Ecophysiological Responses Of Amaranthus Hydrophondricus L. To Cadmium And Lead Stress

With the rapid development of science and technology,heavy metals are widely used.The pollution caused by heavy metals is becoming more and more serious.In order to explore the growth,osmotic regulation,antioxidant enzyme and heavy metal enrichment and transfer capacity of Amaranthus hydrophondricus L.under the stress of Cd and Pb.The growth index,physiological and biochemical index,antioxidant enzyme activity index and Cd and Pb absorption and enrichment characteristics of two varieties of oleracea were studied by pot experiment,to provides theoretical guidance and feasible technical parameters for efficient bioremediation of Cd and Pb contaminated soil.The results showed that:（1）The plant height,fresh weight,biomass,chlorophyll content,soluble protein content and SOD activity increased in different degrees under the stress of single Cd concentration of 25 mg·kg^-1and Pb concentration of 2.5 g·kg^-1;the plant height,fresh weight,biomass,chlorophyll content,soluble protein content and SOD activity decreased in different degrees under the stress of Cd concentration of 250 mg·kg^-1and Pb concentration of 10 g·kg^-1;under the combined stress,the plant height and fresh weight of Cd 25 mg·kg^-1×Pb 2.5 g·kg^-1had no significant difference.However,the interaction stress of high concentration of Cd 250 mg·kg^-1×Pb 10 g·kg^-1inhibited it.（2）Under single stress,the intervention of exogenous heavy metals Cd and Pb could promote the production of soluble sugar and increase the activity of POD;under combined stress,Cd and Pb had a synergistic effect on the content of soluble sugar and the activity of POD.（3）Under single stress,the intervention of exogenous heavy metals Cd and Pb could reduce proline content and CAT activity.CAT was more sensitive to Cd and Pb than SOD and POD.（4）Pb content in aboveground part was significantly lower than that in root part,and Pb transfer coefficient was less than 1.The results showed that the accumulation organ of Pb was root,and the migration ability of Pb was weak,which could not meet the requirements of hyperaccumulator.The remediation effect of Pb contaminated soil is poor.（5）The content of Cd in the grassland was more than 100 mg·kg^-1,and the enrichment coefficient was more than 1,which met the standard of Cd hyperaccumulator.Under the treatment of Cd 250 mg·kg^-1×Pb 10 g·kg^-1,the maximum enrichment factor values of both varieties were obtained.Therefore,Amaranthus hydrophondricus L.is a Cd hyperaccumulator,which can further explore its remediation value for Cd contaminated soil.（6）The highest Cd accumulation of R104 and K472 was 7052.81μg/plant and5016.54μg/plant,respectively.The Cd accumulation of R104 was higher than that of K472,indicating that R104 was better than K472 in remediation of Cd contaminated soil.