| Abstract: | Ultrastructural changes were observed in sporidia of Ustilago avenue (Pers.) Rostr. after treatment with the fungicides nuarimol and imazalil nitrate. Electron microscopic studies of ultrathin sections, as well as of freeze-fracture replicas, showed that nuarimol caused the following marked changes in the ultrastructure of the cells: increased cell wall thickness and invaginated plasmalemma, with concentrations of extracytoplasmic vesicles in some places between plasmalemma and the cell wall; pores were visible in the septa. Nuarimol-treated sporidia were characterised by vacuolisation and accumulation of lipid bodies. Compared with nuarimol, imazalil nitrate caused small cytological changes; elongation of the sporidia and enlarged cell diameters, as well as an increased thickness of the septa, were observed, and an enhanced number of mitochondria with reduced diameters were found. |
