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Leaf Epidermal Transmittance Of Ultraviolet Radiation And Its Implication For Plant Sensitivity To Ultraviolet-Radiation Injury, Ronald Robberecht

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Leaf epidermal transmittance of ultraviolet radiation (280-400 nm) was examined in several plant species to determine the capability of the epidermis to attenuate solar ultraviolet radiation. Epidermal samples were mechanically isolated and examined with a spectroradiometer/integrating sphere for transmittance. A survey of 25 species exposed to natural insolation was conducted. Although the species differed in life form, habitat type, and epidermal characteristics, epidermal transmittance was generally less than 10%. Ultraviolet radiation was attenuated 95 to 99% in more than half of the species. In 16 species, flavonoid and related pigments in the epidermis accounted for 20 to 57% of the …

Effects Of 2-Chloroethyl-Phosphonic Acid (Ethephon) As A Male Gametocide For Induction Of Sterility In Wheat And Barley, Jacqueline Taylor Martin

Doctoral Dissertations

Exploitation of induced male sterility has now become a potential tool in plant breeding. Ethephon (2-chloroethyl-phosphonic acid) has induced male sterility in winter cultivars of wheat and barley.

The purpose of this research was to further elucidate the response of winter wheat (Triticum aestivum L. em Thell), and winter barley (Hordeum vulgate L.) to foliar application of ethephon.

Ethephon was foliarly sprayed on winter cultivars of wheat and barley which were Arthur and Blueboy, and Barsoy and Volbar respectively, at 0.05, 0.10, and 0.20 and 0.40 percent active ingredient, when plants were in mid-boot and late boot stages in the …

Lodging And Other Characteristics Of Seventy Corn Hybrids, Carl Andrew Ross

Masters Theses

In 1975, a lodging study was conducted on forty medium season and thirty full season corn hybrids at Knoxville and Crossville, Tennessee. Lodging and yields were determined at Knoxville and Crossville. Senescence over time, ear height, and number of days to silking and tasseling were determined at Knoxville.

Senescence, ear height and yield has little or no influence on lodging. Among all the factors evaluated, ear height, senescence, and number of days to silking and tasseling affected yields most in the medium season test. Ear height and number of days to silking and tasseling had the greatest effect on yields …

Effects Of Ethephon On The Pattern Of Flowering And Fruit Set Of Summer Squash, Carl Earnest Sams

Masters Theses

The plant growth regulator 2-chloroethylphosphonic acid (ethephon) was applied to summer squash to determine its effects on the flowering pattern. Treatments with all pistillate flowers pruned at anthesis, with and without ethephon applications were also compared to control plants to investigate the factors regulating flowering and fruit set of summer squash.

It was found that plants in the pruned treatments had a greater carbohydrate accumulation than plants in the nonpruned treatments, indicating that carbohydrate accumulation may be inversely associated with fruit development. Ethephon treatments produced more pistillate flowers per plant but also had a large number of aborted flowers. Thus, …

Induced Variability Of Resistance To Root-Knot Nematodes (Meloidogyne Incognita) In Soybeans (Glycine Max), Hendratno

Masters Theses

The purpose of this study was to determine the variability of resistance to root-knot nematodes (Meloidogyne incognita) in soybeans (Glycine max) induced by seed treatment with ethylmethane sulfonate (EMS).

Two soybean varieties, 'Essex' and 'Forrest,' were chosen as the experimental materials mainly on the basis of their distinct level of resistance; 'Essex' is susceptible and 'Forrest' is resistant. The M₂ and control populations were grown and tested for nematode resistance in the greenhouse. The number of gall developed on the roots was used to indicate the level of resistance.

The frequency distribution of the M …

The Cryptogamic Flora Of Desert Soil Crusts In Southern Utah, Davic C. Anderson

Theses and Dissertations

The cryptogamic flora of several soil crusts of arid regions in southern Utah was determined. Twenty-two lichens, Six mosses and fifty-four algal species were identified and their relative abundance estimated.

Influence Of Preharvest Ethephon Applications On Ripening Of Japanese Plum (Prunus Salicina), George Marvin Leavitt

Theses and Dissertations

Ethephon, applied to two plum cultivars, 'Queen Rosa' and 'El Dorado' , at 50 and 100 ppm, gave varying responses on the ripening process. Soluble solids remained unchanged while acid levels dropped. Increased ethylene evolution, color advancement and decreased flesh pr observed.

A Phylogenetic Study Of The Suffrutescent Shrubs In The Genus Atriplex, C. Lorenzo Pope

Theses and Dissertations

Growing on dry saline soils throughout the Intermountain Region of the United States is a group of herbaceous, perennial species of Atriplex, including A. corrugata, A. cuneata, A. cuneata ssp. Introgressa, A. falcata, A. gardneri, A. tridentata, and A. welshii, designated as the Atriplex gardneri complex. Highly adaptive and competitive in the arid salt deserts, these species are valuable as forage for livestock and wildlife. Because of extensive variation present within this complex, considerable taxonomic confusion has resulted. To clarify taxonomic and phylogenetic relationships, selected populations and plants were analyzed morphologically, cytologically, ecologically, phenologically, and genetically. Polyploidy is common within …

Structural Comparisons Of Four Plant Communities In The Great Dismal Swamp, Claire Virginia Dabel

Biological Sciences Theses & Dissertations

Four plant communities in the Great Dismal Swamp, located on the coastal plain in southeastern Virginia, were sampled and estimates of density, basal area and aboveground standing crop biomass were determined, Biomass was estimated as 229,800 kg/ha in the Chamaecyparis thyoides community and as 344,500 kg/ha in the Taxodium distichum community. Biomass for the two hardwood communities, the

Acer-Nyssa community and mixed hardwood (Quercus-Nyssa-Acer-Liriodendron-Liquidamber) community was estimated as 195,700 kg/ha and 194,600 kg/ha respectively and did not differ significantly (P

An Investigation Of The Nucleotide Cyclic 3'5' Adenosine Monophosphate In Young Hypocotyls Of Pisum Sativum L., Gary Marsh Hilton

Biological Sciences Theses & Dissertations

Concentrations of cAMP increased with time in pea hypocotyls assayed at 24 hour intervals over a period of four days. The highest concentration was 20.1 pmoles/mg protein which occurred in 96 hour hypocotyl tips. Ninety-six hour root bodies (dissected region between tip and embryo) achieved a concentration of 8.6 pmoles/mg. Concentrations of cAMP in embryos remained constant around one pmole/mg for three days and values doubled on the fourth day.

Hypocotyls, after germination for 72 hours, were dissected and incubated for various lengths of time in water and 3xl0^-8M IAA. Tips incubated for two hours showed a tenfold …

Annotated Checklist Of The Vascular Plants Of Washington County, Utah, Susan Elizabeth Meyer

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis is comprised of two parts, the annotated checklist of plants and the explanatory text which precedes it.

The checklist includes entries for the 1,207 vascular plant species known to occur in Washington county. each entry consists of species name, floristic component classification, community type occurrence, range termination information, specimen citations, and in some cases notes and relevant synonymy.

The explanatory text includes a discussion of the methods used in the preparation of the checklist, a description of the study area, a conspectus of botanical research in the area, and a summary of the systematic and phytogeographic affiliations of …

Feeding Behavior Of Pen Reared Mule Deer Under Winter Range Conditions, Michael A. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the feeding responses of mule deer to a system of spring livestock grazing. The specific purposes were 1) to determine botanical composition of diets selected by mule deer on a winter range subjected to previous spring grazing by sheep compared to one with no sheep grazing and 2) to develop a basis for predicting selection of individual plants by deer, based on physical characteristics of the plants and the species and physical proximity of associated plants.

The study was conducted within the framework of a completely randomized experimental design with two treatments. Variables controlled for each unit …

Photosynthesis, Dark Respiration, And Growth Of Rumex Patientia L. Exposed To Uv-B (280-315 Nm) Irradiance Corresponding To Reduced Atmospheric Ozone Concentrations, William B. Sisson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Net photosynthesis, dark respiration, chlorophyll concentrations and growth were determined for Rumex patientia L. exposed to UV-B radiation corresponding to reduced atmospheric ozone concentrations. The hypothesis of whether reciprocity is maintained in the response of R. patientia to polychromatic UV-B radiation was tested. On the basis of the relationships derived from these studies, a simulation model was developed for the prediction of photosynthesis and growth of R. patientia exposed to UV-B radiation corresponding to any atmospheric ozone reduction.

Photosynthetic rates were found to be depressed after two hours exposure to UV-B irradiance simulating a 0.18 atm·cm ozone column when the …

Seasonal Patterns Of Photosynthesis And Respiration In Atriplex Confertifolia And Ceratoides Lanata, Richard S. White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Net photosynthesis and dark respiration studies were conducted on Atriplex confertifolia (Torr. and Frem.) S. Wats and Ceratoides lanata (Pursh) J.T. Howell under field and laboratory conditions. These woody species are commonly found in salt desert shrub communities of the Intermountain West. During these investigations, the effects of air temperature, plant moisture stress, soil water potential, irradiation, and plant phenological status were examined with respect to their influence on carbon dioxide (CO₂) exchange.

Intensive field studies were carried out between April and October. This interval corresponded to the major period of physiological activity in both species. The factors …

A Three-Year Field Study Of Cacalia Atriplicifolia, L. With Emphasis On Dispersal Mechanisms, Joann T. Athey

Masters Theses

No abstract provided.

Modeling Studies Of Small Mammal Trapping Phenology, And Plant Succession In The Kaiparowits Region, Kane County, Utah, James A. Raines

Theses and Dissertations

This study makes use of simple statistical models which may be manipulated for projection of changes in the Kaiparowits Region of Southern Utah. A method of determining habitat preferences of small rodents from capture-recapture trapping data is proposed. It is suggested that some aspects of animal behavior regarding trapping may also be explained. Timing of flowering of Oryzopsis hymenoides and Hilaria jamesii as related to enviromental conditions was investigated, and models of the requisite conditions proposed. It is suggested that similar models may be used to describe the timing of other phenological events. Succession on disturbed sites is considered to …

Vegetational Response To Three Environmental Gradients In A Salt Playa Near Goshen, Utah County, Utah, Michael Grant Skougard

Theses and Dissertations

The plant communities and individual plant species in and around a salt playa near Goshen, Utah County, Utah were studied in relation to three environmental gradients. Forty-eight stands were sampled by means of meter square gradients. Frequency data for all participating plant species were taken. Soil samples were collected from each site and analyzed to establish the environmental gradients (i.e., total soluble salts, soil moisture and hydrogen ion concentration. Results indicate that community vegetation types respond differentially to the three gradients and can be segregated on the basis of one or more of the gradients. The total soluble salts gradient …

Ecological Investigations In Cercocarpus Ledifolius Nutt. Communities Of Utah, James Newton Davis

Theses and Dissertations

Cercocarpus ledifolius communities of Utah were sampled to determine which measured environmental characters were influential in determining community structure and dynamics. Nineteen, one-tenth acre stands were sampled by 25 equally spaced .25m2 quadrats. Plant frequency, cover, density, height, diameter, age, elevation, slope and exposure were determined for curl-leaf mahogany within the study area. Soil depth and soil samples were analyzed for texture, pH and soluble salts. Curl-leaf mahogany is found almost entirely on arid rocky slopes, canyon ledges, and plateaus at relatively high elevations on all exposures. The soils were invariably shallow and slightly acidic with sandy loam soils being …

Differential Resource Utilization By The Sexes Of Dioecious Plants, Dwight Carl Freeman

Theses and Dissertations

The distribution of male and female plants was examined in five dioecious, wind pollinated species representing five plant families and two classes (gymnosperms and angiosperms). The arid to semiarid habitats occupied by these species in northern Utah were stratified for sampling into two categories: chronically xeric and seasonally moist. Results show that for all species, males prevail on xeric microsites, while females dominate the more moist parts of each local environment. Habitat partitioning between the sexes is a strategy that maximizes seedset of females and pollen dispersal of males; it also tends to minimize intraspecific competition between the sexes.

Fixation Of Dormant Tilletia Teliospores For Thin Sectioning, John Scott Gardner

Theses and Dissertations

Dormant Tilletia caries teliospores in fixative solution or distilled water were frozen onto specimen chucks of an FTS Sorvall- Christensen frozen thin sectioner and cut or fractured at various temperatures (-20 to -75 C) and thickness settings (10, 15, 20, and 25 um). Cytoplasm of dormant spores was well preserved and organelles were found to differ from those of germinated spores in morphology. Irregular electron dense and electron opaque areas of lipid bodies were sometimes evident in dormant and germinating Tilletia caries teliospores. When dormant teliospores were sectioned in buffered fixative, lipids had an appearance similar to lipids in thin …

A Revision Of The Genus Ranunculus (Ranunculaceae) For The State Of Utah, Margaret Doherty Palmieri

Theses and Dissertations

This study is a taxonomic revision of the genus Ranunculus for Utah. Twenty-five species and 4 varieties are recognized, and are separated by means of a comprehensive key. A list of pertinent synonyms and types, a morphological description, habitat preference and a discussion are presented for each species and variety. Distribution maps and photographs are included. The basis of this study has been morphological comparison of herbarium specimens and collections and observations by the author throughout Utah.

Correlations Between Plant Species Diversity And Flower Characteristics In The Wasatch Mountains Of Utah And Idaho, William Kent Ostler

Theses and Dissertations

An analysis of the relative abundance of the prevalent species in 25 major plant communities of the Wasatch Mountains demonstrates that variation in species diversity is significantly correlated with many floral characteristics. Wind pollinated flowers decrease in abundance while animal pollinated flowers increase along the diversity gradient. Both relationships are highly significant statistically. Color diversity and species diversity are significantly and positively correlated in open communities but are not correlated in forest communities. The percent sum frequency of yellow and pink-magenta flowers decreased with increasing species diversity while blue and whitish flowers increased. Also, zygomorphic flowers and flowers in which …

The Distribution Of Submersed Hydrophytes In Currituck Sound, Steven Harry Davis

Biological Sciences Theses & Dissertations

The rooted submergent flora of Currituck Sound, North Carolina was determined, and the distributions of its species investigated with respect to salinity, substrate texture, depth, pH, turbidity and species co-occurrence. Eight species of hydrophytes were found: Potamogeton pectinatus, Fotamogeton perfoliatus, Ruppia maritima, Zannichellia palustris, Najas guadalupensis, Elodea nuttallii, Vallisneria americana, and Myriophyllum spicatum. The mean salinities at which each species occurred ranged from 1.0 ppt for E. nuttallii to 3.1 ppt for Z. palustris, Ruppia maritima, Z palustris and V. americana were the only species that commonly occurred on coarse-grained substrates. Elodea nuttallii and N. guadalupensis …

Purine-Thiamine Anabolism During Cellular Morphogenesis In Myxococcus Xanthus, Wen-Cherng Tsai

Electronic Theses and Dissertations

Purine-thiamine anabolism during cellular morphogenesis in Myxococcus xanthus was investigated. One of the approaches was to test vegetative and myxospore (2.5 h and 8 h) extracts of M. xanthus CW-2 for their ability to synthesize the second de novo intermediate, 5'-phosphoribosylglycinamide, from beginning precursors either by way of phosphoribosyl-pyrophosphate amidotransferase (EC 2.4.2.14) or ribose-5-phosphate aminotransferase. Results indicate the presence of both the amido- and aminotransferases in both types of extracts, and both enzymes appear to be present at about the same level (per milligram of protein) in vegetative cells, myxospores (2.5 h and 8 h), and in a bacterial prototype, …

Drip And Sprinkler Irrigation Of Carrots And Onions, James D. Melstad

Electronic Theses and Dissertations

Many specialty crops, especially vegetables, are shallow rooted and sensitive to periods of moisture stress. This makes irrigation of vegetables necessary to their production in South Dakota since summer rainfall is normally both inadequate and undependable. A study was initiated in conjunction with the South Dakota Agricultural Experiment Station and the Water Resources Institute to evaluate irrigation of specialty crops in eastern South Dakota. Drop and sprinkler irrigation were utilized for the irrigation of two specialty crops presently grown in South Dakota, carrots and onions. The study was initiated with the following objectives: 1. To compare carrots and onion yields …

Azide Sensitivity In Species Of Chlamydomonas And Carteria, Kim Michael Kobriger

Masters Theses

No abstract provided.

Vascular Flora Of The Kent Branch Watershed, Fluvanna County, Virginia, George M. Diggs

Dissertations, Theses, and Masters Projects

No abstract provided.

Geomorphic Interpretation Of Vegetation On Fisherman Island, Virginia, Mark Eliot Boule

Dissertations, Theses, and Masters Projects

No abstract provided.

A Floristic Study Of Hone Quarry Watershed, Rockingham County, Virginia, Gerald Francis Roe

Dissertations, Theses, and Masters Projects

No abstract provided.

The Effect Of Urea On The Sedimentation Coefficient Of The Curly Top Virus Dimer, Allen H. Smith

Undergraduate Honors Capstone Projects

The purpose of this project is to investigate the effect of increasing concentrations of urea on the sedimentation rate of the curly top virus dimer as measured by ultracentrifugation techniques. In general, urea causes the breaking of hydrogen bonds in macromolecules--in the case of the virus, increased concentrations of urea should cause changes in the configuration of the virus and may possibly cause a separation of the dimer into monomers. From previous centrifugation studies, we know that the dimer has a characteristic sedimentation coefficient(S) of about 80 Svedbergs; the monomer has an S value of about 55 Svedberg units. Increased …