NaCl 胁迫对甘薯叶片叶绿体超微结构及一些酶活性的影响

Effects of Salt Stress on the Ultrastructure of Chloroplast and the Activities of Some Protective Enzymes in Leaves of Sweet Potato

随ＮａＣｌ 胁迫浓度的提高，甘薯叶片叶绿体数目逐渐减少， 类囊体膜片层松散、扭曲、破裂并逐渐解体， 叶绿素含量下降。与此同时，Ｈ２Ｏ２ 、ＭＤＡ 含量增加， ＡＳＰ、ＳＯＤ 活性表现出先上升后下降的趋势。耐盐品种在ＮａＣｌ 胁迫下能维持较强的Ｈ２Ｏ２ 清除能力和较低的ＭＤＡ

The ultrastructure of chloroplast, the contents of chlorophyll, H 2O 2 and malondialdehyde(MDA) as well as the activities of superoxide dismutase (SOD) and ascorbate peroxidase (ASP) of the seedlings of two sweet potato cultivars, salt tolerant Xushu 18 and salt sensitive Shengli baihao, stressed under different concentration of NaCl for 72 hours,were studied with electron microscopy and chemical analysis. The results showed that with the increase of NaCl concentration, the number of chloroplasts of sweet potato leaves decreased, the lamellae were loosened, twisted, ripped and disintegrated gradually (Plates Ⅰand Ⅱ), the content of chlorophyll declined(Fig. 1), the activities of ASP and SOD increased first and then decreased(Fig.3), H 2O 2 accumulated, and MDA content rose (Fig. 2), which resulted from the peroxidation of the cell membrane. Under high NaCl stress, the salt tolerant cultivar Xushu 18 was harmed less seriously which could be explained by the fact that its ASP and SOD activities were still high enough to scavenge H 2O 2, resulting in lower H 2O 2 and MDA contents and higher chlorophyll content than in the salt sensitive one.