First steps towards an explicit modelling of ABA production and translocation in relation with the water uptake dynamics

Abstract

Water flow in the plant continuum is thought to be controlled by the leaf, xylem and the root radial conductances. Leaf conductance is widely recognized as the master control in the system as it can act as a switch in the water flow, even under high transpiration demand. The control of the stomatal aperture by the plant has been the object of numerous research projects since decades and different models have been developed to study stomatal regulation. The plant hormone abscisic acid (ABA) produced in the leaves acts as an endogenous signal triggering stomatal closure, but is also thought to act as a long distance signal that is produced by roots experiencing water deficit. However, the relative contributions of leaf-supplied ABA, root-supplied ABA and xylem water potential in the regulation of water flow remains a matter of controversy. Using a novel functional structural plant model (PlaNet-Maize-ABA), we report here a first attempt to explicitly simulate ABA production, degradation, translocation in all plant organs and their effect on the transpiration flow.