Effects Of Selenium On Rice Growth And Cadmium And Selenium Transport And Enrichment Under Cadmium Stress

Cadmium pollution and selenium deficiency are currently problems in China’s rice production.Selenium relieves the stress of cadmium on rice,reduces cadmium enrichment,and increases selenium absorption to a certain extent.In this experiment,the effects of selenium and cadmium transport and enrichment on the growth of six rice varieties were studied by applying selenium treatment under different cadmium stress.The main research conclusions are as follows:(1)Cadmium reduces the plants height and ear length of rice,hinders the establishment of rice nutrition structure,reduces the size of the "bank",reduces the mass of dry matter produced by photosynthesis,and reduces rice yield.The reason may be that the ability of rice roots to absorb nutrients and photosynthesis is reduced.Selenium increased the 1000-grain weight and yield of rice,and increased the dry matter mass produced by photosynthesis.The reason may be that selenium protects chloroplast function and enhances photosynthesis rate.However,the effect of increasing selenium production in high cadmium soils is reduced.(2)In high-cadmium soils,the cadmium content in various parts increased significantly,and the cadmium transport volume in leaves and stems increased,but the transport efficiency decreased.The cadmium content in each part of the grains increased significantly,the leaf and stem BCF increased,and the ear,brown rice and polished rice BCF decreased.After selenium application,the cadmium content in leaves and stems increased,the cadmium content in ears decreased,the leaf and stem transport volume and transport efficiency decreased,the cadmium content in all parts of the grains decreased significantly,the leaf and stem BCF increased,and the ear,brown and polished rice BCF decreased.Cadmium was mainly distributed in the stalk(82.24%)at the booting stage,and mainly distributed in the ear(57.57%)and the stem(36.06%)at the maturity stage.The cadmium concentration in the grain was cereal layer> chaff> polished rice.The content of cadmium in various parts of rice was significantly positively correlated with the content of cadmium in brown and polished rice.The correlation between leaves and stems at booting stage was higher than that at mature stage,and the correlation between cadmium content at the ear of mature stage and cadmium content in polished and brown rice was the highest.(3)Without selenium treatment,the selenium content in leaves and stems of high-cadmium soils decreased during maturity.Under selenium treatment,the leaf selenium content increased,but the ear selenium content decreased in the high cadmium soil.The selenium transport in lower leaves and stems of high cadmium soils decreased,the selenium transport efficiency in stems decreased,and the selenium content in each part of the grains decreased.The order of the decrease was polished rice> flour layer> brown rice> chaff.Selenium application increased the selenium content in various parts,the selenium transfer amount increased,the leaf selenium transfer efficiency increased,the stem selenium transfer efficiency decreased,and the selenium content in each part of the grain increased.The order of increase was in the order of cereal flour layer> chaff> brown rice> polished rice.The order of the selenium concentration in the grain is as follows: cereal flour layer>chaff> polished rice.The utilization rate of selenium in brown rice is 5.18% to 6.70%,and the utilization rate of selenium in polished rice is 1.16% to 1.92%.(4)CLiangyou 386 may be a high-yield species cultivated in a selenium-rich area in a cadmium-contaminated area.The application of selenium in low cadmium soil can make the cadmium concentration in Huanghuazhan,Cliangyou386,Yliangyou7 and Shenliangyou 5814 polished rice less than 0.2mg/kg.When selenium was applied under high cadmium soil,the cadmium concentration in polished rice was reduced but more than 0.2mg / kg.The application of selenium in low-cadmium soil can make rice reach the standard of selenium-enriched rice,and the application of selenium in high-cadmium soil can only reach the standard of selenium-rich rice in Xiangwanxian 13.