Fig. 4. The effect of heat stress on stomatal behavior and the capacity for photosynthesis.

a Scanning electron microscopy (SEM) images of stomata from plants before (left panels) and after (right panels) 4 h of heat stress. b Changes in stomatal apertures under heat stress. Changes in the c net photosynthesis rate (Pn), d intercellular CO₂ concentration (Ci), e stomatal conductance (Gs), and f transpiration rate (Tr) were determined following 18 h of recovery after heat treatment. Data are shown as the means of six replicates with SEs. Different letters indicate significant differences between treatments, according to one-way ANOVA and Tukey’s multiple range test (P < 0.05).