中文摘要：

以苹果杂交组合（‘华脆’ב金冠’）F1代杂种实生苗群体易感病株系为材料，通过扫描电镜、透射电镜等观察方法，对苹果链格孢菌与寄主叶片互作过程进行了细胞学观察，分析苹果链格孢菌侵染寄主的动态过程和变化规律，以揭示苹果病害发生机制。结果表明，苹果链格孢菌侵染寄主叶片时，多数在表皮分枝扩展，很少通过气孔器或其他方式入侵细胞内部。互作后期，寄主叶细胞内叶绿体和质膜变化显著，多数细胞器降解，表明病原菌已分泌AM毒素作用于寄主。

英文摘要：

In this study,a susceptible cultivar from the cross of ＇Huacui＇ and ＇Golden Delicious＇ was used as our material,the interaction process of Alternaria mali and host leaves was examined with scanning e- lectron microscope and transmission electron microscope in order to understand the dynamic changes of A.mali infects host. The results indicated that A. mali usually spread on the surface of host leaves not through stomatal apparatuses or other ways in the infection process. During the late stage, the chloroplast and plasma membrane of host leaves changed clearly, and many other cell organelles disintegrated, indicated that A. mali had excreted AM toxins acted on host cells,and the host cells started to decline.