Abstract:The plants growing at the Tarim Desert Highway shelterbelt has been safe-guarding the highway located in hinterland of Taklimakan Desert, by preventing sand erosion and sand intrusion. Thus, the sustainability of the green belt is vital to the maintenance of the highway. The objective of this study is on the impact of drought stress to the photosynthetic accumulation of shelterbelt plants. LI-6400 portable photosynthesis system was used to measure the photosynthetic characteristics of three plants (Haloxylon ammodendron, Tamarix ramosissima and Calligonum arborescens) under different water conditions. The results showed that: the net photosynthetic rate, transpiration rate, water use efficiency, light use efficiency and potential photosynthesis capacity of C. arborescens are most sensitive to water deficit, while T. ramosissima was the least sensitive among the three species. The differences in photosynthetic responses of these three species to drought dress indicated that the three species have different adaptive mechanisms to water deficit. In addition, under drought stress, water use efficiency of all three species did not improve and their light use efficiency was even reduced. Under drought and high temperature conditions, T. ramosissima, the only C3 species, maintained more stable photosynthetic accumulation and water use efficiency than H. ammodendron and C. arborescens, the two C4 species, which demonstrated that C3 plants also could have high ability of drought resistance than C4 plants under desert conditions. Although water deficit has inhibited, to certain degree, the photosynthesis ability of all three species, it did not have irreversible impact on their photosynthetic accumulation. Therefore, all plants have demonstrated high ability of drought tolerance, and this ability implies that there might still room for water-saving in shelterbelts irrigation.