Diurnal Photosynthesis and Photoinhibition of Rice Leaves with Chlorophyll Fluorescence Heat shock stress on photosystem Ⅱ in white cucumbers probed by the fast fluoresence rise OJIP Performance index: An expeditious tool to screen for improved drought resistance in the Lathyrus genus Effects of high temperature on leaf photosynthetic characteristics and photosystemⅡ photochemical activity of kernel-used apricot.