To examine the adaptive strategies of representative desert oasis plants developed underwater stress and to interpret the relationship between plants and environment in both arid andextreme arid area in China, stable isotopes of hydrogen (D), oxygen (~(18)O), and carbon(~(13)C)were used to infer possible water utilization patterns and water utilization efficiency(WUE) of several dominant species in Minqin arid oasis-desert ecosystem, GanSu, China andEjin extremely arid oasis-desert ecosystem, Inne...