Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains vii, 75 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 74-75).

Thesis (M.S.)--Southern Oregon University, 2005. / "A thesis submitted to ... Southern Oregon University in partial fulfillment of the requirements for the degree of Master of Science ..." Includes bibliographical references (leaves 101-109). Also available via Internet as PDF file through Southern Oregon Digital Archives: http://soda.sou.edu. Search Bioregion Collection.

The diversity and abundance of ectomycorrhizal fungi in three beech stands were compared during 2012 and 2013 years in two soil horizons. Individual ectomycorrhizal roots tips were morphologically and anatomically characterized. Representative morphotypes were identified by using molecular methods to confirm and verify ectomycorrhizal fungal species.

No description available.

Ectomycorrhizal fungi are essential to seedling establishment in disturbed sites. This dissertation examines the effects of trace metals and soil disturbance on ectomycorrhizal fungi in the laboratory and the field. The first experiment assessed Cu and Zn impact on growth of three ectomycorrhizal species in pure culture. Suillus granulatus and Pisolithus tinctorius were more tolerant to Cu than Paxillus involutus, however, none of the species grew at 250 ppm Cu. Suillus granulatus had the highest Zn tolerance, followed by Paxillus involutus and Pisolithus tinctorius. Sectoring observed in Suillus granulatus was deemed spontaneous and not involved in metal tolerance. The second experiment examined the adsorption of copper and zinc to acidic Uchee fine loamy sand. Contrary to expectations, the soil adsorbed up to 667 ppm Cu and 238 ppm Zn. Adsorption occurred mainly in the non-crystalline fraction of the soil. This analysis is a new approach in mycorrhizal research, and the crucial need for such tactics is discussed. The third experiment surveyed ectomycorrhizae on a mine reclamation project in Wise County, Virginia. Pinus strobus trees planted 1, 8, 13, and 25 years prior to the experiment were sampled. Colonization was lower than in well developed soils, but occurred on all seedlings. Increased colonization and a late stage mycobiont (Tuber) occurred on roots taken from the 25 year old subsite. A new observation was made of Suillus americanus on one year old seedlings. Lack of species overlap among sites suggests localized inoculum sources. The last experiment explored Pinus strobus and Pinus virginiana seedlings naturally regenerating on acidic, bare-mineral soil exposed by a road cut in Floyd County, Virginia. Ectomycorrhizal colonization ranged between 30 to 80 percent. Wide variation among individual samples suggests patchy inoculum distribution. Scleroderma citrinum, a common early-stage fungus, was dominant throughout. Other early stage genera included Rhizopogon, Pisolithus, and Thelephora. Mid to late stage genera including Suillus and Lactarius were identified. Cenococcum, often a dominant taxon, was a minor taxon here. The unusual presence of the ericoid mycobionts Hymenoscyphus and Oidiodendron is discussed. These results suggest that native inoculum can be an important resource for seedling recruitment. / Ph. D.

Fungi are key components in forest ecosystems, being involved in decomposition of plant biomass and the cycling of nutrients in forest soils. Despite their importance little is understood about the influence forest management practices, such as long-term prescribed burning and forest conversion are having on soil fungal communities. Part of the work described in this thesis investigated the effects of long-term repeated prescribed burning on the total soil fungal community, the diversity of mycelial communities of ectomycorrhizal fungi and the influence of biennial prescribed burning on the cellulolytic soil fungal community using stable isotope probing techniques. The influence of long-term repeated prescribed burning on soil fungal communities was investigated through a series of studies conducted at Peachester State Forest, Queensland, Australia. This site has been the centre of a long-term repeated prescribed burning experiment, established since 1972, consisting of plots subjected to biennial, quadrennial or no burning. Denaturing gradient gel electrophoresis (DGGE) was used to show that long-term prescribed burning significantly altered the total fungal community structure in the top 10 cm of soil, when compared with unburned plots. Hyphal ingrowth bags, used to target ectomycorrhizal (ECM) mycelia in soil, along with DGGE analysis, indicated that profiles of the soil fungal community from 2 yr burn plots significantly differed from those of the 4 yr burn and unburned plots. Following analysis of clone assemblages from the different burn regimes, results indicated that this difference reflected an altered ECM fungal community composition. 13C stable isotope probing (SIP), following the incubation of soil with 13C labelled cellulose, and DGGE analysis was found to significantly alter the active fungal community in the upper 10cm of soil at Peachester State Forest. Fewer active fungi in the 2 yr burn plots were found to have incorporated 13C compared to the unburned plots, strongly suggesting that the activities of cellulolytic fungi were negatively affected by the 2 yr burning treatment. The thesis also incorporated work that assessed the effect of forest conversion from native eucalypt to Pinus elliottii plantation on the soil fungal community at Beerburrum State Forest, Queensland, Australia. ITS and 18S RNA and DNA were used, along with terminal restriction fragment length polymorphism (T-RFLP) and DGGE analysis, indicating that total and active fungal communities differed significantly between the native eucalypt forest and first rotation P. elliottii plantation. This suggested that the conversion from native eucalypt forest to P. elliotti plantation significantly altered the soil fungal community at the Beerburrum site. / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--University of California, Davis and San Diego State University, 2003. / Includes bibliographical references (leaves 142-144). Also available via the World Wide Web. (Restricted to UC campuses).

<p>The mycorrhizal mutualism is one of the earliest and most influential of all terrestrial symbioses. As the primary method used by most plants to acquire nutrients from the soil, mycorrhizal fungi help to shape the structure and composition of many ecosystems. Ectomycorrhizal (EM) fungi play an especially significant role because most EM fungi prefer a limited number of host taxa, and EM plant species likewise associate with only a fraction of the available EM fungi. This host preference issue, combined with the high diversity of EM fungi in forest ecosystems, complicates interspecies competition both among fungi and among plants, because these plant and fungal communities interact.</p><p>Despite recent attempts at documenting mycorrhizal fungi in the context of ecological succession, many questions remain about the underlying causal relationships among EM fungi, soil conditions, and plant community assembly. The succession of mycorrhizal fungi often mirrors the succession of plants, and ectomycorrhizal (EM) community composition may affect the outcome of competition among trees during succession. In a pine-oak seral system, we tested the ability of <italic>Pinus taeda</italic> and <italic>Quercus alba</italic> seedlings to associate with EM fungi when planted under both conspecific and heterospecific adults. We found that EM communities under pine and oak canopy were distinct regardless of seedling identity, indicating that the fungal associations of adult trees determine which EM species are available in the soil. In addition, pine seedlings planted under oak canopy showed decreased mycorrhization and growth compared to those planted under pine canopy, while oak seedlings showed no negative effects of heterospecific planting. This impaired ability of pine seedlings to associate with the EM community established under oaks may deter pine recruitment and facilitate the late-seral replacement of pines with oaks.</p><p>While EM fungal communities correlate with the dominant species of host tree, soil properties do as well, making it difficult to establish causality among these three variables. Soil was collected from oak- and pine-dominated stands and dried to kill off mature mycelium, leaving only the spore bank as a source of inoculum for pine and oak seedlings. EM root tips were collected for molecular identification of fungal species based on ITS barcoding, and soil samples from field and laboratory conditions were analyzed for fungal diversity using 454 sequencing. We found a reduced influence of canopy type and a more pronounced influence of seedling identity when compared to the EM communities on seedlings planted in the field, suggesting that adult trees do alter the availability of fungi by directly promoting the growth of their preferred EM associates.</p><p>The availability of EM fungi can also affect seedlings at the interface between EM- an AM-dominated forest. We tested the hypothesis that seedlings of <italic>Dicymbe corymbosa</italic> which recruit outside of monodominant stands have limited access to EM symbionts compared with those which recruit inside <italic>D. corymbosa</italic> stands. EM root tips and rhizosphere soil were collected from seedlings along two transects inside monodominant stands and three transects in the transition zone into mixed forest dominated by AM associates. Seedlings inside monodominant stands yielded both a greater quantity of mycorrhized root tips and a higher diversity of EM species than transition zone seedlings. Of the fungal families commonly found on adult roots, the Boletaceae were notably underrepresented on all seedlings. In the transition zones, high-throughput sequencing of soil also detected a decrease in EM diversity with distance from the parent tree.</p><p>Seedlings of <italic>D. corymbosa</italic> may benefit from recruiting within monodominant stands by tapping into common mycorrhizal networks (CMNs) to acquire low-cost nitrogen and, potentially, photosynthates produced by conspecific adults. Leaves of stand adults, stand seedlings, and mixed-forest seedlings were collected for stable isotope analysis to track the transfer of nitrogen and carbon through CMNs. The &delta;<super>13</super>C and &delta;<super>15</super>N results contradicted each other, suggesting that more complicated interactions may be playing out among adults, seedlings, and fungi.</p> / Dissertation

Thesis (MScBosb)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (Ph.D.)--University of Western Sydney, 2007. / A thesis submitted to the University of Western Sydney, College of Health and Science, Centre for Plant and Food Science, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references.