Meng

Walsh

Fricke

2016

Ann Bot

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Background and Aims It is not clear how plants adjust the rate of root water uptake to that of shoot water loss. The aim of this study on rice was to test the idea that root aquaporins (AQPs) and xylem tension play a role in this adjustment.Methods Three-week-old rice (Oryza sativa L.) plants, which were grown hydroponically, had their entire shoot system removed, and root hydraulic conductivity (exudation analyses) and gene expression (quantitative real-time PCR) of root plasma membrane intrinsic aquaporin proteins (PIPs) was followed within 60 min after shoot excision.Key Results All three PIP1 genes (OsPIP1;1, OsPIP1;2 and OsPIP1;3) and three of the six PIP2 genes tested (OsPIP2;1, OsPIP2;4 and OsPIP2;5) showed a rapid (5 min) and lasting (60 min) decrease in gene expression. Expression decreased by up to 85 % within 60 min. The other three PIP2 genes tested (OsPIP2;2, OsPIP2;3 and OsPIP2;6) showed a varied response, with expression decreasing either only initially (5 min) or after 60 min, or not changing at all. In a follow-up experiment, plants had their shoot system removed and the detached root system immediately connected to a vacuum pump through which some tension (80 kPa) was applied. This application of tension prevented any significant decrease in PIP expression.Conclusions Shoot removal leads to a rapid decrease in expression of all PIP1s and some PIP2s in roots of rice. Xylem tension plays some role in this process.

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Section: Rice Root Pip Aqp Expression In Response To Shoot Removalsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Rapid changes in root hydraulic conductivity and aquaporin expression in rice (Oryza sativaL.) in response to shoot removal – xylem tension as a possible signal

Meng

Walsh

Fricke

2016

Ann Bot

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“…The adequacy of the root system to supply water to leaves can be estimated by the root hydraulic conductance per leaf unit surface area (K RL ) [16]. According to the composite transport model [32], root water supply to the shoot may change according to the shoot demand owing to an adjustment of root hydraulic conductance. Water deficit reduces root growth and the capacity of roots to take up water by suberisation [20,26,33].…”

Section: Introductionmentioning

confidence: 99%

“…Water deficit reduces root growth and the capacity of roots to take up water by suberisation [20,26,33]. Therefore, the root hydraulic conductance may vary in response to external (drought or salinity) or internal (nutritional state, water status, demand of water) factors [32], but the extent by which changes in root morphology influence root hydraulic conductance still needs to be determined.…”

Section: Introductionmentioning

confidence: 99%

Morphological and functional variability in the root system ofQuercus ilexL. subject to confinement: consequences for afforestation

2006

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-We examined root morphological and functional differences caused by restrictions imposed to vertical growth in the root system of holm oak (Quercus ilex L.) seedlings to assess the consequences of using nursery containers in the development of a confined root system for this species. Thus, root morphological, topological and functional parameters, including hydraulic conductance per leaf unit surface area (K RL ), were investigated in one-year seedlings cultivated in three PVC tubes differing in length (20, 60 and 100 cm). Longer tubes showed greater projected root area, root volume, total and fine root lengths, specific root length (SRL) and K RL values than did shorter tubes. On the other hand, the length of coarse roots (diameter > 4.5 mm) and the average root diameter were greater in shorter tubes. The strong positive correlation found between K RL and SRL (r = +0.69; P < 0.001) indicated that root thickness was inversely related to water flow through the root system. We concluded that root systems developed in longer tubes are more efficient for plant water uptake and, therefore, changes in root pattern produced in standard forest containers (i.e. about 20 cm length) may in fact prevent a proper establishment of the holm oak in the field, particularly in xeric environments.Quercus ilex L. / root hydraulic conductance / root morphology / afforestation Résumé -Variabilité morphologique et fontionnelle du système racinaire de Quercus ilex L. soumis au confinement : conséquences pour les reboisements. Nous avons examiné les différences morphologiques et fonctionnelles qui ont été induites par des restrictions imposées au développe-ment vertical des racines de plantules de chêne (Quercus ilex L.). Les paramètres morphologiques, topologiques et fonctionnels du système racinaire, et aussi la conductivité hydraulique par unité de surface foliaire (K RL ), ont été recherchés sur des plantules d'une année cultivées dans des tubes de PVC de différentes longueurs (20, 60 et 100 cm). Les tubes les plus longs présentent des surfaces projetées de racines, des volumes racinaires, des longueurs de racines fines et totales, des longueurs spécifiques SRL et des K RL supérieurs à ceux des tubes courts. Inversement, dans les tubes courts se trouvent des racines de plus fortes sections avec les longueurs les plus grandes de grosses racines (diamètre > 4,5 mm). La forte corrélation positive trouvée entre K RL et SRL (r = +0, 69 ; P < 0, 001) a indiqué que la grosseur de la racine est inversement proportionnelle au flux d'eau transporté. On conclut que les systèmes racinaires développés dans des tubes plus longs sont plus efficaces dans l'extraction de l'eau et, par conséquence, les modifications dans le modèle du développement des racines qui ont été produites dans les conteneurs standards (e.g. environ 20 cm de longueur) pouvaient empêcher l'établissement approprié du chêne in situ, surtout dans des environnements à fortes contraintes hydriques.Quercus ilex L. / conductance hydraulique racinaire / morphologie racinaire...

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“…Water-uptake from soil by a plant's root system has been studied extensively during the past seven decades (Philip, 1957;Gardner, 1960;Cowan, 1965;Landsberg & Fowkes, 1978;Molz, 1981;Passioura, 1988;Steudle & Peterson, 1998;Doussan et al, 1998;Steudle, 2000;Raats, 2007;Roose & Schnepf, 2008;Stroock et al, 2014). A single root has been historically modelled as an infinitely long porous cylinder with a two dimensional radial flow around the cylindrical root (Gardner, 1960;Landsberg & Fowkes, 1978;Ratts, 2007).…”

Section: Introductionmentioning

confidence: 99%

Minimizing hydraulic resistance of a plant root by shape optimization

Chandrashekar

Chen

2016

Mechanics Research Communications

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Analytical solution of the pressure field for water uptake through a composite root, coupled with fully saturated soil is derived by using the slender body approximation. It is shown that in general, the resistance of the root and soil are not additive. This result can play a very important role in modelling water uptake through plant roots and determination of hydraulic resistances of plant roots. Optimum plant root structure that minimizes a single root's hydraulic resistance is also studied in this work with the constraint of prescribed root volume. Hydraulic resistances under the slender body approximation and without such a limitation are considered. It is found that for large stele-to-cortex permeability ratio, there exists an optimum root length-to-base-radius ratio that minimizes the hydraulic resistance.A remarkable feature of the optimum root structure is that the optimum dimensionless stele conductivity depends only on a single geometrical parameter, the stele-to-root base-radius ratio. Once the stele-to-root base-radius ratio and the stele-to-cortex permeability ratio are given, the optimum root length-to-radius ratio can be found. While these findings remain to be verified by experiments for real plant roots, they offer theoretical guidance for the design of bio-inspired structures that minimizes hydraulic resistance for fluid production from porous media.ii ACKNOWLEDGMENTS I would like to sincerely thank Dr. Chen, my thesis advisor, for the encouragement and support that he has provided at every step and for being a great teacher.

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Water uptake by plant roots: an integration of views

Cited by 174 publications

References 56 publications

Rapid changes in root hydraulic conductivity and aquaporin expression in rice (Oryza sativaL.) in response to shoot removal – xylem tension as a possible signal

Rapid changes in root hydraulic conductivity and aquaporin expression in rice (Oryza sativaL.) in response to shoot removal – xylem tension as a possible signal

Morphological and functional variability in the root system ofQuercus ilexL. subject to confinement: consequences for afforestation

Minimizing hydraulic resistance of a plant root by shape optimization

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