Abstract: To screen salt-tolerant Medicago sativa L. germplasm， 43 alfalfa hybrid F₂ materials were treated with four NaCl concentrations （0%， 0.3%， 0.6%， and 1.2%）. Agronomic traits， including germination potential， germination rate， fresh weight， shoot length， and root length， were measured， and key physiological indicators such as proline and malondialdehyde were analysed. Principal component analysis， membership function method， and cluster analysis were used to comprehensively evaluate salt tolerance at the germination stage. The results indicated that 0.6% NaCl was suitable for screening salt tolerance at this stage. Germination rate， root length， shoot length， and relative proline content （R-Pro） were identified as core indicators for evaluation. Seven highly salt-tolerant materials—GW141， GD131， GZ21， GW71， GD111， GD171， and GD301—were selected， which exhibited both agronomic advantages （“high germination rate and strong root development”） and physiological resistance （“strong osmotic adjustment and weak membrane lipid peroxidation”） under salt stress， providing valuable candidates for salt-tolerant breeding and saline-alkali soil improvement.

Key words: Alfalfa, Salt stress, Germination stage, Salt tolerance, Physiological indicators, Comprehensive evaluation, Germplasm screening

摘要： 为筛选耐盐性强的紫花苜蓿（Medicago sativa L.）种质，以43份苜蓿杂交F₂代为材料，设置0%，0.3%，0.6%，1.2%四个NaCl浓度处理，测定发芽势、发芽率、鲜重、芽长和根长等农艺指标，并结合脯氨酸、丙二醛生理指标，运用主成分分析、隶属函数法和聚类分析等方法综合评价其萌发期耐盐性。结果表明：0.6% NaCl可作为紫花苜蓿萌发期耐盐性筛选的适宜胁迫浓度；发芽率、根长、芽长以及脯氨酸相对含量（R-Pro）是评价耐盐性的核心指标。筛选出GW141，GD131，GZ21，GW71，GD111，GD171和GD301共7份极端耐盐种质，这些种质在盐胁迫下同时具备“高发芽率?强根系发育”的农艺优势与“强渗透调节?弱膜脂过氧化”的生理特征，可作为耐盐育种与盐碱地改良的候选材料。

关键词: 紫花苜蓿, 盐胁迫, 萌发期, 耐盐性, 生理指标, 综合评价, 种质筛选