戊唑醇对小麦赤霉菌侵染影响的细胞学研究

Cytological studies of effects of tebuconazole on infection process of Fusarium graminearum on wheat spikes

采用电镜技术研究了三唑类杀菌剂戊唑醇(tebuconazole)对赤霉病菌 Fusarium gra-mineaum 侵染小麦穗部过程的影响。结果表明:人工接种前2天施药,可推迟外稃内表皮、内稃及子房上分生孢子的萌发,但不能完全抑制其萌发,可引起芽管和菌丝严重畸形,不能形成侵染菌丝侵入寄主。而人工接种后2天施药,戊唑醇则严重抑制了病菌菌丝的生长,使寄主体表和寄主组织内的菌丝形态、结构发生了一系列异常变化,并最终塌陷死亡,使菌丝不能扩展到穗轴部位。接种后4天施药,病菌虽已扩展到穗轴,但戊唑醇仍对穗轴中菌丝生长具有明显的抑制作用。对赤霉毒素的免疫细胞化学标记结果表明,药剂处理与未处理的寄主和菌丝细胞中都存在有毒素,但标记密度在药剂处理的寄主和菌丝细胞中明显低于未处理对照。

The effects of a triazol group fungicide tebuconazole on the infection process of Fusarium graminea- rum on wheat spikes were examined by means of electron microscopy and immuno-cytochemical labeling tech- niques.The results revealed that the eonidia of the pathogen were able to germinate on the lemma,palea and ovary of the wheat spikes treated with fungicide 2 days before inoculation.However,the further extension of the hyphae was obviously inhibited.The germ tubers and hyphae became malformed.The penetration hyphae were never detected on these deformed hyphae on the host surface.The spikes treated 2 days after inoculation, the hyphae in the infected lemma,ovary and palea also exhibited a series of morphological and structural alter- ations.Treated the spikes 4 days after inoculation,hyphae were also obviously inhibited in the rachis.Immu- nocytoehemical labeling with antiserum against deoxynivalenol (DON) revealed that Fusarium toxins was lo- calized in the walls,cytoplasm,mitochondria and vacuoles of hyphae cell,and in the walls,cytoplasm mem- bers,chloroplast,cytoplasm and vacuoles of the host cells in the wheat spikes treated and untreated with the fungicide.However,the labeling density of the toxin in the fungicide-treated spikes was markedly lower than that of the untreated control.