Study On The Stability Of Cadmium Absorption And Accumulation In Rice

In order to reduce the Cd content of rice, a passivation agent way is used in the production of low-cadmium planting rice varieties to reduce the effectiveness of cadmium in soil was applied or other technical measures done, but there are many factors which can influence rice plants to absorb and accumulate cadmium in the grain, and they are interacting. In order to ascertain rice genotypes and environmental factors on the accumulation of cadmium in rice, we had chosen multiple rice varieties grown in Hunan Province in different locations and different years for field experiments to study the rice performance in absorption and accumulation of cadmium. The main results were as follows:1. Distribution and accumulation of cadmium in different organs of riceIn 2013,112 representative rice varieties were planted in experimental field of Xiangyin County Agricultural institute as later season. The content of cadmium in tested soil was 0.67mg/kg. The content of cadmium in different organs were analyzed. The results showed that, Cd accumulation in rice plants mainly concentrated in the vegetative organs, accounting for 84.9%, but among different varieties exist larger differences, such as V133 varieties, the accumulation of Cd in stems and leaves was 94.52% of the whole plant, and V118 only accounted for 68.2%.2. Distribution and accumulation of cadmium in rice in different years and locationsThere were significantly difference of Cd content among 112 varieties which conducted in Xiangyin County in different years and the mean value of was 1.31 mg/kg in 2013, with a max of 2.6 mg/kg, the min value was 0.19 mg/kg and the max was 13.68 times higher than the min. while in 2014 the mean value of 112 varieties was 0.72 mg/kg with a max of 1.38 mg/kg, the min value was 0.4 mg/kg, and the max was 3.45 times higher than the min.In order to study genotype and environmental effects of Cd content in rice grain,78 rice genotypes of great different grain Cd concentration were chosen to be grown in Xiang yin, Xiangtan and Hengyang in Hunan province. The results showed that there were significant differences between the genotypes of Cd content in rice grain and environmental effects, and there was a significant difference of Cd content in brown rice stability with the environment and genotype. The Cd accumulation of brown rice in different species and the environment have reached a significant level (P<0.01), there was significant differences in the environment too, the proportion of its effect (SS, sum-of-squares) in the total effect (SS, sum of squares) was 74.05%, followed by genetic and environmental interaction effects and genotype respectively accounted for 17.02% and 8.93%.3. Cd accumulation of rice research under four different regional conditionsIn order to study rice grain Cd concentration differences, A relatively low grain Cd concentration of rice varieties Xiangwanxianl3 was planted with 161 countries in Hunan Province. The results showed that there were significant differences between genotype and environmental effects of Cd content with grain heavy metal, including significantly differences between soil pH value with Cd concentration of heavy metals in brown rice and soil pH value with Cd concentration of heavy metals in soil while Cd concentration of heavy metals in soil and in brown rice’s correlation is not obvious, change scope of soil pH in 58 sampling points in three regions of Tan was 4.6-8.5, with an average of 5.7; change scope of heavy metals Cd content in soil is 0.12-3.03mg/kg, with an average of 0.83mg/kg; change scope of soil pH in the other 103 sampling points was 4.8-8.5, with an average of 5.099; change scope of heavy metals Cd content in soil was 0.18-5.099 mg/kg, with an average of 0.611mg/kg; There were significant difference of heavy metal content in rice, and the magnitude of this difference varies by region, the change scope was 0.001-1.397 mg/kg.There were many factors of absorption and accumulation of heavy metal cadmium in rice plant, on the one hand was rice absorption characteristics, in this study, not the total absorption or in the distribution of plants, among different cultivars showed large differences; second, the influence of environmental factors, the results of this study showed that in different years and locations of rice uptake and accumulation ability of cd also showed a greater difference. In the comprehensive view, the main factors that affect the uptake of cadmium in rice plants are environmental factors. Therefore, in order to reduce the content of rice which planted in cadmium polluted area, mainly using agronomic measures to regulate and control the growth environment in order to reduce the cadmium accumulation in rice plants.