摘要
酸雨对森林、水体和农田等生态系统造成的危害受到许多研究者的重视,并已取得一些成果,但关于木本园林植物的伤害机理及抗性机制没有得到澄清,尤其是对抗氧化系统的影响研究较少。采用盆栽法,以木兰科(Magnoliaceae)树种抗酸性强的阔瓣含笑(Michelia platypetala)和抗酸性弱的红花木莲(Manglieta insignis)为试材,研究了不同pH值模拟酸雨处理对叶片膜脂过氧化和抗氧化系统的影响。结果表明,随着酸雨pH值的下降,两树种叶片抗氧化剂抗坏血酸(ASA)和谷胱甘肽(GSH)质量分数下降;抗氧化酶超氧化物歧化酶(SOD)及谷胱甘肽还原酶(GR)活性下降,而过氧化物酶(POD)活性变化趋势不一致,阔瓣含笑一直呈上升趋势,红花木莲则先上升后下降。此外,超氧阴离子(O2?·)产生速率上升,丙二醛(MDA)含量和膜透性增加;相关性分析表明,O2?·产生速率与MDA和膜透性呈显著正相关,与抗氧化酶SOD,GR和抗氧化剂ASA质量分数呈显著负相关,说明酸雨降低了植物体防御活性氧伤害有关的酶系统和非酶系统抗性能力,提高了体内活性氧含量,膜脂过氧化加剧。与红花木莲相比,阔瓣含笑具有较强的抗氧化能力。本研究结果从自由基的产生及清除的角度,探讨木本园林植物的伤害机理以及抗性机制,也为该类园林树种在江南城市中的选择提供一些科学参考依据。
Acid rain is a serious environmental problem with impact on agriculture, forest and water ecosystem. Many researchers have devoted much attention to forests exposed to acid rain, but mechanism of resistance of woody landscape plants to acid rain hasn＇t clearfied, especially the research for antioxidant system has been relatively limited. In this study, the characteristic of membrane lipid peroxidant and antioxidant system in two Magnoliaceae species, Michelia platypetala with stronger resistance to acid rain and Manglieta insignis with sensitivity to acid rain, were studied under simulated acid rain. The results showed that the content ofglutathione （GSH） and ascorbic acid （ASA） and the activity of superoxide dismutase （SOD） and glutathione reductase （GR） were significantly declined in two species leaves with the decrease ofpH value of simulated acid rain, but the activity ofperoxidase （POD） increased all though in Michelia platypetala leaves, and increased then decreased rapidly in Manglieta insignis leaves. Moreover, the content of malondialdehyde （MDA） and superoxide anion （O2^-） and membrane permeability increased obviously. On the other hand, the production of O2^- were apparently positive correlated with the content of MDA and membrane permeability, and were remarkable negatively correlated with the activities of SOD, GR and the content of ASA. Those observations indicated that the simulated acid rain induced production of O2^- and disordered.the harmonies of antioxidant system, resulted in imbalance of activated oxygen in the production and elimination, and accelerated process of membrane lipid peroxidation. The capability of protective system against active oxygen was higher in Michelia platypetala seedlings than that of Manglieta insignis seedlings. Results of this work can help analyzing mechanism of resistance to acid rain of woody landscape plants, and provide the scientific bases for selecting woody landscape trees of cities in southern Yangtze river.
出处
《生态环境》
CSCD
北大核心
2007年第3期779-784,共6页
Ecology and Environmnet
基金
江苏省级综合性农业科技示范园项目(苏农计(2003)50号)
江苏省农业科技示范推广项目(BC2005344)
关键词
木兰科树种
模拟酸雨
膜脂过氧化
抗氧化系统
tree species of Magnoliaceae
simulated acid rain
antioxidant system
membrane lipid peroxidation
