罗祺圆　许涵杰　郭鹏

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24 h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24 h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。

关键词： 紫花苜蓿；气孔；盐胁迫

中图分类号：S963.22+3.3 文献标识码：A DOI 编码：10.3969/j.issn.1006-6500.2016.04.004

Abstract： The adaptive changes of stomata of alfalfa （Medicago sativa） under the stress of different NaCl concentration（0，0.3%，0.9% and1.5%） 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 increase in stomatal density did not begin until 24 hours later，while the other indicators recovered to different degrees under different NaCl 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.

Key words： alfalfa （Medicago sativa）； stomata； salt stress

土壤盐渍化已成为一个全球性的问题，据粮农组织（FAO）统计，世界各地的盐渍地已超过8.0 × 109 hm2[1]。世界范围内至少20%的耕地正遭受着不同程度的盐渍化危害，我国盐碱化土地面积也近1亿hm2[2]。随着全球环境污染加剧，人口数量增多，水资源日趋匮乏，越来越多的回收水和其他二级水源被用于灌溉，这将会使更多的土地资源受到盐害的威胁[3]。土壤盐分对植物的伤害主要是过多的盐离子打破了植物自身的离子和渗透平衡，造成离子毒害，影响植物的正常生存、生长和繁殖[4]。此外，植物体内产生和积累的活性氧（ROS）引起的氧化胁迫等带来的次生胁迫，同样对植物造成伤害[5]。因盐碱地改造成本高，见效慢，培育耐盐碱环境的作物新品种是盐碱地利用的一个有效思路。……