The objectives of this study are to isolate and characterize pathogenic agrobacteria that cause crown gall in grapevines and test hot water dips as a method for eradicating the infectious bacteria . Crown gall is commonly found among Oregon vineyards and the causative agent, Agrobacterium vitis, is known to be...
Phytophthora infestans, the cause of the devastating late blight disease of potato and tomato, exhibits a clonal reproductive lifestyle in North America. Phenotypes such as fungicide sensitivity and host preference are conserved among individuals within clonal lineages, while substantial phenotypic differences can exist between lineages. Whole P. infestans genomes were...
Primula sect. Parryi comprises five species endemic to western North America: P. parryi, P. angustifolia, P. rusbyi, P. capillaris, and P. cusickiana with four varieties. This section, derived from a clade with representatives in Asia and Europe, exemplifies a phytogeographic pattern in which a widespread species is accompanied by multiple...
Convergent evolution is common throughout the tree of life, but the molecular mechanisms causing similar phenotypes to appear repeatedly are obscure. Yeasts have arisen in multiple fungal clades, but the genetic causes and consequences of their evolutionary origins are unknown. Here we show that the potential to develop yeast forms...
Plant growth stages are identified as distinct morphological landmarks in a continuous developmental process. The terms
describing these developmental stages record the morphological appearance of the plant at a specific point in its life cycle. The
widely differing morphology of plant species consequently gave rise to heterogeneous vocabularies describing growth...
The Arabidopsis Information Portal (AIP), a resource expected to provide access to all community data and combine outputs into
a single user-friendly interface, has emerged from community discussions over the last 23 months. These discussions began
during two closely linked workshops in early 2010 that established the International Arabidopsis Informatics...
Formal description of plant phenotypes and standardized annotation of gene expression and protein localization data require
uniform terminology that accurately describes plant anatomy and morphology. This facilitates cross species comparative
studies and quantitative comparison of phenotypes and expression patterns. A major drawback is variable terminology that is
used to describe...
Rice, maize, sorghum, wheat, barley and the other
major crop grasses from the family Poaceae
(Gramineae) are mankind’s most important source
of calories and contribute tens of billions of dollars
annually to the world economy (FAO 1999, http://www.fao.org; USDA 1997, http://www.usda.gov).
Continued improvement of Poaceae crops is necessary
in order...
Plants possess two myosin classes, VIII and XI. The myosins XI are implicated in organelle transport, filamentous actin
organization, and cell and plant growth. Due to the large size of myosin gene families, knowledge of these molecular motors
remains patchy. Using deep transcriptome sequencing and bioinformatics, we systematically investigated myosin...
The demand for new fungicides to control plant diseases has
led to experimentation with both previously used and newly developed
fungicides. Silver, an older but little used fungicide, was selected for
evaluation because of its high toxicity to microorganisms. Silver
nitrate and a silver electrolytic cell were tested as potential...
Montane forest vegetation as it occurs on the east flank of the
central Oregon Cascades has provided excellent conditions for a
"natural experiment" in the use of various methodologies in studying
vegetational distribution. This "experiment" has reflected on some
theory and practice for the discipline of plant synecology. Detailed
descriptions,...
Three growth forms of the genus Microseris, of the tribe
Cichorieae, family Compositae, were compared with respect to their
anatomical structure. The purpose of this study was to clarify lines
of evolutionary specialization in the genus. Two of the three species
studied, M. laciniata and M. borealis, are perennials, while...
At the time of the eruptions of Lassen Peak in 1914-1915, an
area of vegetation along the east slope of the mountain approximately
1 1/4 miles wide and four miles long was destroyed. Except for a
few surviving trees, all vegetation was destroyed.
A study of the revegetation of this...
The vegetation of the Oregon coast is characterized by a
variety of stages of plant succession which are repeated widely
throughout the sand dune area. During the years from 1960 to 1963
the gradation of upland sand dune succession was studied on 48 plots
within a 150 mile section of...
There is considerable variation among rose varieties in susceptibility
to mildew, and as a result of maturation, leaves of most
susceptible varieties become resistant to infection. The nature of
resistance has been sought in various studies involving environmental,
morphological, and physiological factors. An attempt was made in the
present investigation...
The main objectives of this study were to determine the
effect of certain environmental conditions on the quantity of poly-galacturonase (PG) produced by V. albo-atrum, and to partially
purify and characterize the PGs produced by this fungus in culture
and in infected tomato plants.
V. albo-atrum produced twenty times as...
Many initially healthy Pelargonium seedlings developed symptoms
of Verticillium wilt in an Oregon State University greenhouse
when they attained blooming age. The symptoms first appeared in
May as "edge burning," yellowing, and wilting of leaves. In late
summer, these seedlings which were the offspring of Verticillium
infected plants, became severely...
Three viruses were isolated from dahlias using a modification of
Yarwood's leaf-disc method of inoculation. Two of these isolates have
been reported previously in dahlias. In addition, a fourth virus was
isolated using a liquid-nitrogen transmission technique.
Dahlia virus isolate 1 possessed host range and thermal inactivation
properties similar to...
Longevity and germination of seed of western dwarfmistletoe (Arceuthobium campylopodum Engelm. f. campylopodum) of ponderosa
pine (Pinus ponderosa Laws.) was investigated to determine:
1) the influence of humidity and temperature on seed viability and
deterioration during storage; 2) the physiology of seed dormancy;
3) the composition of seed reserve food...
Contracting nucleolar vacuoles are a general and consistent
feature of somatic tobacco cells growing in microcultures. Nucleolar
vacuoles were studied in cells from callus tissues of two
single-cell clones, H-196 and H-239, of hybrid tobacco (Nicotiana
tabacum X N. glutinosa). Vacuoles periodically contracted either
completely or incompletely, apparently releasing a...
A comparative study was made of Pinus ponderosa Laws, and
Arceuthobium campylopodum Engelm. f . campylopodum to determine
(1) whether or not the parasite or parasitized tissues accumulate
abnormal concentrations of minerals, (2) whether or not there
was evidence of a blockage of mineral translocation in the phloem
because of...
Quercus garryana dominated plant communities are found in
the interior coastal valleys and on foothills from southeastern
Vancouver Island, British Columbia, south to San Francisco,
California. They occur as savannas, intermixed with a variety of
conifers, and in almost pure stands. The diversity of habitats
occupied by the species and...
This thesis reports a portion of a general ecological study of
a stream under conditions of controlled flow and low levels of organic
enrichment. It is concerned with the effects of experimental variations
of light intensity and concentration of soluble organic enrichment
imposed on seasonal variations of temperature and total...
The infectivity of plant viruses was suppressed by
inhibitory substances (IS) in the sap of Chenopodium. Various
methods were attempted to find an efficient method which would allow direct transmission of viruses from Chenopodium to other plants. Viruses used in these experiments were alfalfa mosaic
virus (AMV), tobacco mosaic virus...
Tissue differentiation of the primary root and its associated
laterals is reported. Secretory elements are the first of the primary
tissues to mature. They appear to be located between the precursory
phloem and pericycle in the primary root, but are more closely
associated with the pericycle in long lateral roots....
Recent investigations indicate that several latent viruses of
apples exist in common commercial apple stocks, but these viruses
and their relationships are incompletely understood. This thesis
describes investigations of crab apples as indicators of latent viruses
of apples.
Eighty-eight varieties and species of crab apples were tested
as indicators of...
A biosystematic investigation was undertaken in 15
species and three subspecies of the genus Aster, in western
North America. Previous studies had been based entirely on
external morphological features, and it was believed that
much could be learned about the natural affinities of the
taxa by exploring their cytological and...
Aphanizomenon flos-aquae from Upper Klamath Lake, Oregon
was introduced into culture in a precipitate -free medium developed
by modification of McLachlan's ASM medium. This medium ASMT
No. 8 contained no organic substances other than ethylendiaminetetraacetate
(EDTA) and Trishydroxymethylamino methane (Tris),
and was developed by modifying the concentrations of certain elements,...
An assay for fungicidal activity of sodium N-methyldithiocarbamate
(Na-MDC) and its decomposition products was developed
in which there was a minimum influence due to the widely varying
physical properties of the compounds (i.e. vapor pressure and water
solubility). Decomposition of the toxicant during the tests was
measured and held to...
Arctostaphylos viscida Parry and A. canescens Eastw.,
two well-known and frequently encountered manzanitas in the
Siskiyou Mountains in southwestern Oregon, are shown to
hybridize and to produce an extensive series of morphological
intermediates. The hybridization occurs wherever populations
of these two species meet at contact zones of
serpentine and non-serpentine...
A study was undertaken to determine the reliability of the formation
of a line of demarcation between paired cultures of Fomes
cajanderi Karst. as an indicator of dissimilar compatibility genotypes.
The results were applied to an assay of the number and location of
compatibility genotypes in each of four glaze-damaged,...
Previous work on the rose mosaic virus has produced uncertainty
concerning the identity and properties of this virus. This work was
undertaken to help establish the true identity of the virus and to determine
some of its properties.
A mechanically transmissible virus associated with rose mosaic
virus disease of Rosa...
Fire has played a prominent role in the development and character of the ponderosa pine forests in western North American. Its
records are written in the scars of trees that have survived the fire.
Careful studies of these fire-scars may be used as a means of reconstructing
the fire history...
An investigation was undertaken to determine whether
potassium is indeed necessary for the in vivo synthesis of a
specific protein. The effects of univalent cations on the
inductive formation of nitrate reductase and on the level of
activity of representative non-adaptive enzyme are presented.
Cultures of Neurospora crassa were grown...
Sodium polypectate (SPP) was added to an ethanol-streptomycin
agar (ESA) medium to determine if it would provide a selective
substrate for the growth of Verticillium dahliae and for isolation of
the fungus from soil and plant tissues in the presence of saprophytic
fungi. Sodium polypectate improved greatly the formation and...
A study was conducted of the influence of various climatic and
soil factors on the development of onion pink root disease and of the
influences of temperature, light, pH, carbon and nitrogen sources,
and vitamins on the growth in vitro of an Oregon isolate of the pink
root fungus, Pyrenochaeta...
Manganese has been known to be essential for photosynthesis
for almost 30 years. Subsequent experimentation
indicated a definite function for manganese in oxygen evolution.
However, the mode of action of manganese and
further localization of its site of action have not been
determined.
Ten years ago it was demonstrated that...
Phages of crown gall bacteria were among the first to be
isolated and certain properties of these phages have been studied by
a number of investigators. However, several important characteristics
have not been studied in detail. The present investigation was
made in order to determine the major sources of phages...
An impounded estuary was employed to study primary productivity, community respiration, and community structure as they
related to seasonal and temporal succession, salinity, and water
temperature. Plankton metabolism was studied by means of the
light-and dark-bottle technique. Benthic community metabolism
was determined by using the "diurnal oxygen curve" method.
Four...