摘要
【目的】探讨青枯菌对广藿香的入侵过程及侵染后寄主植物的组织病理学特征。【方法】以青枯菌HX6为供试菌株,分别对伤根及不伤根的广藿香试管苗进行侵染试验。通过扫描电镜观察青枯菌从广藿香根部入侵的过程,并采用光学显微镜观察青枯菌侵染后广藿香的组织病理学变化。【结果】青枯菌侵染前期,伤根的植株比不伤根的植株发病更严重;侵染后期,两者的病情指数均为100。电镜观察发现侵染24 h后,青枯菌及其胞外分泌物在广藿香根部出现;48 h时后,在茎部导管出现。青枯菌入侵造成植株茎部导管离析、扭曲及破裂,随之,叶表皮组织也逐渐破坏,植株死亡。【结论】青枯菌对广藿香具有强的亲和性,侵染速度快,青枯菌及其胞外致毒素能直接破坏寄主维管组织,使得水分运输受阻,造成植株枯萎死亡。
Objective To investigate Ralstonia solanacearum infection process in Pogostemon cablin （Blanco） Benth. and to observe the histopathological changes of the infected plants. Methods The test-tube plantlets of Pogostemon cablin were used as host plants, and Ralstonia solanacearum HX6 was used as infecting strain. Invasion and colonization of R. solanacearum from the root of host plants were observed under scanning electronic microscope （SEM）, and changes of the stem vessel and leaf abaxial epidermis of infected plants were observed via optical microscopy. Results At the prophase of infection, the disease developed faster in the plants with wound root than in the plants without wound root. With the prolongation of infection time, all the plants with or without wound root showed wilting, the disease index being 100. Under SEM, the bacteria and their extracellular secretion occurred in root section at hour 24 after inoculation, and in the vessel of stems at hour 48 after inoculation. Observation of infected tissues by optical microscopy indicated that the stem vessels seperated, twisted and broke, the leaf epidermal tissues were destroyed, and then the plants were dead. Conclusion R. solanacearum has affinity to invade P. cablin plants quickly through roots. The bacteria and their extracellular exotoxins cause vessel tissue broken and then block water transport, which results in the death of host plants.
出处
《广州中医药大学学报》
CAS
北大核心
2013年第2期236-239,287,288,共6页
Journal of Guangzhou University of Traditional Chinese Medicine
基金
国家自然科学基金项目(编号:30873376)
关键词
广藿香/生长和发育
青枯菌
广藿香/超微结构
广藿香/病理学
Pogostemon cablin/growth ＆ development
Ralstonia solanacearum
Pogostemon cablin/ultrastructure
Pogostemon cablin/pathology
