CoCl_2对Na_2CO_3胁迫下苜蓿幼苗叶片细胞膜的保护作用

The protective effects of cobalt on the plasma membrane of Medicago sativa seedling leaves under Na_2CO_3 stress

本研究报道了CoCl2对Na2CO3胁迫下苜蓿幼苗叶片细胞膜的保护作用及机制，研究结果表明,在120mmol／LNa2CO3胁迫的前期，苜蓿幼苗叶片多胺含量及抗氧化酶活性显著升高，过氧化物酶除外，而活性氧水平、脂质过氧化程度和细胞膜相对透性无显著变化；当120mmol／LNa2CO3胁迫延长至24-28d时，乙烯产生速率大幅度上升，多胺氧化酶及二胺氧化酶活性显著升高，精胺、亚精胺和腐胺含量显著下降；抗氧化酶活性显著下降，活性氧水平与脂质过氧化程度显著提高，细胞膜稳定指数大幅度下降。在120mmol／LNa2CO3溶液中加入CoCl2至50μmol／L，在胁迫的整个过程中乙烯产生被显著抑制，同时相对提高了抗氧化酶的活性，并在胁迫后期显著减轻了多胺氧化酶活性升高、多胺含量下降及脂质过氧化程度的增加，减缓了细胞膜稳定指数的下降，从而对Na2CO3胁迫下苜蓿幼苗叶片细胞膜表现出一定的保护作用。

The protective effects and mechanism of cobalt action on the plasma membrane of Medicago sativa seedling leaves under Na2CO3 stress are reported in this paper. When a stress of 120 mmol/L Na2CO3 was initiated, the polyamine content and activities of anti-oxidative enzymes （except peroxidase） increased significantly, while ethylene production was markedly reduced, yet the reactive oxygen levels, lipid oxidation degrees and membrane stability index did not change significantly. When the stress lasted 24-28 days, ethylene production increased significantly, and the activities of anti-oxidative enzymes, polyamine oxidases and diamine oxidases increased markedly, while the content of spermine, spermidine and putrescine were greatly reduced, and reactive oxygen levels and lipid anti-peroxidation degrees were predominantly enhanced. The membrane stability index was significantly reduced. When CoCl2 was added to the 120 mmol/L Na2CO3 solution at a concentration of 50 /Lmol/L, ethylene production was markedly inhibited during the whole process of stress, while the activities of anti-oxidative enzymes were promoted. When the stress lasted 24-28 days, the addition of CoCl2 reduced the improvement of polyamine oxidases, diamine oxidases, the reduction of polyamine content and anti-oxidative enzyme activities, thus alleviating the increment of lipid peroxidation, and even the reduction of the membrane stability index. It showed the protective effects on the plasma membrane of M. sativa seedling leaves under Na2CO3 stress.