Abstract: With climate warming, the plant phenology in Northwest China desert area has an advancing trend. Based on  34year phenological observation data of 16 plant species in the Minqin desert area of Gansu, and by using one linear trend equation,  this paper analyzed the changes in the duration days of the phenology of these plant species and in the accumulated temperature in the phenological duration. With the increase of air temperature , there was an increasing trend in the duration days of the phenology. The accumulated temperature in the duration of the phenology increased significantly, and spring and autumn were the more sensitive seasons in the changes of the accumulated temperature. The increase or decrease of the accumulated temperature was mainly caused by the increase or decrease of the duration days of phenology, followed by the increase of air temperature, which suggested that the duration days of the phenology of plant species could not be shortened or extended indefinitely with the increase or decrease of air temperature.

Key words: Root sourced signaling, Stomata, Model, Water use efficiency, Water saving