盐胁迫下野生大豆叶片中Na+、Cl-积累导致活性氧伤害

以耐盐性强弱不同的野生大豆(JWS耐盐性强，N23232耐盐性弱)为材料，采用砂培试验研究了NaCl胁迫下野生大豆叶片中Na^ 、Cl^-含量及活性氧代谢的变化。结果表明，盐胁迫下供试两种群野生大豆叶片Na^ 、Cl^-含量增加，N23232比JWS更明显；耐盐性弱的N23232叶片O2^-产生速率和H2O2含量上升，膜脂过氧化产物MDA和电导率迅速上升，其叶片中Na^ 、Cl^-含量变化与O2^-、H2O2、MDA和电导率增加呈极显著或显著正相关，而O2^-产生速率和H2O2含量上升与MDA和电导率变化呈极显著正相关。表明在NaCl胁迫下，由于Na^ 、Cl^-在叶片中的积累而导致了活性氧的积累，活性氧诱发膜脂过氧化、破坏膜结构，导致膜结合酶H^ -ATPase和H^ -PPase活性降低，膜透性增加。耐盐种群JWS在盐胁迫下Na^ 、Cl^-积累量少、活性氧水平较低，对膜系统伤害少，膜结合酶活性高，因而能维持液泡膜正常的代谢功能，可能是其耐盐性强的原因之一。

ACCUMULATION OF Na+ 、Cl- IN THE LEAVES OF WILD SOYBEAN SEEDLINGS LEAD TO THE OXIDATIVE DAMAGE UNDER SALT STRESS

The different salt tolerance of wild soybean (JWS salt-tolerant, N23232 salt-sensitive) were used to study the changes of Na +?Cl - contents and active oxygen metablism in the leaves under NaCl stress by the methods of pot experiment. The results showed that the Na +?Cl - contents increased in the leaves of the two population wild soybean under salt stress and the Na +?Cl - contents was greater in N23232 than that in JWS. For salt-sensitive wild soybean(N23232),the O -. 2 generation rate and H 2O 2 content increased, product of lipid peroxidation(MDA) and electrical conductivity increased in the leaves under 130 mmol/L NaCl stress. There were some significantly positive correlation among the Na +?Cl -?O -. 2?H 2O 2?MDA and electrical conductivity respectively, and also between O -. 2?H 2O 2 and MDA?electrical conductivity in the salt-sensitive wild soybean(N23232). It suggested that the content of Na +?Cl - increased lead to the accumulation of active oxygen and the oxidative damage. This oxidative damage expressed as the increase of MDA, the decrease of membrane-associated enzyme(H +-ATPase and H +-PPase) activities and the increase of electrical conductivity. However, the Na +?Cl - contents in the leaves of salt-tolerant wild soybean were maintained at a lower level, and no changes were detected in O -. 2?H 2O 2 and MDA contents with respect to the control. Therefore, the damage effects of active oxygen species were lower on the salt-tolerant wild soybean than that on the salt-sensitive ones, and the membrane-associated enzyme(H +-ATPase and H +-PPase) activities maintained at a higher level. The results indicated that the high level of H +-ATPase and H +-PPase activities in salt-tolerant wild soybean might be one of the factors of salt tolerance.