抗旱性不同的小麦幼苗在水分和盐胁迫下抗氧化酶和多胺的变化

CHANGES IN ANTIOXIDATIVE ENZYMES AND POLYAMINES IN WHEAT SEEDLINGS WITH DIFFERENT DROUGHT RESISTANCE UNDER DROUGHT AND SALT STRESS

分别对抗旱小麦 8139和干旱敏感小麦甘麦 8号的幼苗进行两周的水分胁迫和 Na Cl胁迫 ,并对其叶片中一些生理指标的变化进行了研究。结果表明 ,水分胁迫下 8139中 O 2 与 H2 O2 的含量及膜脂过氧化程度均低于敏感品种 ,胁迫后第七天与第十四天其中 SOD与 CAT活性明显高于甘麦 8号 ;盐胁迫下两种小麦中的 H2 O2 、MDA含量及 SOD、POX酶活性在各时期均无明显差别。水分胁迫下 ,8139中多胺 (腐胺 Put,亚精胺 Spd,精胺 Spm)含量显著高于甘麦 8号 ;盐胁迫下 ,两品种中多胺含量在胁迫 7d后才表现出差异。由此可见 ,水分胁迫下两品种清除自由基的能力明显不同 ,而在盐胁迫下则差别不大。表现在生长上 ,水分胁迫下 8139地上部分干物质的累积量高于甘麦 8号 ,而在 Na Cl胁迫下两者之间差别不大 。

The effects of drought and salt stress on several biochemical indices in the leaves of wheat were studied in the seedlings of a drought resistant and a drought sensitive cultivar. The cultivars (cv. 8139 and cv. Ganmai 8 respectively) were grown under drought (PEG6000) and salt (NaCl) stresses for two weeks. Compared with the drought sensitive cultivars grown under drought stress, PEG stressed 8139 contained lower levels of superoxide (O 2  ),hydrogen peroxide (H 2O 2), malondialdehyde (MDA) and much more higher activities of superoxide dismutase (SOD), catalase (CAT). Under salt stress, there was no significant difference at any stage between the two cultivars in the levels of H 2O 2, MDA and SOD and POX activities. Furthermore, the drought resistant wheat grown under drought stress had significantly higher levels of polyamines, including putrescine (Put), spermidine (Spd) and spermine (Spm), but under salt stress, the significant difference between the two cultivars was not observed until the seedlings had been stressed for 7 days. These results showed that the two cultivars were significantly different from each other in the ability of scavenging free radicals under drought, but not salt stress.It implied that the mechanism(s) imparting drought resistance was different from that of salt tolerance.