Thesis (doctoral)--University of Tartu, 2004. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [135]-151).

Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 60-66).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 50-54.

No description available.

Call number: LD2668 .T4 1963 C96 / Master of Science

A native desert Rhizobium, AZ-M1, was isolated from a nodulated mesquite tree (Prosopis juliflora var. velutina) following inoculation of mesquite seed with a desert soil. This strain and a selected commercial strain (31A5) were used in a greenhouse study to determine their N fixation efficiency against applied N fertilizer. Strain AZ-M1 was a more efficient N fixer than 31A5. The survival rate of the two strains was tested in three different desert soils in a controlled laboratory study. The native strain AZ-M1 grew and survived in the soils over a period of one month. The commercial strain did not grow and the population decreased from 10⁸ cells gm⁻¹ of dry soil to below 10⁴ cells after 14 days. Soil factors affected survival of both strains. The competitiveness of the two strains was compared in a greenhouse experiment. The native isolate out competed strain 31A5 in nodule occupancy regardless of cell number when applied as a mixed inoculant. A high incidence of double occupancy was found in the root nodules when double strain inoculants were applied. The two rhizobia were fast growing rhizobia, lowering the pH of a defined medium. Strain AZ-M1 showed a high intrinsic resistance to 3 antibiotics among 12 tested. Strain AZ-M1 has been shown to be highly effective, fairly competitive and survive better in desert soils than strain 31A5.

No description available.

No description available.

<p>The microbial life of sub-Antarctic islands plays a key role in the islands ecosystem, with microbial activities providing the majority of nutrients available for primary production. Knowledge of microbial diversity is still in its infancy and this is particularly true regarding the diversity of micro-organisms in the Antarctic and sub-Antarctic regions. One particularly important functional group of micro-organisms is the diazotrophs, or nitrogen-fixing bacteria and archaea. This group have not been well studied in the sub-Antarctic region, but play an important role in the nutrient cycling of the island. This thesis explored the diversity of nitrogen-fixing organisms in the soil of different ecological habitats on the sub-Antarctic Marion Island.</p>