Diversity in stomatal function is integral to modelling plant carbon and water fluxes

Abstract

Stomatal pores on leaf surfaces respond to environmental and physiological signals to regulate leaf gas exchange. Mathematical models can predict stomatal conductance (g ), with one parameter (m or g) reflecting the sensitivity of g to the photosynthetic rate (A), atmospheric carbon dioxide concentration and atmospheric humidity, and a second parameter (g) representing the minimum g . Such models are solved iteratively with a photosynthesis model to form the core of many models of crop or ecosystem carbon and water fluxes. For three decades, g models have frequently been used assuming fixed parameter values for m or g and g across species and major plant functional types. This study of temperate tree species reveals significant interspecific variation in stomatal function. Applying species-specific parameterizations substantially reduced error in model predictions of g by 34 to 64% and A by 52 to 60% and resulted in significant correlation between modelled and measured values. This work challenges the long-held assumption of fixed parameter values and, in doing so, suggests an approach for reducing modelling error across a wide range of ecological and agricultural applications.

The response of stomatal conductance to seasonal drought in tropical forests

“…With the observed large inter‐tree‐specific variation in slope parameter, we further showed that accounting for such biotic variation led to improved model estimates of g s (Figure ). This finding is consistent with previous work, which illustrated the diversity in stomatal slope is integral to modelling plant water fluxes (Wolz et al, ). Our results did not show that accounting for the abiotic (e.g.…”

Detecting the fingerprint of drought across Europe’s forests: do carbon isotope ratios and stem growth rates tell similar stories?

“…While recent work has shown that stomatal regulation and function can vary considerably among temperate trees (Wolz et al 2017), carbon isotope changes in response to drought were remarkably consistent across a diverse group of species and a range of environmental conditions (Fig. 2a).…”

Ecosystem processes at the watershed scale: Influence of flowpath patterns of canopy ecophysiology on emergent catchment water and carbon cycling

“…It is well established that different tree species vary in water use strategies and carbon assimilation based on physiological characteristics (e.g., xylem anatomy, stomatal conductance, and root architecture) and leaf display (e.g., Ford, Hubbard, & Vose, ; Ford, Laseter, Swank, & Vose, ; Pataki & Oren, ; Pataki, Oren, Katul, & Sigmon, ; Vose et al, ; Wolz, Wertin, Abordo, Wang, & Leakey, ). In terms of the regulation of water use, isohydric species such as red maple ( Acer rubrum ) , tulip poplar ( Liriodendron tulipifera ), and evergreen trees with tracheid xylem including loblolly pine ( Pinus taeda ) have relatively high peak water use but reduce transpiration rapidly with decreasing atmospheric humidity to maintain leaf pressure.…”

“…Results suggest that the well-known zonation of forest communities over hydrologic gradients is not just a local adaptation but also provides a property that regulates hillslope to catchment-scale behaviour of water use and drought resistance. KEYWORDS carbon cycling, ecohydrologic behaviour, ecosystem resistance, functional organization, water use, watershed 1 | INTRODUCTION It is well established that different tree species vary in water use strategies and carbon assimilation based on physiological characteristics (e.g., xylem anatomy, stomatal conductance, and root architecture) and leaf display (e.g., Ford, Hubbard, & Vose, 2010;Ford, Laseter, Swank, & Vose, 2011;Pataki & Oren, 2003;Pataki, Oren, Katul, & Sigmon, 1998;Wolz, Wertin, Abordo, Wang, & Leakey, 2017). In terms of the regulation of water use, isohydric species such as red maple (Acer rubrum), tulip poplar (Liriodendron tulipifera), and evergreen trees with tracheid xylem including loblolly pine (Pinus taeda) have relatively high peak water use but reduce transpiration rapidly with decreasing atmospheric humidity to maintain leaf pressure.…”