Abstract: The analysis on the phenological characteristics in Minqin desert area based on 34 years phenological observation data showed that there were 2 phenological types in bourgeon period, 4 phenological types in leaf expansion period, 4 phenological types in flowering period, and 2 phenological types in fruit ripeness period. Sin〖JP2〗ce 1974, the mean annual air temperature and the mean monthly air temperature of February, March, and June in the area had a significant warming trend, and the phenology of plants in spring also had an evident advance trend. The bud expanding period of the phenological type ‘low temperature-short sunshine-early budded’ advanced 97 days. From bourgeon period to leaf expansion period, to flowering period, and to fruit ripeness period, the magnitude of phenological advance reduced gradually. The advance of phenology was related with the rising temperature of current month. Two phenological types in bourgeon period and 4 phenological types in leaf expansion period were the differentiation of the adaptation of plants to the air temperature in spring and late fall, while four phenological types in flowering period and 2 phenological types in fruit ripening period were the adaptive responses of the diversities of plant’s flowering period and fruit-ripening period to the local drought environment.

Key words: Umbilical orange, Phosphorus deficiency, Strong light stress, Photoinhibition, Chlorophyll fluorescence, Dissipation mechanism of energy