关键词: 黄瓜, 水杨酸, 干旱胁迫, 含氮化合物

Abstract: A pot experiment was conducted under adequate water and different drought stress combined with or without rhizosphere application of Salicylic acid（SA）to investigate the effect of exogenous SA on nitrogenous compounds and the related enzymes in cucumber（Cucumis sativus L.）seedlings under different drought stress treatments．Results showed that total nitrogen and soluble protein content，nitrate reductase（NR）and glutamine synthetase（GS）activities declined under drought stress，while the content of inorganic nitrogen and free amino acid increased，and the changes were more pronounced as the stress strengthening and time prolonging．Exogenous application of 0.1 mmol · L-1 SA in the condition of drought stress significantly increased the activities of NR and GS，the content of total nitrogen and soluble protein，while decreased the accumulation of inorganic nitrogen．Also，the content of free amino acid in the early period of drought stress was enhanced after SA application．Compared with no SA treatments，NR and GS activities in SA treatments increased significantly under slight（19.63% and 12.62%）and heavy（21.92% and 12.72%）drought stress．The above results suggested that SA enhanced the ability of nitrogen reduction and assimilation under drought stress，which might be a key reason for improving the drought tolerance of plants.

Key words: cucumber, salicylic acid, drought stress, nitrogenous compound