外源亚精胺和精胺对NaHCO3胁迫下南蛇藤抗氧化系统的影响

研究了叶面喷施亚精胺和精胺对NaHCO₃胁迫下南蛇藤叶片抗氧化系统的影响.结果表明：外源亚精胺和精胺处理使NaHCO₃胁迫下南蛇藤叶片O₂^-·产生速率、H₂O₂、丙二醛(MDA)含量和电解质外渗率显著降低(P<0.05).亚精胺处理明显提高了盐胁迫下超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)等抗氧化酶的活性，以及还原型谷胱甘肽(GSH)、类胡萝卜素(CAR)和脯氨酸(Pro)等抗氧化剂的含量，但对还原型抗坏血酸(AsA)含量没有作用；精胺处理明显提高NaHCO₃胁迫下POD和APX的活性以及GSH、CAR和Pro的含量，但对SOD和AsA含量影响不显著，甚至引起CAT活性明显降低.亚精胺和精胺处理明显改善了NaHCO₃胁迫下南蛇藤的生长.外源亚精胺和精胺可以改善NaHCO₃胁迫下南蛇藤叶片的膜保护功能，减少叶片中活性氧的积累，从而提高南蛇藤对NaHCO₃胁迫的抗性.

Research advances in soil magnesium pollution of magnesite mining area and related mechanisms

This paper studied the effects of foliar spraying spermidine and sperm ine on the leaf antioxidant system of Celastrus orbiculatus under soil NaHCO 3 stress. The results showed that under the stress, spraying spermidine and sp ermine could significantly decrease the leaf O2〖SX(B-*3〗-〖〗·〖SX)〗 production rate, H2O2 and MDA contents, and electrolyte leakage of C. orbiculatus (P<005). Spra ying spermidine increased the leaf SOD, CAT, POD and APX activities and GSH, CAR and Pro contents obviously, but had no effect on leaf AsA content. Spraying sp ermine also increased leaf POD and APX activities and GSH, CAR and Pro contents obviously, but had lesser effect on leaf SOD activity and AsA content, and even , caused a significant decrease in leaf CAT activity. In the meantime, spermidin e and spermine effectively improved the growth of C. orbiculatus seedlings. It was suggested that under soil NaHCO3 stress, exogenous spermidine and sperm ine could improve the functions of membrane protective system and decrease the O 2〖SX(B-*3〗-〖〗·〖SX)〗 accumulation in C. orbiculatus leaves, an d consequently, increase the C. orbiculatus tolerance to NaHCO3 exposure.