Abstract: In the past few years, many reports showed that the plant phonology trended towards earlier in spring but later in autumn in Europe, America and Asia. So the research on the response of vegetation to climate change would be of great theoretical and practical significances for scientifically understanding climate change and adaptability of vegetation and also for working out the measures to adapt climate change. The Jiuquan Oasis is situated in an arid and semiarid region of northwest China. It is one of the main distribution regions of Populus euphratica, and also a sensitive region to climate change as well as an ideal place to study climate change in arid and semiarid regions. Based on the daily temperature data from the meteorological stations in the Jiuquan Oasis during the period from 1955 to 2010, this paper analyzed the beginning and ending dates of growth season and the beginning date of yellow leaves of P. euphratica, and the response of P. euphratica to global climate change with the methods of climate trending rate, inverse distance weighted interpolation, and Mann-Kendall abrupt change test. The results are as follows: (1) In recent 56 years, the beginning date of growing season of P. euphratica became earlier, but the ending date became later, and the beginning date of yellow leaves was in a clear delaying trend; (2) The results of inverse distance weighted interpolation analysis show that the beginning date of growth season of P. euphratica became earlier in recent 56 years, it, however, was not significantly, and the movingup amplitude was in an order of Dinxing>Yumen>Guazhou>Dunhuang. The ending date of growth season and the beginning date of yellow leaves of P. euphratica were delayed obviously, and they were in orders of Dinxing>Yumen>Dunhuang>Guazhou and Dinxing>Dunhuang>Yumen>Guazhou; (3) The results of abrupt change analysis show that the abrupt changes of beginning and ending dates of growing season and beginning date of yellow leaves of P. euphratica occurred in 1961, 1997 and 2006. Thus it can be seen that the response of P. euphratica to climate change was sensitive in the study area.

Key words: Oasis, Populus euphratica, growing season, yellow leaf, climate change, Jiuquan