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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. For. Glob. Change | doi: 10.3389/ffgc.2019.00049

A dynamic optimality principle for water use strategies explains isohydric to anisohydric plant responses to drought

 Assaad Mrad1*,  Sanna Sevanto2, Jean-Christophe Domec1, 3,  Yanlan Liu1, Mazen Nakad1 and  Gabriel G. Katul1
  • 1Nicholas School of the Environment, Duke University, United States
  • 2Earth and Environmental Sciences, Los Alamos National Laboratory, United States
  • 3Atmosphere Plant Soil Interactions (INRA), France

Optimality principles that underlie models of stomatal kinetics require identifying and formulating the gain and the costs involved in opening stomata. While the gain has been linked to larger carbon acquisition, there is still debate as to the costs that limit stomatal opening. This work presents an Euler-Lagrange framework that accommodates water use strategy and various costs through the formulation of constraints. The reduction in plant hydraulic conductance due to cavitation is added as a new constraint above and beyond the hydrological balance and analyzed for three different types of whole-plant vulnerability curves. Model results show that differences in vulnerability curves alone lead to relatively iso- and aniso-hydric stomatal behavior. Moreover, this framework explains how the presence of competition (biotic or abiotic) for water alters stomatal response to declining soil water content. This contribution corroborates previous research that predicts that a plant's environment (e.g., competition, soil processes) significantly affects its response to drought and supplies the required mathematical machinery to represent this complexity. The method adopted here disentangles cause and effect of the opening and closure of stomata and complements recent mechanistic models of stomatal response to drought.

Keywords: drought, Dynamic optimality, Isohydric, Photosynthesis, plant hydraulics, stomata, transpiration, Water use strategies, competition

Received: 28 Mar 2019; Accepted: 12 Aug 2019.

Edited by:

Heather R. McCarthy, University of Oklahoma, United States

Reviewed by:

Cameron D. McIntire, University of New Mexico, United States
Luiza Maria T. Aparecido, Arizona State University, United States  

Copyright: © 2019 Mrad, Sevanto, Domec, Liu, Nakad and Katul. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Assaad Mrad, Nicholas School of the Environment, Duke University, Durham, 27708, North Carolina, United States,