Abstract: A hydroponic experiment with different concentrations of Cd and Pb was conducted to investigate the capabilities of sunflower, ricinus, alfalfa, and mustard in accumulating Cd and Pb. After treated for five weeks, the Cd and Pb contents in the roots and shoots of test plants increased with increasing concentrations of medium Cd and Pb. In treatment 20 mg Cd·L^-1, sunflower roots had the highest Cd content (237.86 mg·kg^-1), and its shoots accumulated 89.48 mg·kg^-1 of Cd. In treatment 200 mg Pb·L^-1, mustard roots showed better capability in enriching Pb (597.22 mg·kg^-1). In treatment 100 mg Pb·L^-1, sunflower shoots had the highest content of Pb (318.33 mg·kg^-1). For the test plants, the enrichment coefficients of Cd and Pb decreased with increasing concentrations of medium Cd and Pb, and had definite correlations with plant biomass and the concentrations of medium Cd and Pb. In the treatments with combined application of Cd and Pb, there existed definite antagonism in the Cd and Pb uptake by the plants. Through the comparison of plant biomass and of the enrichment characteristics of Cd and Pd by roots and shoots, it was considered that relative to the other three test plants, sunflower could be selected as a potential candidate for the phytoextraction of soil Cd and Pb.

Key words: Black soil, Soil organic carbon, Simulation