Tolerance And Accumulation Characteristics Of Polygonum Chinense L. Under Cadmium, Copper And Lead Stress

According to the distribution characteristics of Polygonum chinense L., we determined that Polygonum chinense L. taken from Luchang Copper Mines in Huili in western Sichuan, China as the research object, which had some differences in the ecological environment. A pot experiment was conducted to study Cd, Cu and Pb tolerance and accumulation characteristics of Polygonum chinense L..The result showed as follows:(1) The plant showed some tolerance and enrichment ability under the Cd stress. The plant height, root length, root projected area, root surface area, root volume, chlorophyll, POD activity in root, CAT and POD activity in leaves enhanced firstly and then weakened with the Cd concentration increased. The plant grew normally, no obvious poisoning phenomenon at soil Cd concentrations<75mg kg-1and the plant height, root length, root projected area, root surface area, root volume, chlorophyll, POD activity in root, CAT activity in leaves were all higher than the controls. At high concentrations of Cd (≥100mg kg-1) stress, plant height, root length, POD activity in root were lower than the controls. At the soil Cd concentration of125mg kg-1, the highest concentrations in roots and shoots were1215.50and77.10mg kg-1, respectively. At the soil Cd concentration of25mg kg-1, the highest accumulations in roots and shoots were161.04and114.01μg pot-1, respectively. The BCF in roots were2.13-8.92, and the BCF in shoots were more than1.0at the soil Cd concentration of5、25and100mg kg-1, the TF of plants were0.07-1.05.(2) The plant showed some tolerance and enrichment ability under the Cu stress. The plant height, root length, root projected area, root surface area, root volume, CAT and POD activities of plants increased firstly and then decreased with the Cu concentration increased. The plant grew normally, no obvious poisoning phenomenon at low Cu concentrations and the plant height, root length, root projected area, root surface area, root volume, biomass of stems and leaves. However, the growth was inhibited under high Cu concentrations stress. POD and CAT in leaves under various Cu concentrations stress were all higher than the controls obviously. At the soil Cu concentration of1500mg kg-1, the highest concentration in roots and shoots were877.33and308.36mg kg-1respectively. At the soil Cd concentration of500and1500mg kg-1the highest accumulations in roots and shoots were645.17and460.71μg pot-1, respectively. The BCF in roots were0.41-1.65, more than1.0at the soil Cd concentration of100and250mg kg-1, the BCF in shoots were0.06-1.40. the TF of plants were0.15-1.10..(3) The plant showed some tolerance and enrichment ability under the Cd stress. The plant height, root length, root projected area, root surface area, root volume, CAT in leaves and POD activities increased firstly and then decreased with the Pb concentration increased. The plant height was all higher than the controls obviously at T1-T6(100-1250mg kg-1)(P<0.05). The root length and POD in roots were all higher than the controls under low Pb stress, which were inhibited at soil Pb concentrations≥1000mg kg-1. POD in leaves at soil Pb concentrations>1000mg kg-1were obviously higher than the control. At the soil Cu concentration of1000mg kg-1, the highest concentration in roots and shoots were1494.01and165.56mg kg-1, and the highest accumulations in roots were1570.55μg pot-1respectively. The BCF in roots were0.87-2.15, more than1.0at the soil Cd concentration of1250mg kg-1, the BCF in shoots were0.05-1.68. the TF were0.22-0.78..Generally speaking, Polygonum chinense L. showed some tolerance and enrichment abilities of Cd、Cu and Pb. Althouhg the enrichment of single plant was poor, the strong vitality and perennial features let the plant to be an bioremediation plant which was good at controlling the heavy metal soil pollution.