Thesis (Ph.D.)--University of Western Sydney, 2000. / "Thesis submitted in accordance with the requirements for the degree of Doctor of Philosophy, School of Science, University of Western Sydney (Nepean)." "October 2000." Bibliography : leaves 143-179.

Thesis (M.S.)--Rutgers University, 2007. / "Graduate Program in Ecology and Evolution." Includes bibliographical references (p. 64-66).

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Cathy L. Cripps. Includes bibliographical references (leaves 194-212).

Nous avons étudié les réponses à la contrainte hydrique du système biologique formé par l'association plante hôte – communautés de champignons ectomycorhiziens (ECM) en prenant comme espèces modèles deux chênes méditerranéens correspondant à des types biologiques contrastées décidu (Quercus pubescens) et sempervirent (Q. ilex). Nous avonstesté l'hypothèse selon laquelle les interactions fonctionnelles entre plantes hôtes et communautés associées pourraient être régulées par le niveau de ressource hydrique. A l'aide d'une expérimentation réalisée en conditions contrôlées, nos résultats ont montré que Q. pubescens réduisait davantage sa production que Q. ilex en réponse au déficit hydrique. La colonisation racinaire par les champignons ECM a varié selon les deux chênes et la disponibilité de l'eau. La longueur des racines colonisées était positivement corrélée à la croissance des plantes et à l'immobilisation des nutriments chez l'espèce décidue Q.pubescens mais pas chez Q. ilex. In natura, nous avons testé les traits de communautés ectomycorhiziennes dans un gradient environnemental de trois forêts de Q. ilex. Sur chaque site, le taux de colonisation racinaire et la richesse des espèces ECM ont diminué avec l'horizon échantillonné alors que parallèlement les ECM de la famille dominante Russulaceae augmentaient. Sur tous les sites, le type d'exploration dit «contact» était dominant, particulièrement dans le site sec. La composition des espèces a varié considérablement d'un site à l'autre avec un nombre élevé d'espèces rares, à l'échelle locale et à l'échelle régionale. Dans les trois sites, l'application d'une perturbation de sol de faible dimension a induit uneréponse forte de la communauté ECM. La diversité spécifique et la richesse ont diminué après la perturbation avec la disparition de la plupart des espèces de Russulaceae, de Cantharellaceae et de Clavulinaceae. Les types d'exploration contact ont fortement diminué alors que les types courte distance ont répondu positivement à la perturbation. Une mosaïque d'espèces stress-tolérantes comprenant plusieurs espèces des genres Sebacina sp et Helvellasp, ont dominé les communautés après la perturbation. Ces travaux apportent des éléments de compréhension du fonctionnement et de la réponse du système chênes méditerranéens - communautés ECM face à la contrainte climatique, les expérimentations in natura permettant d'affiner notre connaissance des stratégies écologiques de recolonisation ectomycorhizienneaprès perturbation. / The effect of drought had been investigated on the biological system -host plantectomycorrhizal community ECM- using different approaches. In a first part, we evaluated the drought-resistance of Quercus species and their associated ECM fungi, comparing the responses of two oak species differing in their leaf habitat, Q. pubescens vs Q. ilex (deciduous vs evergreen) in a controlled experiment. Our results showed that Q. pubescens reduced more its production than Q. ilex according to drought treatments. The total length of colonized fine roots was positively correlated with plant growth and nutrient immobilization in Q. pubescens but not in Q. ilex. In a second part, we investigated ECM community traits in three Q. ilex forests across an environmental gradient. At each site, both ectomycorrhizal colonization rate and species richness decreased with increasing soil depth, while the dominant family Russulaceae increased in abundance with increasing soil depth. At all sites, contact exploration type strongly dominated, with the highest abundance in the driest site. Species composition varied significantly across sites with high number of rare species at local and regional scales. At all sites, the application of an experimental soil disturbance provoked strong responses of the ECM community. Species richness and diversity decreased after disturbance with disappearance of numerous species of Russulaceae, Cantharellaceae and Clavulinaceae. The relative abundance of contact exploration types decreased after the disturbance whereas the opposite pattern was observed for short distance exploration type. A mosaic of stress-tolerance species of Sebacina sp and Helvella sp, dominated after disturbance. These studies provide an understanding of the functioning and the responses of the system Mediterranean oaks – ECM communities facing climatic constraints. In natura experiments provide us insights on our understanding of ecological strategies of ectomycorrhizal fungi after disturbance.

Pisolithus is an important ectomycorrhizal genus world-wide, however to date we remain largely ignorant of the genetic and functional variation that exists within isolates of this genus. Fifty-three isolates of Pisolithus were obtained from various locations in central and eastern Australia and genetic variation within the isolates was assessed using ITS-RFLP and ITS sequencing analyses. RFLP analysis initially grouped the isolates into eight RFLP types. Neighbour-joining analysis of ITS sequences with Pisolithus ITS sequences available in databases clustered the majority of isolates into four groups within two major clades, each comprising isolates of similar basidiospre characteristics. Most Australian isolates correspond with recent provisional descriptions of P. albus or P. marmoratus. One isolate (LJ30) had low sequence identity (61.6-78.0%) to the other isolates and probably represents a separate undescribed Australian species. Significant intraspecific variation was observed in ITS-RFLP profiles for the putative P. albus isolates, suggesting that the sole use of RFLP analysis in diversity assessment may over-estimate Pisolithus species richness. Investigations were also initiated to identify if a relationship exists between genetic and physiological diversity in Australian Pisolithus. It is, however, clear that extensive physiological variation exists in Australian Pisolithus isolates. The size and distribution of genets of Australian Pisolithus species I and II ( putative P. albus and P. marmoratus) was also assessed using microsatellite-primed PCR to gain a better understanding of the likely distribution of underground mycelial networks and possible reproduction strategies in native soils. The data demonstrate that both species have the ability to be long-lived and extend for significant distances in native soils in undisturbed conditions. The field site for Pisolithus species I, however, also contained of a large number of small individuals suggesting that this species may employ a life-history strategy combining r-, C and S characteristics depending on local soil conditions / Doctor of Philosophy (PhD)

Pisolithus is an important ectomycorrhizal genus world-wide, however to date we remain largely ignorant of the genetic and functional variation that exists within isolates of this genus. Fifty-three isolates of Pisolithus were obtained from various locations in central and eastern Australia and genetic variation within the isolates was assessed using ITS-RFLP and ITS sequencing analyses. RFLP analysis initially grouped the isolates into eight RFLP types. Neighbour-joining analysis of ITS sequences with Pisolithus ITS sequences available in databases clustered the majority of isolates into four groups within two major clades, each comprising isolates of similar basidiospre characteristics. Most Australian isolates correspond with recent provisional descriptions of P. albus or P. marmoratus. One isolate (LJ30) had low sequence identity (61.6-78.0%) to the other isolates and probably represents a separate undescribed Australian species. Significant intraspecific variation was observed in ITS-RFLP profiles for the putative P. albus isolates, suggesting that the sole use of RFLP analysis in diversity assessment may over-estimate Pisolithus species richness. Investigations were also initiated to identify if a relationship exists between genetic and physiological diversity in Australian Pisolithus. It is, however, clear that extensive physiological variation exists in Australian Pisolithus isolates. The size and distribution of genets of Australian Pisolithus species I and II ( putative P. albus and P. marmoratus) was also assessed using microsatellite-primed PCR to gain a better understanding of the likely distribution of underground mycelial networks and possible reproduction strategies in native soils. The data demonstrate that both species have the ability to be long-lived and extend for significant distances in native soils in undisturbed conditions. The field site for Pisolithus species I, however, also contained of a large number of small individuals suggesting that this species may employ a life-history strategy combining r-, C and S characteristics depending on local soil conditions / Doctor of Philosophy (PhD)

Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 182-201.

Thesis (Ph.D. (Biochemistry, Microbiology & Biotechnology)) - Rhodes University, 2008.

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Cathy L. Cripps. Includes bibliographical references (leaves 105-121).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains viii, 72 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 61-64).