A root functional-structural model allows to assess effects of water deficit on water and solute transport parameters

Bauget Fabrice, Protto Virginia, Pradal Christophe, Boursiac Yann, Maurel Christophe. 2023. A root functional-structural model allows to assess effects of water deficit on water and solute transport parameters. Journal of Experimental Botany, 74 (5):erac471 : 1594-1608.

https://doi.org/10.1093/jxb/erac471

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Résumé : Root water uptake is driven by a combination of hydrostatic and osmotic forces. Water transport was characterized in primary roots of maize seedlings grown hydroponically under standard and water deficit (WD) conditions, as induced by addition of 150 g.L -1 polyethylene glycol-8000 (water potential= -0.336MPa). Flow measurements were performed by the pressure chamber technique in intact roots or on progressively cut root system architectures (RSA). To account for the concomitant transport of water and solutes in roots under WD, we developed within realistic RSAs a Hydraulic Tree Model integrating both solute pumping and leak. This model explains the high spontaneous sap exudation of roots grown in standard conditions, the non-linearity of pressure-to flow relationships, and negative fluxes observed under WD conditions at low external hydrostatic pressure. The model also reveals the heterogeneity of driving forces and elementary radial flows throughout RSA, and how this heterogeneity depends on both plant treatment and water transport mode. The full set of flow measurement data obtained in individual roots grown under standard or WD conditions was used in an inverse modeling approach to determine their respective radial and axial hydraulic conductivities. This approach allows to resolve dramatic effects of WD on these two components.

Mots-clés Agrovoc : système racinaire, absorption d'eau, modèle mathématique, pression hydrostatique, physiologie végétale, relation plante eau

Mots-clés libres : MaCS4Plant, OpenAlea, Root hydraulics, Solute transport, Root architecture

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Agences de financement européennes : European Research Council, European Commission

Programme de financement européen : H2020

Projets sur financement : (EU) Targeting Root Hydraulic Architecture to improve Crops under Drought

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