关键词: 空心菜;土壤重金属;Pb;Cd;生物量;抗氧化酶

Abstract:

The effects of single lead (Pb) and cadmium (Cd) stresses on the growth, lipid peroxidation and antioxidant enzyme system of swamp cabbage (Ipomoea aquatica Forsk.) were investigated by pot experiment. The results showed that low Pb concentrations stress could slightly increase the biomass of swamp cabbage, whereas its growth would be significantly inhibited under high concentrations. The biomass in 900 mg/kg Pb treatment was only 32.4% of that in the control. Its growth was also inhibited under Cd stress. The biomass in 7 mg/kg Cd treatment was 83.6% of that in the control. The leaf content of malondialdehyde (MDA) increased with increasing Pb and Cd concentrations. The MDA contents under the highest concentrations of Pb and Cd increased by 12.9% and 29.5%, respectively compared to the control, indicating that swamp cabbage was more resistant to Pb than Cd. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in its leaves increased initially and then declined with the increasing of Pb concentration. The results indicated that the three anti-oxidative enzymes had remarkably synergistic effects under low concentrations of Pb than Cd, and could increase swamp cabbage adaptation to heavy metal stresses.

Key words: swamp cabbage (Ipomoea aquatica Forsk.), soil heavy metal, plumbum, cadmium, biomass, anti-oxidative enzyme