菜豆锈病菌侵染对寄主超微结构的作用及菜豆抗锈病的细胞学表现

THE EFFECTS OF Uromyces appendiculatus ON ULTRASTRUCTURE OF SNAP BEAN AND ITS RUST RESISTANCE IN CYTOLOGY

在电镜下观察发现 ,菜豆锈病菌侵染菜豆后 ,逐步对其超微结构产生影响 :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 ;线粒体脊模糊不清 ,直至叶绿体解体 ;线粒体空泡化 ;少数细胞的细胞壁分解 ;不同细胞的细胞器堆积在一起。同时 ,病原菌的侵染激发了寄主抗病性的细胞学表现 :供试的抗感菜豆品种都表现为在病原菌侵入位点的寄主细胞壁内侧有高电子致密物质沉积 ;与吸器母细胞接触的寄主细胞壁加厚以及在吸器颈周围有电子不透明物质形成。只是这 3种反应在抗病品种中表现得更加强烈。此外 ,抗病品种中还有一些特有的抗性特征 ,如被侵染细胞及其相邻细胞的快速坏死 ,吸器母细胞侵入位点的寄主细胞壁外侧也有一种高电子致密物质沉积 ,抗病品种中真菌吸器周围聚集含大量线粒体的寄主细胞的细胞质 ,且吸器外基质比感病品种中的宽。

The results under transmission electron microscope were as follows.Infection of Uromyces appendiculatus caused changes in ultrastructure of host cell.At the early and middle stage of infection process,the host cell became plasmolyzed.The chloroplast was malformed.The thylakoid inside chloroplast became disordered and the crista of the mitochondrion was indistinct.At the later stage,some chloroplasts collapsed and some mitochondrion disappeared.Some host cell walls disorganized and organelles came from different host cells congregated together.At the same time,infection of the pathogen induced rust resistance of host in cytology.The results indicated that there was deposition of electron opaque material against host inner cell wall where a haustorial mother cell had penetrated.This kind of deposition was also observed around the haustorial neck.Moreover,host cell wall became thicker where a haustorial mother cell was preparing to penetrate the host cell.These three kinds of changes occurred in allvarieties,buttheyweremoreintensiveinresistantones.Besides,somechangeswereobservedonly in the resistant variety.For example,rapidly cell necrosis occurred in infected and linked cells.Fillet of adhesive material formed around the contact area between fungus and host cell.The plasma of host cell where mitochondrion was rich accumulated around the haustorium and the extra haustorial matrix was wider in resistant varieties than in susceptible ones.