| In order to find the theoretical basis for the safe production of rice,the key pe-riod of rice cadmium（Cd）accumulation and the cadmium accumulation of rice under different concentrations of cadmium stress were studied.The effects of cadmium stre-ss(50μg?L-1)on the accumulation of cadmium.The relationship between cadmium s-tress and rice cadmium was studied by using different concentrations of cadmium st-ress.The relationship between stress tolerance and cadmium accumulation in rice was studied,and the correlation between rice stress resistance and rice was studied.The law for the safe production of rice to provide a theoretical basis.The main test con-clusions are as follows:（1）In this study,a hydroponic experiment was conducted to study the effects of cadmium stress on rice growth and cadmium accumulation in rice seedlings.6 ca-dmium concentration gradients were used to study the effects of cadmium stress on rice growth.Zhongjiazao17 and Taiyou 390 were the two varieties.Compared with CK,Cd10 low concentration could effectively promote rice And the efflue-nt intensit y and yield of rice stem were higher than CK,and there was no significa-nt differen ce between plant height and effective tiller number.And inhibited the gro-wth of rice under 50μg?L-1 Cd concentration.The location of the cadmium content and cadmiu m concentra-tion is proportional to the rice,Cd content in brown rice increased with the increaseof stress concentration,Rice yield,Cd10 yield increased compared to CK but not signifycant,other treatments yield increased with the concentration of Cd de-creased,there were significant differ-rences among treatments in yield,Therefore,the hydroponic study has elucidated the effect of light-medium-heavycadmium stress on rice growth and cadmium content in rice,and provided the datasupport and the-oretical basis for the safe production evaluation of paddy soil.（2）Using hydroponic experiment method,the study of different concentrations of cadmium stress on rice superoxide dismutase（SOD）activity and malondialdehyde（M DA）content,SOD activity and MDA content of the research of cadmium content in brown rice and rice.MDA content increased with the time of cadmium stress.Main rice leaf SOD activity and MDA content cadmium with brown rice content were sig-nificantly related.Therefore,the study can determine the cadmium content inbrown rice by measuring the activity of SOD and MDA in leaves under different Cd stress.（3）In this study,Cd accumulation in rice at different growth period,Cd distrib-ution in different part of the rice and the intrinsic relationship between them were in vestigated by water culture experiment with low concentration of exogenous cadmium addition at different growth stages of rice.The results showed that:after adding exo-genous Cd at different growth stages,the cadmium a-ccumulation in the rice at boot-ing stage and heading stag were 2.53,2.9 mg?kg-1,and the cadmium accumulation in Xiangwanxian 13 is 3.43,4.05 mg?kg-1,respectively,which were much higher than that of the national food hygiene standards(Cd<0.2 mg?kg-1).It is evident that the percentage of contribution to the Cd accumulation was 38.72%and 29.05%for zhon-gjiazao17 and 31.73%and 37.63%for Xiangwanxian13 at their booting stage and he-ading stage,respectively.Therefore,this study can provi-de scientific basis and theor-etical guidance for the application of soil conditioner and foliar inhibitor in the actu-al safe production process of paddy field,and to control thecadmium pollution of rice to realize safe production of rice. |
