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  • Microbial and biochemical dynamics of ectomycorrhizal mat and non-mat forest soils

    Creator:
    Kluber, Laurel A.
    Abstract:
    Dense hyphal mats formed by ectomycorrhizal (EcM) fungi are prominent features in Douglas-fir (Pseudotsuga menziesii) forest soils and have been estimated to cover up to 40% of the forest floor in some stands. Although previous studies have examined various aspects of EcM fungi, little is known about their associated microbial...
    Resource Type:
    Dissertation
    Full Text:
    Ectomycorrhizal Mat and Non- mat Forest Soils Abstract approved: David D. Myrold Dense hyphal mats

  • Response of Soil Microbial Activity and Community Composition to Timber Harvest in an Oregon Douglas-Fir Forest

    Creator:
    Martin, Kelsey M.
    Abstract:
    Forests and forest soils are some of the largest biologically active carbon reservoirs in the world. Therefore, understanding how disturbances, such as forest harvest, influence biogeochemical cycling is particularly important for managing forests sustainably. Timber harvest can have large impacts on forest soils, which may affect the long-term productivity and...
    Resource Type:
    Masters Thesis
    Full Text:
    . Abstract approved: ______________________________________________________ David D. Myrold

  • Linking soluble C to microbial community composition and dynamics during decomposition of ¹³C-labeled ryegrass

    Creator:
    McMahon, Shawna K.
    Abstract:
    Ryegrass residue consists of three main C fractions: readily available soluble C, intermediately available cellulose and hemicellulose, and slowly available lignin. Changes in chemical composition during decomposition influence rate of degradation as well as composition of the microbial community involved. Use of ¹³C-labeled plant material coupled with analysis of phospholipid...
    Resource Type:
    Masters Thesis
    Full Text:
    advisors, David Myrold and Peter Bottomley, and Mark Williams for helping me grow into myself as a

  • Microbial community dynamics associated with rhizosphere carbon flow

    Creator:
    Butler, Jessica L.
    Abstract:
    The cycling of root-deposited photo synthate (rhizodeposition) through the soil microbial biomass is widely recognized as a critical component of ecosystem functioning. Little is currently known about the flow of photosynthate through the microbial biomass however. My research goal was to examine if and how the flow of root-deposited photo...
    Resource Type:
    Masters Thesis
    Full Text:
    Dynamics Associated with Rhizoshere Carbon Flow. Abstract approved: Tbavid D. Myrold The cycling of

  • Inoculation potential of soil-borne Frankia on red alder (Alnus rubra Bong.)

    Creator:
    Martin, Kendall J.
    Abstract:
    Inoculation trials were set up in fumigated nursery beds for red alder (Alnus rubra Bong.) seedling production. Frankia inoculum was applied in eight treatments: control, nodule suspension, and three levels of cell suspension (strain ArI5) applied with and without a peat carrier. Seedlings were evaluated at midseason and lifting. The...
    Resource Type:
    Dissertation
    Full Text:
    my life partner, Nan Pengo. I would also like to acknowledge my Major Professor, Dr. David Myrold

  • 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
    Full Text:
    ., and D. D. Myrold (1992). Quantitation of soil Frankia by bioassay and gene probe methods: response to

  • Response of soil microbial communities and nitrogen cycling processes to changes in vegetation inputs

    Creator:
    Brewer, Elizabeth Ann
    Abstract:
    Changes in the type and amount of plant inputs can occur gradually, as with succession, or rapidly, as with harvesting or wildfire. With global change it is anticipated that both gradual and immediate scenarios will occur at increasing frequency. Changes in vegetation inputs alter the quality and quantity of soil...
    Resource Type:
    Dissertation
    Full Text:
    Input. Abstract approved: ______________________________________ David D. Myrold

  • Contributions of ammonia-oxidizing bacteria and archaea to nitrification in forest soils

    Creator:
    Lu, Xinda
    Abstract:
    Prior to 2005, ammonia oxidation, the first step of nitrification, was thought mediated mainly by ammonia-oxidizing bacteria (AOB). However, the discovery of Thaumarchaeota carrying the genes coding for the ammonia monooxygenase (AMO) enzyme led to the discovery that ammonia-oxidizing archaea (AOA) also contribute to nitrification. Despite the uptick in studies...
    Resource Type:
    Masters Thesis
    Full Text:
    : _____________________________________________________________________ David D. Myrold Prior to 2005, ammonia oxidation, the first step of nitrification, was

  • The genetic diversity of Ceanothus-infective Frankia

    Creator:
    Ritchie, Nancy J.
    Abstract:
    Frankia from root nodules of nine different species of Ceanothus were characterized. DNA was amplified directly from nodular material using the polymerase chain reaction (PCR). The amplified region includes the 3' end of the 16S rRNA gene, the intergenic spacer (IGS), and a large portion of the 23S rRNA gene....
    Resource Type:
    Masters Thesis
    Full Text:
    approved: David D. Myrold Frankia from root nodules of nine different species of Ceanothus were

  • Soil pH and calcium effects on nodulation of nursery grown red alder

    Creator:
    Crannell, Wanda K.
    Resource Type:
    Masters Thesis
    Full Text:
    CALCIUM EFFECTS ON NODULATION OF NURSERY GROWN RED ALDER. Abstract approved: Ht49414' David D. My ld