Abstract: The purpose of this study was to investigate the effects of exogenous salicylic acid (SA),abscisic acid(ABA) and jasmonic acid (JA) on resistance induction,membrane permeability and surface structure of Kentucky bluegrass (Poa pratensis L.) infected with powdery mildew. The seedlings of Poa pratensis ‘Ever Glade’ were inoculated with powdery mildew. When they were treated with different concentrations of SA,ABA and JA,the disease index,resistance effect,leaves relative conductivity,MDA content,stomata and mastoid characteristics were analyzed. The results showed that appropriate concentration of exogenous SA,ABA and JA could increase the resistance of Kentucky Bluegrass to powdery mildew. When the concentration of JA was 1.5 mmol·L^-1,the disease resistance induction effect was the best,there were the most significant decline in the relative electrical conductivity and MDA content of the leaves. The color of the stomata deepens and the depression was aggravated,while there was no regularity between powdery mildew resistance and stomata length,width,aspect ratio and density. The mastoid was long and cylindrical,the apex was gradually pointed,the projection area of the mastoid increased effectively. It is beneficial to improve the disease resistance of Poa pratensis.

Key words: Poa pratensis, Exogenous hormone, Powdery mildew, Membrane permeability, Surface structure

摘要： 为探讨外源水杨酸（Salicylic acid，SA）、脱落酸（Abscisic acid，ABA）和茉莉酸（Jasmonic acid，JA）对染白粉菌草地早熟禾（Poa pratensis L.）的抗性诱导、膜透性及表面结构的影响。本试验选用无病害侵染的草地早熟禾品种‘超级哥来德’的幼苗接种禾布氏白粉病菌（Erysiphe graminis DC.ex Merat），分别用不同浓度SA，ABA和JA处理后，分析其病情指数、抗病效果、叶片相对电导率、丙二醛（Malondialdehyde，MDA）含量、气孔和乳突特征。结果表明：适宜浓度的外源SA，ABA和JA诱导均可提高草地早熟禾抗白粉病性。其中JA为1.5 mmol·L^-1时抗病诱导效果最佳，且叶片相对电导率和MDA含量下降最明显。诱导后的气孔颜色加深且凹陷加剧，但抗白粉病性与气孔长度、宽度、长宽比及密度间没有相关性；乳突呈长圆柱状，向顶逐渐变尖，有效加大乳突投影面积，有利于提高草地早熟禾抗病性。

关键词: 草地早熟禾, 外源激素, 白粉病, 膜透性, 表面结构