Effects Of Intercropping On Selenium Enrichment Of Three Genotypes Radish

Selenium（Se）is an indispensable trace element for human and animals.It has the functions of antioxidation,anti-cancer and anti-virus.Because humans and animals mainly absorb Se from plants,and Se was absorbed into the food chain through plants,there was important that the effect of Se on plant growth and metabolism.Radish is one of the most common vegetables in the daily diet of urban and rural residents,and radish has the advantages of short growth period,strong reproductive capacity,high yield and wide distribution.In order to study the ecological toxicological effects of Se on radish,pot experiment was conducted to study the effects of Se on growth Se enrichment of radish.Furthermore,three different genotypes of radish were intercropped with each other under Se stress to select an intercropping mode which could significantly improve the Se enrichment ability of radish and benefit the growth of radish,and provide a reference for the production of Se-enriched radish.The main results were as follows:1.The results of Se enrichment characteristics of radish seedlings showed that:（1）Under different Se concentrations（0,5,10,25,50,75,100 mg/kg）,the biomass,dry matter and photosynthetic pigment content in all parts of radish seedlings decreased with the increase of soil Se concentration.（2）The superoxide dismutase activity and soluble protein content in radish seedlings were higher,peroxidase activity was higher and lower,and catalase activity was lower than the control.（3）With the increase of soil Se concentration,the Se content in different parts of radish seedlings showed an increasing trend,and the Se accumulation in each part was higher than the control.The Se accumulation in each part of radish seedlings reached the highest level when the Se concentration was 25 mg/kg.The results showed that Se application in soil could inhibit the physiological growth of radish seedlings,and more than 5 mg/kg of Se application could exert stress on the growth of radish seedlings.2.The effects of three different genotypes of radish on Se enrichment characteristics under soil Se stress showed that:（1）Under soil Se stress,white radish intercropped with green radish could increased the biomass,photosynthetic pigment content,net photosynthetic rate,stomatal conductance,intercellular CO₂ concentration,transpiration rate,enzyme activity,soluble protein and total phosphorus content of white radish,and Se accumulation content in edible part increased by 19.64%,while the biomass,photosynthetic pigment content,net photosynthetic rate,stomatal conductance,transpiration rate,enzyme activity,soluble protein content,total potassium content of green radish were decreased,and Se accumulation content in edible part decreased by 31.18%than the control.（2）white radish intercropped with red radish could inhibited the growth of white radish,the Se accumulation content in edible part of white radish was decreased by36.67%than the control,but promoted the growth of red radish,the Se accumulation content in edible part of red radish was increased by 5.20%.（3）The biomass,photosynthetic pigment content,net photosynthetic rate,stomatal conductance,transpiration rate,enzyme activity and soluble protein content of green radish and red radish were all decreased when the green radish intercropped with red radish,but the Se content of each part of green radish and red radish was increased,and the Se accumulation content in edible part of green radish was increased by 8.43%,and the Se accumulation content in edible part of red radish was decreased by 31.27%.（4）Among the three kinds of radish intercropped species,the Se accumulation content in edible parts of white radish,green radish and carrot were decreased by 49.46%,53.56%and 66.23%respectively than there control,while the Se accumulation content in green radish was the highest,but the Se accumulation content in white radish has a least reduce.3.The two experiments showed that Se application of more than 5 mg/kg in soil could inhibit the growth of radish seedlings and had a exert stress on seedlings.The Se accumulation content of radish seedlings was the largest when the soil Se concentration was 25 mg/kg.Under soil Se stress,white radish intercropped with green radish could improve the Se enrichment ability in edible part of white radish.Green radish intercropped with red radish could effectively improve the Se enrichment ability in edible part of green radish.White radish intercropped with red radish could effectively improve the Se enrichment ability in edible part of red radish.The Se enriched ability in edible part of three different genotypes radish seedlings was lower than there control after intercropping.