Abstract:Nitraria sphaerocarpa Maxim.is a typical desert plant,which often forming N.sphaerocarpa bubbles with varying sizes.To further explore the photosynthetic adaptation mechanism of N.sphaerocarpa canopy for the arid desert environment,we use the measurement system of LI-8100 carbon flux and the modified assimilation chamber to study the photosynthetic characteristics of N.sphaerocarpa canopy in the mid-July and mid-August.The results showed that:the soil respiration rate and soil evaporation rate in mid-July were both higher than those in mid-August;the canopy photosynthetic rate and water use efficiency in mid-August decrease compared with those in mid-July,and the difference was significant (P<0.05).Path analysis between canopy photosynthetic rates of N.sphaerocarpa and environmental factors indicated that photosynthetic active radiation was the major factor to affect canopy photosynthetic rates of N.sphaerocarpa,and play a direct role in canopy photosynthetic rates in mid-July and mid-August;meanwhile,the interaction of air relative humidity,air temperature and photosynthetic active radiation also has a greater influence on canopy photosynthetic rates of N.sphaerocarpa in mid-August.Canopy photosynthetic rate of N.sphaerocarpa in mid-July under high temperature and strong light environment was higher than that in mid-August,which indicated that N.sphaerocarpa had a highly adaptability to the high temperature and light intensity in desert environment.