Abstract: The effects of saline-alkali stress on the physiological characteristics of alfalfa (Medicago sativa ‘Zhongmu No.1’) seedlings were studied. Alfalfa seedlings were stressed with the different concentrations of NaCl, Na₂SO₄ (0, 50, 100, 150, 200, 250 mmol·L^-1), NaHCO₃ and Na₂CO₃ (0, 30, 60, 90, 120, 150 mmol·L^-1) under greenhouse conditions. Survival rate, plant height, proline (Pro), malondialdehyde (MDA) and soluble sugar contents of tested seedlings were determined. Results indicated that seedling survival rates had not significant differences between different NaCl and Na₂SO₄ concentrations compared with control and the survival rates decreased with the increase of alkali salt concentration. The plant height of alfalfa decreased with stress increase, whereas proline, MDA and soluble sugar contents increased. The change ranges of tested indices under alkali salt stress were higher than that under neutral salt stress. The effects of saline-alkali stress on alfalfa were ordered as Na₂CO₃ >NaHCO₃ >NaCl >Na₂SO₄.

Key words: Medicago sativa ‘Zhongmu No.1’, Neutral salt, Alkali salt, Physiological characteristics

摘要： 为了探讨盐碱胁迫对中苜一号苜蓿（Medicago sativa ‘Zhongmu No.1’）耐盐性的影响，在温室条件下用不同浓度的NaCl和Na₂SO₄（0，50，100，150，200和250 mmol·L^-1）以及NaHCO₃和Na₂CO₃（0，30，60，90，120和150 mmol·L^-1）对中苜一号苜蓿进行胁迫，测定其生长及生理指标。结果表明：中性盐胁迫对苜蓿幼苗存活率无显著影响，随着碱性盐浓度的升高，中苜一号苜蓿的存活率逐渐降低；随着盐浓度增加，苜蓿幼苗的株高下降，而脯氨酸（Pro）、可溶性糖和丙二醛（MDA）含量均呈升高的变化趋势，并且碱性盐胁迫下各项指标的变化幅度均大于中性盐胁迫，其作用顺序依次为：Na₂CO₃ >NaHCO₃ >NaCl >Na₂SO₄。

关键词: 中苜一号苜蓿, 中性盐, 碱性盐, 生理特性