Results from approximately 400 fungus-host pure culture
inoculations indicate that specificity of ectomycorrhizal associations
is a complex phenomenon and cannot be based solely on field observations
of sporocarp-host associations. Of the numerous sporocarp-host
specific fungi tested, most formed ectomycorrhizae with one or more
unexpected, non-associated hosts. These results conclusively demonstrate...
The influence of mycorrhizae on the nutrient uptake of
strawberries and red raspberries was investigated. On red raspberries
innoculation with a mycorrhizal fungus resulted in increased P uptake
and a greater concentration of P in the shoots of the plants. The
strawberries were innoculated with 2 species of mycorrhizal fungus....
The several thousand fungi known to form ectomycorrhizae have co-evolved with their host plants and have developed impressive physiological and ecological diversity. Exploration of some relationships of enzyme activities and phytohormone production of selected ectomycorrhizal fungi to distribution and tree hosts is reported in this thesis. The data have particular...
Small-mammal community composition, microhabitat selection, and
dispersal of mycorrhizal fungal spores were studied in southwestern
Oregon. Sampled habitats exhibited structural variation resulting
from silvicultural practices.
In 1981, the effect of clearcut treatment on these phenomena was
evaluated. In 1982, the effect of forest structure was studied.
Discriminant function analysis (DFA)...
Basidiospores of Rhizopogon viriicolor Smith and R. colossus
Smith were inoculated onto container-grown Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) seedlings and grown under two levels of
soluble fertilizer and one level of slow-release fertilizer. Both
fungi formed abundant (54%) ectomycorrhizae under the soluble
fertilizer regimes. Slow-release fertilizer greatly reduced percent
ectomycorrhizae...
The mycorrhizal rootlets of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) and red alder (Alnus rubra Bong.) were extensively investigated. A jet-black mycorrhiza was found to be dominant on Douglas-fir rootlets. The fungal symbiont was identified as Cenococcum graniforme (Sow.) Ferd. and Winge. Two forms of mycorrhizae predominated on root systems of...
Studies were conducted on inoculation of container-grown plants
with vesicular-arbuscular (VA) mycorrhizae.
Intraradical vesicles formed in colonized roots were found to
serve as propagules and significantly contribute to the infectivity
of these roots. A procedure was developed for separating
intraradical vesicles from roots; isolated intraradical vesicles were
able to colonize...
The influence of vesicular-arbuscular mycorrhizae (VAM) on
populations of general taxonomic and functional groups of naturally-occurring
rhizosphere bacteria and actinomycetes associated with
roots of sweet corn (Zea mays var. rugosa) and subterranean clover
(Trifolium subterraneum L.) was assayed using selective media.
Sporangial production by Phytophthora cinnamomi was also used as...
The colonization of several species of plants by vesicularar-buscular
mycorrhizae (VAM) was studied to determine how host, soil,
or symbiont factors interacted to enhance growth of the host plant.
Seedlings of two species of the Cuppressaceae and two of the
Taxodiaceae formed VAM; colonization significantly improved growth.
This response to...
Published June 1983. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
A study was conducted to characterize the vesicular-arbuscular
(VA) fungi of apples grown in Oregon. Using roots and soil from
apple orchards as inoculae, six different fungal species were found
in pot cultures: Gigaspora margarita Becker and Hall, Glomus fasciculatum
(Thaxter sensu Gerdemann) Gerd. and Trappe, Glomus mosseae
(Nicol. and...
Field and greenhouse bioassays were used to compare the mycorrhizal associations of Douglas-fir seedlings from undisturbed forests, and nonburned and burned portions of clearcuts on three Sites in the west-central Cascades of Oregon. Field soil transfers and greenhouse soil pasteurization and reinoculation were used to investigate soil biology and inoculum...
A greenhouse bioassay was used to investigate effects of natural and manmade disturbances on native ectomycorrhizal populations of Douglas-fir and western hemlock on a steep southeast slope in the
west central Cascade Mountains. Total and mycorrhizal root tips were counted on seedlings grown in soils collected from (a) two 100+...
Many higher plants have mycorrhizae associated with their roots. These structures are often essential for survival and growth (Harley & Smith 1983). Mycorrhizae are known for the abilities to enhance nutrient absorption. While nitrogen-fixing organisms are found as components of the mycorrhizosphere, mycorrhizal fungi are not presently known to fix...
A study, consisting of two sequential greenhouse experiments, was
designed to determine the effects of soil liming upon the fungal
partner in a mycorrhizal association. A Willamette Valley foothill
soil, of the Jory series, was limed in increments to achieve a range
of acidity and alkalinity. The P-deficiency and P-fixing...
Mycorrhizal fungi in arid and semiarid rangelands have received little study in southwest Asia and north Africa, although they are important in food production and rangeland productivity. The desert truffles of the genera Terfezia and Tirmania form fruiting-bodies and mycorrhizae with rangeland plants. This thesis treats the taxonomy and the...
A greenhouse bioassay was used to compare the effects
of soils collected at different distances from hardwood
species on the growth, mycorrhiza formation, and foliar
nutrient concentrations of Douglas-fir seedlings. Soil
nutrient concentrations and bulk densities were also
determined. Soils were collected from two southwestern
Oregon sites that had been...
Miombo woodland and dambo grassland soils were selected to study the effect of soil transfer on early growth of B. petersiana, C. spectabilis, and C. calothyrsus on degraded sites in northern Zambia. The experiment was conducted on previously slash and burned, cultivated, and abandoned sites. Both sterile and unsterile miombo...
Interest in measuring soil quality continues to increase worldwide in view of demands on land productivity and the necessity to preserve soil resources, yet identification of suitable indicators for soil quality assessment is still evolving. This study adapted 10 biological, physical, and chemical indicators of soil quality identified by the...
The hypothesis that inoculation of transplants with vesicular-arbuscular mycorrhizal (VAM) fungi before planting into saline soils would alleviate salt effects on growth and productivity was tested on lettuce (Lactuca sativa L.) and onion (Allium cepa L.). A secondary hypothesis was that the fungi isolated from a saline soil would be...
Mycorrhizae are important for plant growth, particularly in nutritionally poor soils. Vesicular-arbuscular mycorrhizae (VAM) are the primary form of mycorrhizae found in tropical plants, and their persistence in the soil as colonizing fungal propagules following deforestation cannot be directly
measured. Utilizing the "most probable number" (MPN) method for estimating infective...
Striga, a genus of obligate parasitic weeds in the family Orobanchaceae, has been
identified as the most important biological factor limiting agricultural productivity in sub-Saharan Africa. Germination of Striga seeds is triggered by strigolactone root exudates
from host plants. Strigolactones also induce hyphal branching in arbuscular mycorrhizal
(AM) fungi, which...
A grassland restoration project was conducted in Canyonlands National Park on an area recently disturbed due to construction. Two native grasses (Oryzopsis hymenoides and
Stipa comata) were seeded with 18 different soil treatments. Stipa density and relative mycorrhizal colonization were measured. None of the soil treatments resulted in significantly greater...
The vast majority of terrestrial plant species live in symbiosis with arbuscular mycorrhizal fungi (AMF). AMF and plants live in complex networks, with roots of individual plants hosting multiple AMF, and single AMF colonizing multiple plants concurrently. Through the exchange of resources, the two partners of this symbiosis can have...
A Study conducted at The Island, Lake Billy Chinook, in Central Oregon, examined
differences in the pattern of soil properties between a sagebrush-grass and a juniper-sagebrush-grass community. Juniper invasion is linked with the desertification
process in which the sagebrush shrubs and perennial grasses decline. Patterns in soil
nutrients and other...