The effects of different concentrations of NaCl (0, 0. 1％, 0.3 ％, 0. 5 ％, 0.7 ％, 0.9 ％) on growth rnof alfalfa (Medicago sativa) (survival rate, root length, stem length, leaf number) and the contents of Na+,rnK+, Ca2+ , Mg2+ in the different organs were assessed and the ratio of K/Na, Ca/Na, and Mg/Na were anarnlysed. The survival rate, root length, and stem length were all negatively correlated with salt concentration,rnexcept when the NaCl concentration was ≤0. 1％. The content of Na+ in root, stem and leaves and the content rnof Ca2+ in roots were all positively correlated with salt concentration. However, the contents of K+ and Mg2+,rnand the ratios of K/Na, Ca/Na, Mg/Na in roots, stems and leaves significantly decreased with an increase of rnsalt concentration. Salt stress on alfalfa caused significant differences in the comparisons. The reason for salt rninjury and salt-tolerance in alfalfa are discussed in relation to ion toxicities.%研究了不同浓度NaCl胁迫下(盐浓度处理为0,0.1%,0.3%,0.5%,0.7%,0.9%)苜蓿不同器官的生长情况(存活率、根长、茎长、叶片数),以及不同器官中Na+、K+、Ca2+、Mg2+的含量,并分析了K/Na、Ca/Na、Mg/Na值的变化.结果表明,存活率、根长、茎长与盐浓度呈负相关,且当NaCl≤0.1%时,有利于苜蓿的生长.除根茎叶中Na+含量、根中Ca2+与盐浓度呈正相关,茎叶中的Ca2+与盐浓度相关性不明显外,根茎叶中K+、Mg2+、K/Na、Ca/ Na、Mg/Na均随盐浓度增加而显著下降,且盐处理与对照差异显著(P＜0.05).另外从离子角度讨论了盐对苜蓿的毒害以及耐盐的原因.
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