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

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/9306t1982

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • 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 VAM decreased with increasing seedling age and increased phosphorus availability. The initial growth enhancement by VAM was less in species with large seeds than those with small seeds. All three of the VAM fungi tested enhanced seedling growth, although isolates differed in this ability. Nine different species and strains of VAM fungi were tested for ability to enhance legume growth and nitrogenase activity by Rhizobium nodules and for development of external mycelium (as estimated by sand aggregation) when colonizing Trifolium subterraneum and Lotus corniculatus hosts. The fungi varied in their ability to colonize roots and form external mycelium. Growth was most enhanced by isolates that formed abundant mycelium, but those isolates did not necessarily colonize the roots extensively. Highest values for nitrogenase activity by Rhizobium nodules (per gm fresh weight) and development of external mycelium were measured at the first harvest before plant growth differed significantly. At later harvests, the treatments with the best growth enhancing isolates or with amendments of more phosphorus had the highest total nitrogenase activities per plant. To monitor development of VAM hyphae in soil or on roots, an immunofluorescence assay was developed from cell wall extracts of Glomus epigaeum chlamydospores. Antiserum was specific for the genus Glomus with little detectable cross reaction with closely related genera of the endogonaceous fungi Acaulospora and Gigaspora, or other soil fungi. The immunofluorescent assay technique effectively distinguished Glomus species in the rhizosphere of colonized plants. The density of VAM hyphae was examined in 3 different soil types in relation to the proximity of host root tissue, using the immunofluorescence assay and soil aggregation techniques. The soil aggregation method to measure extra-matrical hyphae was effective only in sandy soils. The immunofluorescence system worked in both sandy and silt loam soils but was not useful in peat soils. A higher density of VAM fungus hyphae occurred in soil near roots than in soil from which root growth was restricted by nylon screening. Root colonization by VAM fungi was greater in river sand than in silt loam or peat, more external hyphae developed in sandy soils than silt loams. The magnitude of plant growth enhancement is a function of a three-way interaction between host, symbiont, and the soil, but the extra-matrical phase is most influenced by edaphic factors.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2013-07-17T16:29:23Z (GMT). No. of bitstreams: 1 KoughJohnL1985.pdf: 977273 bytes, checksum: c65629763745a9a21d8d5c59927071d1 (MD5) Previous issue date: 1984-06-01
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-07-17T16:29:23Z (GMT) No. of bitstreams: 1 KoughJohnL1985.pdf: 977273 bytes, checksum: c65629763745a9a21d8d5c59927071d1 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-07-01T19:50:22Z (GMT) No. of bitstreams: 1 KoughJohnL1985.pdf: 977273 bytes, checksum: c65629763745a9a21d8d5c59927071d1 (MD5)
  • description.provenance : Submitted by Katy Davis (kdscannerosu@gmail.com) on 2013-06-27T18:11:35Z No. of bitstreams: 1 KoughJohnL1985.pdf: 977273 bytes, checksum: c65629763745a9a21d8d5c59927071d1 (MD5)

Relationships

In Administrative Set:
Last modified: 08/10/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items