Photosynthetic Responses of Two Woody Halophyte Species to Saline Groundwater Irrigation in the Taklimakan Desert

The study of plant photosynthesis under different degrees drought stress can provide a deeper understanding the mechanism resistance. In Taklimakan Desert, saline groundwater is only local water source with regard to shelterbelt construction and determines growth photosynthetic changes. this study, daily dynamics gas exchange parameters their responses photon flux density at three irrigation levels (W1 = 17.5, W2 25, W3 35 mm) were measured for two main species, i.e., Calligonum mongolicum (C) Haloxylon ammodendron (H). H was better adapted than C. Net rate (PN) mainly related soil status in root system activity layer. July, variations PN transpiration (Tr) C higher H. increased use efficiency (WUE) increases PN, while decreased Tr obtain WUE. Either or H, reduced low light metabolic capacity, thus adaptability potential. We suggest prerequisite physiological mechanisms possible morphological adjustments required adapt species desert conditions.