中文摘要：

以生菜幼苗为材料，采用溶液培养，研究外源水杨酸（salicylic acid，sA）对不同浓度（50、100、150、200mmol／L）NaCl胁迫下生菜幼苗生长和叶片光合特性的影响．结果表明，NaCl胁迫显著降低了生菜植株生长量、净光合速率、气孔导度、叶绿素含量，其中叶绿素a含量降低幅度最大；外源SA显著提高了盐胁迫下生菜幼苗叶片叶绿素含量、净光合速率、气孔导度，增强了盐胁迫下生菜植株的光合能力，从而使植株生长量明显提高，有效增强了生菜的抗盐能力．

英文摘要：

Using lettuce seedlings as material, effects of exogenous salicylic acid on seedlings growth and photosynthetic characteristics in lettuce seedlings under NaCI stress were studied by hydroponic experiments. The results showed NaCI stress decreased the growth rate, net photosynthesis （Pn）, stomatal conductance （Gs） and the content of chlorophyll, especially that of chlorophyll a, of lettuce plants significantly. Salicylic acid could improve the content of chlorophyll, net photosynthesis （Pn）, stomatal conductance （Gs） of NaCl-stressed lettuce plants. It was suggested that salicylic acid can significantly alleviate the injury of NaCl stress to lettuce seedlings and increase seedling growth, enhance the photosynthesis.