SSR Analysis Of Barnyard Grass And Study On Antioxidant Enzyme Under Cadmium Stress

Barnyard grass is a common weed in the field.With the discovery of more advantages and application value of barnyard grass,the research direction of barnyard grass is more and more extensive.Recent studies have shown that barnyard grass can be used as a remediation plant for soil heavy metal cadmium pollution.In this experiment,based on SSR results,genetic diversity analysis and classification of 43 barnyard grass samples were performed using Popgene 1.32 and NTsys 2.1e software;cadmium ions with concentrations of 0mg/L,50mg/L,100mg/L and 150mg/L were used for stress treatment of barnyard grass seeds.Germination rate,germination index and vigor index of barnyard grass seeds were calculated;at the tillering stage,0mg/kg,50mg/kg,100mg/kg and 150mg/kg concentrations of cadmium ions were used to treat barnyard grass varieties with strong cadmium ion resistance,MDA content and antioxidant enzyme（SOD,POD,CAT）activities of barnyard grass were determined.This study provided reference basis for the application and classification of barnyard grass resources in Heilongjiang province.（1）Thirteen pairs of SSR primers were used to amplify the genomic DNA of 43 pieces of barnyard grass,and the number of bands from each primer was 3¹4,a total of 101 bands were amplified,among which 78 bands were polymorphic,accounting for 77.23% of the total number of bands.The primers EG₁,EG₂ and EG₃20 were respectively amplified into 11,12 and 5 bands,with a polymorphism ratio of 100%.The genetic diversity of 43 species of barnyard grass was rich,and cluster analysis divided them into three categories.（2）The results showed that MDA content of 4 kinds of barnyard grass seedlings decreased gradually at first,then decreased to the lowest level at 15 or 20 days after treatment,and then increased slightly.The activity of SOD,POD and CAT of the four kinds of barnyard grass increased continuously,and the activity reached the highest at 25 days after treatment,indicating that the four kinds of barnyard grass had strong resistance to the heavy metal cadmium.（3）In this experiment,43 barnyard grass seeds were stressed with different concentrations of cadmium ion.The results showed that when the concentration of cadmium ion was 150mg/L,the germination rate of no.2 rice barnyard grass,no.29 chain barnyard grass and no.42 barnyard grass was 96.7%,and that of no.43 large barnyard grass was 98.3%.The germination index of no.2 rice was the highest,which was 12.75.The activity index of no.29 chain barnyard grass was the highest,which was 190.13.