外源亚精胺对铅胁迫下甜瓜幼苗抗氧化代谢的调控效应

Regulating Effect of Exogenous Spermidine on Antioxidant Metabolism of Melon Seedlings Under Pb Stress

以"齐甜一号"甜瓜为试材,研究了10 mg·L^-1的铅(Pb)胁迫下不同浓度亚精胺(Spd)对甜瓜幼苗光合作用和抗氧化酶的影响,以期研究亚精胺提高甜瓜幼苗抗铅毒害的内在机理。结果表明:在10 mg·L^-1铅的毒害下叶绿素含量和可溶性蛋白质含量降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性下降,丙二醛(MDA)、H2O2含量及O2产生速率升高。外源亚精胺的施用显著提高了甜瓜叶绿素和可溶性蛋白质含量,提高了抗氧化酶的活性;降低了膜脂过氧化程度。上述结果表明,亚精胺能够减轻铅对甜瓜幼苗的毒害作用,其中0.5 mmol·L^-1和1.0 mmol·L^-1 Spd的效果最佳。

In order to explore the mechanism that spermidine(Spd)improved melon seedlings resistance to Pb stress,‘Qitian No.1’melon was used as the experimental materials,the effects of Spd with different concentrations on photosynthetic character and antioxidant metabolism of melon seedlings under Pb stress(10mg·L^-1)were studied.The results showed that contents of chlorophyll and soluble protein decreased,the activities of antioxidant enzymes SOD,POD,CAT decreased either.However,O2 prodection rate,H2O2and MDA contents increased under Pb stress.Exogenous Spd with different concentration increased the activity of antioxidant enzymes and photosynthetic parameters of melon seedling and decreased O2,H2O2and MDA contents.The above results suggested that Spd improved the toxicity of melon seedlings with Pb stress,which at dose of 0.5 mmol·L^-1 and1.0mmol·L^-1 Spd were more significantly.