EMS Mutagenesis And It’s Effect On Salt Tolerance Of Amaranth Mutant Seedlings

Amaranthus tricolor L.is one of the most important crops and vegetables to human.Nowadays,soil salinization is becoming more and more serious,which has serious impacts on production and cultivation of greenstuffs.Edible amaranth are relatively tolerant to salinity.It is important to breed amaranth cultivars with strong salt tolerance and adaptability so that we can exploit the planting area of crop cultivation and improving the utlization of saline-alkali soil in China.It is a simple,rapid and effective method to obtain salt-tolerant mutants of amaranth by chemical mutagenesis.Mutation breeding is a commonly used breeding method,which is easy to operate and saves space and time.High mutation frequency was found in crops mutagenesis when treating seeds with ethyl methanesulfonate(EMS).It also caused less chromosomal aberration and adverse.EMS was widely used in plant germplasm innovation and became one of the most widely used mutagen with high mutagenic efficiency.In this experiment,two cultivars(red leaf anaranth and green leaf amaranth)were used as materials,and EMS mutagenesis was carried out to select the best mutagenic concentration.With NaCl as the selection pressure,the optimum salt stress concentration was selected,and the physiological and biochemical indexes and the preliminary evaluation of salt tolerance were carried out.The following research results were obtained:1.After treatment at concentrations of 0,0.2%,0.4%,0.6%,0.8%,and 1.0%EMS for 4 h,8 h,and 12 h,respectively,the growth ability of M1 red leaf amaranth and M1 green leaf amaranth was significantly decreased.The semi-lethal concentration dose and time combination of EMS treatment of red leaf amaranth and green leaf amaranth seeds were 0.8%/4 h,0.6%/8 h,respectively.2.The growth of red leaf amaranth and green leaf amaranth was inhibited under NaCl stress,and the inhibition increased with the increase of NaCl concentration(0,0.4%,0.8%,1.2%,1.6%,2.0%).Under NaCl treatment,red leaf amaranth and green leaf amaranth showed radicle yellowing,stopping growth,plant dwarf,and a significant decrease in survival rate and rooting rate.The critical concentration of red leaf amaranth and green leaf amaranth seeds resistant to NaCl stress was 1.19%and 1.16%respectively after mutagenesis.3.After using different concentrations of NaCl to treat amaranth seedlings,it was found that with the increase of salt concentration,the activities of antioxidant enzymes(SOD,POD,CAT),the content of soluble protein and proline in the leaves of amaranth increased,and then decreased when the concentration is 1.2%.Amaranth can resist adverse damage by increasing the activity of antioxidant enzymes and accumulating osmotic adjustment substances within a certain salt stress concentration range.Through the determination and comprehensive evaluation of the physiological and biochemical indexes at the seedling stage,it was concluded that the salt tolerance of the red leaf amaranth and the green leaf amaranth was enhanced after EMS mutagenesis.The experiment also showed that SOD,POD,CAT,proline and soluble protein can be combined as a salt tolerance evaluation and screening index system in the salt tolerance screening of amaranth seedlings.