Abstract: To screen out high-quality salt-tolerant Lolium multiflorum germplasm resources， the salt tolerance of 50 accessions of Lolium multiflorum with different ploidy levels were evaluated in this study. Under different NaCl concentration treatments of 0， 50， 100， 150， 200 and 250 mmol·L^-1， the root length， shoot length， germination rate， germination potential， germination index， and vigor index after seed germination were measued. Salt tolerance of the experimental materials was assessed by using correlation analysis and other methods. The results showed that the D values of the 50 materials ranged from 0.037 to 0.972. At a Euclidean distance of 13.5， the 50 accessions were classified into 1 salt-tolerant accession， 9 moderately salt-tolerant accessions， 15 moderately salt-sensitive accessions， and 25 salt-sensitive accessions. Salt stress treatment of the screened extreme materials with different ploidy at the seedling stage showed that both plant height and biomass were inhibited， while relative water content and chlorophyll content were decreased， indicating that plant growth and physiological processes were suppressed under salt stress. Comprehensive comparison between the seed germination and seedling stages revealed that tetraploid Lolium multiflorum germplasm exhibited better salt tolerance than diploid materials. The findings provide theoretical support for breeding salt-tolerant Lolium multiflorum materials.

Key words: Lolium multiflorum, Salinity stress, Germination period, Seedling stage, Physiological characteristic

摘要： 为筛选耐盐优质多花黑麦草种质资源，本研究对50份不同倍性多花黑麦草种质进行耐盐性鉴定。在0，50，100，150，200和250 mmol·L^-1 NaCl不同盐浓度处理下，对萌发后种子的根长、芽长、发芽率、发芽势、发芽指数和活力指数的测定，利用相关性分析等方法对试验材料进行耐盐性评 价筛选。结果表明：50份材料的D值变化范围为0.037~0.972，在欧氏距离13.5处，50份多花黑麦草被划分成1份耐盐材料、9份中等耐盐材料、15份中等盐敏感材料和25份盐敏感材料。对筛选出的不同倍性的极端材料进行苗期盐胁迫处理发现，幼苗株高与生物量均受到抑制，相对含水量与叶绿素含量下降，表明在盐胁迫下，植株的生长与生理过程受到抑制。综合种子萌发期和苗期盐胁迫发现，四倍体多花黑麦草种质的耐盐性表现优于二倍体。本研究可为耐盐多花黑麦草材料选育提供理论支撑。

关键词: 多花黑麦草, 盐胁迫, 萌发期, 苗期, 生理特性