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用低盐（５０ｍＭＮａＣｌ）和高盐（２００ｍＭＮａＣｌ）溶液分别处理２年生胡杨并与杂种胡杨作比较，以观察盐分胁迫下胡杨的光合反应及生长反应．光合作用及相关参数的测定结果表明，两个树种的ＣＯ２补偿点随盐分浓度的升高而升高，ＲｕＢＰ羧化酶活性随盐分浓度的升高而降低；用高盐处理，在土壤盐分浓度达到０７％ＮａＣｌ时，胡杨的净光合速率仍能在经历一段时间的下降后逐渐回升至相当于对照处理的７０％；而杂种胡杨的光合速率只有在土壤盐分浓度低于０２％ＮａＣｌ时方可恢复，当土壤盐分浓度达到０５％ＮａＣｌ时植株即死亡．叶绿素ａ和ａ／ｂ比率随盐分水平的升高而升高，叶绿素ｂ和类胡萝卜素的含量则随之降低．荧光分析表明，盐分胁迫造成胡杨光合速率下降的原因不是对光合器官的破坏，而是对光合暗反应的抑制．测定叶片伸长速率和叶片数及比叶面积，发现胡杨在盐胁迫的初期主动调节生长速率并脱落部分叶片（在高盐处理后第１天，胡杨叶片的伸长速率下降７０％，至第３天，开始落叶）；在处理过程中，胡杨叶片的比叶面积随盐分水平的升高而降低，说明有叶片肉质化现象．这些均有利于增强抗盐性．
The 2-year-old Populus euphratica was treated with low salt (50mM NaCl) and high salt solution (200mM NaCl) to compare with the photosynthesis and growth responses of Populus euphratica under salt stress. The results of photosynthesis and related parameters showed that the CO2 compensation point of two tree species increased with the increase of salt concentration and the activity of RuBP carboxylase decreased with the increase of salt concentration. When reaching 07% NaCl, the net photosynthetic rate of Populus euphratica gradually rose to 70% of that of the control after a period of decline. However, the photosynthetic rate of Populus euphratica was only lower than 02% NaCl can only resume, when the soil salt concentration reached 0 5% NaCl plant died. The ratio of chlorophyll a and a / b increased with the increase of salinity level, while the contents of chlorophyll b and carotenoid decreased. Fluorescence analysis showed that the reason why the photosynthetic rate of Populus euphratica decreased due to salt stress was not the damage to photosynthetic organs but the inhibition of photosynthetic dark response. The leaf elongation rate, number of leaves and specific leaf area were measured. The results showed that Populus euphratica could actively regulate the growth rate and shed some leaves at the initial stage of salt stress (on the first day after salt treatment, the elongation rate of Populus euphratica leaves decreased by 70% 3 days, the beginning of deciduous); In the process of treatment, the specific leaf area of Populus euphratica leaves decreased with the increase of salt levels, indicating the phenomenon of leaf succulent. These are conducive to enhancing salt resistance.