模拟酸雨和铜复合污染对白花泡桐生理特性的影响及其解毒机制

Complex effects of simulated acid rain and Cu on the physiological characteristics of Paulownia fortunei and its detoxification mechanism

采用盆栽方法,研究了模拟酸雨(pH分别为4.0、5.0)和Cu(0～200mg·kg-1)复合污染对白花泡桐生理特性的影响及其解毒机制.结果表明:未加Cu处理时,不同酸雨处理间,白花泡桐的叶绿素、类胡萝卜素、超氧阴离子、过氧化氢和丙二醛含量均差异不显著;100和200mg·kg-1Cu处理时,pH4.0处理的叶绿素和类胡萝卜素含量显著低于,而超氧阴离子、过氧化氢和丙二醛含量显著高于pH5.0处理.Cu处理的叶绿素a/b值明显高于未加Cu处理.随着酸雨酸度增加,叶片铜含量明显减少,而根部铜含量明显增加.pH5.0时,随Cu浓度增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性均持续增强,植物络合素和谷胱甘肽(GSH)总量均明显增加;而在pH4.0时,SOD、POD、CAT和APX活性呈先升后降,而GSH总量在Cu浓度为200mg·kg-1时明显下降.模拟酸雨加剧了高浓度Cu对白花泡桐的氧化胁迫.

A pot experiment was conducted to study the effects of simulated acid rain （pH 4.0, 5.0） and Cu （0-200 mg·kg^-1） on the physiological characteristics of Paulownia fortunei and its detoxification mechanism. With no Cu addition, the leaf chlorophyll, carotenoid, O2^·-, H2O2, and MDA contents of P. fortunei had no significant differences between the two acid rain treatments. However, with the addition of 100 and 200 mg Cu·kg^-1, the chlorophyll and carotenoid contents of treatment pH 4.0 were lower, while the O2^·-, H2O2 and MDA contents were higher than those of treatment pH 5.0. The chlorophyll a/b ratio of treatments Cu was higher than that of the control. The leaf Cu content decreased obviously with the increasing acidity of stimulated acid rain, but the root Cu content was in reverse. With increasing Cu addition, both the activities of superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, and ascorbate peroxidase （APX） and the total contents of phytochelatins （PCs） and glutathione （GSH） in treatment pH 5.0 increased, while the activities of SOD, POD, CAT and APX in treatment pH 4.0 decreased after an initial increase, and the total contents of glutathione （GSH） decreased greatly in treatment 200 mg Cu·kg^-1 . All of these demonstrated that the oxidative stress of high Cu concentration to P. fortunei was aggravated by stimulated acid rain.