中文摘要：

采用温室水培法，研究不同浓度NaCl溶液胁迫下（CK：0g／L；S1：1g／L；S2：1．5g／L；S3：2g／L；S4：2．5g／L；S5：3g／L）青檀当年生幼苗叶片的质膜透性、脯氨酸含量、硝酸还原酶活性和根系活力的动态变化。结果表明：S3、S4、S5处理下青檀叶片质膜透性的增加幅度一般高于CK、S1和S2处理；CK和S1处理时叶片脯氨酸含量的增加幅度小于S2、S3、S4、S5处理，而S3、S4和S5处理下叶片的脯氨酸含量显著高于CK、S1和S2；处理过程中青檀幼苗叶片硝酸还原酶活性均表现出波动性，其中S4、S5处理下叶片硝酸还原酶活性呈较明显的双峰曲线形状；根系活力也如此，总体而言，S3、S4和S5处理下青檀幼苗的根系活力显著低于CK。故明显影响青檀幼苗4种生理指标的NaCl溶液临界浓度为2g／L.

英文摘要：

Effects of different levels of NaCl solution （CK： 0 g/I., S1 ： 1 g/L, S2 ： 1. 5 g/L, S3 ： 2 g/L, S4 ： 2.5 g/L, S5 ： 3 g/L） on plasma membrane permeability, proline content, nitrate reductase activity of leaves and root activity of Pteroceltis tatarinowii Maxim. seedlings were investigated under hydroponic culture conditions in a greenhouse. The results indicated that the increases in plasma membrane permeability of CK, S1 and S2 were generally lower than those of S3, S4 and S5. The increases in proline contents of CK and S1 were lower than those of S2, S3, S4 and S5, and proline contents of S3, S4 and S5 were significantly higher than those of CK, S1 and S2. Nitrate reductase activity of each treatment fluctuated as stress time progressed. Both the nitrate reductase activity of S4 and that of S5 versus stress time curves appeared the two-bell shape rather obviously, root activity of each treatment fluctuated as stress time progressed, and generally speaking, root activities of S3, S4 and S5 were highly significantly lower than that of CK. The preliminary conclusion was drawn that 2 g/L was the critical concentration of NaCl solution which obviously affects the plasma membrane permeability, proline content and nitrate reductase activity of leaves as well as root activity of P. tatarinowii seedlings.