青杨叶锈病菌(Melampsora larici-populina Kleb.)侵染过程的超微结构研究

 采用电子显微镜技术对青杨叶锈病菌(Melampsora larici-populina Kleb.)的侵染过程进行了研究。发现该菌夏孢子萌发产生1~3个芽管,且具较多的树杈状分枝。芽管由气孔侵入,侵入前不形成明显的附着胞或仅个别芽管形成附着胞。芽管侵入气孔后在气孔腔内形成气孔下囊,再分化出圆形的膨大体而产生1~2支初生菌丝。初生菌丝在寄主细胞间扩展,与叶肉细胞壁接触后分化出吸器母细胞,吸器母细胞中的细胞器与胞间菌丝相同,双核。吸器母细胞产生侵入钉侵入叶肉细胞内部形成吸器,成熟吸器由细长具颈环的管状颈部和膨大的吸器体组成,此时胞间菌丝在吸器母细胞处分化出次生菌丝,在叶肉细胞间扩展形成次生菌落,产生孢子堆。病菌在寄主细胞间隙或沿寄主细胞壁延伸时,寄主细胞仍保持正常状态。

ULTRASTRUCTURE OF POPLAR LEAF INFECTED BY RUST FUNGUS (Melampsora larici-populina Kleb.)

The infection process of Melampsora larici populina Kleb. on leaves of poplars was examined with electron microscopy. The results showed that there were 1-3 germ tubes developed from a germinated urediniospore and the germ tubes always developed several branch tubes further. The germ tubes directly penetrated into the leaf through stomata. Sometime, several tubes penetrated through one stoma at the same time. No penetrate directly through epidermal cell was observed in this study. No well defined appressorium was formed before the penetrated of the pathogen. After invading into stomata the germ tubes developed substomatal vesicles and further formed round inflated bodies usually with one or two infection hypha. In tercellular hypha extended at first between host cell, then penetrated host cell and produced haustoria there. There was no difference in organelle structure between the haustoria and intercellular mycelia. The mature haustoria consisted of a tube like neck and a expanded body. When pathogen hyphae grew in the intercellular space between cells or along the cell wall, the host cell of mesophyll maintained in normal state.