锰污染对酸模叶蓼生长、锰吸收及抗氧化物活性的影响

采用土培方法,研究了广西某锰矿区未开采区、探矿区、恢复区、开采区和尾矿坝的土壤对酸模叶蓼(Polygonum lapathifolium Linn.)的生长、Mn吸收及抗氧化酶系统的影响。结果表明,酸模叶蓼的根、茎、叶中Mn含量随着土壤Mn浓度的增加而增加,Mn含量依次为根茎叶;尾矿坝土壤中(T6处理),叶片Mn含量达到最大值5566.9 mg/kg。锰污染显著提高了酸模叶蓼叶片中H_2O_2和MDA的含量,但锰污染对酸模叶蓼的生物量无显著影响。锰污染土壤显著降低了酸模叶蓼叶片中SOD、POD、APX和As A等抗氧化物的活性,而CAT的活性则呈先上升后下降的趋势,表明Mn污染促使酸模叶蓼启动了抗氧化酶系统;Mn污染同时显著提高了酸模叶蓼叶片中-SH、GSH和PCs的含量,表明-SH、GSH和PCs在解毒酸模叶蓼Mn毒害的过程中起重要作用。

Effects of Manganese Contamination on the Growth,Mn Accumulation and Antioxidants of Polygonum lapathifolium Linn.

The effects of manganese contamination on various enzymatic and non-enzymatic antioxidants in the leaves of Polygonum lapathifolium Linn. were studied. As a newly identified manganese hyperaccumulator, P.lapathifolium was grown in soils with various Mn concentrations for 70 d. Plant leaves were analyzed for activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and contents of ascorbic acid (AsA), glutathione (GSH), phytochelatins (PCs), total acid soluble SH, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and superoxide anion (O₂^·-) evolution rate. The results showed that Mn content in the roots, stems, and leaves of P. lapathifolium increased with Mn concentrations in the soil. Both the MDA and H₂O₂ contents significantly increased with Mn treatment. However, the biomass of P. lapathifolium showed no significant differences compared with that of the control. The activities of SOD, POD, APX and AsA significantly decreased with increasing Mn treatment, which indicated that P. lapathifolium stimulated the antioxidant enzyme system. The contents of GSH, PCs and -SH were significantly higher than those of the control. These results indicate that both enzymatic and non-enzymatic antioxidants play significant roles in Mn detoxification in this plant.