关键词: 宽卵形叶, 披针形叶, 胡杨, 水势

Abstract: The water potential of two types of differently shaped leaves, lanceolate leaves and broad-ovate leaves in Populus euphratica, was surveyed for day and month change. It was shown that the water potential of two types exhibits the same diurnal change trend, that is, it submits the single apex pattern, and the minimum value in a day appears to be from 14:00 to 18:00 in the afternoon. At Yahepu and Alagan sections, the month change on water potential of the two types of differently shaped leaves is also represented the same change trend. At Alagan section, the water potential of Populus euphratica leaves firstly decreases and increases subsequently from May to August; at Yahepu section, they gradually increase at wells B1 and B2, at well B3 the water potential of lanceolate leaves in July descends. After analyzing the correlation between the water potential of Populus euphratica leaves and temperature, the depth of groundwater, we found that when the depth of groundwater is shallower, such as at wells B1 and B2 at Yahepu section, there is most evident positive correlation between the water potential and the depth of groundwater. At this time, the depth of groundwater is the key factor influencing the change on water potential of Populus euphratica leaves. On the contrary, when the depth of groundwater is deeper, such as at Alagan section, there is evident negative correlation between the water potential and temperature, and the climate becomes the key factor influencing them. This study has a certain reference meaning on the effect of different environmental factors to the water potential of differently shaped leaves and regulation and improvement of ecological water delivery to small climate at different sections in the lower reaches of Tarim River.

Key words: broad-ovate leaves, lanceolate leaves, Populus euphratica, water potential