种衣剂17号包衣对小麦条锈菌发育影响的超微结构研究

本研究采用电镜技术研究了种衣剂17号对小麦条锈菌发育的影响。观察结果表明,该种衣剂引起病菌和寄主细胞内发生了一系列变化。病菌菌丝和吸器内脂肪粒和液泡明显增加;菌丝壁和吸器壁呈不规则加厚;菌丝分枝处无隔膜产生或隔膜畸形;有的吸器母细胞产生的畸形入侵栓,大都不能穿透寄主细胞壁,初生吸器外间质内沉积有染色较深的物质,次生吸器可产生多个不规则分枝,但不能扩张膨大;菌丝外渗的物质可能引起寄主细胞的坏死;大多数受侵寄主细胞可分泌形成较大的胼胝质,有时寄主细胞分泌的物质可将吸器体完全包围起来。上述结果表明,种衣剂17号不仅可直接作用于条锈菌,而且也可通过影响寄主而间接地影响病菌。

ULTRASTRUCTURAL STUDY ON THE EFFECTS OF SEED COAT FORMULATION NO. 17 ON WHEAT STRIPE RUST DEVELOPMENT IN HOST WHEAT

The seedlings from wheat seed coated with seed coating formulation (SCF) NO. 17 containing fungicide triadimenol and other chemicals were inoculated with a virulent race of Puccinia striiformis West. The effects of SCF No. 17 on development of the fungus were examined with electron microscope. The results showed that SCF No. 17 caused a series of changes in the fuagal cell and host cell. The lipid bodies and vacuoles increased in the cytoplasm of hyphae and primary haustoria. The appearance and accumulation of electron-dense vesicles between the fungal plasmalemma and walls made their walls thickened irregularly, and wall thickening at hyphal top was very obvious. Septum did not form at hyphal branch or septal wall did not extend to hyphal cell center because of appearance of electron-dense vesicles. Some haustorial mother cells produce malformed penetration pegs which did not penetrate through host cell wall. It was observed that the extrahaustorial matrix of primary haustoria became enlarged and contained some electron-dense material, and the secondary haustoria formed several branches but did not generally expand at all. With the degeneration of hyphae, some electron-dense material leaked into host intercellular space from the .hyphae, the material may cause death of host cells. Most infected host cells secreted larger callose which usually extended beyond the joint part between the neck and body of haustoria. Sometimes the material secreted by infected host cell enclosed whole haustorium. The results from electron microscope observation indicated that SCF No. 17 not only directly acted on the fungus, but also indirectly affected it by influencing host, and host cell necrosis was not the inhibition cause of the fungal development.