A modeling approach to determine the importance of dynamicregulation of plant hydraulic conductivities on the water uptakedynamics in the soil-plant-atmosphere system

tWe present here a new model, PlaNet-Maize, with the purpose of investigating the effect of environmentaland endogenous factors on the growth and water relations of the maize plant. This functional–structuralplant model (FSPM) encompasses the entire soil-plant-atmosphere continuum with a sub-organ resolu-tion. The model simulates the growth and development of an individual maize plant and the flux of waterthrough the plant structure, from the rhizosphere to the leaf boundary layer. Leaf stomatal conductanceand root radial and axial conductivities are considered as functions of local water potential. Finally, asimple carbon allocation rule is included in the model to allow the feedback effect of water deficit onplant growth. The model was successfully used to reproduce experimental plant hydraulic behavior inresponse to water deficit. The quantitative contribution of leaf conductance and root conductivities wereassessed individually and in combination.Our results highlight the importance of regulating hydraulic properties in FSPM as these can stronglymodify the water uptake dynamics and lead to emerging water uptake behaviors. The modeling resultsalso indicate that plant hydraulic properties can theoretically be tailored to improve plant water use inchallenging environments