A constraint–relaxation–recovery mechanism for stomatal dynamics

Abstract

Models of guard cell dynamics, built on the OnGuard platform, have provided quantitative insights into stomatal function, demonstrating substantial predictive power. However, the kinetics of stomatal opening predicted by OnGuard models were threefold to fivefold slower than observed in vivo. No manipulations of parameters within physiological ranges yielded model kinetics substantially closer to these data, thus highlighting a missing component in model construction. One well‐documented process influencing stomata is the constraining effect of the surrounding epidermal cells on guard cell volume and stomatal aperture. Here, we introduce a mechanism to describe this effect in OnGuard2 constructed around solute release and a decline in turgor of the surrounding cells and its subsequent recovery during stomatal opening. The results show that this constraint–relaxation–recovery mechanism in OnGuard2 yields dynamics that are consistent with experimental observations in wild‐type Arabidopsis, and it predicts the altered opening kinetics of ost2 H+‐ATPase and slac1 Cl− channel mutants. Thus, incorporating solute flux of the surrounding cells implicitly through their constraint on guard cell expansion provides a satisfactory representation of stomatal kinetics, and it predicts a substantial and dynamic role for solute flux across the apoplastic space between the guard cells and surrounding cells in accelerating stomatal kinetics.

When everything changes at once: finding a new normal after genome duplication

“…Although AHA1 has diverse functions throughout the plant (e.g. [67][68][69][70][71]), it is very important in guard cell opening (and closing) [65,69,[72][73][74]. While AHA1 does not seem to be under selection in Ca.…”

On-site identification of ozone damage in fruiting plants using vapor-deposited conducting polymer tattoos

“…Biochemical assays require time and dedicated facilities and cannot be easily performed on-site or on demand, meaning that temporal information is lost during the process of sampling, digesting, and assaying field samples. External ozone gas detectors that are inserted into the soil do not reveal tissue damage (10), and stomatal flow detectors that are adhered to plant surfaces (11,12) only yield useable data after months or years of continuous monitoring (13,14).…”

Optimized Protocol for OnGuard2 Software in Studying Guard Cell Membrane Transport and Stomatal Physiology

“…OnGuard incorporates all of the fundamental properties in guard cell membrane transport and metabolism, and is sufficient to accurately simulate a wide range of physiological activities of guard cells and corresponding stomatal movements. It has been shown capable of the real predictive power needed to yielded many unexpected outputs (Chen et al, 2012;Wang et al, 2012) and testable results (Chen et al, 2012;Wang et al, 2012;Wang et al, 2014a;Minguet-Parramona et al, 2016;Wang et al, 2017;Jezek et al, 2019). The advances made with OnGuard have led to a more profound understanding of the complex regulatory mechanisms underpinning how guard cells respond to the environmental changes (Wang et al, 2017).…”

“…It provides a reliable tool to investigate the mechanistic link between guard cell membrane transport and foliar transpiration. Recently, a constraintrelaxation-recovery mechanism (CRR) that simulates the effect of the surrounding epidermal cells on guard cell volume was introduced into the OnGuard2 system (Jezek et al, 2019). As the software upgrades and features updated, several operations is also changed.…”