外源甜菜碱对 2 0 0mmol LNaCl胁迫下大麦幼苗的伤害有显著的缓解效应 ,0 .5～ 1 0 .0mmol L的甜菜碱均可以有效抑制盐胁迫导致的叶片中MDA含量的上升 ,增加根系含水量与幼苗鲜重 ,降低植株体内Na+ K+ 比 ,尤以 1mmol L甜菜碱的效应最明显。甜菜碱可以显著提高盐胁迫下大麦幼苗根系多胺含量 ,促进叶片内腐胺与亚精胺向精胺的转化 ,提高叶片的 (Spd +Spm) Put的比值。表明外源甜菜碱对大麦幼苗盐胁迫下离子平衡和多胺合成和代谢的调节作用可能是其缓解盐害的一个重要机制。 Exogenous betaine significantly reduced the damage of barley seedlings under 200 mmol LNaCl stress. 0.5-11.0 mmol L betaine could effectively inhibit the increase of MDA content in the leaves caused by salt stress and increase the root system Water content and fresh weight of seedling decreased the Na + K + ratio in plants, especially the effect of 1mmol L betaine. Betaine could significantly increase the content of polyamines in roots of barley seedlings under salt stress, promote the transformation of putrescine and spermidine to spermine, and increase the ratio of (Spd + Spm) Put in leaves. It is suggested that the regulation of exogenous betaine on ion balance and polyamine synthesis and metabolism under barley salt stress may be one of the important mechanisms to alleviate salt damage.