Abstract: In order to investigate the effects of exogenous salicylic acid on germination and drought stress of Dracocephalum tanguticum,different concentrations of SA(0,0.2,0.4,0.6,0.8 mmol/L) were used to soak the seeds of D.tanguticum,and then the seed germination and seedling physiological characteristics of D.tanguticum were studied under 20% PEG-6000 simulated drought stress.The results showed that 0.6 mmol/L SA had the best effect on germination by soaking seed,the germination rate,germination energy,germination exponent and vigor index were increased by 34.82%,34.42%,34.87% and 54.86% respectively compared with CK;Under drought stress,the exogenous SA increased the content of proline and decreased the malondialdehyde content at the concentration of 0.6 mmol/L,however,the chlorophyll and soluble protein contents were similar compared with CK.In conclusion,exogenous SA could improve the seed germination by promoting germination energy,germination exponent and vigor index,and increase the ability of D.tanguticum to resist drought stress by enhancing the ability of plants to resist osmotic stress,reducing the cell membrane damage,and 0. 6 mmol/L SA soaking for 24 h was the best.

Key words: Dracocephalum tanguticum, Salicylic acid, Germination characteristics, Water stress;Drought resistance, Soaking seeds

摘要： 为了探讨外源水杨酸对干旱胁迫下甘青青兰(Dracocephalum tanguticum)种子萌发及幼苗抗旱能力的影响，采用PEG-6000模拟干旱胁迫，以不同浓度外源水杨酸（0、0.2、0.4、0.6、0.8 mmol/L）对藏药甘青青兰进行浸种 24 h处理，研究不同浓度SA对甘青青兰种子萌发及幼苗抗旱性的影响。结果表明，0.6 mmol/L SA浸种甘青青兰种子萌发效果最好，种子发芽率、发芽势、发芽指数和活力指数较CK（蒸馏水处理）分别提高了34.82%、34.42%、34.87%和54.86%；干旱胁迫（20% PEG-6000模拟干旱）下，与CK相比，0.6 mmol/L SA浸种显著提高了甘青青兰幼苗叶片中脯氨酸含量，降低丙二醛含量，但幼苗叶片中叶绿素含量和可溶性蛋白含量与CK无显著差异。说明外源水杨酸浸种可通过提高种子发芽势、发芽指数和活力指数，进而促进种子萌发，并增强植物抗渗透胁迫能力，降低细胞膜脂过氧化损伤，提高甘青青兰幼苗的抗旱能力，且0.6 mmol/L SA浸种24 h效果最佳。

关键词: 甘青青兰, 水杨酸, 萌发特性, 水分胁迫, 抗旱性, 浸种