By using 20% PEG6000 to simulate drought stress and spraying different concentrations (0 ,0 .5 ,1 .0 , 1 .5 mmol· L-1 and 2 .0 mmol · L-1 ) of salicylic acid (SA ) , the effects of SA on growth of wild Solanum nigrum seedlings under drought stress were studied .The results showed that ,under drought stress ,the plant height ,fresh weight and root length of Solanum nigrum seedlings were reduced ,and the contents of chlorophyll and soluble protein were de-creased ,while the contents of proline and MDA and the activities of antioxidase were increased .When the Solanum ni-grum seedlings under drought stress were treated by SA ,the plant height ,root length and fresh weight were substantially increased as compared with the control group (drought stress without SA ) .Especially under the treatment of 1 .5 mmol· L-1 SA ) ,they were increased by 20 .8% ,28 .0% and 29 .7% ,respectively .Compared with the control ,the treatment of 1 .5 mmol·L-1 SA increased the contents of chlorophyll ,proline and soluble protein by 31 .9% ,65 .4% and 42 .8%respectively ,raised the activities of superoxide dismutase (SOD ) ,peroxidase (POD ) and catalase (CAT ) by 30 .2% , 87 .8% and 50 .3% respectively ,but decreased the content of malonaldehyde (MDA ) by 37 .8% .It was concluded that proper concentration of exogenous salicylic acid could mitigate the damage of drought stress on Solanum nigrum seedlings , and the effect of 1 .5 mmol·L-1 SA was optimal .%利用20％的PEG6000模拟干旱胁迫，同时用不同浓度（0、0．5、1．0、1．5、2．0 mmol·L-1）的水杨酸（SA ）喷施幼苗，研究了不同浓度水杨酸处理对干旱胁迫下野生龙葵幼苗生长的影响。结果表明：干旱胁迫下，龙葵幼苗植株变矮、鲜重降低、根长缩短，叶绿素和可溶性蛋白含量减少，抗氧化酶活性、游离脯氨酸和丙二醛含量增加；经SA处理干旱胁迫下龙葵幼苗株高、根长和鲜重都有明显增加，特别是1．5 mmol · L-1 SA处理组分别增加20．8％、28．0％和29．7％，1．5 mmol·L-1 SA处理组龙葵幼苗叶绿素含量提高31．9％、脯氨酸含量提高65．4％，可溶性蛋白含量提高42．8％，超氧化物歧化酶（SOD ）、过氧化物酶（POD ）与过氧化氢酶（CAT ）活性达到最高，与对照相比分别增加了30．2％、87．8％和50．3％；SA处理使丙二醛（MDA ）含量降低了37．8％。综合来看，适当浓度的SA可以缓解干旱对龙葵幼苗造成的伤害，并以1．5 mmol·L-1外源SA缓解效果最好。
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