披碱草属不同种质资源耐低氮评价OA

The genus Elymus is an important native grass species for ecological restoration.Screening low nitro-gen-tolerant germination germplasm and improving nitrogen use efficiency are one of the effective approaches for near-natural restoration of degraded grasslands.In this study,twelve indicators during germination and seed-ling growth stages of 60 Elymus germplasms were measured under low nitrogen(0.01 mmol·L-1)and control(1.00 mmol·L-1)conditions using the petri dish germination method.Their responses to low nitrogen were explored,and comprehensive evaluation of low nitrogen tolerance was conducted by combining membership function and systematic clustering analysis.The results showed that under low nitrogen stress,all the indicators of the germplasms were decreased.The average germination rate,germination vigor,germination index,seed-ling length,root length,seedling fresh weight,root fresh weight,total fresh weight,seedling dry weight,root dry weight,total dry weight,and root-shoot ratio decreased by 5.95%,12.07%,8.21%,6.40%,14.80%,29.04%,36.28%,25.54%,30.00%,40.74%,28.77%and 8.08%,respectively.There were significant differences in low nitrogen tolerance among the different germplasms.Seven germplasms,including E22,E58and E47,had a comprehensive low nitrogen tolerance coefficient exceeding 0.850,while E32 and E49 were below 0.66.Based on the low nitrogen tolerance coefficient,cluster analysis divided the tested germ-plasms into six categories:super-strong,medium-strong,low-strong,low-weak,medium-weak,and super-weak.Among them,10 materials,including E47 and E22,were classified as super-strong low nitrogen-tolerant germplasms,and 3 materials,including E49 and E32,were classified as super-weak low nitrogen-tol-erant germplasms.This study provides excellent parental materials for the mining and functional research of can-didate genes related to Elymus low nitrogen tolerance,genetic improvement,and breeding of new varieties.