Abstract: Appropriate concentrations of ethephon can improve the drought tolerance of turfgrasses， but the specific mechanism of action remains unclear. As an osmotic regulator， proline plays an important role in plant responses to stress. In this study， Kentucky bluegrass （Poa pratensis） and perennial ryegrass （Lolium perenne） were used as materials. We examined the effects of ethephon on physiological indices of turfgrasses in response to drought stress， analyzed changes in the expression of genes related to proline biosynthesis and catabolism， and explored the role of proline in ethephon-improved drought resistance of turfgrasses. The results showed that ethephon alleviated the decrease of relative water content and the increase of electrolyte leakage of turfgrass leaves induced by drought stress， thus contributing to improved drought tolerance. Under drought stress， proline content increased in the two Poa pratensis cultivars， whereas the changes were inconsistent among Lolium perenne cultivars. Ethephon treatment down-regulated the expression of Proline Dehydrogenase （Pro DH） gene in Poa pratensis under drought stress， thereby inhibiting proline degradation. In conclusion， promoting proline accumulation by suppressing the expression of the Pro DH gene might be one of the mechanisms by which ethephon improves drought tolerance in Poa pratensis.

Key words: Ethephon, Turfgrass, Proline, Drought stress, Gene expression

摘要： 适宜浓度的乙烯利可以提升草坪草的耐旱性，但具体作用机制未知。脯氨酸作为渗透调节物质，在植物逆境胁迫响应中发挥重要作用。本文以草地早熟禾（Poa pratensis）和多年生黑麦草（Lolium perenne）为材料，检测乙烯利对干旱胁迫下草坪草生理指标的影响，并分析脯氨酸合成与降解代谢相关基因表达的变化，探讨脯氨酸在乙烯利提升草坪草抗旱性中的作用。结果表明：乙烯利可缓解干旱胁迫诱导的草坪草叶片相对含水量的下降和电解质渗透率的上升，对耐旱性提升有一定作用。干旱胁迫下草地早熟禾两个品种的脯氨酸含量升高，但多年生黑麦草品种脯氨酸含量变化不一致。乙烯利处理能够下调干旱胁迫下草地早熟禾脯氨酸脱氢酶基因（Proline Dehydrogenase， Pro DH）的表达，从而抑制脯氨酸降解。综上，通过抑制Pro DH基因表达，促进脯氨酸积累可能是乙烯利提高草地早熟禾的耐旱性的机制之一。

关键词: 乙烯利, 草坪草, 脯氨酸, 干旱胁迫, 基因表达