| Formation of iron plaque on root surface and its effect on Cd uptake and translocation by rice at different growth stages were investigated in pot experiment. The results showed that the formation of iron plaque on root surface was affected by different rice cultivars and growth stages, the amount of iron plaque of two rice cultivars（YD6 and NK57） decreased with the increase of growing stages. Compared to tillering stage, the amount of iron plaque for YD6 and NK57 decreased 82.9% and 44.4% at booting stage，and 85.2% and 82.5.2% at maturing stage, respectively. Both Cd concentration in root and shoot of the two rice cultivars increased with the increase of growing stages. Cd concentration in grain of YD6 was significant higher than that of NK57. Bio-accumulation factor and distribution ratio of Cd varied with different rice cultivars and growing stages. The capacity of Cd translocation from iron plaque and root to grain for YD6 was significant greater than that for NK57. At maturing stage, there was a significant negative correlation between the amount of iron plaque and Cd concentration in shoot or in grain（P<0.01）, indicating that the formation of iron plaque could inhibit Cd transferring from root to shoot and grain. The results implied that Cd transfer to rice grain could be reduced by regulating the formation of iron plaque at different growing stages, and Cd damage to human health would be mitigated. |
