盐胁迫下不同紫花苜蓿品种萌发期和苗期的耐盐性综合评价OA

To evaluate the differences in salt tolerance among different alfalfa(Medicago sativa L.)cultivarsun-der salt stress conditions and screen high-quality salt-tolerant germplasm resources,this study used 25 alfalfa cultivars as experimental materials,with two treatments of salt stress(200 mmol·L-1 NaCl solution)and con-trol(ultrapure water).Germination and growth parameters were measured during the germination period(eight indicators,such as germination energy and germination rate,etc.)and seedling stage(six indicators,such as plant height and branch number,etc.),and a comprehensive evaluation of salt tolerance was conducted using methods such as membership function value,comprehensive salt tolerance(D value),and cluster analyses.The results showed that salt stress significantly reduced all germination parameters,with the seed vigor index exhibiting the highest reduction rate(-92.26%),whereas the seedling dry weight was the least affected(-11.76%).Cluster analysis classified the 25 alfalfa cultivars into five salt tolerance grades at the germination stage:included 2 of the strongest salt-tolerant cultivars,4 strong salt-tolerant cultivars,5 moderate salt-toler-ant cultivars,10 weak salt-resistance cultivars,and 4 salt-sensitive cultivars.Further evaluation of salt toler-ance of 12 representative alfalfa cultivars during the seedling stage revealed salt stress had extremely significant effects on the plant height,above-ground fresh weight,relative water content,and electrical conductivity of alfalfa(P<0.01),with significant differences between cultivars.By integrating the indicators of both germina-tion and seedling stages,the three strongest salt-tolerant cultivars,namely'Xinmu No.4''Zhongmu No.4',and'Bara520YQ',were ultimately selected as important germplasm resources for salt-tolerant breeding and cultivation in saline-alkali soil regions.