NaCl胁迫对秋茄幼苗根系抗氧化系统的影响

Effect of NaCl Stress on Antioxidant System in Kandelia candel Roots

摘要:

为探讨红树植物秋茄（Kandelia candel）幼苗根系抗氧化系统对盐胁迫的生理响应，以Hoagland完全营养液沙培秋茄幼苗60 d后，用不同浓度NaCl处理秋茄根系1、3、5、7 d，对其生理生化指标的变化进行研究。结果表明，胁迫相同天数，200和400 mmol L^-1 NaCl处理的秋茄根系O₂^·和H₂O₂含量保持较低水平，而600 mmol L^-1 NaCl处理的则明显增加；MDA含量在200和400 mmol L^-1 NaCl处理下保持稳定，而600 mmol L^-1 NaCl处理的显著升高；SOD、POD、CAT、APX和GR活性随NaCl浓度升高总体上表现先上升后下降的趋势，处理3和5 d后的酶活性均显著高于对照，而600 mmol L^-1 NaCl处理7 d后的酶活性明显低于对照；AsA和GSH含量总体上均明显高于对照。因此，秋茄幼苗是通过根系功能较强的抗氧化系统清除活性氧以提高植株的耐盐性。

Abstract:

In order to understand the response of antioxidant system in roots of Kandelia candel seedlings to salt stress, sixty-day-old mangrove Kandelia candel seedlings cultured in sand with Hoagland solution were treated with 0, 200, 400 and 600 mmol L^–1 NaCl for 1, 3, 5, and 7 days, respectively. The results showed that the contents of O₂^· and H₂O₂ remained low level treated with 200 and 400 mmol L^–1 NaCl for the same days, but increased significantly under 600 mmol L^–1 NaCl. MDA content remained stable under 200 and 400 mmol L^–1 NaCl compared to control (0 mmol L^–1 NaCl), while increased remarkably under 600 mmol L^–1 NaCl. The activities of SOD, POD, CAT, APX, and GR increased at first and then decreased with increment of NaCl concentration treated for the same days. The activities of these enzymes were significantly higher than those in control treated for 3 and 5 days, but they were significantly lower than those in control treated with 600 mmol L^–1 NaCl for 7 days. The contents of AsA and GSH were significantly higher than those in control. Therefore, it was suggested that Kandelia candel roots could improve the resistance to salt stress through strong antioxidant system to scavenging active oxygen.