镉胁迫对小白菜(Brassica campestris L.)抗氧化机理的影响  

Responses and resistance mechanism of Brassica campestris L. to cadmium stress

作　　者：刘可慧[1] 于方明[2,3] 李明顺[2,3] 周振明[2,3] 谌斌[2,3] 蓝殿[2,3] 孙双玉[2,3] 

机构地区：[1]桂林电子科技大学应用科技学院,广西桂林541004 [2]广西师范大学环境与资源学院,广西桂林541004 [3]广西环境工程与保护评价重点实验室,广西桂林541004

出　　处：《生态环境》2008年第4期1466-1470,共5页Ecology and Environmnet

基　　金：国家自然科学基金项目(30560032);广西教育厅项目(200707MS048);广西环境科学重点学科项目;桂林电子科技大学博士启动基金项目(No.Z20718);广西师范大学博士启动基金项目

摘　　要：采用水培的方法,研究了不同Cd2+水平(0、1、2.5、5、10、15mg·L-1)对小白菜(Brassica campestris L.)抗氧化酶(SOD、POD、CAT)活性、非酶物质(SH、GSH、PCs)含量以及生长的影响。结果表明,小白菜叶片和根系SOD活性随Cd处理质量浓度的增加呈降低的变化趋势,POD、CAT活性以及MDA含量随Cd处理质量浓度的增加而增加。小白菜的生物量、根长、株高、叶绿素质量分数随Cd处理质量浓度的增加显著降低(P<0.05),表明Cd抑制了小白菜的生长,破坏了叶绿素的合成。小白菜地上、地下部镉质量分数均随Cd处理质量浓度的增加而显著增加(P<0.05)。当Cd处理质量浓度为15mg·L-1,小白菜地上、地下部镉质量分数分别达到637.5、1663.0mg·kg-1,表明小白菜对Cd有良好的富集效果。小白菜根系与叶片中SH、GSH和PCs含量均随Cd处理质量浓度增加而增加的变化趋势,表明SH、GSH和PCs在解毒小白菜Cd毒害中起着重要作用。A hydroponic experiment was carried out to study the effects of different cadmium levels （0-15 mg· L^-1） on various enzymatic antioxidants and non-enzymatic antioxidants in Brassica campestris L., including superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT） and malondialdehyde （MDA）, glutathione（GSH）, phytochelatins（PCs） and total acid soluble SH. The results showed that with the increase of Cd in the solution, the activity of SOD decreased, but the activity of POD, CAT was increased. Under the stress of Cd, the content of MDA increased too, the enhanced of MDA which indicated that Brassica campestris L., was stressed by Cd and have a lot of ROS has not be eliminated. The content of GSH, PCs, SH were increased and a large number of phytochelatins was induced by the exposure of Cd, but in roots higher than leaves, it may related to the higher Cd concentration in the roots. Under the stress of Cd, the biomass, shoot high and root high ofBrassica campestris L., was significantly decreased. Under 15 mg· L^-1 Cd, the concentration of Cd in the shoots and roots were reached 637.5 and 1 663.0 mg kgl, respectively. These results showed that under oxidative stress caused by Cd, the phytochelatins were induced and the activities of the antioxidative enzymes were enhanced to increase the tolerance ofBrassica campestris L.

关 键 词：CD 小白菜 抗氧化酶 非酶物质 

分 类 号：X171.5[环境科学与工程—环境科学] Q945.78[生物学—植物学]