扁穗牛鞭草种茎EMS化学诱变突变体创制OA

Hemarthria compressa is a perennial species of the Poaceae family,with fast growth rate,strong adaptability and stress resistance.It is a very important forage resource in the southern region of China.This study investigated the use of ethyl methanesulfonate(EMS)as a chemical agent to produce mutants of H.compressa.Stems of seedlings were used to provide cells of H.compressa for exposure to EMS and two factors were tested:EMS concentration(0%,0.2%,0.4%,0.6%,0.8%or 1.0%)and treatment time(2,4 or 6 h).It was found that the optimal EMS concentration and treatment time for mutagenesis of H.compressa is 0.6%and 6 hours.Phenotypic comparison testing identified an excellent H.compressa mutant among the EMS-mutatated population,designated number 5-5-4.Comparative testing of mutant 5-5-4 and the wild type under low phosphorus stress conditions showed that 5-5-4 had greater root and root tip number,longest root length and total root length,and a more developed root hair structure than the wild-type.Low phosphorus stress resulted in a significant decrease in phosphorus uptake,but the phosphorus use efficiency was greatly improved and the phosphorus utilization efficiency in roots and stems of mutant 5-5-4 was higher than in the wild type.Under low phosphorus stress,the activities of acid phosphatase,superoxide dismutase and peroxidase were also higher in roots of the mutant and roots of the mutant exhibited greater presence of phosphate-solubilizing bacteria,including Bacillus,Ramlibacter and Rhodoferax in the rhizosphere.In summary,this study used EMS chemical mutagenesis technology to generate H.compressa mutants and analyzed the tolerance to low phosphorus stress and associated physiological parameters in a promising mutant,resulting in new germplasm resources with low phosphorus tolerance.These results provide both technical data for further mutagenesis work and breeding material development of improved H.compressa varieties to support animal husbandry in low phosphorus areas in southern China.