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Physiology Of Cold Acclimation And Deacclimation Responses Of Cool-Season Grasses: Carbon And Hormone Metabolism, Xian Guan

Masters Theses

Winter injury of cool-season turfgrasses in northern climates is a significant issue, leading to losses in turf cover and subsequent increased inputs for recovery. Despite the different potential causes for winter injury, the overall level of plant freezing tolerance has been shown to account for a majority of the variation in winter survival of grasses. Freezing tolerance is achieved through cold acclimation, based on a series of physiological and biochemical changes that increase cell stability at freezing temperatures. Winter injury can result from insufficient cold acclimation, or rapid cold deacclimation triggered by temperature fluctuations or freeze-thaw cycles. Previous research has …

Volatile Profiles And Resistance To Herbivory In Eastern Hemlock, Elizabeth A. Mckenzie

Masters Theses

Eastern hemlock hosts the hemlock woolly adelgid, an introduced sap-feeding insect that causes rapid deterioration of the host. Like most conifers, eastern hemlock produces a variety of constitutive and induced defenses, primarily terpenoids. To explore the relationship of terpenoid defenses with adelgid infestations, we artificially infested hemlocks at a forest site and a plantation site, and compared their terpenoid concentrations to those in control trees. Infested trees showed lower terpenoid concentrations than control trees, suggesting that eastern hemlock not only fails to induce production of terpenoids in response to adelgid infestation, but becomes less able to produce carbon-based defenses due …

Sequence Analysis Of Maize Yellow Stripe3 Candidate Genes, Dennis B. Depaolo

Masters Theses

The work presented here focuses on the molecular mechanism of phytosiderophore secretion in graminaceous plants. In maize, yellow stripe3 (ys3) is a mutant that is deficient in its ability to secrete iron-chelating compounds of the mugineic acid family known as phytosiderophores. Phytosiderophores are specific to grasses and are used for the acquisition of iron. Genetic linkage mapping of the ys3 locus lead to a region of interest on chromosome 3 defined by marker UMC1773. The sequence of eleven candidate genes (GRMZM2G390345, GRMZM2G390374, GRMZM2G342821, GRMZM5G800764, GRMZM2G502560, GRMZM5G849435, GRMZM2G105766, GRMZM5G876835, GRMZM2G036976, GRMZM2G502563, miR167g) revealed several small deletions …

Molecular Marker Assisted Backcross Development And Evaluation Of An Environmentally Friendly, Commercially Acceptable Low Seed Phytate Soybean, Jeffrey David Boehm Jr.

Masters Theses

Soybean [Glycine max (L). Merrill] is the world’s top oilseed crop. High protein soymeal is a primary soybean use and staple food of livestock and fish. The storage form of phosphorus (P) in the seed is phytic acid, or phytate [myo-inositol 1,2,3,4,5,6 hexakisphosphate] which binds and chelates key nutritional cations forming stable salts that are non-digestible. Livestock waste laden with phytate P is an environmental concern, and a source of nonpoint P pollution causing eutrophication and surface water quality deterioration. The primary objective of this research was the development of a commercially acceptable low phytate (LP) soybean …

Aminocyclopyrachlor Efficacy For Non-Cropland Weed Control, José Javier Vargas Almodóvar

Masters Theses

The production of chemicals for crop protection purposes evolved after World War II with the commercialization of the auxin herbicides 2,4-D and MCPA. Their utility and effectiveness created an interest for North American and European companies to develop and research thousands of agrochemicals available today.

Recently discovered and introduced to the market by DuPont Crop Protection, aminocyclopyrachlor is the first broad spectrum synthetic auxin herbicide in this chemical class, and is structurally similar to the auxin herbicides: aminopyralid, clopyralid and picloram. Aminocyclopyrachlor has activity on broadleaf weed species with limited activity on monocot species. Aminocyclopyrachlor is absorbed via plant roots …

Evaluating The Performance Of Low-Lignin Transgenic Bioenergy Feedstocks In The Field, Holly Lauren Baxter

Masters Theses

Lignin in the cell walls of lignocellulosic biomass limits the accessibility of carbohydrates for breakdown into fermentable sugars and subsequently biofuels. The resistance of plant biomass to enzymatic or microbial deconstruction, known as biomass recalcitrance, can be overcome by reducing lignin content or modifying its composition through genetic modification of the lignin biosynthetic pathway. However, few studies to date have assessed the performance of low-lignin biofuel feedstocks under field conditions. Because lignin plays a vital role in several developmental and stress-related processes, characterization of these plants under the appropriate agronomic conditions is necessary to confirm that the improved biofuel-related traits …

Evaluating Pollination Ecology Of The Endangered Pityopsis Ruthii (Small) Small (Asteraceae), Philip Anthony Moore

Masters Theses

Pityopsis ruthii (Small) Small, also known as Ruth’s golden aster, is a federally endangered herbaceous perennial, endemic to two river systems, the Hiwassee and the Ocoee, within the Cherokee National Forest, Polk County, Tennessee. There are approximately 13,000 individuals that may be at high risk of short-term extirpation (Thompson and Schwartz, 2006). Little is known of the basic reproduction and life history of P. ruthii. Clebesh and Sloan (1993), Cruzan (2001), Park (1998), and Wadl et al. (2014) found evidence that seed production and seed viability are highly variable. Clebesh and Sloan (1993) indicated that pollinator visitation was highly temporal …

Effects Of Organically Enhanced Biofertilizer And Fertilizer Briquettes On Mineral Nutrition, Quality, And Yield Of Corn And Soil Health, John Heggie Winings

Masters Theses

Interest in alternate fertilizers has increased in recent years in order to improve crop nutrition and soil health. The efficacy of these fertilizers on corn (Zea mays L.) production and quality has been scarcely documented. Two alternative fertilizers, organically enhanced NPSFe Unity biofertilizer (Unity) manufactured from sterilized organic additives extracted from municipal wastewater biosolids and NPKZn briquettes (briquettes) produced by compacting solid fertilizers into a super-granule between 1-3 grams, were evaluated for nutrient concentrations, growth, quality, and yield of corn, residual soil nutrient levels, and soil microbial community structure relative to the conventional fertilizers ammonium sulfate and urea at …

Evaluation Of Crumb Rubber Dynamics For Improving Athletic Field Quality, Kyley Hampton Dickson

Masters Theses

Crumb rubber (CR) is an amendment used to reduce surface hardness and increase wear-tolerance on athletic fields. Turf managers can topdress CR particles into highly trafficked portions of athletic fields; however, optimum particle size and topdressing depth combinations for use on bermudagrass (Cynodon spp) athletic fields have not been determined. Optimum CR particle size and depth to maximize performance of hybrid bermudagrass (C. dactylon (L.) Pers. x C. transvaalensis Burtt-Davy, 'Tifway') athletic field turf established on a Sequatchie silt loam soil was investigated at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) in 2011 and …

Genetic Variation And Trait Associations For Forage Yield And Quality Among F1 Half-Sib Families Of Switchgrass, Matthew Eric Bobbitt

Masters Theses

Switchgrass (Panicum virgatum L.) is widely accepted as a forage crop throughout the United States. It is known for its performance on field sites that may be marginal for row crop production and as a warm season grass to fill gaps for cool season forages. With the increase of fuel and fertilizer costs, forage producers need higher yields and better quality than ever before. The objectives of this research were to: (i) compare four F₁ [first generation] half-sib populations for their potential of producing superior lines for forage production, (ii) assess the genetic variances for yield, and (iii) …

Genetic Variability For Biomass Yield, Yield Components, And Ethanol Yield Among Half-Sibs Of Switchgrass, Eifion Wyn Hughes

Masters Theses

For bioenergy crops to be an economical alternative to fossil fuels, rapid biological and technological advancements will need to occur. Some advancements can be accomplished by producing new switchgrass (Panicum virgatum L.) varieties with higher biomass and ethanol yields. The objective of this research was to quantify biomass and ethanol yield potential of four F₁ [F1] half-sib populations for future variety development as a bioenergy crop.

The four parental lines were PI 421999 (AR), PI 607837 (TX), PI 421552 (Cimarron), and Exp. # NSL-2001-1 (OK). Seed for one hundred and forty F₁ [F1] half-sib progeny were produced …

Do Plants Play A Part In Student Satisfaction?, Amanda Diane Plante

Masters Theses

Environmental psychologists have found relationships between plants, nature and satisfaction. Student satisfaction is important across grade levels. Two studies were conducted to determine the effect of spending time with live plants on student satisfaction and academic performance. In the first study, a quasi-experimental nonequivalent control group design was used to determine how participation in garden labs would affect high school student satisfaction with school and academic performance. Ecology students in the variable group participated in ten gardening labs during the semester. During labs, students did hands-on gardening activities in the school greenhouse and garden. Students in the variable and control …

Synthetic Turf Surface Temperature Reduction And Performance Characteristics As Affected By Calcined Clay Modified Infill, Eric Hall Reasor

Masters Theses

Synthetic turf research plots containing crumb rubber (CR) infill were established in Knoxville, TN in 2012 and 2013. Calcined clay (CC) was amended to CR in several ratios: a 50:50 (vol vol-1) blend; a 50:50 blend with a polymer coating on CC (50 CR:50 CCC); a 15 mm layer of CC under 15 mm of CR (CR over CC); and a 15 mm layer of CC over 15 mm of CR (CC over CR). A 100% CR and a 70:30 blend of CR to sand (70 CR:30 S) were included for comparison. Surface temperature was measured in the summer of …

Increasing Nursery Crop Canopy Density: Implications For Sustainable Insect Pest Management, Whitney Michelle Yeary

Masters Theses

Consumers are attracted to woody ornamental plants that have symmetrical, dense canopies. In order to get the desired canopy density and symmetry, growers often manipulate growth by pruning or applying chemical plant growth regulators. Another method of acquiring a dense plant canopy is for growers to purchase in vitro-propagated liners instead of traditional cutting-propagated liners. This work analyzed the validity of all three methods on several woody ornamental species. Liners from Cutting-propagated (CP) and in vitro-propagated (IVP) sources were purchased and treatments of pruning and PGRs were applied. Pruning only increased the canopy density of rhododendron (Rhododendron L. ‘Roseum Elegans’) …

Comparison Of Oak And Sugar Maple Distribution And Regeneration In Central Illinois Upland Oak Forests, Peter J. Frey

Masters Theses

Although white oak (Quercus alba) dominated much of the mid-west and eastern US hardwood forests prior to European settlement, changes in disturbance frequencies and habitat fragmentation, coupled with other biotic pressures, are allowing sugar maple (Acer saccharum Marshall) to displace oak in the upland forest understory. Since our understanding of how disturbance mechanisms influence oak regeneration is not fully clear, there is lack of consensus on how to employ management practices. We collected seedling microhabitat data from 5 upland oak forest sites in central Illinois, each differing in age class and/or silvicultural treatment to determine: 1) Whether …

Morphological And Ecological Investigations Of Species Of Bulrush (Scirpus) In Illinois, Julian G. Moore

Masters Theses

Two closely related species of bulrush, Scirpus atrovirens (Green bulrush) and Scirpus georgianus (Georgia bulrush), are widely distributed in Illinois. They are difficult to separate in the field, but readily distinguishable under magnification in the lab. These two species have been found in moist meadows, shallow marshes, edges of wet forests, and ditches. The objective of this study was to evaluate the morphological and ecological distinctness of the species with the aim toward discovering and describing other features to distinguish them reliably. Eighty plants of Scirpus atrovirens and 80 of Scirpus georgianus were examined. Fifty S. atrovirens and 50 S. …