Photoinhibition and Recovery of Photosynthesisin Leaves of Camellia sinensis

Photosynthetic characteristics and chlorophyll fluorescence parameters were determined in tea plant leaves and its disks in natural and simulated light.The results showed that net photosynthetic rate (Pn), apparent quantum yield(AQY),and photochemical efficiency of PSⅡ(Fv/Fm) of tea plant leaves decreased after exposed to midday high irradiance, indicating that photoinhibition occurred.Once light intensity was near to light saturation point Fv/Fm and potential efficiency of PSⅡdeclined, and the extent of reduction increased with the light intensity increased,which testified that photoinhibition of tea plant happens easily. However, the value of Fv/Fm were close to the level observed in the morning, recovering for 2～4 h in weak light after photoinhibition, it indicated that photoinhibition only induced by high light is reversible. The extent of photoinhibition varied with varieties and leaf age in tea plant.