Combined with materials measured on leaves water potential of Populus euphratica oliv in the process of ecological water delivery in the lower reaches of Tarim River, the influence of ground-water depths and soil salinity on leaves water potential of P. euphratica was analyzed. We found that there was evident negative correlation between the leaves water potential of P. euphratica and ground-water depths. The deeper the ground-water depths were, the lower the leaves water potential of P. euphratica was, the more serious drought stress P. euphratica suffered from. Besides, there was evident negative correlation between the soil salinity and the leaves water potential of P. euphratica. The bigger the soil salinity was, the lower the leaves water potential of P euphratica was, the more serious drought stress was indicated from which P. euphratica suffered. For sections rather distant for Daxihaizi Reservoir as well as for those places of wells rather distant from the river course, ground-water depths and the soil salinity were high; the leaves water potential of P. euphratica was low. The leaves water potential of P. euphratica can reflect the degree at which P. euphratica suffers from drought and salt stress, and has an important reference meaning in analyzing proper ground-water depths for the survival and growth of P. euphratic in the lower reaches of Tarim River.
