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The study aim was to compare the antagonistic interaction between saprotrophic soil fungi and embryonic development of geohelminths Toxocara canis and Ascaris suum. The experimental cultures were fertilized eggs of T. canis and A. suum incubated together with mycelium of strains: Fusarium culmorum, Metarhizium anisopliae, Paecilomyces fumosoroseus, Trichoderma viride and Trichothecium roseum. In the control cultures the eggs of both nematode species were incubated without fungi. The experiment was conducted at temp. 26ºC for 60 days. Compared with the control, all of the tested species of fungi significantly extended the embryonic development of both T. canis and A. suum. Most inhibitory effect on the rate of embryonic development of T. canis and A. suum had three fungal species: P. fumosoreus, M. anisopliae and T. viride. Compared with the control, on the 60th day of incubation in the presence of each of the tested fungal species, a larger percentage (p<0.05) of morphological abnormalities was stated in developing embryos of T. canis (49–69%) than in A. suum (15.1–67.7%). Among the examined fungal species, only incubation with P. fumosoroseus resulted in significantly greater (p<0.05) incidence of embryonic malformations (embryopathies) in T. canis, as compared with A. suum. Also the percentage of dead larvae of T. canis in the control and in cultures with fungi (12% and 100%, respectively) was significantly higher in comparison with A. suum (0.5% and 10.3–36%, respectively). The highest percentage of non-viable larvae of A. suum was found in the presence of P. fumosoroseus, and the lowest in the presence of M. anisopliae. Findings may indicate that T. canis eggs are more sensitive to antagonistic interaction of the examined fungal strains than A. suum eggs.
T he paper deals with the succession of basidiomycete macrofungi on abandoned farmland. T T he research was carried out in the unique complex of old fields of different age located on the southwest edge of the Białowieża old-growth forest (NE Poland). T T hese lands undergo spontaneous secondary succession leading to formation of a continental fresh pine forest. Regular observations of basidiomata in 16 permanent plots (11 plots of 1000 m2, 5 plots of 400 m2) representing initial, optimal and terminal stage of vegetation development from psammophilous grassland to a pine forest with 100-year-old tree stand were conducted for three years. Soil and vegetation analyses were also carried out as well as quantitative examination of ectomycorrhizae in root samples. T he series yielded 300 species of macromycetes (including 6 collective taxa) found in permanent plots plus 18 species outside the plots. T T he species composition, spatial distribution of sporocarps, and quantitative structure of fungal communities changed along the successional gradient. Increasing diversity of fungi resulted from persistence of species typical of open areas and species associated with younger trees, as well as accumulation of species associated with older trees and more developed stands. Some species typical of younger phases were replaced with species arriving later in the chronosequence. Species usually occurred long before and after attaining maximum abundance and frequency. Species associated with certain periods of vegetation development could be distinguished, as well as species accompanying the phytocoenoses regardless of their developmental stage. Patterns in structural changes of the fungal community, e.g., in number of species, abundance, frequency and production of carpophores, could also be recognised. T T hey were different in ectomycorrhizal and in saprotrophic fungi. T T he occurrence of the former was influenced mainly by the presence of symbiotic trees and their age, stand structure and soil properties, while occurrence of the latter was affected by microclimatic factors and by diversity of accessible substrates. Changes in fungal communities were consistent with vegetation changes, but were also specific to this group of organisms.
According to the research carried out in 1998-2000 it was found that small particles of the shoots left in the orchard after pruning are the place of the numerous fungi development. It was observed that the greatest number of species appeared 12 months after winter pruning. The species colonising fragments of bark and wood included typical patogenic species, pathogens of weakness, and saprotrophs. Some of isolated species may in favourable conditions become the cause of bark and wood diseases as well as apple rot.
In 1998–2001 the studies on one-year-old and two-year-old plantations of St. John’s wort (Hypericum perforatum L.), cultivar Topaz were carried out. The percentages of plants with diseases symptoms as well as indexes of infected plants were examined directly in the field. The fungi were isolated from superficially disinfected plants fragments namely from roots, stem bases and leaves, using in first year mineral culture medium and the next years St. John’s wort glucose extract agar. Necrosis of the roots of one-year-old and two-year-old plants were observed. Morover the disintegration and softening of lower parts of shots occurred. Plant organs with such disease symptoms were colonized by a complex of pathogenic fungi wherefrom Fusarium spp., Rhizoctonia solani, Botrytis cinerea and Phoma exigua var. exigua turned out to be of economic importance. Among the species of Fusarium colonizing the roots of one-year-old and two-year-old plants F. avenaceum, F. culmorum, F. equiseti, F. oxysporum and F. solani most often occurred. This species of Fusarium were isolated from external as well as from internal part of shoots of two-year-old plants. Seimatosporium hypericinum, not yet recorded in Poland, was commonly obtained from the stems showing cracks in the bark of diseased stems as well as from leaves showing red-amber necrotic spots.
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