目的 研究外源NO对NaCl胁迫下水飞蓟种子萌发、幼苗生长生理的影响。方法 用0.05～0.60 mmol/L 亚硝基铁氰化钠（SNP）溶液浸种，在0.7% NaCl胁迫下发芽，观察种子发芽势、发芽率、发芽指数和活力指数。并观察幼苗生长情况，检测叶片中丙二醛（MDA）、光合色素和渗透性物质量，以及保护酶活性。结果 0.7% NaCl胁迫下，水飞蓟种子萌发和幼苗生长受到显著抑制，用0.05～0.60 mmol/L SNP溶液浸种能促进水飞蓟种子萌发和幼苗生长，降低叶片中MDA量，增加光合色素（叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素）和渗透性物质（可溶性糖、可溶性蛋白和脯氨酸）量，提高保护酶[超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）]活性。结论 0.05～0.60 mmol/L SNP浸种能提高水飞蓟种子和幼苗的抗盐能力。不同栽培类型水飞蓟对SNP敏感度不同，其中，0.10 mmol/L SNP对白色种皮处理效果最好；0.40 mmol/L SNP对黑色种皮处理效果最好。

Objective To investigate the effects of exogenous nitric oxide (NO) on the physiology of the seed germination and seedling growth of Silybum marianum under NaCl stress. Methods The seeds of S. marianum were treated by sodium nitro prusside (SNP) at the concentration of 0.05—0.60 mmol/L under 0.7% NaCl stress. Some physiological indexes were measured, such as germination energy, germination rate, germination index, and vigor index of the seeds, and contents of malondialdehyde (MDA), photosynthetic pigment, osmosis substances, and the activities of the protective enzymes in leaves. Results The seed germination and seedling growth of S. marianum were obviously inhibited under NaCl stress. Soaking seeds with 0.05—0.60 mmol/L SNP could alleviate the damage of NaCl stress. Under this treatment, the contents of photosynthetic pigment (including chlorophyll a, chlorophyll b, total chlorophyll, and carotinoid) and osmosis substances (including soluble sugar, soluble protein, and proline), and the activities of protective enzymes (including SOD, POD, and CAT) in the leaves were significantly increased, while the MDA content in the leaves was decreased. Conclusion Soaking seeds with 0.05—0.60 mmol/L SNP could promote the salt resistance of the seeds and seedlings of S. marianum. The different cultivars of S. marianum differ in the sensitivity to SNP. The optimal concentration of SNP for the seed soaking of S. marianum with white and black skins is 0.10 and 0.40 mmol/L, respectively.

江苏省镇江市农业支持项目（R0201100292）；南京农业大学SRT资金支持项目（1114A15）