Effects of drought on membrane lipid peroxidation and protective enzyme activities of five Potentilia species under drought stress of PEG were studied. The results showed that as the severity increase of drought stress, MDA content of five Potentilia species showed an increasing trend, MDA content in Potentilia paradoxa and Potentilia freyniana increased the most, indicating that lipid peroxide ability was the weakest, cells were damaged the greatly, drought resistance was the weakest. SOD, POD, CAT activity increased first with the degree of drought stress increased and then decreased, indicating that under light drought stress five Potentilia species can start the protective enzyme system to enhance the resistance, but with the stress level increased, the balance of protective enzymes was destroyed, which aggravated lipid peroxidation resulting in membrane damage.%用聚乙二醇模拟干旱胁迫,研究了干旱胁迫对5种委陵菜属植物膜脂过氧化作用及保护酶活性的影响.结果表明:随着干旱胁迫程度的加重5种委陵菜的MDA含量呈递增趋势,其中伏委陵菜与三叶委陵菜的增幅较大,表明其膜脂抗过氧化能力最弱,细胞被破坏的程度最大,抗旱能力最弱.SOD、POD、CAT活性随着干旱胁迫程度的增加呈现先上升后下降的变化趋势,表明在轻度干旱胁迫下5种委陵菜均能启动保护酶系统提高抗性,但随着胁迫程度增加,其保护酶系统平衡遭到破坏,加剧膜脂过氧化而造成膜损伤.
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