不同程度盐胁迫对乌拉尔甘草叶片亚显微结构的影响

Effects of different level of salt stress on ultrastructure in leaves of Glycyrrhiza uralensis

目的通过盆栽试验研究不同程度盐胁迫对乌拉尔甘草叶片亚显微结构的影响。方法以二年生乌拉尔甘草苗为材料,设置2个盐水平,分别为12 g/kg NaCl干土(Na_1)、15 g/kg(Na_2),同时设置对照组(CK),采用超薄切片技术制备样品,并于透射电子显微镜下观察细胞结构。结果发现对照组的叶片叶绿体结构紧实,膜系统完整;中度盐浓度下(12 g/kg NaCl)叶绿体内存在极少淀粉粒,并被大量的线粒体包围;高盐浓度下(15 g/kg NaCl)淀粉粒增多,波浪状细胞壁,叶绿体被膜严重损伤而降解,边缘结构遭到破坏,类囊体膨大,片层结构排列松散且片层间距加大,叶绿体降解呈离散状态,线粒体嵴膨大,部分出现空泡化现象。结论盐胁迫对乌拉尔甘草叶片细胞叶绿体、线粒体等的超微结构具有损伤作用,且盐浓度愈高损伤作用愈明显。

Objective In this study,a pot experiment was conducted to investigate the ultrastructure in leaves of Glycyrrhiza uralensis under different concentrations of salinity. Methods Various components of the experiment were two salt treatments（ 12 g/kg and 15 g/kg NaCl） and one in distilled water,the ultrastructure in leaves of G. uralensis was using the ultrathin section and observed by transmission electron microscopy. Results The results indicated,the regular and compact chloroplast had integrated membrane system under the water free of salinity. The chloroplast with little starch grain was closed in a mass of mitochondria under low concentration of salinity（ 12 g/kg NaCl）. The membrane system of chloroplast departing from cell wall and a lot of starch grain was increased and destroyed,the thylakoids of dissociative chloroplast was intumescent,degenerated and loosened obviously,and the vacuolated mitochondria were observed under higher concentration of salinity（ 15 g/kg Na Cl）. Conclusion This suggested that salt stress had damage effects on the ultrastructure chloroplast and mitochondria in leaves of Glycyrrhiza uralensis. The higher the salt concentration was,more obvious the damage effect was. It would provide the cytological basis for Glycyrrhiza uralensis planting in saline-alkali land.