Microfungal Communities Research Articles

An Experimental Study of a Microfungal Community on Plant Detritus in a Mediterranean Woodland Stream

The seasonal pattern and mechanism of the distribution of microfungi on dead leaves in a woodland stream were studied. Three different leaf litter types were sampled monthly in three manipulated sectors of the stream. The leaf litters have leaves of European turkey oak (sector O), leaves of alder + willow (sector A-W) and leaves of oak + alder + willow (sector O-A-W). Thirty-nine species of fungi were isolated; fourteen species were common to all three sectors: 3 were restricted to sectors O and O-A-W, 7 to sectors A-W and O-A-W, 3 to sectors O and A-W. and 9 to sector O-A-W. Sectors A-W and O-A-W were most similar in fungal populations, sectors O and A-W most different. Eleven isolates were propagated on turkey oak and alder leaves. Significant weight loss and protein enrichment were noted for some species.

Microfunghi del suolo di aree floristicamente omogenee di tre cenosi boschive delle Prealpi bellunesi

Abstract Soil microfungi in homogeneous areas of three plant communities of North Italy.—The soil microfungi associated with three different community types in Prealpine region of North Italy were investigated. Frequency values for the taxonomic entities isolated were calculated, based on occurrence at sampling sites, in each community. Most of the entities were quantitatively rare. The microfungal communities associated with Acer pseudoplatanus and Fraxinus excelsior, with Ostrya carpinifolia and with Fagus sylvatica appeared to be a distinctive group, even if many of them contained a substantial number of species wich are common with other vegetation types.

The soil microfungal community of a South Dakota grassland

The soil microfungi of a western South Dakota grassland were quantitatively surveyed using the dilution plate technique. A 250-membered sample yielded 62 taxonomic entities. Principal forms included Acremonium sp. 4407, Aspergillus fumigatus, A. niveus, A. terreus, Chrysosporium pannorum, Fusarium oxysporum, F. solani, Mammaria echinobotryoides, Mortierella gracilis, Paecilomyces marquandii, Penicillium funiculosum, Penicillium janthinellum, Penicillium lilacinum, and Trichoderma harzianum. Comparison to other grassland surveys has revealed that the South Dakota community is most like that from the Pawnee National Grassland in eastern Colorado with less similarity to mycofloras reported for grasslands in Wisconsin and Oklahoma. Aspergillus terreus, A. fumigatus, A. niveus, Fusarium oxysporum, F. solani, Penicillium janthinellum, P. lilacinum, and Mortierella gracilis are prominent in temperate grassland communities worldwide. A slight seasonal trend was detected at the species level. Aspergillus fumigatus and Paecilomyces marquandii were predominant forms in the spring collection while Penicillium janthinellum and Papulospora sp. were present in greatest numbers in the fall. Relative densities for other species indicated that there may be heightened activity in populations of infrequent taxa in the spring. Twenty-seven and 10% of the colonies developing on dilution plates prepared in the fall and spring, respectively, grew from spores.

Study of the Microfungal Community of an Andosol

(1) Variations in the composition of the microfungal community of an andosol under a beech forest in northern Spain, both during the course of a year and between the different soil horizons, were studied. Microfungi were recovered by soil dilution, by soil washing and from the surface of leaves. (2) The species-diversity decreased with increasing depth, and was associated with increasing dominance of Aureobasidium pullulans (de Bary) Arnold in the lower soil horizons. Mortierella minutissima van Tieghem was characteristically present in spring isolates, while Trichoderma pseudokoningii Rifai was characteristic of summer isolates. (3) The similarities between microfungal recoveries from the various soil horizons and from different seasons of the year were compared by means of three-dimensional ordinations and dendrograms. (4) Similarity between the different horizons at one particular season was greater than within the same horizon at different seasons, and the floras of subhorizons A1l and A12 were always similar. Winter recoveries differed widely from those of the rest of the year. (5) The microfungal community colonizing the surfaces of fallen leaves in autumn and winter was quite different from the soil community.

Comparison of soil microfungal populations in disturbed and undisturbed forests in northern Wisconsin

Soil dilution plates were used to isolate populations of microfungi associated with the different soil horizons of five secondary successional forests, which arose after fire or clear-cutting, and three virginal (reference) stands. Ordinations of the populations within each horizon, based on similarities in the species composition of the microfungal communities, revealed the disturbed stands differed from their respective reference stands, although there was no consistent displacement of the stands in the ordinations. Most of the differences entailed alterations in frequency and (or) density, although a few species were predominant in one forest type but not in its counterpart. The most recently disturbed areas exhibited the greatest displacements from their reference stands. The ordinations suggested there is a sequential recovery of the mycoflora in the disturbed stands on loamy sand soils which would eventually result in a population similar to that in the reference stand.

Microfungal biomass and number of propagules in an andosol

The microfungal community of an andosol, under an acid beech forest located in a zone of the Province of Navarra (Spain) characterized by a temperate climate and high rainfall was studied. Mycelial length, number of spores and fungal biomass were eslimated by the agar-film technique. The number of fungal propagules were estimated by plate counting. There was a pronounced decrease of fungal propagules and mycelial biomass with soil depth; the highest values were obtained in the spring and the autumn. Seasonal variations were attenuated with increasing depth. In autumn the leaves of the A 00 horizon contained a great number of fungal spores but there was little mycelial growth.

Soil microfungi associated with aspen in Saskatchewan: synecology and quantitative analysis

The soil microfungi associated with 26 communities of aspen (Populus tremuloides) in Saskatchewan were investigated using a dilution plate technique. Frequency values for the taxonomic entities isolated were calculated, based on occurrence at six sampling sites in each community. Most of the entities were quantitatively rare. The frequency values of the 51 commonest entities were used for quantitative analysis of microfungal community relationships by principal components analysis and by agglomerative classification. These analyses demonstrated only limited correlations of microfungal community structure and species performance with the edaphic and vegetational factors studied. The microfungal communities of aspen stands in the boreal forest region of Saskatchewan appeared to be a distinctive group characterized by the abundance of Mortierella spp. The remaining communities, from all other parts of the province, were distinct from the boreal communities but did not form other discrete groups. Many of them contained a substantial number of species which are common grassland soil microfungi, such as Fusarium spp. Almost all the common species found in aspen soils in this study have been reported previously from soil.

The Soil Microfungi of a Chronically Irradiated Oak‐Pine Forest

The effects of chronic ionizing radiation on the soil microfungal community of an oak—pine forest was investigated by the dilution plate method and the contact slide technique. Twenty samples were collected and 10 slides inserted in the soil at each of 10 points along a radiation gradient varying from less than 1 to over 1800 R/day 2 cm below ground. A minimum of 55 fungi were selected at random off the isolation plates prepared from each of the 200 soil samples, and 5 slides per dose were examined. The 15,770 isolates obtained were distributed among 267 taxa. Subsurface radiation levels in the vegetated area ranged from less than 1 R/day in the undisturbed forest to 20 R/day under an almost pure stand of Carex pensylvanica. These exposures only indirectly affected the microfungi, producing minor distributional changes. Species diversity remained virtually constant throughout the area. The mean propagule level was approximately 100,000/g dry soil. Moniliaceous and mucoraceous fungi producing upright, morphologically complex reproductive structures characterized the population. The eight most abundant fungi, typically isolated throughout the world from podzolic soils supporting conifer—hardwood forests, were Penicillium terlikowskii, Mortierella isabellina, Aspergillus parvulus, Oidiodendron tenuissimum, P. nigricans, P. spinulosum, Monocillium humicola v. brunneum, and Mortierella nana. These eight taxa represented 71% of the isolates but only 5% of the species. A transitional zone devoid of higher plants except for a few scattered clumps of carex had a subsurface radiation level of 70 R/day. Species diversity was greatest in this region, where mesic and pioneer populations overlapped. The mean number of fungi was approximately 16,000/g dry soil. Only a few dominant forms of low density occurred in this area, notably, P. funiculosum, P. purpurogenum, Trichoderma viride, P. terlikowskii and Monocillium humicola v. brunneum. Distributional patterns of the microfungi correlated with the radiation gradient in the Devastated Zone, a region with no living higher plants. At subsurface radiation exposures of 175—1,250 R/day, no species was abundant and the mean number of propagules was reduced to approximately 3,00/g dry soil. Coefficient of community (CC) values and morphological complexity decreased as exposures to radiation increased. CC50 occurred at 1,600 R/day. Species diversity was reduced but remained constant along the gradient as shifting groups of more and more resistant forms occurred, culminating in a population dominated by the morphologically simple yeasts. A subsurface radiation level of 1,830 R/day, the maximum dose in this study, reduced the fungi to a mean level of only 500 propagules/g dry soil. The population contained yeasts but was characterized by intensely melanized, extremely slowgrowing, sterile isolates capable of producing only a rudimentary pseudomycelium. It is postulated that these are the most radioresistant of the fungi isolated and that resistance is related to their pigmentation. The contact slide results were comparable to those obtained by the dilution plate method except that basidiomycetes, not isolated by the latter, were the most radiosensitive fungi. Their dicaryotic hyphae were not observed on any slides receiving over 500 R/day.

Soil Microfungi of Dry to Mesic Conifer‐Hardwood Forests in Northern Wisconsin

The Soil microfungi in 36 northern Wisconsin conifer—hardwood forests have been surveyed by the dilution plate technique. Populations of 180 isolates from six sites in each forest examined, and frequency (sites of occurrence) was used to assess species importance. The 6,461 isolates represented 476 taxonomic entities, but only 87 (18%) of these occurred in three or more forests or had one frequency of at least 50% The principal forms in the conifer—hardwood unit were Mortierella vinacea II, Trichoderma spp., Mortierella isabellina, Penicillium nigricans, Mortierella nana, Pullularia pullulans, and Monocillium humicola var. brunneum. A few of the top—ranking conifer—hardwood microfungi are widely distributed in Wisconsin soils, others have occurred in similar types in northern and southern Wisconsin, and a third assemblage (including Mortierella vinacea II and M. nana) has been isolated only from conifer and conifer—hardwood soils in the State. An ordination, based upon compositional similarity in the microfungal communities, revealed a greatest difference between maple and hemlock soil populations. When tree importance values were superimposed on the three—dimensional microfungal ordination, spheres of occurrence were apparent for all major tree dominants. This finding confirmed the hypothesis that species composition in soil microfungal communities is correlated with vegetation, but litter calcium content, rather than the linear dry—to—mesic vegetational gradient, correlated with the first axis in the microfungal ordination. In a beech—hemlock forest soil, related densities for several dominant taxa varied with season. Both spores and hyphal fragments gave rise to colonies on the dilution plates prepared for six forest soils, and there was a direct correspondence between total colonies and numbers of germinating spores. A comparison of densities for four dominant species indicated a possible antibiotic interaction.

The Soil Microfungi of Upland Boreal Forest at Candle Lake, Saskatchewan

SUMMARY The soil microfungi of upland boreal forest at Candle Lake, Saskatchewan, were surveyed by using a dilution plate technique. Altogether 113 taxonomic entities were isolated, most of these being quantitatively rare forms. The most prevalent species found were Mortierella vinacea, M. isabellina, M. ramanniana, Pullularia pullulans, Trichoderma viride, T. album, Chrysosporium sp., Penicillium frequentans, P. pinetorum and P. kapuscinskii. Together these accounted for over 60% of the total isolates. The microfungi showed a pattern of continuous variation among the forest communities sampled, but it was not possible to demonstrate a clear correlation between the composition of microfungal communities and the dominant vegetation. The results are discussed particularly in relation to comparable surveys of microfungi that have been carried out in Wisconsin.

The Soil Microfungi of Upland Boreal Forest at Candle Lake, Saskatchewan

SUMMARYThe soil microfungi of upland boreal forest at Candle Lake, Saskatchewan, were surveyed by using a dilution plate technique. Altogether 113 taxonomic entities were isolated, most of these being quantitatively rare forms. The most prevalent species found were Mortierella vinacea, M. isabellina, M. ramanniana, Pullularia pullulans, Triehoderma viride, T. album, Chrysosporium sp., Penieillium frequentans, P. pinetorum and P. kapuseinskii. Together these accounted for over 60% of the total isolates. The microfungi showed a pattern of continuous variation among the forest communities sampled, but it was not possible to demonstrate a clear correlation between the composition of microfungal communities and the dominant vegetation. The results are discussed particularly in relation to comparable surveys of microfungi that have been carried out in Wisconsin.