Abstract:In this study, soil and hydroponics culture systems were used to investigate the effects of iron plaque on the uptakes of Cd, Mn, Cu and Zn by rice seedlings supplied with different levels of Fe and Cd. The three iron levels(as FeSO4·7H2O) were 0, 1 and 2 g/kg in soil culture, and the six levels were 0，10，30，50，80 and 100 mg/L in solution culture. The cadmium levels(as 3CdSO4·8H2O) were 0，2 and 10 mg/kg in soil, and 0，0.1 and 1.0 mg/L in solution. After harvest, the contentrations of Fe, Cd, Mn, Cu and Zn in iron plaque, roots and shoots were determined. The results showed that the iron plaque(DithioniteCitrateBicarbonate DCB-Fe) on root surface was increased with the increase of Fe concentration in the two culture systems. In the soil culture experiment, the Cd and Mn contentrations in the iron plaque(DCB-Cd and DCB-Mn) are slightly increased with the increase of external Fe, and the concentrations of all elements in roots are higher than those in the iron plaque. In the hydroponics culture experiment, the Mn and Cu contentrations in the iron plaque are increased only when higher Fe is added, and the contentrations of Mn, Cu and Zn in the iron plaque are higher than those in roots. The contentrations of Zn in iron plaque are not significantly changed in both soil and hydroponics culture experiments. In general, the concentrations of Cd, Mn, Cu and Zn in roots and shoots are decreased with the increase of Fe supply in soil and nutrient solution, and the concentrations of Cu and Zn in the Cdaddition treatments are lower than those in the no Cd-addition treatments. The above results indicate that the iron plaque may play a limited role in Cd uptake and its translocation in rice plants, and the effects of the iron plaque on the uptakes of Mn, Cu and Zn depend on the culture systems and elements species. However, antagonistic interaction between elements probably contributes to the decreases of the concentrations of Cd, Mn, Cu and Zn in roots and shoots.