Agronomic and microbiological studies were conducted on "Anchor" alfalfa (Medicago sativa L.) established from uninoculated seed on three Aridisols in central Oregon. Significant responses to 230 Kg N per ha (NH₄NO₃), which was applied in mid-April and after each first and second harvests, were observed in yield parameters of the...
This thesis presents novel findings regarding
symbiotic, physiological, and antigenic characteristics of
representatives from an indigenous soil-borne population
of Rhizobium meliloti. Nodules were sampled from 'Vernal',
'Anchor', and 'Saranac' alfalfa, and the isolates analyzed
serologically. Rhizobium meliloti serogroup 31 was
identified as a dominant nodule occupant, with a greater
and...
Agrobacterium rhizogenes has been shown to cause root
proliferation and increased water use efficiency in
certain woody dicots. Root proliferation may be desirable
in herbaceous legumes as a means of increasing potential
sites for infection by Rhizobium species and subsequent
nodulation and nitrogen fixation. Thus, A. rhizogenes was
used to...
Nitrogen fertilization of seedling legumes is a controversial practice intended to provide N to the plant during periods when seed N, soil N, and N₂ fixation may not meet plant requirements; eg. prenodulation, postharvest, or in the event of an inoculation failure. Field experiments were conducted in 3 consecutive years...
Previous research had identified four serogroups of Rhizobium trifolii
indigenous to Abiqua soil (fine, mixed, mesic, Cumulic Ultic Haploxerolls).
Nodulation of subterranean clover (Trifolium, subterraneum L.) by two of the
serogroups, 6 and 36, was influenced by the application of CaC0₃ to the soil.
The studies described in this thesis...
The uptake of methylammonium (MA) by Chesapeake Bay phytoplankton was measured in short term experiments by using the 14C radioisotope. This uptake was inversely related to ambient NH4+ concentrations, and the specificity for uptake of both substrates was demonstrated by competitive inhibition. At stations with low ambient NH4+, MA uptake...
A commercially important polyelectrolyte, xanthan, was chosen for
a systematic analysis of the relationship between molecular
conformation and surface properties. In the first study the effects
of ionic strength, xanthan concentration and temperature on the
xanthan molecular conformation were investigated by potentiometric
titration. The effects of the same factors and...
Populations of Western Tragopans Tragopan melanocephalus were studied at two areas (Machiara and Salkhala) in the Neelum Valley of northeastern Pakistan. A total of 130 sightings of birds was noted during the breeding seasons in 1982 and 1983, but only 100 were re-located for vegetation analysis. More sightings of birds...