【摘要】 为进一步认识植物对酸雨胁迫的适应性机制,本文选择具有较强耐酸性作物水稻为试材,研究酸雨（AR）（p H 3.5和p H 2.5）对水稻根系抗氧化酶活性及其同工酶组成的影响.发现AR胁迫5 d后,p H 3.5组水稻幼苗根系中SOD（超氧化物歧化酶）、CAT（过氧化氢酶）、POD（过氧化物酶）活性均上升,且同工酶谱条带均增粗变亮,H₂O₂、O₂^·-、MDA含量和质膜透性均增加,根长、根表面积、根体积、根冠比均减小;而p H 2.5组根系中虽SOD、CAT活性上升但POD活性下降,其中SOD、CAT同工酶谱条带变粗变亮且较p H 3.5组更粗更亮而POD 3、POD 4、POD 5条带明显变细变暗,O₂^·-、H₂O₂、MDA含量和质膜透性与根系生长各指标降幅均大于p H 3.5组.恢复5 d后,p H3.5组下水稻根系中SOD、CAT、POD、H₂O₂、O₂^·-、MDA含量和质膜透性恢复至对照水平,而p H 2.5引发的活性氧伤害未恢复.因此,AR胁迫下水稻幼苗根系SOD、CAT、POD同工酶表达量增加促使活性增强有助于清除AR诱发的活性氧积累,增强植物对酸雨的耐受性,调控能力受酸雨强度限制.更多还原

【Abstract】 To clarify the adaptation in plants to acid rain stress,we chose rice with stronger acidity tolerance as experimental object to study the effect of acid rain（AR）（p H 3.5/pH 2.5）on antioxidant enzyme activities and isozyme composition in rice roots.After 5-day exposure,activities of SOD,CAT and POD in rice roots treated with pH 3.5 AR were increased,and isozyme bands were thickened and brighter.Meanwhile,contents of H₂O₂,O₂^·-,MDA and membrane permeability were all increased while root length,root surface area,root volume and root/shoot ratio were decreased.In pH 2.5 AR treating group,activities of SOD and CAT were increased and bands of SOD and CAT isozyme were thicker and brighter than those in pH 3.5 AR group.But the activity of POD was decreased and bands of POD 3,POD 4 and POD 5 were obviously darkened.The increased contents of O₂^·-,H₂O₂and MDA and membrane permeability and the decreased root length,root surface area,root volume and root/shoot ratio were all larger than those treated with pH 3.5 AR.After a 5-day recovery,all parameters of rice root under pH 3.5 AR stress were recovered to the control level whereas oxidative damage caused by p H 2.5 AR was irreversible.Therefore,the increase in SOD,CAT and POD isozyme in rice root could promote the activities of antioxidative enzymes to scavenge excessive accumulation of reactive oxygen species induced by AR and enhance plant tolerance to acid rain.Moreover,the regulating effect of antioxidave isozyme was limited by the intensity of acid rain.更多还原