向日葵品种对锈病抗性的组织学和超微结构研究

Histology and ultrastructure of different combination between Puccinia helianthi Schw.and sunflower cultivars

为了进一步了解向日葵与向日葵锈病病菌的互作关系及品种的抗性机制,采用电子显微镜技术对向日葵品种对锈病抗性的组织学和超微结构进行研究。在电镜下观察发现,向日葵锈病菌侵染向日葵后,在感病品种和抗病品种上发育的组织学和超微结构特征有明显差异。病菌在感病品种细胞间隙分布有大量的胞间菌丝,寄主细胞发生质壁分离;叶绿体变形,叶绿体的片层结构排列零乱,直至叶绿体解体。在抗病品种上表现为菌丝生长受抑,没有观察到吸器的产生,寄主细胞的早期坏死与锈菌的发育受阻密切相关。品种的抗病性可能与饥饿阻止真菌生长有关。

In order to know the interaction between sunflower and Puccinia helianthi Schw.and resistance mechanism,the combinations between P.helianthi Schw.and sunflower cultivars were examined by electron microscopy.The observation revealed striking differences in the fungal development and the host responses after infection by the pathogen.Pathogen hyphae grew in the intercellular space between cells or along the cell wall in the susceptible sunflower cultivars.At the early and middle stage of infection process,the host cell became plasmolyzed.The chloroplast was malformed.The thylakoid inside chloroplast became disordered.At the later stage,some chloroplasts collapsed.The main histological manifestation of the pathogen development in the resistant sunflower cultivars includes inhibition of hyphal growth,no haustorium produced.Host cells＇ necrosis was closely related with the inhibition of hyphal development.It is possible that starvation was the primary cause of the cessation of fungal growth.