Effects of leaf application of nanometer silicon to the accumulation of heavy metals in rice grains

A pot experiment was conducted to investigate the effects of leaf application of Si on the accumulation of Cd, Pb, Cu and Zn uptake in rice (Oryza sativa L. cv. youyou 128) grains. The results showed that the weight of per 100 grains, weight of per spike, spike number of rice and the accumulation of Cu in grains were decreased significantly (P0.01), but the accumulation of Cd, Zn, Pb in the grains increased with the increasing of Cd concentration in the soil. The accumulation factor of heavy metals in grains was in the order: Cd Zn Cu Pb. Leaf application of Si alleviated the toxicity of heavy metals on rice. Compared with leaf application of inorganic Si, or- ganic Si was more positive in alleviating heavy metal toxicity. The leaf application of Si increased significantly (P0.05) the weight of per 100 grains and weight of per spike, and decreased significantly (P0.05) accumulation of Cd, Pb, Cu, Zn in the grain, the accumulation factor and the accumulate amount of heavy metals in grains. With the increasing of Cd concentration in soil, the alleviating of Si applica- tion on heavy metal toxicity was more pronounced in the soils contaminated with higher level of Cd. These indicated that leaf application of Si might be an efficient alternative to alleviate heavy metal toxicity and to decrease accumulation of heavy metal in rice grains.