| Heavy metal pollution of soil and wetlands has been a serious problem, because of its toxicity to environment and humans. Screening new high biomass and accumulator or hyperaccumulator plants was the focus of bioremediafion. In these study Polygonum lapathifolium L. is a Polygonaceae herb found at a lead-zinc mine area in Yingjing, Sichuan, China. The main results obtained were as follows.(1) Polygonum lapathifolium can both grow normally with no visible symptoms of toxicity at Cd concentration≤40 mg L-1 in solution culture and≤150 mg kg-1 in soil culture. When compared with the control, under the two culture conditions, plant hight, contentration of chlorophyll, and the biomass of roots and shoots under Cd stress were lower, but root lengths were higher than the control in soil culture. When Cd concentrations were 10-55 mg L-1 in solution culture, The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were higher than control. the Cd concentrations in the shoots were113.2-367.9 mg kg-1, the bioconcentration factors (BCF) in shoots and translocation factors (TF) under Cd stress were 6.21-11.32 and 0.41-1.67. In soil culture, when Cd concentrations were 25-150 mg kg-1, the Cd concentrations in the shoots were10.8-89.7 mg kg-1, the accumulations of Cd in shoots were 43.70-66.28% of the total amount in the plant, the BCF and TF in shoots under Cd stress were 0.40-0.61 and 0.20-0.67.(2) Polygonum lapathifolium can grow normally with no visible symptoms of toxicity at Cu concentration≤50 mg L-1 in solution culture. When compared with the control, root length, plant hight, contentration of chlorophyll, and the biomass of roots and shoots under Cu stress were lower. When Cu concentrations were 20-60 mg L-1, the activities of SOD, POD and CAT were significantly higher (P<0.05). When Cu concentrations were 20-80 mg L-1, the Cu concentrations in shoots were 134.2-420.7 mg kg-1, the accumulations of Cu in shoots were 45.4-71.7% of the total amount in the plant, the BCF and TF in shoots under Cu stress were 4.00-6.71 and 0.36-0.86.(3) Polygonum lapathifolium can grow normally with no visible symptoms of toxicity at Pb concentration≤400 mg L-1 in solution culture. When compared with the control, root length, Plant hight, and contentration of chlorophyll all increased at a lower Pb level (100 mg L-1), and decreased significant at a higher Pb level (≥300 mg L-1)(P<0.05), the biomass of roots and shoots under Pb stress were both lower, and the activities of SOD, POD and CAT were higher. When Pb concentrations were 100-700 mg L-1, the Pb concentrations in shoots were 228.0-1477.4 mg kg-1, the accumulations of Pb in shoots were 33.8-53.8% of the total amount in the plant, the BCF and TF in shoots under Cu stress were 1.22-2.28 and 0.33-0.54.(4) Polygonum lapathifolium can both grow normally with no visible symptoms of toxicity at Zn concentration≤80 mg L-1 in solution culture and≤1500 mg kg-1 in soil culture. When compared with the control, under the two culture conditions, plant hight, biomasses and the contentration of chlorophyll were lower, but root lengths were higher than the control in soil culture. In solution culture, When Zn concentrations were 20-150 mg L-1, the activities of SOD, POD and CAT were higher, the Zn concentrations in shoots were 627.0-5417.1 mg kg-1, the accumulation of Zn in shoots was 62.6-78.4% of the total amount in the plant, the BCF and TF in shoots under Zn stress were 14.04-31.35 and 0.57-0.89. In soil culture, when Zn concentrations were 300-3000 mg kg-1, the Zn concentrations in shoots were 138.8-883.6 mg kg-1, the accumulation of Zn in shoots was 63.5-77.9% of the total amount in the plant, the BCF and TF in shoots under Zn stress were 0.28-0.51 and 0.27-0.64.Generally speaking, Polygonum lapathifolium had a stong tolerance and accumulation characteristics of Cd and Zn, and had some tolerance and accumulation ability.
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