The primary objective of this thesis is to study, characterize
and compare four types of Scenedesmus obliquus pigment mutants with
the wild-type strain. The specific nature of the carotenoids synthesized
in both heterotrophically and myxotrophically-grown cells, Hill
reaction activity, photoreduction activity, and total photosynthetic
activity of these cells are examined....
A study of the McKenzie River floodplains, terraces and glacial
outwash plains was undertaken to classify and describe the vegetation
and soils of a previously little studied synecological unit.
During the summer of 1971, 54 analytic vegetation and soil
plots (stands) were studied. Cover and frequency of all trees, shrubs,...
Cultural and developmental characteristics of a collection of
Anthracobia melaloma with a brown hymenium and a barred exterior
appearance were examined. It grows well in culture on CM and
CMMY agar media and has a growth rate of 17 mm in 18 hours. It is
heterothallic and produces asexual multinucleate...
Alnus rubra (Bong. ) seedlings were grown in sand culture and
irrigated with nutrient solution containing CdCl₂
ranging from 5 μg to 100 mg per liter. Treatment of A. rubra seedlings for 4 weeks
with 50 and 100 mg CdCl₂
per liter of nitrogen-free nutrient solution
decreased in situ nitrogenase...
Spores of Equisetum were germinated and the resulting
gametophytes grown to maturity in standard microcultures. Light and
electron microscope observations were made of the chloroplasts
within the gametophytes.
These chloroplasts were found to be oval to dumb-bell shaped
organelles possessing organized grana. By means of time-lapse
movies they were shown...
A taxonomic study of the genus Ophionectria Saccardo is presented.
The genus is described and the only remaining species, the type species,
Ophionectria trichospora, is described and figured. Ophionectria
trichospora is compared with Nectria haematococca to define relationships
between the two genera.
All other species formerly placed in Ophionectria are...
Cambial activity was studied in trees infested by the balsam
woolly aphid and in non-infested trees of grand and subalpine fir.
Infested and non-infested samples of grand fir were collected near
Corvallis during 1968 and 1969. Samples of subalpine fir, noninfested
and infested, were collected near Odell Lake, at approximately...
Eight primary ambrosia fungi, Raffaelea canadensis, R.
sulcati, Ambrosiella brunnea, A. ferruginea, A. gnathotrichi, A.
hartigii, A. sulcati, and A. sulphurea (Fungi Imperfecti), were found
in association with 11 ambrosia beetle species (Scolytidae and Platypodidae).
The fungi are reported from new beetle symbionts, new
tree hosts, and/or increased geographical distribution....
Two sampling lines were established in the intertidal region at
each of three geographically separate sites on the coast of Oregon.
Each sampling line, which was positioned in the zone dominated by
the brown alga Hedophyllum sessile, was one meter in height and
extended 50 meters horizontally. Information was sought...
Race identification of stripe rust (Puccinia striiformis West. )
is influenced by environment, pathogen variability and host age.
Isolates of stripe rust were collected in the Pacific Northwest and
characterized on two sets of differential varieties; the "Oregon" and
the United States. Six of the seven isolates tested on the...
Numerous isolates of Armillaria mellea were obtained within
a 250 by 450 foot Study Area in a ponderosa pine plantation in central
Oregon. These isolates were recovered from roots of armillaria-killed
young-growth pine, from large stumps of the former pine
overstory, including roots away from the stump proper, and from...
The acyclic monoterpene geraniol was biosynthesized from
¹⁴CO₂ in Pelargonium graveolens (rose geranium) and isolated from
the hexane-extractable fraction in five experiments. Experiments 1
and 2 were preliminary experiments in which the total incorporation
of label into geranium oil was determined. In experiments 3 and 4a and
4b both incorporation...
Root-knot nematodes were among the earliest plant-parasitic
nematodes to be recognized. Before 1949, they were considered as the
one species Heterodera marioni (Cornu 1887) Goodey 1932. In 1949
Chitwood completed a taxonomic study of the root-knot nematodes and
placed them in a separate genus Meloidogyne. Economically they are
one of...
The amounts of residual dichlobenil (2,6-dichlorobenzonitrile)
in water and hydrosoil were compared periodically following application
of the wettable powder and granular formulations of the
herbicide to separate ponds at ten pounds of active ingredient per
surface acre {0.6 ppmw (parts per million by weight) }. Dichlobenil
was measured by electroncapture...
This study was initiated to determine the tolerance to copper
of Aspergillus niger, Stemphylium sarcinaeforme, Monilinia
fructicola and Fusarium oxysporum f. sp. lycopersici. Included
were strains of the latter two fungi that were induced to tolerate
relatively high levels of copper by continual culture on sublethal
levels of the toxicant....
In 1967, Doi et al. proposed the hypothesis that 'yellows type
diseases' are caused by mycoplasma. Since then more than 60
yellows diseases have been associated with mycoplasma-like bodies
(MLB) (Maramorosch, 1973). The majority of these associations are
based upon electron microscopic observations of mycoplasma-like
bodies in situ. However, little...
Factors limiting effective extraction and purification of bean
yellow mosaic virus (BYMV) were investigated. Since the use of published
techniques for purifying BYMV resulted in low yields of partially
purified virus, an improved method for partial purification of this
virus was developed. The following treatments of infectious crude extract
decreased...
The cell wall of dry, dormant conidia of Aspergillus nidulans
is three-layered. The wall of hydrated conidia is five-layered and
the germ tube wall is continuous with the innermost layer. The
outermost layer consists of rodlets measuring 10 nm in diameter.
Mitochondria and endoplasmic reticulum increase in number and
amount,...
Strawberry plants infected with June yellows and witches'-broom
disease were grown in a mist chamber and treated with varying concentrations
of oxytetracycline. Treatment with 50 ppm oxytetracycline
produced phytotoxicity effects in strawberries infected with June yellows.
However, treatment with 10 ppm oxytetracycline resulted in a
significant (one percent level) increase...
In vitro tests showed mycelial growth of Pyrenochaeta
terrestris was inhibited by root and bulb extracts from the pink root
resistant onion cultivar Nebuka, but not by extracts from the susceptible
Southport White Globe. The active principle was shown to be
fungistatic rather than fungicidal. It is present in both...