Antioxidative responses to cadmium stress in the hyperaccumulator Arabis paniculata Franch
Cd胁迫下超富集植物圆锥南芥抗氧化机理

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.