盐胁迫下大麦和小麦叶片脂质过氧化伤害与超微结构变化的关系

研究了耐盐的大麦和不耐盐的小麦幼苗在 NaCl 胁迫下叶片脂质过氧化作用、膜系统伤害、叶肉细胞超微结构变化三者之间的关系。在盐胁迫初期,叶肉细胞能维持较高的 SOD 活性,脂质过氧化作用较弱,膜系统基本完整;随着胁迫强度加大,SOD 活性下降,脂质过氧化作用加强,膜透性增加,细胞内的电解质和紫外吸收物质大量外渗,细胞器破坏,甚至整个叶肉细胞结构崩溃。试验结果表明盐胁迫下超微结构的变化反映了细胞内膜系统的紊乱和伤害,而膜系统的伤害可能是脂质过氧化作用增强的结果。

CORRELATION BETWEEN LIPID PREOXIDATION DAMAGE AND ULTRASTRUCTURAL CHANGES OF MESOPHYLL CELLS IN BARLEY AND WHEAT SEEDLINGS DURING SALT STRESS

The correlation among lipid preoxidation,destruction of membrane system and ultrastruc- rural changes of mesophyll cells during salt stress was studied with the NaCl-resistant barley (Jian No.4)and NaCl-sensitive wheat(Ning Mai No.4)seedlings.During initial period of salt stress,mesophyll cells was able to maintain higher SOD activity,less lipid preoxidation and approximately integral membrane system;with the increasing intensity of salt stress,SOD acti- vity lowered,MDA content increased obviously,electrolytes and UV-absorbed substances in cells leaked,cell organelles were destroyed severely,and even whole cell structure was ruined. The barley was able to maintain more intact cell structure and less damage of membrane system than the wheat did.These results indicated that changes of ultrastructure of mesophyll cells were consistent with disorder and damage of their membrane systems,and the damage of membrane system might be as a result of the increase of membrane lipid preoxidation.