Fig. 2
Effects of the heat shock on some characteristics related to photosynthetic system in water spinach. a Initial fluorescence value (F0) and (b) Color visual images of dark-adapted leaves in four cultivars at 25 °C and 42 °C, respectively. c Quantum efficiency of open PSII reaction centers in the dark-adapted state (Fv/Fm) and (d) color visual images of dark-adapted leaves in four cultivars at 25 °C and 42 °C, respectively. e Non-photochemical fluorescence quenching (NPQ), and (f) color visual images of dark-adapted leaves in four cultivars at 25 °C and 42 °C, respectively. Every column in each graph represents the mean (± S.E.) of three replicates. The statistical analyses were conducted in the same variety under different temperature conditions and the significant one was labelled with asterisks (*)