水花生抗氧化系统在抵御Cu^(2+) 胁迫中的作用

The Role of Antioxidant Systems in Cu^(2+) Stress Resistance in Alternanthera philoxeroides

在Hoagland培养基中加入CuSO4 以模拟水体Cu2 +污染环境 ,从不同Cu2 +浓度和中毒时间两个角度 ,研究了水花生 (Alternantheraphiloxeroides (Mart.)Griseb .)的酶与非酶抗氧化系统在抵御Cu2 +胁迫中的作用。实验结果显示 ,轻—中度污染的Cu2 +(小于 70mg/L)即能刺激水花生超氧阴离子 (O-·2 )的积累 ,并导致脂质过氧化和膜透性的改变。在Cu2 +胁迫过程中超氧化物歧化酶 (SOD)、过氧化物酶 (POD)能发生大幅度应激性提高 ,并在实验范围内的较高浓度和中毒中后期起主要抗氧化作用 ,过氧化氢酶 (CAT)在此过程中作用不明显 ,谷胱甘肽过氧化物酶 (GSH_Px)在较低浓度和中毒早期能被小幅度激活并起作用 ,抗坏血酸 (AsA)通过还原型向氧化型的转变 。

CuSO 4 was added into Hoagland solution to imitate Cu 2+ polluted water environment, and the roles of the two antioxidation systems in resisting Cu 2+ stress in Alternanthera philoxeroides (Mart.) Griseb. was studied. The results showed that Cu 2+ pollution less than 70 mg/L in concentration could stimulate the accumulation of superoxide radical (O -· 2), thus lead to lipid peroxidation and increase of membrane permeability. Superoxide dismutase (SOD) and peroxidase (POD) were both induced in high level and took important parts in antioxidation at higher concentration of Cu 2+ and in middle and late phases of Cu 2+ stress. Catalase (CAT) had little effect. Glutathione peroxidase (GSH_Px) was induced in lower level and showed its function in lower Cu 2+ concentration and in early phase. Ascorbic acid (AsA) could also function at higher Cu 2+ concentration by transition from reduced state to oxidized state.