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Studies On The Giant Mealie Witchweed, Striga Forbesii Benth., In Zimbabwe, David Allen Knepper

Biological Sciences Theses & Dissertations

Of the seven species of Striga found in Zimbabwe, S. forbesii Benth. is currently the most destructive in terms of crop damage. Owing to its limited occurrence worldwide as a pest of crops, relatively little work has been done on this species.

Striga forbesii has been found to be a consistent problem on both maize and sorghum in the Hunter's Road District of KweKwe, Zimbabwe. Results of a pot study and field observations, indicate S. forbesii can successfully parasitize Urochloa panicoides Beauv., Sorghum arundinaceum (Desv.) Stapf, and Rottboellia cochinchinensis (L.) L.f., all of which are widespread weeds of arable land. …

The Genus Marasmius From The Southern Appalachian Mountains, Dennis Edmund Desjardin

Doctoral Dissertations

The genus Marasmius (Tricholomataceae, Agaricales, Basidiomycotina) constitutes one of the larger genera of litter-decomposing and litter-binding mushrooms, represented worldwide by approximately 500 species. Thirty-eight taxa representing eight sections of the genus are recognized as occurring in the southern Appalachian Mountains. Seven of these taxa are new to science, while an additional 14 are reported for the first time from the study area. In addition, one new section is proposed.

Descriptions of southern Appalachian species of Marasmius have been compiled from data on macro- and micromorphological features of basidiomata, supplemented with data on geographical and ecological distribution. Details on nomenclature and …

The Effects Of Varying Light Exposure Times On The Colonization And Sporulation Of Gigaspora Margarita In The California Pepper, Mary E. Kirker

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Mary E. Kirker on July 24, 1989.

Vegetative Analysis Of The Monahan Reclaimed Mined Land Area, Jeff L. Vickers

Electronic Theses & Dissertations

The Monahan reclaimed mined land area is located in Crawford County, Kansas, and is approximately one mile north and one mile east of Cherokee, Kansas. Strip and shaft mining both occurred at the site. The reclamation project was performed in 1984, with seeding of native grasses comprising the final stage.

The study was designed to evaluate the revegetation portion of the project. Data was collected to determine basal cover and frequency of plant species occurring on the site; soil pH measurements were also included in the study. This information was used to develop a comparative evaluation of the grass species …

Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An ecologically based model of forest succession is presented. In the model, trees compete for a share of limited growth resources available from their environment. Competition is reflected by each tree's effect on the resource pool and is not explicitly modeled. Model parameters were fit to field data from subalpine forests of the Rocky Mountains. A technique for estimating model parameters from understory-tolerance rankings and silvical characteristics of each species is also presented. The model's output was consistent with our current understanding of forest dynamics. Emergent properties of the model also mimicked natural processes such as self-thinning, release, and maximum …

Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify.

This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen.

The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic …

An Apple Rest Model For Mild Winter Conditions, Jose Ignacio Del Real Laborde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two areas of research are reported: an experiment on the effects of warm temperature prestratification treatments on seed dormancy and a new chill unit model.

Crabapple seeds (Malus sargentii Rehd.) were allowed to imbibe water and were given warm pretreatments at temperatures of 16, 20, 24 and 28C for periods of 3, 10, 20 or 30 days before cold stratification at 4C for 20, 40, 60, 80 or 100 days. Pretreatments resulted in increased chilling requirements for seedling emergence. A short chilling period (20 days) also altered the leaf area, shoot length, internodal length and root/shoot ratio of the …

Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …

The Ethnobotany Of Sweet Flag, Acorus Calamus L., Timothy J. Motley

Masters Theses

One of the more interesting and attractive components of aquatic ecosystems is sweet flag, Acorus calamus L., a herbaceous perennial belonging to the Araceae, a primarily tropical family. Sweet flag is one of the few extratropical members.

The primary purpose of this work is to present a compilation of the various traditional and contemporary uses of sweet flag by various cultures.

Information regarding the known ethnobotanical and economic uses of the rhizome and aromatic essential oil as a flavoring agent is given, as well as its medicinal uses and value as an insecticide. In addition, a discussion of the …

Woody Vegetation Of A Mesic Sand-Forest In Mason County, Illinois, Sean E. Jenkins

Masters Theses

An inventory was completed of the woody vegetation of a 6.5 hectare section of a mesic sand-forest near Forest City, Mason County, Illinois. This forest, which is located on stabilized sand dunes in the Illinois River Section of the Illinois River and Mississippi River Sand Areas Division, has a stand composition of 247.5 stems/ha (above 10 cm dbh.), and a basal area of 16.1 sq. m/ha. A total of 21 woody species are present on the site with Black oak comprising 84% of the Basal area and 61% of the total individuals, and having an importance value of 144.9. Black …

Tissue Culture In Rice (Oryza Sativa L. Subsp. Japonica Var. Lemont), Young M. Woo

Masters Theses

The purpose of this study was to obtain callus induction and subsequent plantlet regeneration from various explants of rice (Oryza sativa L. subsp. japonica var. Lemont). Callus induction occurred from the somatic cells of ovary wall, immature and mature embryos, immature endosperm, stem nodes, and seedlings. Plantlets were regenerated from embryo-, endosperm-, and stem node-derived calli on differentiation media. Stem nodes were the most responsive to callus induction. Requirements for optimal callus formation and plantlet regeneration differed from each culture. The study investigated the effects of cold treatment of explants, initial culture in darkness, media, and subculture for individual explant …

Vascular Flora Of Northwestern Highland County, Virginia, Theresa Alee Theodose

Dissertations, Theses, and Masters Projects

No abstract provided.

Cyanogenesis In The Euphorbiaceae, Lucinda L. Horton

Masters Theses

Fresh samples of nine species included in the family Euphorbiaceae, Acalypha qracilens, Acalypha ostryaefolia, Acalypha rhomboidea, Acalypha virginica, Chamaesyce maculata, Chamaesyce supina, Cnidoscolus stimulosus, Euphorbia corollata, and Poinsettia dentata, were tested for the production of cyanide using the Feigl-Anger technique. Two of these taxa were tested for polymorphism of cyanogenesis by repeated testing of the same individuals within a population. Two of these nine species, Acalypha ostryaefolia and Cnidoscolus stimulosis, gave positive results, although not every individual tested was positive. One of the species tested for polymorphism, Acalypha ostryaefolia, …

River Birch (Betula Nigra L.) Forest Communities In Cass And Mason Counties, Illinois, Charles Anthony Uhlarik

Masters Theses

During the fall of 1988 and the spring of 1989, four stands of river birch (Betula nigra L.) were surveyed in Cass and Mason Counties, Illinois. All study areas were divided into quadrats 25 m on a side (0.154 acres) and the maximum number of quadrats were placed to completely survey each forest. The relative density, relative dominance, and importance value was calculated for each species (dbh greater than 10 cm) in each forest area. Also, seedlings (less than 2.5 cm dbh) and saplings (2.5-10.0 cm dbh) were recorded in each area. River birch is the dominant overstory …

The Development And Failure Of Historic Agricultural Communities Of Utah: A Case Study Of Johns Valley, Utah, Wayne R. Shelley

Theses and Dissertations

Many agricultural communities have developed in Utah since the first settlement, but many no longer exist today. Some of these early communities experienced a "boom and bust," while others struggled for several years and were eventually abandoned. Johns Valley is a good example of these historic communities, as it experienced rapid growth and times of success and prosperity, yet it struggled and was eventually abandoned.
The situation in Johns Valley, from its early settlement to its demise, demonstrates the hope of the people who settled there and their efforts to make Johns Valley a productive and successful area. History also …