小麦雪霉叶枯病菌的侵染过程

INFECTION PROCESS OF GERLACHIA NIVALIS IN WHEAT LEAF

本文报道了小麦雪霉叶枯病菌Gerlachia nivalis的叶面侵染过程。该菌分生孢子发芽后相互结合,形成网状复合体,产生粗壮的叶面菌丝,经由气孔保卫细胞间隙侵入,不产生特化的侵染机构。侵染菌丝在叶肉细胞间和细胞内扩展,也可由气孔逸出在叶面蔓延。分生孢子梗由分生孢子座上产生,由气孔抽出。产孢细胞顶端有环痕。叶面菌丝亦能产孢。寄主组织病变特点表明该菌产生活性很强的胞外酶。

The present paper gives detailed description on the infectionprocess of Gerlachia nivalis in wheat leaf.On the leaf surface theinoculated conidia fused with each other by means of anastomosis ofgermtubes or projections and formed a conidial complex,from whichthe vigorous superficial hyphae developed and penetrated into stomatalslits without any specific infection structures.Infection hyphae grewprofusely into intercellular spaces and then entered mesophyll cells.At the margin of lesions hyphae grew out through stomatal slits andspread on leaf surface.The conidiophores which were produced onsporodochia,extruded out via stomata and formed conidis.The aerialmycelia formed conidia also.The symptom development of the diseaseinduced alternations in host tissue suggests that the pathogen maysecrete some strong extracellular enzymes.