Thesis (Ph. D.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available online.

Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Dec. 9, 2009). Includes bibliographical references.

Ectomycorrhizal (ECM) fungi form mutualistic symbioses with trees in boreal and north temperate forests and have key roles in regulating biogeochemical cycles. The extensive mycelium produced by many ECM fungi enables resources to be transported over large distances. Some ECM fungi are considered to be specialists and have a restricted range of host plant species whilst others are considered generalists and can form mycorrhizas with a number of species. Little is currently known about the reasons why specialist and generalist mutualists have evolved and so this project aims to investigate the basis for these different strategies. The resource stoichiometry between plant and fungal partners was predicted to be a key factor: specialist fungi may be more efficient in obtaining nutrients from litter and transporting these rapidly to host plants and in return may receive larger amounts of plant photosynthate. Here, stable and radioisotopes were used to trace and quantify transfer of carbon and phosphorus, and fine-scale spatial-temporal analysis of amino acid transportation between host plants and fungi. The photon-counting scintillation imaging (PCSI) was used to show the amino acid was transported long-distance by ECM fungi intact and that the transportation was highly directional but the speed of transfer varies between species of ECM. The transportation of amino acid and phosphorus from generalist fungus to the host plant was rapid compared to the specialist fungus.

Thesis (Ph. D.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1996. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 67-78). Also available on the World Wide Web.

Thesis (M.Sc.)--University of Western Australia, 2003.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 47-52). Also available on the World Wide Web.

Patterns and rates of nutrient input to the forest floor in litterfall, throughfall and stemflow were investigated in plots of low and high abundance of ectomycorrhizal species. The aim of the study was to examine the comparative advantage of the ectomycorrhizal species in nutrient acquisition and cycling on nutrient-poor soils in Korup. Litterfall was similar in both forests with annual estimates of 9.00 and 8.33 t ha-1 yr-1 for LEM and HEM forests respectively. Litterfall distribution followed a mono-modal pattern, with peaks in the dry season in both forests and the HEM forest showing stronger seasonality. The concentrations N, K and Ca in total litterfall were higher in the LEM forest while those of P and Mg were higher in the HEM forest. The bulk of nutrients in total litterfall was in leaf litter with the reproductive fractions having the highest concentrations of nutrients. Ectomycorrhizal species showed lesser internal redistribution of nutrients than non-ectomycorrhizal species which resulted in their higher leaf litter concentrations of nutrients. Breakdown of litter was relatively faster in the LEM forest with an annual decomposition constant (KL) of 3.21 compared to 2.43 for the HEM forest. The reproductive fractions had relatively higher annual decomposition constants of 8.20 and 4.27 in the LEM and HEM forests respectively compared to the other fractions. The overall element mobility in decomposing leaf litter was similar in both forests and in the following order: Mg>K>Ca>P>N. Mineralization of N, P and K in the decomposing leaf litter was similar in both forests and higher in the HEM forest for Mg and Ca. Throughfall was 96.6% and 92.4%, and stemflow 1.5% and 2.2%, of gross rainfall in LEM and HEM forests respectively. Considerable amounts of Ca, Mg and P were brought to the forest canopy in gross rainfall (24-45% of total input through this route) with higher amounts of K and Ca leached from plant parts by the rainwater. The amounts of P, K and Ca in stemflow and throughfall were of the same magnitude in both forests with the enhancement of N slightly higher in the LEM forest and Mg in the HEM forest.