Thermal Analysis of Stomatal Response under Salinity and High Light

Abstract

A non-destructive thermal imaging method was used to study the stomatal response of salt-treated Arabidopsis thaliana plants to excessive light. The plants were exposed to different levels of salt concentrations (0, 75, 150, and 220 mM NaCl). Time-dependent thermograms showed the changes in the temperature distribution over the lamina and provided new insights into the acute light-induced temporary response of Arabidopsis under short-term salinity. The initial response of plants, which was associated with stomatal aperture, revealed an exponential growth in temperature kinetics. Using a single-exponential function, we estimated the time constants of thermal courses of plants exposed to acute high light. The saline-induced impairment in stomatal movement caused the reduced stomatal conductance and transpiration rate. Limited transpiration of NaCl-treated plants resulted in an increased rosette temperature and decreased thermal time constants as compared to the controls. The net CO2 assimilation rate decreased for plants exposed to 220 mM NaCl; in the case of 75 mM NaCl treatment, an increase was observed. A significant decline in the maximal quantum yield of photosystem II under excessive light was noticeable for the control and NaCl-treated plants. This study provides evidence that thermal imaging as a highly sensitive technique may be useful for analyzing the stomatal aperture and movement under dynamic environmental conditions.

Environmental Stress and Plants

“…This study represents for the first time a full transcriptomic analysis of sugar beet under salt stress that involves a potential competitive endogenous RNA (ceRNA) network, thus providing a basis to study the potential functions of lncRNAs/circRNAs. Orzechowska and colleagues [24] used a nondestructive thermal imaging method to study the stomatal response of Arabidopsis thaliana treated with salt and excessive light. The initial plant response associated with stomatal opening shows an exponential increase in temperature kinetics.…”

Drought stress tolerance mechanisms and their potential common indicators to salinity, insights from the wild watermelon (Citrullus lanatus): A review

“…The timely stomatal closure of the wild watermelon results in lower internal CO 2 which then results in significantly reduction of the photosynthesis activity, and this can be thought to contribute to the survival of the plant as the energy is focused mostly in maintaining the plant under drought stress ( Figure 1 ). The stomatal response of the wild watermelon to drought has shown similar trends as stomatal response to salinity in other crop species like melon, bottle gourd, pumpkins, luffa studied by Modarelli et al., 2020 ) and Arabidopsis thaliana ( Orzechowska et al., 2021 ) thus the timely stomatal closure can be considered an important tolerance mechanisms for the wild watermelon during both drought and possibly for salinity stress too. However, in terms of salinity tolerance, precise physiological mechanisms need to be established in addition to safe guarding photosynthetic machinery through stomatal closure.…”

“…Under drought stress where soil moisture is limited and/or high atmospheric evaporative demand, partial or complete stomatal closure allows plants to maintain a favorable water balance while limiting the carbon gain. Salinity-generating stress also results in stomatal regulation, an important strategy that enables plants to cope with NaCl-induced osmotic and ionic stresses ( Orzechowska et al., 2021 ). Plants exposed to salinity close their stomata to protect against water loss.…”

Evaluation of Tyrosinase and Carcinoma Inhibitory Activities from the Extract of Wedelia trilobata (L.) Hitchc

“…This situation might be the result of an osmotic and toxic action. Salt has disrupted the plantʼs osmotic equilibrium, resulting in lower water intake and stomatal closure, which limits transpiration 16 . Salt induction results in the buildup of Na + and Clions in root tissues as well as an imbalance in the acquisition of other nutrients.…”