Effects Of Rice Varieties On Accumulation Of Cd And Pb In Soils

Cadmium(Cd)and lead(Pb)are the most important heavy metals in the soil.As the development of industry and the population growth,the pollution of Cd and Pb becomes more and more serious,and is causing serious threat to huma health.Rice is one of the most important crop worldwide,especiall in Asia.In order to better understand the difference in the uptake and accumulation of Cd and Pb from the soil bydiffernet rice cultivars,an experiment was performed by comparing 20 rice cultivarson a field which has been slightly polluted by Cd and Pb near a mining area in Sanming City,Fujian province.The main results are follows:1.Cadmium(Cd)and lead(Pb)was mainly accumulated in rice roots as compared with the other parts of rice.The concentration of Cd and Pb in brown rice decreased with increasing rice yield.The Cd in the brown rice of japonica hybrid rice was lower than that in other rice.No obvious relationships were observed between Pb content in the brown rice and rice types.2.The content of iron-plaque on rice roots was positively correlated with Cd content in the Fe plaque.The contents of Cd in the Fe-plauqe and in the rice root were positively correlated.The content of iron-plaque was positively correlated with Pb content in the Fe plaque while the Pb content in rice root tended to decrease with increasing content of Pb in Fe-plaque.More Fe-plauqe on rice roots,more Cd and less Pb was absorbed by the rice roots.3.Among the various transfer factors(TFs)in each part of rice plant,TFleaf-grain was best correlated with the bio-accumulation factors of Cd and Pb by rice grains from the soils,indicating that the transfer between leaf and rice grains was the key step for Cd and Pb to be transported into rice grains.4.Among the 20 rice cultivars,Chun-you 84,Yong-you 9 and one red rice belonged to high-yield and low-Cd cultivar,so they are recommended to be cultivated on Cd-polluted soil.Chun-you 84 and the red rice belonged to high-yield and low-Pb cultivar,which should be preferentially cultivated on Pb-polluted soils.Dong-lian 5 and Yang-liang-you 6 belonged to low-yield and low-Pb cultivar.The high-yield,low-Cd and low-Pb rice cultivars were Chun-you 84 and red rice,which should be preferentially cultivated on Cd-Pb compound polluted soils.