中文摘要：

利用扫描电镜技术，研究了紫花苜蓿在不同浓度（0，0．3％，0．9％，1．5％）NaCl溶液处理下气孔的适应性变化。通过对苜蓿叶片的气孔长度、气孔宽度、气孔开度、气孔密度及潜在气孔导度指数等气孔特征的观察，探讨气孔特征与耐盐性的关系。结果显示：苜蓿叶片在盐胁迫24h后，除气孔密度变化不明显外，其他指标均随盐浓度的增加而呈下降趋势；盐胁迫24h后气孔密度才开始增加，而其他指标则随盐浓度的不同出现不同程度的恢复现象。这说明在盐胁迫下，苜蓿叶片通过调节气孔大小及开闭来减少水分蒸腾的同时，还通过增加气孔数目来维持光合作用，增强其耐盐性。

英文摘要：

The adaptive changes of stomata of alfalfa （Medicago sativa） under the stress of different NaCl concentration（0,0.3%,0.9% andl.5%） were studied by the technique of scanning electron microscope. The relationship between stomatal feature and salt tolerance were discussed by investigating these indices such as stomatal length, stomatal width, stomatal aperture, stomatal density, potential conductance index and so on. The main conclusions were that except for the change of stomatal density of alfalfa leaves were not very noticeable after the first day under salt stress, other indicators decreased with the increase of salt concentration and treat time. The in- crease in stomatal density did not begin until 24 hours later, while the other indicators recovered to different degrees under different NaC1 stress. The research showed that leaves of alfalfa enhanced its salt tolerance by reducing transpiration through regulating the size and activity of stomata while improving photosynthesis through increasing the number of stomata.