Screening And Identification Of Different Rice Cultivars For Cd Tolerance And The Alleviation Of Exogenous GSH On Rice Under Cd Stress

Cadmium is a kind of harmful heavy metal elements in plants and animals.With the development of the industry,the pollution of Cd become more and more serious.it is through the water,the soil and other ways to be absorbed by the plant,and through the food chain into the body,causing harm to the human body.Cadmium in the soil by enrichment of crop is the most important way to enter the body.Rice is one of the most important crops in China.Compared with other crops,rice’s ability of tolerant to cadmium and cadmium uptake is stronger,and this may causing a risk of excessive Cd content in milled rice.So the research to the growth of rice under cadmium stress has important significance.In order to realize the growth of health and safety of rice in cadmium polluted soil,rice varieties should have good characteristics of cadmium tolerance and low Cd accumulation first.This needs to carry on the research on rice’s Cd tolerance,uptake and translocation.In this paper,we used principal component analysis and cluster analysis to analyze data.We studied the Cd tolerance,uptake and translocation of 29 rice cultivars,and screened out the tolerant variety LianJing7 and the sensitive variety 9you418.We had a research to the effects of cadmium stress on root activity,the content of MDA and the content of chlorophyll in the two cultivars rice seedlings.In addition,we also studied the effects of exogenous GSH on the two cultivars rice seedlings under cadmium stress.The main results are as follows:1 The Cd tolerance accumulation and translocation of different cultivars rice are significantly different.According to the ability of Cd tolerance,the 29 rice varieties were divided into five groups.Over all,the translocation factor of conventional japonica rice is significantly lower than indica hybrid rice and indica japonica hybrid rice.The ability of Cd accumulation in different rice varieties is different.Generally speaking,the Cd accumulation of conventional japonica rice was the lowest,followed by the indica japonica hybrid rice,the hybrid indica rice accumulated the highest amount of Cd.There is no direct relationship between the tolerant ability to cadmium in rice and its Cd uptake and translocation ability.2 The root activity and chlorophyll content were decreased much less in lianjing7 than in 9you418 under cadmium stress,which mean the former has a better cd-tolerence.Lianjing7 has a less MDA content and more CAT activity than 9 you 418,shows a better antioxidant capacity.The allocation rate of cadmium in the cell wall in lianjing7 is higher than 9you418 at subcellular level under cadmium stress and in cell organelles is lower3 The exogenous GSH can increase the root length,plant height,chlorophyll of the two kinds of rice under Cd stress.In addition the exogenous GSH reduced the contrent of MDA and increased the CAT activity in the two kinds of rice.When the exogenous GSH was added,the content of Cd in shoots of rice and the translocation factor decreased significantly,resulting in a large number of Cd are retained in the roots.These may be why exogenous GSH could alleviate the toxicity of cadmium...