Abstract：By using Li-6400 portable photosynthesis system produced by LI-COR company,six-year old Sapium discolor,Liquidambar formosana and Choerospondias axillaries,in the upper and middle reaches of Dongjiang River were selected as experimental materials for comparative studies on photosynthetic and physiological parameter characteristics,such as photosynthesis,transpiration,and water use efficiency,etc,and photosynthesis and photo-response characteristic of the three plantation tree species in natural habitats.The results showed that the photosynthesis-light response curves of the three species could be well simulated by the non-rectangular hyperbola model(R2>0.98) and exponential curves(R2>0.98).Apparent quantum efficiency and dark respiration rate in a descending order of Sapium discolor,Choerospondias axillaries,Liquidambar formosana,the photosynthetic ability of Sapium discolor was higher than that of Choerospondias axillaries,Liquidambar formosana,while Sapium discolor showed high photosynthate consumption.There were significant differences in maximum net photosynthetic rate between Sapium discolor and Choerospondias axillaries,Liquidambar formosana(P<0.05).The three species were between shade plants and sun plants,specifically,Sapium discolor has high adaptability to high light,and shows great adaptable and plastic to different light intensity,and wider light ecological amplitude,and has higher ability to use low light and high light.The net photosynthetic rate of Sapium discolor was highest,followed by Choerospondias axillaris,Liquidambar formosana,the transpiration rate in a descending order of Sapium discolor,Choerospondias axillaris,Liquidambar formosana,and water use efficiency in a descending order of Liquidambar formosana,Sapium discolor,Choerospondias axillaris.
2010, Vol. 8 
