Abstract: The experiment aim is to explore the salinity tolerance of different Medicago sativa L. seedlings,screen suitable salinity tolerance evaluation indicators,and to establish a mathematical evaluation model for salinity tolerance. Using potted sand culture method,17 morphological and physiological indicators of 20 M. sativa varieties were determined with 0 and 150 mmol·L^-1 NaCl treatments for five weeks in this study. Based on the salt-tolerant coefficient of each single indicator,a comprehensive evaluation was performed by principal components analysis,membership function method and stepwise regression analysis. The results showed that the 17 single indices were transformed into five independent comprehensive indices. The cumulative contribution reached 87.07%. Then,the comprehensive salinity tolerance evaluation value (D value) was obtained and used to cluster analysis,and one highly salt-tolerant,seven salt-tolerant,four moderately salt-tolerant,six salt-sensitive and two highly salt-sensitive M. sativa L. varieties were screened out. Finally,a mathematical model for the evaluation of M. sativa L. salt tolerance was established,D'=-0.284+1.342 ADW+0.182 LN (R²=0.967,P=0.001),and the aboveground dry weight and leaf number per plant indices were selected as indicators to evaluate the salt tolerance of M. sativa L. seedling.

Key words: Medicago sativa L., Seedling stage, Salt tolerance, Comprehensive evaluation

摘要： 为了探讨紫花苜蓿苗期耐盐特性，筛选耐盐性快速评价指标并建立耐盐性数学评价模型，本研究以20个紫花苜蓿品种为材料，采用盆栽沙培法，设置两个NaCl处理水平：0和150 mmol·L^-1，胁迫5周后测定各品种的17个形态和生理指标，以各单项指标的耐盐系数为基础，运用主成分分析、隶属函数值法和逐步回归分析等方法进行综合评价。结果显示：将17个单项指标转换为5个相互独立的综合指标，累计贡献率为87.07%；获得各品种综合耐盐评价值(D值)，对D值进行聚类分析，筛选出1个高度耐盐、7个耐盐、4个中度耐盐、6个盐敏感和2个盐高敏感品种。建立紫花苜蓿苗期耐盐性评价数学模型：D'=-0.284+1.342 ADW+0.182 LN (R²=0.967,P=0.001)，并筛选出地上部干重和单株叶片数为紫花苜蓿苗期耐盐性评价指标。

关键词: 紫花苜蓿, 苗期, 耐盐性, 综合评价