Cd胁迫下超富集植物圆锥南芥抗氧化机理

采用土培的方法研究了不同Cd2+添加量(0、10、20、40、80、160、240mg.kg-1)对多金属超富集植物圆锥南芥(Arabis paniculata Franch)抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶POD、抗坏血酸过氧化物酶CAT、过氧化物酶APX)活性、非酶物质(巯基SH、谷胱甘肽GSH、植物络合素PCs)含量以及生物量、叶绿素、丙二醛(MDA)、半胱氨酸(Cysteine)、脯氨酸(Proline)含量的影响.结果表明,随着Cd添加量的增加,圆锥南芥的生物量、Cd含量、富集系数、转运系数呈增加趋势,SOD活性、叶绿素含量呈下降趋势.POD、CAT、APX活性以及MDA含量均呈先升高后降低的变化趋势.圆锥南芥叶片中SH、GSH、PCs含量随Cd添加量的增加而增加,当Cd添加量为240mg.kg-1时,SH、GSH、PCs含量分别比对照提高了92.7%、70.2%、143.4%,表明SH、GSH、PCs在解毒Cd毒害中起着重要作用.

Antioxidative responses to cadmium stress in the hyperaccumulator Arabis paniculata Franch

The effects of cadmium (Cd) on various enzymatic antioxidants and non-enzymatic antioxidants in Arabis paniculata Franch were studied. A. paniculata, a newly identified multi-metal hyperaccumulator, was grown in soils with various Cd concentrations (0, 10, 20, 40, 80, 160 and 240 mg·kg-1) for 135 days. Plant leaves were analyzed for contents of glutathione (GSH), phytochelatins (PCs) and total acid soluble SH, chlorophyll, malondialdehyde (MDA), cysteine, proline and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). The results showed that the plant biomass, Cd content, bioaccumulation factor and translocation factor increased, while the chlorophyll content and SOD activities decreased as the soil Cd concentrations rose. The activities of enzymatic antioxidants (POD, CAT and APX) and the contents of MDA increased at soil Cd concentration below 40 mg·kg-1and then decreased after this. The contents of GSH, PCs and SH rose with Cd concentration. Compared to the control, the contents of GSH, PCs and SH increased by 92.7%, 70.2% and 143.4% respectively at a soil Cd concentration of 240 mg·kg-1. The results indicated that both enzymatic and non-enzymatic antioxidants play significant roles in Cd detoxification in this plant.