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Filtering by: Academic Affiliation Botany and Plant Pathology Remove constraint Academic Affiliation: Botany and Plant Pathology Degree Name Doctor of Philosophy (Ph.D.) Remove constraint Degree Name: Doctor of Philosophy (Ph.D.) Rights Statement Copyright Not Evaluated Remove constraint Rights Statement: Copyright Not Evaluated

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The fruits and seeds of the Rancho La Brea Pleistocene deposits

Creator:

Templeton, Bonnie Carolyn

Abstract:

More than 4,000 specimens of fruits and seeds were extracted from the matrix removed from inside the skulls of sabre-tooth cats excavated from various pits in the Rancho La Brea deposits. Of this number, spproximately 1,445 specimens are involved in this study. Many comparisons with modern fruits and seeds made...

Resource Type:

Dissertation
A recent disturbance history of forest ecosystems at Mount Rainier National Park

Creator:

Hemstrom, Miles A.

Abstract:

An analysis was made of the recent catastrophic disturbance history of forests at Mount Rainier National Park. Basic data were tree ages from ring counts of increment cores taken from the early seral cohort, field mapping of age class boundaries and aerial photograph interpretation. Maps of present stand ages were...

Resource Type:

Dissertation
Plant communities and succession in Oregon coastal salt marshes

Creator:

Jefferson, Carol A.

Abstract:

The purpose of this study was to determine plant species composition, community structure, successional relationships, vegetational development and plant distributions in estuarine salt marshes on the Pacific Coast of Oregon. Quadrat and transect samples of plant presence and cover, collected from April 1971 - June 1974, were subjected to phytosociological...

Resource Type:

Dissertation
Salt marsh reestablishment following dike breaching in the Salmon River estuary, Oregon

Creator:

Mitchell, Diane Lynne

Abstract:

A 22 ha, 1S yeas old, diked permanent pasture in the Salmon River estuary in Lincoln County, Oregon, was chosen for a study to determine the potential for natural salt marsh restoration with dike breaching. Two undiked fragments of relatively undisturbed salt marsh, one at each end of the study...

Resource Type:

Dissertation
Distributional patterns and taxonomic structure of diatom assemblages in Netarts Bay, Oregon

Creator:

Whiting, Mark Carlos

Abstract:

Epiphytic, planktonic and benthic diatom assemblages were investigated in Netarts Bay, Oregon. Samples were collected for a one-year period from February 1980 to March 1981. A planktonic flora was observed only during periods of offshore enrichment when marine neritic species were abundant and were transported into the bay by tidal...

Resource Type:

Dissertation
In vitro culture and growth modeling of Tuber spp. and inoculation of hardwoods with T. melanosporum ascospores

Creator:

Michaels, Thomas Joseph

Abstract:

In vitro growth of twelve isolates of Tither spp., the true truffles, was quantified by an agar-melt procedure. All isolates grew poorly on media commonly used for the culture of mycorrhizal fungi, but responded markedly to the addition of nitrate, as well as other inorganic ions, to malt and potato-dextrose...

Resource Type:

Dissertation
Population biology of rare mariposa lilies (Calochortus: Liliaceae) endemic to serpentine soils in southwestern Oregon

Creator:

Fredricks, Nancy Ann

Abstract:

Population dynamics, plant communities, and abiotic environments of three narrowly endemic, allopatric mariposa lilies (Calochortus Pursh) are described and compared. All were restricted to ultramafic soils in southwestern Oregon with high concentrations of nickel, zinc, and chromium, and low calcium to magnesium ratios. Soils inhabited by the three species differed...

Resource Type:

Dissertation
Plant reproductive ecology and community structure along a subalpine snowmelt gradient

Creator:

Ingersoll, Cheryl A.

Abstract:

The seasonal duration of snow cover is a primary factor influencing the patterns of vegetation in high subalpine and alpine environments, but little is known concerning the responses of plant reproduction and seedling recruitment to gradients of snow-release. Vegetation patterns of a high subalpine site in the Oregon High Cascades...

Resource Type:

Dissertation
Production dynamics of sediment-associated algae in two Oregon estuaries

Creator:

Davis, Michael W.

Abstract:

Sediment-associated gross primary production, oxygen uptake, microalgal biomass expressed as chlorophyll a concentration, macroalgal biomass and total organic matter concentration expressed as ash-free dry weight were measured monthly at medium sand, fine sand and coarse silt sites between 0.5 m and 2.0 m above MLLW during an entire year at...

Resource Type:

Dissertation
Fungal and bacterial associations in heart rots of Abies concolor (Gord. and Glend.) Lindl. and techniques for estimating damage in southwestern Oregon

Creator:

Aho, Paul E.

Abstract:

Infection courts for microorganisms invading white fir heartwood were determined to be primarily branches and basal wounds. Of 11 hymenomycetes isolated from infected trees, only four: Echinodontiurn tinctorium, Phellinus chrysoloma, Pholiota adiposa, and Hericium abietis were of major significance in terms of frequency of infection and damage caused. Two or...

Resource Type:

Dissertation
Epiphytic macrolichens in relation to forest management and topography in a western Oregon watershed

Creator:

Berryman, Shanti D.

Abstract:

This dissertation describes patterns in epiphytic macrolichen community composition, diversity, and biomass across various stand types in the Blue River watershed of western Oregon. It first examines the relative importance of ecological factors such as stand age, remnant tree retention, and topography to lichen communities in the landscape. It then...

Resource Type:

Dissertation
Biomass dynamics of dead Douglas-fir and western hemlock boles in mid-elevation forests of the Cascade Range

Creator:

Graham, Robin Lee Lambert

Abstract:

The rate and manner of bioniass loss from decomposing Douglas-fir and western hemlock boles in mid-elevation forests of the central Cascade Range were measured. Bole bark and wood were considered separately. Loss of bole wood due to respiration was measured by change in bole wood density. Loss of bole wood...

Resource Type:

Dissertation
The relationship of phloem graft union responses to pear decline

Creator:

Ostrowski, Richard Carl

Abstract:

Since 1948, pear decline has been responsible for the devitalization and death of many pear trees in the Pacific Coast states and British Columbia. Use of anatomical abnormalities of the graft union as a diagnostic technique to separate pear decline from other disorders exhibiting similar symptoms was evaluated. Modifications in...

Resource Type:

Dissertation
The Phellinus pini complex : genetic and population studies within and between species

Creator:

Dreisbach, Tina A.

Abstract:

Three species comprising the Phellinus pini complex have been documented in the USA, including P. pini, P. chrysoloma, and P. cancriformans. However, overlap in morphological features and ecological characteristics make species identification difficult. In addition, some researchers have questioned the existence of P. pini in the USA, suggesting instead that...

Resource Type:

Dissertation
Coniothyrium rose canker in Oregon

Creator:

Intrama, Siriphong

Abstract:

An isolate of Coniothyrium obtained from a stem canker on Nocturne rose from the Botany Department Farm, Corvallis, Oregon was studied with respect to morphological and cultural characters, pathogenicity and mineral nutrition. The hyphae of the isolate were smooth, septate and branched. The hyphal cells averaged 16.37 X 3.52 microns....

Resource Type:

Dissertation
The interactions of Pratylenchus penetrans with host plants, Longidorus elongatus and Verticillium dahliae

Creator:

Yorston, John McKay

Abstract:

The root-lesion nematode, Pratylenchus penetrans (Cobb 1917). Filipjev and Shuurmans Stekhoven, 1941, is widely distributed throughout Oregon and other temperate zones of the world. Economically it is probably the most important plant parasitic nematode in Oregon because of its abundance, wide host range of economic plants and interactions with other...

Resource Type:

Dissertation
Taxonomy of Phacelia section Miltitzia (hydrophyllaceae)

Creator:

Halse, Richard R.

Abstract:

A systematic study was made of the species comprising Phacelia section Miltitzia. These species, which are commonly found in the Great Basin physiographic province of western North America, are distinguished from other members of Phacelia by their yellow, marcescent corollas and their transversely corrugated seeds. This project utilized morphological, cytological,...

Resource Type:

Dissertation
Logs as sites of tree regeneration in Picea sitchensis-Tsuga heterophylla forests of coastal Washington and Oregon

Creator:

Harmon, Mark E.

Abstract:

Logs are seedbeds for trees in many Picea sitchensis-Tsuga heterophylla forests of Washington and Oregon. Factors affecting this close association, including seed retention and seedling establishment on logs and successional changes in log characteristics, are explored In this study. Field and laboratory experiments indicated that competition with vegetation on the...

Resource Type:

Dissertation
Contributions to the plant ecology of the Oregon coastal sand dunes

Creator:

Wiedemann, Alfred M.

Abstract:

Sand dunes are found along the coasts of most of the large land masses of the world. Because of their proximity to man and his activities, the maritime sand dunes of Europe, particularly Germany, France, Holland and Scandinavia, have the longest history of stabilization activities and botanical investigation. There are...

Resource Type:

Dissertation
Description and classification of the forests of the upper Illinois River drainage of Southwestern Oregon

Creator:

Atzet, Thomas

Abstract:

The purpose of this study was to develope a plant community classification within the Siskiyou mountains, a small range within the Klamath geological province well known for its geologic and floristic diversity. Forest land managers have expressed the need for identification of basic Land classes that will aid in the...

Resource Type:

Dissertation
Active survival of Verticillium dahliae in soil

Creator:

Martinson, Charlie Anton

Resource Type:

Dissertation
Population viability analysis of endangered plant species : an evaluation of stochastic methods and an application to a rare prairie plant

Creator:

Kaye, Thomas N.

Abstract:

Transition matrix models are one of the most widely used tools for assessing population viability. The technique allows inclusion of environmental variability, thereby permitting estimation of probabilistic events, such as extinction. However, few studies use the technique to compare the effects of management treatments on population viability, and fewer still...

Resource Type:

Dissertation
Lichen response to the environment and forest structure in the western Cascades of Oregon

Creator:

Martin, Erin P.

Abstract:

Lichens are an important part of the biota in western Oregon forests, where they perform valuable ecological roles and contribute significantly to biodiversity. Lichens in western Oregon are threatened by a number of factors including air pollution and land use practices. If we wish to maintain the persistence of lichens...

Resource Type:

Dissertation
Ecology and distribution of riparian vegetation in the Trout Creek Mountains of southeastern Oregon

Creator:

Evenden, Angela G.

Resource Type:

Dissertation
Twenty-one years of secondary succession in Pseudotsuga forests of the western Cascade Range, Oregon

Creator:

Halpern, Charles B.

Resource Type:

Dissertation
Production dynamics of a Zostera marina L. bed in Netarts Bay, Oregon

Creator:

Kentula, Mary E.

Resource Type:

Dissertation
Morphology, physiology and pathogenicity of Trichoconis padwickii Ganguly, the cause of Stackburn disease of rice

Creator:

Chuaiprasit, Chalermlarb

Resource Type:

Dissertation
The culture and biochemical analysis of some estuarine phytoplankton species

Creator:

DeMort, Carole Lyle

Abstract:

The biochemical composition of ten species of estuarine phytoplankton was determined. Studies were made of their growth in various culture media and of their relative value as food for oyster larvae. Nine of the species were isolated from Yaquina Bay, Oregon. An attempt was made to select species which commonly...

Resource Type:

Dissertation
Impacts of ponderosa pine forest restoration treatments on the ectomycorrhizal fungal community and fine root biomass in the Blue Mountains of Oregon

Creator:

Smith, Jane E. (Jane Elizabeth)

Abstract:

Before the arrival of Euro-Americans, the inland Pacific Northwest was settled by native people whose frequent intentional burning of the landscape promoted open stands dominated by large fire-resistant ponderosa pine. Fire suppression for nearly a century, livestock grazing, and logging of the largest trees has resulted in forests characterized by...

Resource Type:

Dissertation
The distribution of intertidal diatoms associated with the sediments of Yaquina Estuary, Oregon

Creator:

Amspoker, Michael C.

Abstract:

Sediment samples were collected from eight sampling sites along the Yaquina Estuary, Oregon from Yaquina Bay to Elk City near the head of the estuary. Samples were collected in November 1973, February 1974, May 1974 and August 1974 from two or three intertidal levels depending on the magnitude of the...

Resource Type:

Dissertation
Resistance mechanisms of Port-Orford-cedar to Phytophthora lateralis

Creator:

Oh, Eunsung

Abstract:

Breeding Port-Orford-cedar for resistance to Phytophthora lateralis, a causal agent of root disease, begins by screening, through artificial inoculation, phenotypically resistant trees selected from natural stands. The successful program selected tolerant or resistant POC parent trees for the purpose of disease management. Candidate resistant POCs were used in my dissertation...

Resource Type:

Dissertation
Phylogenetics, population genetics, molecular epidemiology, and pathogenicity of the Douglas-fir Swiss needle cast pathogen Phaeocryptopus gaeumannii

Creator:

Winton, Loretta M.

Abstract:

A hierarchical series of studies, based mainly on molecular data, was conducted to elucidate the life history of the Douglas-fir Swiss needle cast pathogen Phaeocryptopus gaeumannii at macro- and micro-evolutionary scales. This information was then utilized to design and evaluate molecular diagnostic tools for use in studies on the epidemiology...

Resource Type:

Dissertation
Effects of host resistance on Mycosphaerella graminicola populations

Creator:

Cowger, Christina

Abstract:

Mycosphaerella graminicola (anamorph Septoria tritici) causes Septoria tritici blotch, a globally important disease of winter wheat. Resistance and pathogenicity generally vary quantitatively. The pathogen reproduces both sexually and asexually, and the pathogen population is highly genetically variable. Several unresolved questions about the epidemiology of this pathosystem are addressed by this...

Resource Type:

Dissertation
The imprint of coarse woody debris on soil biological and chemical properties in the western Oregon Cascades

Creator:

Spears, Julie D. H.

Abstract:

The abundance and spatial heterogeneity of coarse woody debris (CWD) on the forest floor is a prominent feature of Pacific Northwest (PNW) forest ecosystems. The effect of CWD on soil solution chemistry, nutrient cycling and availability, soil physical structure and formation of soil organic matter, however, remains unknown. Therefore, studies...

Resource Type:

Dissertation
Distribution and prediction of Swiss needle cast of Douglas-fir in coastal Oregon

Creator:

Rosso, Pablo H.

Abstract:

This study was directed to improve our understanding of the ecology of Swiss needle cast (SNC) of Douglas-fir, a disease that produces extensive damage to forests and plantation in the coastal region of Oregon and Washington. A disease prediction model for the coastal area of Oregon was built by establishing...

Resource Type:

Dissertation
Analysis and prediction of patterns in lichen communities over the western Oregon landscape

Creator:

Peterson, Eric B.

Abstract:

The diverse lichen flora of the Pacific Northwest is being impacted by population growth and by forest management practices. Accumulating information about our lichen flora will improve our conservation strategies. This dissertation first collects information to improve our understanding of how lichen communities vary among forests of differing structure, and...

Resource Type:

Dissertation
Port-Orford-cedar and Phytophthora lateralis : grafting and heritability of resistance in the host, and variation in the pathogen

Creator:

McWilliams, Michael G.

Abstract:

Port-Orford-cedar (Chamaecyparis lawsoniana) is a forest tree native to a small area of Oregon and California. A root disease caused by Phytophthora lateralis causes widespread mortality of Port-Orford-cedar. This dissertation examines three important elements of the Port-Orford-cedar P. lateralis pathosystem related to breeding for disease resistance: use of resistant rootstocks...

Resource Type:

Dissertation
The effects of nitrogen manipulations and hydrology on the establishment and competitive abilities of wetland prairie plant species (western Oregon)

Creator:

Davis, Kimberly J.

Abstract:

Many studies suggest that weedy plant species are most successful when soil nitrogen in abundant. Consequently, I used soil nitrogen manipulations to determine if altering nitrogen would affect the establishment of both weedy and native plant species in a western Oregon wetland prairie. In two studies, we added carbon amendments...

Resource Type:

Dissertation
Shrub epiphyte communities in relation to stand management in forests of western Oregon

Creator:

Rosso, Abbey L.

Abstract:

This dissertation describes the epiphyte communities on tall shrubs in forests of western Oregon, with a focus on potential effects of management practices on these communities. Shrubs and other hardwoods have recently gained recognition as hotspots of diversity for epiphytes in young conifer forests of the region. Yet little is...

Resource Type:

Dissertation
Factors influencing the effects of host diversity on plant disease epidemics for wheat stripe rust and potato late blight

Creator:

Garrett, Karen A.

Abstract:

Most studies of plant disease epidemiology have focused on epidemics in host populations composed of a single genotype. But crop plant diversity can be a useful means of improving the deployment of resistance genes. In a series of experiments with wheat stripe rust and potato late blight, we studied factors...

Resource Type:

Dissertation
A two-component regulatory system controlling antibiotic production by Pseudomonas flourescens Pf-5

Creator:

Corbell, Nathan

Abstract:

Tn5 mutagenesis of apdA (for antibiotic production) and deletion of gacA (for global antibiotic and cyanide) resulted in the same pleiotropic phenotype in Pseudomonas fluorescens (i.e. production of an array of secondary metabolites including the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol as well as a tryptophan-side-chain oxidase, hydrogen cyanide, and an...

Resource Type:

Dissertation
Below ground biology of Botrychium pumicola (Ophioglossaceae)

Creator:

Camacho, Francisco J.

Resource Type:

Dissertation
Fescue taxonomy in the Pacific coast states

Creator:

Wilson, Barbara L.

Abstract:

Accurate taxonomy is essential to preservation and management of native grasses. Four problems in fescue taxonomy were investigated: the identity of the native fescue that dominates western Oregon and Washington prairies, the relationship of native Festuca roemeri to closely related grasses, the status of F. howellii and F. washingtonica, and...

Resource Type:

Dissertation
Effects of single and multiple stressors on communities of wheat and wild oats

Creator:

Pfleeger, Thomas G.

Abstract:

Most plant toxicology tests developed in support of environmental laws use a single stress applied to an individual plant. While tests using individual species or stresses require fewer resources and are easier to interpret, they are under increasing criticism for being unrealistic and missing important ecological interactions. The objective of...

Resource Type:

Dissertation
A biochemical analysis of the interaction of victorin and oats

Creator:

Navarre, Duroy A.

Abstract:

Victoria blight of oats is caused by the fungus Cochhobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. Previously, a 100-kD protein that binds victorin in vivo only in susceptible genotypes was identified as the P protein of the glycine decarboxylase complex (GDC)....

Resource Type:

Dissertation
Molecular phylogenetic analyses of Riccia and Marchantiales

Creator:

Wheeler, John A. (John Allen)

Resource Type:

Dissertation
Molecular characterization of a protein toxin involved in the Pyrenophora tritici-repentis/wheat interaction

Creator:

Tuori, Robert P.

Resource Type:

Dissertation
Phylogeny, cospeciation, and host switching in the evolution of the ascomycete genus Rhabdocline on Pseudotsuga and Larix (Pinaceae)

Creator:

Gernandt, David S.

Abstract:

The relative role of cospeciation and host switching in the phylogenetic history of ascomycete foliar symbionts is addressed in the orders Leotiales and Rhytismatales, fungi associated predominantly with Pinaceae (Coniferales). Emphasis is placed on comparing the evolution of the sister genera Pseudotsuga and Larix (Pinaceae) with that of the pathogenic...

Resource Type:

Dissertation
Molecular and genetic analyses of genome variability in Ustilago hordei

Creator:

Agnan, Jacqueline

Abstract:

Pulsed-field gel electrophoresis (PFGE) of the strains representing the 14 races of U. hordei, the causal agent of covered smut on barley, revealed extensive polymorphism in chromosome length and number. The purpose of this study was to determine by two approaches the exact chromosome number for each U. hordei race,...

Resource Type:

Dissertation
Copper and streptomycin resistance in Pseudomonas syringae isolated from Pacific Northwest nurseries

Creator:

Scheck, Heather J.

Resource Type:

Dissertation
Evolution and ecology of the Ceanothus-Frankia symbiosis

Creator:

Jeong, Soon-Chun

Abstract:

The evolutionary relationship between Frankia and actinorhizal plants was evaluated by reconstructing molecular phylogenetic trees from nifH, 16S rDNA, and rbcL nucleotide sequences. Subgroupings in Frankia phylogenetic trees reconstructed from nifH and from 16S rDNA sequences were consistent in terms of plant origins of Frankia strains. Although the branching order...

Resource Type:

Dissertation
Auxin and cytokinin interaction in tomato (Lycopersicon esculentum Mill.)

Creator:

Coenen, Catharina

Abstract:

The phytohormones auxin and cytokinin control plant development through a complex network of interactions which include synergistic, additive, and opposite effects whose mechanisms are unknown. The auxin-insensitive diageotropica (dgt) mutant provided a tool to dissect the relationship between auxin- and cytokinin-induced responses in tomato. Morphological, physiological, and molecular data support...

Resource Type:

Dissertation
Acyl-ACP thioesterases and beta-ketoacyl-ACP synthase regulate fatty acid chain length in seed oils of Cuphea wrightii

Creator:

Leonard, Jeffrey M.

Resource Type:

Dissertation
Biology and control of Fusarium spp. on Douglas-fir (Pseudotsuga menziesii)

Creator:

Hoefnagels, Mariëlle Henriette, 1965-

Abstract:

Fusarium spp. are among the most important pathogens of Douglas-fir (Pseudotsuga menziesii) seedlings in bareroot nurseries. Currently the most effective disease control method is soil fumigation with methyl bromide. As methyl bromide is phased out, however, other disease management strategies may become more important. We explored two alternative approaches to...

Resource Type:

Dissertation
Ecological assessment after the addition of genetically engineered Klebsiella planticola SDF20 into soil

Creator:

Holmes, Michael T.

Abstract:

The objectives in this research were to assess whether Klebsiella planticola SDF20 could survive in soil and result in ecological effects to soil foodweb organisms and plant growth. Four experiments were conducted using soil microcosms. Klebsiella planticola SDF20 has been genetically engineered to produce ethanol from agricultural waste for use...

Resource Type:

Dissertation
The sequestrate relatives of Russula in Australia and New Zealand

Creator:

Lebel, Teresa

Resource Type:

Dissertation
Genetic variability in the eastern filbert blight pathosystem

Creator:

Osterbauer, Nancy K.

Abstract:

The heritability of resistance to eastern filbert blight, caused by Anisogramma anomala, in European hazelnut (Corylus avellana) was evaluated in the progeny of seven cultivars crossed in 12 combinations. Progeny produced by crossing 'VR6-28' with three susceptible cultivars segregated 1:1 for complete resistance to eastern filbert blight. Histograms of disease...

Resource Type:

Dissertation
Canopy epiphyte studies in the central Oregon Cascades : implications for the management of Douglas-fir forests

Creator:

Sillett, Stephen Charles

Abstract:

This thesis includes four separate studies. The first two studies assessed edge effects in a 700-year-old forest. After 20 years of exposure, epiphyte assemblages on the clearcut edge were similar to those of the forest interior, but there were some differences in vertical distribution patterns. Several species restricted to the...

Resource Type:

Dissertation
Interrelationship of wheat cultivar mixtures, stripe rust and yield

Creator:

Akanda, Shamsul I.

Resource Type:

Dissertation
Taxomony and mycorrhizal ecology of the desert truffles in the genus Terfezia

Creator:

Alsheikh, Abdulmagid M.

Abstract:

Mycorrhizal fungi in arid and semiarid rangelands have received little study in southwest Asia and north Africa, although they are important in food production and rangeland productivity. The desert truffles of the genera Terfezia and Tirmania form fruiting-bodies and mycorrhizae with rangeland plants. This thesis treats the taxonomy and the...

Resource Type:

Dissertation
Interactions of ammonia monooxygenase in Nitrosomonas europaea with hydrocarbons and substituted hydrocarbons

Creator:

Keener, William Kelvin

Resource Type:

Dissertation
Reevaluation of systematic relationships in Triticum L. and Aegilops L. based on comparative morphological and anatomical investigations of dispersal mechanisms

Creator:

Morrison, Laura A.

Abstract:

Comparative morphological and anatomical studies of the dispersal mechanisms characterizing the wheat complex (Triticum L. and Aegilops L.) have documented patterns of adaptive radiation which may have significance for evolutionary relationships. These patterns, which form an array of diverse types of diaspores among the diploid taxa, appear conceptually to have...

Resource Type:

Dissertation
Ecology of benthic microalgae of estuarine intertidal sediments

Creator:

Riznyk, Raymond Zenon

Abstract:

The benthic microalgae of sediments of the two tidal flats in Yaquina Bay, Oregon were investigated to determine the environmental factors limiting the abundance and the horizontal and vertical distribution of these organisms. The Southbeach tidal flat which is under the marine realm of deposition consists of fine to medium...

Resource Type:

Dissertation
Pathogenic variability and adaptation of Septoria tritici to different wheat cultivars

Creator:

Ahmed, Hafiz Uddin

Abstract:

Experiments were done to determine pathogenic variability and pathogenic adaptation of Septoria tritici to different wheat cultivars. Fifteen S. tritici isolates from California, Oregon, and Texas were evaluated on seedlings of two sets of geographically diverse wheat cultivars under greenhouse conditions. Significant isolate effects, cultivar effects, and isolate X cultivar...

Resource Type:

Dissertation
Mediation of conifer root growth by mycorrhizal fungi and plant growth regulators

Creator:

Scagel, Carolyn F.

Abstract:

Many mycorrhizosphere microorganisms can produce plant growth regulating compounds in vitro. Plant growth regulating compounds are known to mediate root growth and development. In reforestation practices, conifer tree seedling growth and survival are linked to rapid root growth and development after outplanting. Multifactorial experiments were conducted to document variations in...

Resource Type:

Dissertation
Analysis of putative elements of plant signal transduction chains

Creator:

Verhey, Steven D.

Abstract:

The thesis begins with an introduction to signal transduction and an analysis of current understanding of plant signal transduction. There are similarities between plants and animals, but also key differences, including lack of protein kinase C and of a cAMP signaling pathway in plants, and presence in plants of calcium...

Resource Type:

Dissertation
Serological and biological characterization of seed-borne isolates of blackeye cowpea mosaic and cowpea aphid-borne mosaic potyviruses in Vigna unguiculata (L.) Walp

Creator:

Bashir, Muhammad

Resource Type:

Dissertation
Genetic analysis of catechol siderophore by Erwinia carotovora

Creator:

Bull, Carolee Theresa, 1962-

Resource Type:

Dissertation
Mycorrhizal and other root endophytic fungi of lupines in the Pacific Northwest

Creator:

O'Dell, Thomas E.

Abstract:

We investigated the root endophytic fungi of lupine using four approaches: (1) occurrence of fungal colonization in field-collected roots; (2) growth response of L. latifolius to inoculation with two types of fungi; (3) structure of root colonizations of Pinus and Lupinus by Phialocephala fortinii, a septate endophytic fungus of lupine;...

Resource Type:

Dissertation
Partial characterization of the P4 pathotype of pea seedborne mosaic virus

Creator:

Kohnen, Paul D.

Abstract:

Biological, serological, and molecular characteristics of the P4 pathotype of pea seedborne mosaic potyvirus (PSbMV) were investigated. The characterization allowed P4 to be differentiated from other pathotypes of the same virus. P4 was distinguished from P1 on the basis of host symptomatology. It induced varied, but often distinctive symptoms in...

Resource Type:

Dissertation
Interactive effects of stripe rust and plant competition in heterogeneous wheat populations

Creator:

Finckh, Maria Renate

Abstract:

Disease has been implied as an important selective force acting in plant populations. This study was conducted to determine the effects of stripe rust (Puccinia striiformis) on the population dynamics of wheat (Triticum aestivum) cultivar mixtures. Five wheat cultivars were grown in pure stands and all possible mixtures at three...

Resource Type:

Dissertation
Effects of intercropping beans with maize on angular leaf spot and rust of beans

Creator:

Boudreau, Mark Alan, 1958-

Abstract:

Experiments were performed to determine the nature of maize influence on bean disease in additive-type intercrops. Overall effects of intercrops on angular leaf spot (caused by Phaeoisariopsis griseola) in Kenya indicated >23% reductions (P<0.05) in area under the disease progress curve (AUDPC) in two of three season-site combinations. Fertilization tended...

Resource Type:

Dissertation
Mycorrhizal fungi and their relationship to plant succession in subalpine habitats

Creator:

Cazares, Efren

Resource Type:

Dissertation
Systematic and reproductive studies of Mimulus (Scrophulariaceae) in the Pacific Northwest : implications for conservation biology

Creator:

Meinke, Robert James

Abstract:

The Mimulus washingtonensis complex is a group of morphologically similar species centered in the Pacific Northwest. All are rare, and most are under consideration for listing as endangered. Morphometric and pollination data were used in developing a revised taxonomy for the group. Five species and two varieties are recognized. Mimulus...

Resource Type:

Dissertation
Effects of substrate relief, light intensity and herbivory on the distribution and abundance of periphyton in laboratory streams

Creator:

DeNicola, Dean M.

Resource Type:

Dissertation
Biology, epidemiology, and biological and chemical control of Phytophthora vignae

Creator:

Fernando, W. Gerard Dilantha

Abstract:

Phytophthora vignae, causal agent of stem and root rot of cowpea (Vigna unguiculata), was reported for the first time in Sri Lanka. The pathogen was found in cowpea field soils from 3 of 5 geographic regions sampled. Only one site however, had plants exhibiting disease symptoms. Of the eight cowpea...

Resource Type:

Dissertation
Variation in plant response to inoculation with different isolates of vesicular arbuscular mycorrhizal fungi

Creator:

Ianson, David C.

Resource Type:

Dissertation
Molecular karyotyping of Ustilago hordei and related smut fungi

Creator:

McCluskey, Kevin

Resource Type:

Dissertation
Rhynchosporium orthosporum in orchardgrass, isolation frequency, colonization, variability, and an evaluation of cultivar resistance

Creator:

Fernandez, Jesus Perez

Resource Type:

Dissertation
Genetics of sexuality and population genetics of Phellinus weirii

Creator:

Angwin, Peter A.

Abstract:

Phellinus weirii (Murr.) Gilbertson, cause of laminated root and butt rot, is a heterothallic basidiomycete lacking clamp connections. Two biological species groups of the fungus have been hypothesized, the Douglas-fir and cedar-types, on the basis of physiological, morphological and epidemiological differences. Single-spore and vegetative isolates differ in cultural morphology, nuclear...

Resource Type:

Dissertation
The disease cycle of side rot of pear, caused by Phialophora malorum

Creator:

Sugar, David

Abstract:

Potential sources of inoculum of Phialophora malorum were investigated. P. malorum was found to be a soil-borne fungus whose role as a postharvest pathogen of pear is dependent upon passive dispersal with infested soil. P. malorum survived in soil under a wide range of conditions, with greatest survival in cool,...

Resource Type:

Dissertation
Epidemiology and population biology of Inonotus tomentosus as a pathogen of forests of British Columbia

Creator:

Lewis, Katherine JoAnn

Abstract:

The root disease fungus Inonotus tomentosus, common in the old growth boreal forests of British Columbia, poses a threat to the health of second growth forests established on sites with a previous history of root disease. Colonized stumps occur in groups of 1 to 6; the groups are clumped within...

Resource Type:

Dissertation
Microbial analysis of coniferous forest and nursery soils : effects of ectomycorrhizae, volatiles, and humic-rich organic substrates

Creator:

Schisler, David Albert

Abstract:

Fusarium spp. frequent conifer nursery soils yet are rarely recovered from coniferous forest soils. Experiments were performed to determine what influence humic-rich organic amendments and volatiles from soil, ectomycorrhizal fungi and ectomycorrhizae have on the populations of several physiologic and taxonomic microbial groups potentially related to this phenomenon. A comparative...

Resource Type:

Dissertation
Cytokinin oxidase activity from Phaseolus vulgaris L. cv. Great Northern callus tissues

Creator:

Chatfield, J. Mark

Abstract:

Cytokinin oxidase activity in callus tissues of Phaseolus vulgaris L. cv. Great Northern has been examined using an assay based on the oxidation of radioactively labeled N⁶ -(Δ² -isopentenyl) adenine (i⁶Ade) to adenine (Ade). Conditions for the quantitative extraction and assay of the enzyme have been established. The substrate specificity...

Resource Type:

Dissertation
Effects of current velocity, irradiance, and herbivory on algal assemblages in laboratory streams

Creator:

Steinman, Alan D.

Abstract:

Effects of current velocity, irradiance, and grazing on the biomass, taxonomic structure, physiognomy, and chemical composition of lotic algal assemblages were investigated. Four experiments, lasting 32 to 75 days, were conducted in laboratory streams to determine how these factors affect algal assemblages singly, and in concert with each other. Regardless...

Resource Type:

Dissertation
Characterization of the replication, incompatibility, and recombination regions of Pseudomonas syringae pv. phaseolicola plasmid pEXC8080

Creator:

Poplawsky, Alan R.

Resource Type:

Dissertation
Pathogenesis and intertree transmission of Verticicladiella wageneri in Douglas-fir (Pseudotsuga menziesii)

Creator:

Hessburg, Paul F.

Abstract:

Verticicladiella wageneri Kendr. is a vascular wilt pathogen of Douglas-fir in the Pacific Northwest, The disease is characterized by black staining of colonized sapwood; crown symptoms are those typical of a wilting syndrome. Histopathological studies revealed that the pathogen is limited to the xylem but causes vascular dysfunction in both...

Resource Type:

Dissertation
Responses of algal populations to parasitism by Aphelidium chlorococcarum and chytrids in an Oregon sewage lagoon

Creator:

Woods, Wendy W.

Abstract:

The abundance of algal species and their parasites was monitored weekly for two years in a sewage lagoon at the Corvallis Airport, Oregon. During the cooler months, Euglena species were dominant followed by a Chlamydomonas assemblage in the spring and a predominantly Scenedesmus assemblage in the summer and fall. Parasites...

Resource Type:

Dissertation
Epidemiology of disease caused by Pseudomonas syringae as an epiphyte and its frequency, distribution, and characteristics as an endophyte of pear

Creator:

Whitesides, Steven K.

Abstract:

Conditions were established for inducing pear blossom blast caused by Pseudomonas syringae (Ps) on both attached and detached shoots. The incidence of disease was proportional to the log of Ps population under optimal temperature, moisture and bloom developmental stage. Highest incidence of infection followed occurrence of a major exotherm in...

Resource Type:

Dissertation
Serological identification of common and strain-specific antigens in Agrobacterium

Creator:

Bouzar, Hacene

Abstract:

Two new methods, one of broad specificity and the other of narrow specificity, were developed for the identification of agrobacteria. The former method was based on ribosomal antigens that were common to members of the closely related Agrobacterium and Rhizobium genera. Antisera to unwashed 50 S ribosomal subunits from five...

Resource Type:

Dissertation
Postemergence herbicides and take-all disease in winter wheat : alterations in the incidence and severity of disease and crop growth

Creator:

Geddens, Ray M.

Abstract:

Eight postemergence herbicides were evaluated to determine their influence on the incidence and severity of take-all disease caused by the fungus Gaeumannomyces graminis var. tritici in winter wheat. Mecoprop ((+)-2-(4-chloro-2-methylphenoxy)propanoic acid), difenzoquat (1,2- dimethyl- 3,5- diphenyl -1H- pyrazolium), dinoseb amine (amine salt of 2-(1-methylpropy1)-4,6-dinitrophenol), and diclofopmethyl (methyl ester of (+)-2-[4-(2,4-dichlorophenoxy)...

Resource Type:

Dissertation
A potato growth and production model

Creator:

Apple, Jeanne Debons

Abstract:

A potato plant growth and production model is developed with the objectives of analyzing management alternatives and exploring the nature of the early dying syndrome. The geographic area of focus was the centerpivot irrigated circles of Oregon's Columbia Basin. A problem analysis of the potato production system of this area,...

Resource Type:

Dissertation
Relationship of extra-matrical hyphae of vesicular-arbuscular mycorrhizal fungi to plant growth response

Creator:

Kough, John Lawrence

Abstract:

The colonization of several species of plants by vesicularar-buscular mycorrhizae (VAM) was studied to determine how host, soil, or symbiont factors interacted to enhance growth of the host plant. Seedlings of two species of the Cuppressaceae and two of the Taxodiaceae formed VAM; colonization significantly improved growth. This response to...

Resource Type:

Dissertation
Pathological and ecological aspects of decline and mortality of Chamaecyparis nootkatensis in southeast Alaska

Creator:

Hennon, Paul Edward

Abstract:

Alaska-cedar (Chamaecvparis nootkatensIs (D. Don) Spach) is a valuable tree that is suffering from a serious decline and mortality of unknown cause throughout southeast Alaska. Epidemiological and pathological studies were initiated to determine if a pathogen is the primary cause of this problem. By examining old aerial photographs and by...

Resource Type:

Dissertation
Establishment of Poria carbonica in wood and colonization by basidiomycetes of Douglas-fir utility poles during air seasoning

Creator:

Przybylowicz, Paul

Abstract:

Influence of temperature and wood moisture content on spore germination and colonization of Douglas-fir (Pseudotsuga jnenziesii) heartwood by Poria carbonica basidiospores and chlamydospores was studied. Both spore types germinated and colonized wood at moisture contents above the fiber saturation point, but not below. Germination and wood colonization occurred at 22°C...

Resource Type:

Dissertation
The effects of abscisic acid on gene expression during wheat germination

Creator:

Ballo, Barbara

Abstract:

Germination of immature (Stage III) and mature (Stage V) wheat (Triticum aestivum L. var. Chinese Spring and Yamhill) embryos is prevented by the inclusion of 10⁻⁴ M abscisic acid (ABA) in culture medium. In addition, Stage III embryos develop into mature embryos in culture medium containing ABA. In the absence...

Resource Type:

Dissertation
Forest structure and regeneration in the Tsuga heterophylla - Abies amabilis transition zone, central Western Cascades, Oregon

Creator:

Stewart, Glenn H.

Abstract:

The dynamics of stands in the mid-elevation old-growth Douglas-fir (Pseudotsuga menziesii) forests of the central western Oregon Cascade Range were investigated using stand structure analysis. Trees with different growth rates were commonly present in the same stand, which resulted often in a weak correlation between tree diameter and age. Thus,...

Resource Type:

Dissertation
Soil fungal hyphal dynamics and seasonal hypogeous sporocarp production in western Oregon Douglas-fir forests

Creator:

Hunt, Gary, 1945-

Abstract:

Total length and biomass of fungal mycelium in the soil of a young Douglas-fir stand in the central Oregon Coast Range were estimated over 27 months with the agar-film technique. In a second study, phenology and taxonomy of hypogeous (belowground) sporocarps were studied over 32 months in a nearby, young...

Resource Type:

Dissertation
The spatial distribution of wood-nesting ants in the central Coast Range of Oregon

Creator:

Nielsen, Gary R. (Gary Richard), 1956-

Resource Type:

Dissertation
The effects of abscisic acid on gene expression during embryogenesis in wheat

Creator:

Williamson, John D. (John David), 1948-

Resource Type:

Dissertation

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Academic Affiliation

Botany and Plant Pathology[remove]215

Advisor

Trappe, James M.13
Chambers, Kenton L.12
Phinney, Harry K.9
Chilcote, W. W.8
Chilcote, William W.8
more Advisors »

Commencement Year

Commencement Year range begin – Commencement Year range end

Current results range from 1962 to 2006

View distribution

Committee Member

Bottomley, Peter6
Mills, Dallice5
Moore, Larry5
Powelson, Mary5
Armstrong, Don4
more Committee Members »

Creator

Agnan, Jacqueline1
Ahmed, Hafiz Uddin1
Aho, Paul E.1
Akanda, Shamsul I.1
Alsheikh, Abdulmagid M.1
more Creators »

Date

Date range begin – Date range end

Current results range from 1962 to 2005

View distribution

Decade

2000-200913
1990-199943
1980-198958
1970-197934
1960-196967

Degree Field

Botany and Plant Pathology172
Botany38
Plant Pathology5

Degree Level

Doctoral215

Degree Name

Doctor of Philosophy (Ph.D.)[remove]215

File Format

application/pdf5

Language

English [eng]215

Non-Academic Affiliation

Oregon State University. Graduate School215

Peer Reviewed

No202

Resource Type

Dissertation215

Rights Statement

Copyright Not Evaluated[remove]215

Subject

Mycorrhizas5
Stripe rust5
Wheat -- Diseases and pests5
Douglas fir -- Diseases and pests4
Douglas fir3
more Subjects »

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