新疆塔里木河下游胡杨不同叶形水势变化研究

 以塔里木河下游生态输水后胡杨披针形叶和宽卵形叶作为实验材料,对这两种异形叶水势的日、月变化规律进行了比较研究。结果表明,两种异形叶水势的日变化趋势基本一致,大体上略呈单峰形,在午后14：00—18：00期间出现全天最低值;胡杨两种异形叶水势的月变化趋势也大体相同,表现为从5—8月阿拉干断面胡杨两种异形叶水势均呈先降低后增高的趋势;亚合浦马汗断面B1和B2井位处胡杨叶水势呈逐渐增高趋势,B3井位处胡杨披针形叶水势先降低后增高,7月最低。运用国际通用软件SPSS10.0对气温、地下水埋深与胡杨两种异形叶水势之间的关系进行了相关性分析,发现它们之间存在显著的相关关系。该研究对了解不同环境因子对胡杨两种异形叶水势的影响效应以及生态输水对塔里木河下游不同断面局部小气候的调节和改善作用有一定的参考意义。

Change on Water Potential of Differently Shaped Leaves in Populus euphratica in Lower Reaches of Tarim River, Xinjiang

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.