Characteristics Of Cadmium Accumulation In Aerial Parts Of Rice And Study On Extraction Method Of Available Cadmium In Soil

Two rice varieties?a high cadmium accumulation cultivar and a low cadmium-accumulating cultivar?were used to study the accumulation of cadmium in the panicle and ripening stages of the aboveground parts of rice under different cadmium content.Cadmium response mechanism to provide a theoretical basis.In addition,six kinds of extractants were used to extract cadmium from available soil.The correlation between the available cadmium content and the accumulation of cadmium in different parts of rice was analyzed.It was found that the extraction of soil available cadmium was different.The main findings are as follows:1.The cadmium accumulation in different organs of rice was very different.At all heading and maturing stages,the contents of cadmium in the shoots of rice were in the order of stem>leaf>panicle,all heading stage to maturity stage.Spike cadmium content showed a downward trend,the cadmium accumulation in the shoots showed a decreasing trend of stem>leaf>panicle,panicle stage and maturity stage,and the accumulation of cadmium in stem and leaf decreased,and the accumulation of stem and cadmium at full heading stage was 1.23².46 times,1.31 to 2.15 times.In terms of breeds,cadmium content and cadmium accumulation in the shoots at the same stage and maturity stage were all in the order of Weiyou 46>XiangWan xian 13.2.Leaf cadmium output and cadmium content of shoots had positive effects on cadmium content in brown rice,and the effect of cadmium and cadmium was the highest.The direct diameter coefficient was 0.852,and the direct diameter coefficient was 0.7013.The direct effect of stem and cadmium on the cadmium output was 0.50334,but the stem and cadmium output was 0.7208 and0.5386,respectively.The results showed that the stem and cadmium output was brown The effect of cadmium accumulation is mainly through the leaves and branches,and the branches are only the transport channels of various nutrients in rice plants,and the leaves are the main storage organs of cadmium in the shoots.3.The average extraction rate of NH₄Cl>DTPA>CaCl₂>NH₄OAc>NaNO₃>H₂O and NH₄Cl was 32.94%,which was 1.59²00 times of that of other extractants,The results showed that the extraction capacity of different extractants was very different.The average coefficient of variation of different extracts showed the lowest H₂O,only 0.1375,and the variation coefficient of other extractants was between 0.21 and 0.325.4.CaCl₂-Cd content can represent the bioavailability of heavy metal cadmium in soil.Ca Cl₂-Cd content was significantly or positively correlated with stem and leaf cadmium output and spike and cadmium transport.The correlation coefficient was 0.7109*⁰.9329**.The content of H₂O-Cd was the same as that of spike and cadmium,The results showed that the contents of DTPA-Cd,NH₄OAc-Cd,NH₄Cl-Cd and NaNO3-Cd were not significantly correlated with cadmium content in different parts of rice.The correlation coefficients were-0.95**,-0.8807**,respectively.