Plant responses to rising vapor pressure deficit

Abstract

Summary Recent decades have been characterized by increasing temperatures worldwide, resulting in an exponential climb in vapor pressure deficit (VPD). VPD has been identified as an increasingly important driver of plant functioning in terrestrial biomes and has been established as a major contributor in recent drought‐induced plant mortality independent of other drivers associated with climate change. Despite this, few studies have isolated the physiological response of plant functioning to high VPD, thus limiting our understanding and ability to predict future impacts on terrestrial ecosystems. An abundance of evidence suggests that stomatal conductance declines under high VPD and transpiration increases in most species up until a given VPD threshold, leading to a cascade of subsequent impacts including reduced photosynthesis and growth, and higher risks of carbon starvation and hydraulic failure. Incorporation of photosynthetic and hydraulic traits in ‘next‐generation’ land‐surface models has the greatest potential for improved prediction of VPD responses at the plant‐ and global‐scale, and will yield more mechanistic simulations of plant responses to a changing climate. By providing a fully integrated framework and evaluation of the impacts of high VPD on plant function, improvements in forecasting and long‐term projections of climate impacts can be made.

High Vapor Pressure Deficit Decreases the Productivity and Water Use Efficiency of Rain‐Induced Pulses in Semiarid Ecosystems

“…Whereas our conceptual hypothesis (Figure 1) assumes that GEP and G canopy have similar sensitivity to VPD, previous studies have shown that differences in the VPD sensitivity of assimilation and stomatal conductance cause ecosystem-scale intrinsic water use efficiency (iWUE = GEP/G sfc ) to vary with environmental conditions (Beer et al, 2009;Grossiord et al, 2020;Zhang et al, 2019). The relatively high VPD conditions at these sites constrain both GEP and G sfc , causing iWUE to become invariant or decline with further increases in VPD (Grossiord et al, 2020;Zhang et al, 2019). Additionally, our comparison of events under high VPD (~4.5 kPa) and moderate VPD (~3.5 kPa) spans a relatively narrow range of VPD for which previous research on a site in this study (US-Wkg) demonstrates that iWUE did not show a clear response to increasing VPD (Zhang et al, 2019).…”

“…In response to increasing VPD, plants decrease stomatal conductance to reduce water loss (Buckley, 2019;Collatz et al, 1991;Leuning, 1995). These plant responses can decrease ecosystem-scale canopy conductance, GEP, and ET (Anthoni et al, 1999;Ding et al, 2018;Grossiord et al, 2020;Novick et al, 2016;Sulman et al, 2016;Wharton et al, 2009;Zhang et al, 2019). Additionally, physical manifestations of high VPD (warmer temperatures; increased evaporative demand) may influence ET by increasing rates of soil and interception evaporation and may stimulate temperature-dependent autotrophic and heterotrophic respiration during periods of sufficient water availability.…”

Exogenous Abscisic Acid Can Influence Photosynthetic Processes in Peas through a Decrease in Activity of H+-ATP-ase in the Plasma Membrane

“…Photosynthesis is the basis of plant productivity and participates in tolerance to stressors. Its activity has both positive and negative controls through regulation of CO 2 entry by stomata [ 18 ]; e.g., stomata can be opened by decreased concentration of CO2 [ 18 , 19 , 20 , 21 ] or high intensity light [ 21 ] and closed by increased concentration of CO 2 [ 18 , 22 , 23 ] or development of vapor pressure deficit [ 21 , 23 , 24 ]. Some phytohormones, namely indole-3-acetic acid [ 18 ] and cytokinins [ 18 , 25 , 26 , 27 ], participate in the stomata opening; in particular, cytokinins eliminate the stomata closing induced by increased CO 2 concentration [ 18 ].…”

Remote sensing of the impact of flash drought events on terrestrial carbon dynamics over China

“…LAI is the green leaf area per unit ground area, which can be used to detect changes of vegetation state (e.g., defoliation). Photosynthetic CO 2 uptake is influenced by stomatal conductance, Rubisco activity, and LAI [ 34 ]. When the photosynthetic process is suppressed during drought, the vegetation structure may remain unchanged [ 35 ].…”