Abstract: Aiming to investigate the effects of NH₄H₂PO₄, citric acid and EDTA on the accumulation and translocation of lead (Pb) and cadmium (Cd) by Pteris vittata L., a pot experiment was conducted using two types of Pb and Cd co-contaminated soils (fluvoaquic soil and meadow cinnamon soil) collected from northern China. Results indicated that EDTA significantly increased the aboveground Pb concentrations of P. vittata by 33.9 folds in fluvoaquic soil and by 5.97 folds in meadow cinnamon soil, respectively. Due to the inhibition of EDTA on the biomass of P. vittata, the extent of increase in Pb amount accumulated in the aboveground part was less, being 9.22 folds in fluvoaquic soil and 1.18 folds in meadow cinnamon soil, respectively. Similarly, EDTA increased the aboveground Cd concentrations of P. vittata by 9.16 folds in fluvoaquic soil and 2.40 folds in meadow cinnamon soil respectively, but did not increase the amount of Cd accumulated in the aboveground parts of P. vittata. Neither NH₄H₂PO₄ nor citric acid treatment increased the concentration of Pb and Cd in P. vittata. This study can provide a basis for the remediation of Pb-Cd cocontaminated soil.

Key words: size class structure, community stability, secondary deciduous broad-leaved forest, survival curve, species composition