Title: A Dynamic Optimality Principle for Water Use Strategies Explains Isohydric to Anisohydric Plant Responses to Drought

Abstract

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 a 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 soil hydrological balance and is 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.

Authors:

Mrad, Assaad ^[1]; Sevanto, Sanna Annika  ^[2];

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Domec, Jean -Christophe ^[3]; Liu, Yanlan ^[1]; Nakad, Mazen ^[1]; Katul, Gabriel ^[1]

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+ Show Author Affiliations

1. Duke Univ., Durham, NC (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Duke Univ., Durham, NC (United States); UMR INRA-ISPA 1391, Gradignan (France)

Publication Date:

2019-08-28

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1579698

Report Number(s):

LA-UR-19-22773
Journal ID: ISSN 2624-893X

Grant/Contract Number:  

89233218CNA000001; NSF-EAR-1344703; NSF-AGS-1644382; NSF-IOS-1754893

Resource Type:

Accepted Manuscript

Journal Name:

Frontiers in Forests and Global Change

Additional Journal Information:

Journal Volume: 2; Journal ID: ISSN 2624-893X

Publisher:

Frontiers Media S.A.

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; biological science; Earth sciences; drought; dynamic optimality; isohydricity and anisohydricity; photosynthesis; plant hydraulics; stomata; transpiration; water use strategy