Abstract: Recent researches on the mechanisms of environmental regulation of citrus photosynthesis showed that the photoinhibition of photosynthesis induced by strong light or ultraviolet radiation was related to the inactiveness of PSⅡ reaction center,and photorespiration and xanthophyll cycle played a pivotal role in protecting photosynthetic apparatus.Under temperature stress,lower CO₂ assimilation was mainly due to the decrease of RuBPCase activity and the inactiveness of PSⅡreaction center,and species sensitivity existed.The decline of photosynthetic CO₂ assimilation under high water stress was due to non-stomatal limitation,while that under low water stress was due to stomatal limitation.The citrus growth,yield and quality could be increased by increasing photosynthesis under elevated CO₂ concentration.The mechanisms of photosynthesis regulation by minerals such as nitrogen,phosphorus,sulfur and iron,as well as the effects of salt stress on photosynthesis were discussed,and the directions for future research were suggested.

Key words: Amount of soil water stored, Forest land, Wasteland, Loess Plateau, Annual changes of soil moisture