外源抗坏血酸缓解水稻幼苗的铝胁迫效应

Effects of exogenous ascorbic acid on alleviating aluminum stress in rice seedlings

关键词:  水稻, 铝胁迫, 抗坏血酸, 活性氧, 抗氧化酶, 生理生化

Key words:  rice, aluminum(Al³⁺)stress, ascorbic acid(AsA), ROS, antioxidant enzyme, physiology and biochemistry

摘要:

为探讨外源抗坏血酸对铝胁迫下水稻氧化损伤的影响,该文以峰1A(不育系,籼稻)和滇优35号(杂交,粳稻)两个水稻品种为材料,采用溶液培养法研究外源抗坏血酸(AsA)对50 μmol·L^-1 Al³⁺胁迫下水稻根尖H₂O₂和内源AsA含量以及抗氧化酶活性的影响。结果表明:铝胁迫24 h时,水稻根尖内源AsA含量为对照的0.90倍,与对照相比,根尖H₂O₂增加了0.55倍至1.3倍,SOD、POD、CAT及APX活性分别增加了0.83倍至1.6倍、1.0倍至1.3倍、0.85倍至1.2倍、1.0倍至1.8倍; 外源AsA处理铝胁迫水稻24 h,水稻根尖内源AsA含量为对照的1.2倍,SOD、POD、CAT及APX活性分别增加了1.2倍至2.2倍、1.5倍至1.6倍、1.3倍至1.7倍、1.2倍至2.6倍,根尖H₂O₂含量增加了0.1倍至0.6倍。这些研究结果说明铝胁迫加剧了细胞膜的过氧化程度,并诱导抗氧化酶活性以清除活性氧,外源AsA通过提高抗氧化酶活性和内源AsA含量以缓解水稻Al³⁺胁迫引起的氧化损伤,降低细胞膜系统伤害,促进水稻生长,为外源AsA提高水稻适应铝胁迫能力提供了理论依据。

Abstract:

The aim of the experment was to study the effects of exogenous ascorbic acid(AsA)on oxidative damage of rice under aluminum(A1³⁺)stress. A hydroponic experiment was conducted with the Peak 1A(sterile line, Indica)and Dian Superior 35(Hybrid, Japonica)to study the effects of exogenous AsA on the contents of H₂O₂ and endogenous AsA and the activities of antioxidant enzyme in roots of the two rice varieties under 50 μmol·L^-1 A1³⁺ stress. The results showed that the content of endogenous AsA was 0.90-fold of the control, and the content of H₂O₂ was 0.55-fold to 1.3-fold, the activities of SOD, POD, CAT and APX were 0.83-fold to 1.6-fold, 1.0-fold to 1.3-fold, 0.85-fold to 1.2-fold, 1.0-fold to 1.8-fold higher than that of the control in roots of the two rice varieties under A1³⁺ stress for 24 h, respectively. Under exogenous AsA treatment for 24 h, the content of endogenous AsA was 1.2-fold of the control, and the activities of SOD, POD, CAT and APX were 1.2-fold to 2.2-fold, 1.5-fold to 1.6-fold, 1.3-fold to 1.7-fold,1.2-fold to 2.6-fold higher than that of the control, respectively, while the content of H₂O₂ was only 0.1-fold to 0.6-fold higher than that of the control in rice roots. There results indicate that Al³⁺ stress can increase the degree of membrane peroxidation, and induced antioxidant enzyme activities to enhance the ability of scavenging ROS. While application of exogenous AsA not only could alleviate the oxidative damage induced by Al³⁺ stress, but also had a significant effect on reducing the damage of cell membrane system by enhancing antioxidant enzyme activities and AsA content, thereby promoting the rice growth, which provided theoretical information for exogenous AsA to improve the ability of rice to adapt to Al³⁺ stress.