Home About us Contact
|
Home About us Contact | ||
|
|
||
Fungal Community Composition (fungal + community_composition)
Selected AbstractsCo-existing grass species have distinctive arbuscular mycorrhizal communitiesMOLECULAR ECOLOGY, Issue 11 2003P. Vandenkoornhuyse Abstract Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing the majority of land plants, and are of major importance in plant nutrient supply. Their diversity is suggested to be an important determinant of plant community structure, but the influence of host-plant and environmental factors on AM fungal community in plant roots is poorly documented. Using the terminal restriction fragment length polymorphism (T-RFLP) strategy, the diversity of AM fungi was assessed in 89 roots of three grass species (Agrostis capillaris, Festuca rubra, Poa pratensis) that co-occurred in the same plots of a field experiment. The impact of different soil amendments (nitrogen, lime, nitrogen and lime) and insecticide application on AM fungal community was also studied. The level of diversity found in AM fungal communities using the T-RFLP strategy was consistent with previous studies based on clone libraries. Our results clearly confirm that an AM fungal host-plant preference exists, even between different grass species. AM communities colonizing A. capillaris were statistically different from the others (P < 0.05). Although grass species evenness changed in amended soils, AM fungal community composition in roots of a given grass species remained stable. Conversely, in plots where insecticide was applied, we found higher AM fungal diversity and, in F. rubra roots, a statistically different AM fungal community. [source] Spatial separation of litter decomposition and mycorrhizal nitrogen uptake in a boreal forestNEW PHYTOLOGIST, Issue 3 2007Björn D. Lindahl Summary ,,Our understanding of how saprotrophic and mycorrhizal fungi interact to re-circulate carbon and nutrients from plant litter and soil organic matter is limited by poor understanding of their spatiotemporal dynamics. ,,In order to investigate how different functional groups of fungi contribute to carbon and nitrogen cycling at different stages of decomposition, we studied changes in fungal community composition along vertical profiles through a Pinus sylvestris forest soil. We combined molecular identification methods with 14C dating of the organic matter, analyses of carbon:nitrogen (C:N) ratios and 15N natural abundance measurements. ,,Saprotrophic fungi were primarily confined to relatively recently (< 4 yr) shed litter components on the surface of the forest floor, where organic carbon was mineralized while nitrogen was retained. Mycorrhizal fungi dominated in the underlying, more decomposed litter and humus, where they apparently mobilized N and made it available to their host plants. ,,Our observations show that the degrading and nutrient-mobilizing components of the fungal community are spatially separated. This has important implications for biogeochemical studies of boreal forest ecosystems. [source] Effects of Mycorrhizae and Nontarget Organisms on Restoration of a Seasonal Tropical Forest in Quintana Roo, Mexico: Factors Limiting Tree EstablishmentRESTORATION ECOLOGY, Issue 2 2005Michael F. Allen Abstract We initiated a study of the effects of mycorrhizal fungal community composition on the restoration of tropical dry seasonal forest trees. Tree seedlings were planted in a severely burned experimental site (1995 fire) during the growing season of 1998 at the El Edén Ecological Reserve, in north Quintana Roo, Mexico. Seedlings of Leucaena leucocephala, Guazuma ulmifolia, Caesalpinia violacea, Piscidia piscipula, Gliricidia sepium, and Cochlospermum vitifolium were germinated in steam-sterilized soil and either remained uninoculated (nonmycorrhizal at transplanting) or were inoculated with mycorrhizal fungi in soils from early-seral (recently burned) or late-seral (mature forest) inoculum. Inoculum from the early-seral soil was largely Glomus spp., whereas a diverse community of arbuscular mycorrhizal fungi were reintroduced from the mature forest including species of Scutellospora, Gigaspora, Glomus, Sclerocystis, and Acaulospora. Plants grew better when associated with the mature forest inoculum, unlike a previous experiment in which plants grew taller with the early-seral inoculum. Reasons for the different responses include a less-intense burn resulting in more residual organic matter. In addition to mycorrhizal responses, plants were severely affected by deer browsing. One tree species, C. vitifolium found in the region but not in the reserve, was eliminated by a resident fungal facultative pathogen. Several practical conclusions for restoration can be made. The common nursery practice of soil sterilization may be detrimental because it eliminates beneficial mycorrhizal fungi; species not native to the site may not survive because they may not be adapted to the local pathogens; and herbivory can be severe depending on the landscape context of the restoration. [source] Effects of Forest Use on Aphyllophoraceous Fungal Community Structure in Sarawak, MalaysiaBIOTROPICA, Issue 3 2008Satoshi Yamashita ABSTRACT Aphyllophoraceous fungi are expected to reflect changes in the environmental conditions caused by forest use. To reveal the effects of forest uses on the fungal community structure, we performed a 3-month survey of aphyllophoraceous species in five forest types (undisturbed primary forest, isolated patches of primary forest, old and young fallow forest, and rubber plantations) in Sarawak, Malaysia in 2005. We used a canonical correspondence analysis (CCA) to reveal the relationships between fungal community composition and the environmental variables (canopy openness, soil water potential, amount and composition of coarse woody debris, litter mass, basal area, plant species composition). A total of 155 samples from 67 species were collected during the study period. The fungal species density represented by the number of species in a transect differed significantly among forest types. The fungal species density increased significantly with increasing number of pieces of coarse woody debris (CWD), but decreased significantly with increasing the scores of second axis of principal component analysis (PCA) for plant species composition. In the CCA ordination, automatic forward selection revealed that only the number of pieces of CWD significantly affected the fungal species composition. The occurrences of Flabellophora licmophora, Coriolopsis retropicta, Microporus vernicipes, and Amauroderma subrugosum were positively correlated with the number of pieces of CWD. Our study clearly demonstrated that forest use negatively affected aphyllophoraceous fungal diversity and suggest that the quantity of CWD would be an important determinant of fungal diversity and composition. [source] Ectomycorrhizal fungal succession in mixed temperate forestsNEW PHYTOLOGIST, Issue 2 2007Brendan D. Twieg Summary ,,Ectomycorrhizal (ECM) fungal communities of Douglas-fir (Pseudotsuga menziesii) and paper birch (Betula papyrifera) were studied along a chronosequence of forest development after stand-replacing disturbance. Previous studies of ECM succession did not use molecular techniques for fungal identification or lacked replication, and none examined different host species. ,,Four age classes of mixed forests were sampled: 5-, 26-, 65-, and 100-yr-old, including wildfire-origin stands from all four classes and stands of clearcut origin from the youngest two classes. Morphotyping and DNA sequences were used to identify fungi on ECM root tips. ,,ECM fungal diversities were lower in 5-yr-old than in older stands on Douglas-fir, but were similar among age classes on paper birch. Host-specific fungi dominated in 5-yr-old stands, but host generalists were dominant in the oldest two age classes. ECM fungal community compositions were similar in 65- and 100-yr-old stands but differed among all other pairs of age classes. ,,Within the age range studied, site-level ECM fungal diversity reached a plateau by the 26-yr-old age class, while community composition stabilized by the 65-yr-old class. Simple categories such as ,early stage', ,multi stage', and ,late stage' were insufficient to describe fungal species' successional patterns. Rather, ECM fungal succession may be best described in the context of stand development. [source] | ||||||||||