The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to...
The effects of manganese nutrition on growth, mineral composition,
carbohydrate and nitrogen metabolism, IAA oxidase and phenols
of 'Northwest' strawberry plants are reported. Growth and mineral
composition response were investigated in sand culture and Hoagland's
solution 2 modified to contain 0.0, 0.5, 2.5, 12.5, 25.0, 62.5 and
125.0 ppm substrate...
Investigations were conducted to study in detail some biochemical and physiological aspects of ripening in pears. Anjou pears
picked at different degrees of maturity were treated with Ethrel
(2-chloroethane phosphonic acid), 4000 ppm, and ethylene, 500 ppm,
for different lengths of time. Respiration rate was measured twice
daily and changes...
Vegetatively propagated peppermint (Mentha piperita L., cv. Black Mitcham) was used to determine the effects of night temperatures (8°C vs 25°C) on the plant growth in terms of fresh weight and leaf area, and on metabolite contents. The plants were sampled after 14 days, 21 days and 28 days in...
Describing functions have traditionally been used to obtain the
solutions of systems of ordinary differential equations. In this
work the describing function concept has been extended to include
nonlinear, distributed parameter partial differential equations. A
three-stage solution algorithm is presented which can be applied to
any nonlinear partial differential equation....
Field studies to determine appropriate cutting management
regimes consistent with yield, quality, and persistence
of stand were conducted on several alfalfa varieties in the
Columbia Basin region of Oregon.
Two groups of treatments, including consecutive cuts at
the same stage of maturity and cuts made at varying maturities,
were imposed...
The primary purpose of this investigation was to determine the
conditions necessary for the preparation of cell-free extracts of
nodule bacteroids capable of catalysing the reduction of acetylene to
ethylene and nitrogen to ammonia. Initial investigations were conducted
to determine whether intact soybean root nodules would reduce
acetylene to ethylene...
Procedures were developed for assaying the biosynthesis of (-)-
kaurene-¹⁴C and other intermediates in gibberellin (GA) synthesis
from mevalonic acid-¹⁴C in cell-free enzyme extracts of immature
pea (Pisum sativum L. cv. Alaska) seeds. This system was utilized
to investigate three aspects of GA biosynthesis: (1) apparent capacities
for (-)-kaurene biosynthesis...