Search

Radial growth rate of (K(r)) 153 strains 6 species of micromycetes from different ecological niches was studied on 7 agar media: three standard (malt extract agar, potato-dextrose agar, Czapek's agar), and on agar media with plant polymers (carboxymethylcellulose, xylan, soluble starch and apple pectin). Endophytic and plant pathogenic strains (biotrophs) of all studied species did not differ significantly in their ability to grow on nutrient media of different composition--average values of K(r) for these two groups were the same (0,200 and 0,199 mm/h, respectively). Soil micromycetes (saprophytes) characterized by the lowest average growth rate (0,169 mm/h) and significantly differed from the endophytic and plant pathogenic ones. Average of the radial growth rates of studied microscopic fungi were higher on standard nutrient media than with plant polymers ones. Growth parameters of endophytes and plant pathogens of all studied species on various agar media differed from the soil strains. High growth rate of endophytic and plant pathogenic strains of Fusarium poae, Alternaria alternata and Ceratocystis sp. provides them the rapid colonization of plants. Penicillium funiculosum strains equally can exist as saprophytes in soil and as endophytic plant symbionts. A wide range of K(r) variation of endophytic dark pigmented Mycelia sterilia indicates the presence in this group of different species of micromycetes, which have no sporulation.

The results of studying the mycoflora of winter triticale grains and seedlings after artificial and natural inoculation are presented. The species of Fusarium, Alternaria, Helminthosporium, Septoria, Cladosporium, Penicillium, Rhizopus were identified. Fusarium spp., prevailed over other fungi as to the number of its isolates. Its isolates (n = 142) were distinguished, 5 species were identified. It is significant, that most isolates of Fusarium graminearum caused a disease of grains. The species F. oxysporum dominated on winter triticale seedlings.

Species composition of fungi, isolated from the sugar beet leaves, roots and rhizosphere, collected in Poltava and Kyiv regions has been studied. Species Alternaria, Trichoderma, Cladosporium, Acremonium, Penicillium, Fusarium, Mycelia sterilia were found in all investigated samples. Basidiomycetes were isolated from the leaf samples in separate cases.

The work authors have used 52 strains of F. oxysporum for the collection of cultures of the Department of Physiology and Taxonomy of Micromycetes of IMV of the NAS of Ukraine. The strains were isolated from three habitats--grain cultures, cultivated and noncultivated soils of different regions of Ukraine. Activity of some hydrolytic (cellulose, endo-1,4-beta-xylanase, beta-glucosidase and amylase) and redox (monophenol-monooxygenase and peroxidase) enzymes of F. oxysporum strains. It has been shown that strains isolated from plant substrates produced more actively hydrolytic enzymes--cellulose, endo-1,4-beta-xylanase and beta-glucosidase. As to the degree of these enzymes activity the studied strains were distributed in the following order: strains from plants (P) > strains from cultivated soil (CS) > strains from noncultivated soils (NS). The soil strains NS > CS > P proved to be more active as to activity manifestation of the redox enzymes (monophenol-monooxygenase and peroxidase).