Distribution And Accumulation Control Of Cadmium In Rice Grown In Contaminated Soil

With the development of industry and the modernization of agriculture,the heavy metal pollution of soil in our country has become more and more serious,and the pollution of heavy metal cadmium is relatively outstanding.When rice is planted in the contaminated soil,it can absorb and accumulate cadmium in soil,whice caused the problem of food security has seriously threatened the safety of human life.Therefore,it is an urgent problem to reduce the accumulation of heavy metal Cd in rice.In this paper,the distribution characteristics of Cd and other elements in rice grain grown in contaminated Soil were studied by SRXRF synchrotron radiation X ray method.Based on the characteristics of this distribution,different agronomic measures were adopted,including the change of water management and the addition of different forms of Se.To study their effects on the accumulation of Cd in rice,wich provide theoretical basis and technical support for the effective control of rice Cd accumulation.The following conclusions can be obtained through the above research:?The Cd is mainly distributed on the outer surface of rice grain grown in contaminated soil,which is part of the department of rice bran and chaff,and the content of Cd in the highest part is the bran,endosperm has the less distribution,There was a certain correlation between the distribution of Cd and K and Ca in rice grains.The distribution of Cd in rice grains was very different from the distribution of As and Se,and the content of As and Se are lower than the content of Cd,it shows that elements Cd have antagonistic effect with As and Se in rice grains.?In the Cd polluted farmland,using the whole growth period of waterlogging treatment,Cd concentration of the rice straw,rice husk,rice can decreased significantly.later stage of flooding had no significant effect on the uptake of Cd by rice.The Cd content of rice straw was significantly higher than that of rice husk,rice bran,rice part.The Cd is mainly distributed in the rice bran,and fine rice should be considered in the choice of edible rice department.?Under the conditions of Cd pollution,Se(VI)could inhibit the growth and induce toxicity of rice on a degree of oversensitivity.The accumulation of Se(VI)in rice stems and leaves was significantly higher than Se(IV),while in the root system,that was the contrary.With concentration of 2mg/kg Cd,Se(VI)can improve the absorption of Cd in rice stems and leaves,reduce the absorption of Cd in rice root.While the concentration of Se(IV)reached 2mg/kg,Se(IV)will reduce the absorption of Cd in rice stem leaf and root.Se(VI)can improve the ability of Cd from rice roots to the stem and leaf,while Se(VI)can reduce the transfer ability of Cd from rice root to stem and leaf.That only Se(IV)can reduce Cd uptake by the rice.