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Habitat And Demography Of The Ozark Chinquapin (Castanea Ozarkensis) At Roaring River State Park In Barry County, Missouri, Danielle Evilsizor

Electronic Theses & Dissertations

The Ozark chinquapin, Castanea ozarkensis Ashe, is a chestnut tree with a range concentrated in the Interior Highlands of North America. Like other North American members of Castanea, it was reduced from an overstory tree to an understory shrub by the invasive chestnut blight fungus (Cryphonectria parasitica [Murrill] M.E. Barr) during the early 20^th century. However, relatively little is known about the habitat of this species or its health and reproductive capability post chestnut blight. Chapter one of this study analyzed the habitat of this species through a random forest species distribution model (SDM) to predict where …

Freezing Tolerance Of Herbaceous Legumes Within Southwestern Ontario: Evidence Of Disproportionate Freezing Sensitivity, Samuel L. Rycroft

Electronic Thesis and Dissertation Repository

Legumes (Fabaceae) represent a diverse and ecologically significant plant taxon; most described legumes form mutualisms with diazotrophic rhizobia, potentially fixing substantial quantities of nitrogen within habitats where they are well-established. Stressors causing lethal or sub-lethal impacts in legumes or rhizobial symbionts may therefore impact the nitrogen dynamics of such habitats. In recent decades, variability of winter temperatures, precipitation, and soil freeze-thaw cycling has increased in temperate regions. Without adequate snow cover to insulate roots and shoot bases, herbaceous plants will likely be exposed to more frequent or severe freezing. In southwestern Ontario, a pattern of disproportionate freezing sensitivity relative to …

Addressing Water Hyacinth (Pontederia Crassipes) Impacts On Aquatic Biota In Lake Okeechobee, Joseph Salerno

All HCAS Student Capstones, Theses, and Dissertations

The incursion of water hyacinth, Pontederia crassipes in Lake Okeechobee has resulted in management systems to be implemented to reduce the coverage of the invasive macrophyte. Its residence in the Lake Okeechobee ecosystem and the effects it has on organisms in the lake, whether it be positive or harmful is unknown. This study attempted to assess the potential effects that water hyacinth has on aquatic biota in Lake Okeechobee. Biotic data were collected on open water, water hyacinth covered, and native vegetation covered habitats via hook-and-line fishing, electrofishing, baited minnow traps, and the sampling of plant roots over a thirteen-month …

Evaluating Habitat Use By Nekton In Widgeon Grass (Ruppia Maritima), Shoal Grass (Halodule Wrightii), And Unvegetated Bottom Habitats In The Grand Bay National Estuarine Research Reserve, Jessica Woodall

Master's Theses

Seagrass beds support high biodiversity and animal abundance, serve as feeding grounds for a variety of animals, offer shelter from predation, and act as a nursery habitat for juveniles. The species composition of seagrass beds can impact their use as habitat by animals. Two common species of seagrass in the Gulf of Mexico are Ruppia maritima (widgeon grass) and Halodule wrightii (shoal grass). The shallow coastal waters of the Grand Bay National Estuarine Research Reserve (NERR) support both species, but the use of each seagrass as habitat by nekton is poorly understood, which can limit management decision-making. Nekton communities were …

Characterization Of Radiotolerance In Potato And Development Of A Gamma Radiation Phytosensor., Robert Graham Sears

Doctoral Dissertations

As humans pursue space travel and nuclear energy, the risk of harm from ionizing radiation increases. On Earth or in space, plants are essential to our personal and environmental health. Plants serve as sentinels, bioremediators and food sources in areas of high ionizing radiation, therefore it is essential to understand how ionizing radiation affects plant biology. This work aimed to understand plant responses to ionizing radiation in the potato chassis and apply that knowledge to generate novel phenotypes for nuclear energy and space applications. The first gamma radiation phytosensor was developed for monitoring at standoff distances greater than three meters. …

Characterization Of Lignin Structural Variability And The Associated Application In Genome Wide Association Studies, Nathan D. Bryant

Doctoral Dissertations

Poplar (Populus sp.) is a promising biofuel feedstock due to advantageous features such as fast growth, the ability to grow on marginal land, and relatively low lignin content. However, there is tremendous variability associated with the composition of biomass. Understanding this variability, especially in lignin, is crucial to developing and implementing financially viable, integrated biorefineries. Although lignin is typically described as being comprised of three primary monolignols (syringyl, guaiacyl, p-hydroxyphenyl), it is a highly irregular biopolymer that can incorporate non-canonical monolignols. It is also connected by a variety of interunit linkages, adding to its complexity. Secondary cell wall …

Regulation Of Protein Synthesis In Arabidopsis Thaliana Through A Bioinformatic And Mathematical Lens, Ricardo Andres Urquidi Camacho

Doctoral Dissertations

Organisms exist under constantly varying environmental and internal conditions, which necessitate the differential regulation of gene expression. To synthesize proteins, the ribosome translates the information encoded in the nucleotide sequence of an mRNA into the final, functional amino acid sequence. Knockouts of ribosomal proteins lead to lethality. One such protein is the ribosomal protein 6 of the small subunit (eS6/RPS6). We confirmed that the knockout of either one of two eS6 paralogs in Arabidopsis leads to stunted growth and chlorosis. Here, these phenotypes have been further characterized in seedlings by precisely quantifying the ribosome loading of mRNAs as well as …

Effect Of Cultural Strategies And Application Technologies On Weed Control In Flooded And Furrow-Irrigated Rice, Noah Hunter Reed

Graduate Theses and Dissertations

Weed control is a major problem that rice (Oryza sativa L.) producers face in the Mid-south every growing season. Restricted use of some rice herbicides has also highlighted the need for more research to be conducted on cultural weed control strategies and application technologies in rice. The aim of these studies was to evaluate rice weed control using various rice row widths, bed widths (irrigation-furrow spacing), rice cultivar selection, and nozzle type selection. Three field experiments were conducted in 2021 and 2022 across four sites at Lonoke, AR, Pine Tree, AR, Rohwer, AR, and Stoneville, MS. In experiment one, as …

Developing Recommendations For Broad Mite, Polyphagotarsonemus Latus Banks, In Blackberry, Rubus Subgenus Rubus, Jared Bradley Linn

Graduate Theses and Dissertations

Broad mite, (Polyphagotarsonemus latus Banks) (Acari: Tarsonemidae), is an economically important pest of blackberry production across the world. Since it was first reported on primocane-fruiting blackberries in 2010, little work has gone into developing IPM tools and understanding impact on floricane-fruiting cultivars. The objective of this thesis was to evaluate the effect of broad mite feeding on floricane-fruiting cultivars of blackberry, develop an efficient and accurate field scouting strategy, and investigate the impact of cultivar and trellising technique on the development of broad mite populations. Experiments consisted of evaluating floricane fruiting cultivars by quantifying broad mite populations and cataloging their …

Cellular Control Of Proteostasis, Cytoskeleton Organization, And Polarity Remodeling During Infection-Related Development By The Rice Blast Fungus, Audra Rogers

Graduate Theses and Dissertations

Understanding the intricate processes underlying fungal infection-related development is crucial for combating plant pathogens. In this study, we investigate the coordination of morphogenetic transitions during plant infection by Magnaporthe oryzae, the blast fungus. We focus on three key aspects: protein quality control, cytoplasmic microtubule organization, and cell-end marker proteins. M. oryzae forms a specialized infection cell known as an appressorium. The proper formation of this cell is crucial for the pathogen to infect a susceptible host. First, we investigate protein quality control mechanisms during infection-related development. Our findings demonstrate that aggregated proteins are sequestered into quality control compartments within conidia …

Evaluation Of Water Hardness And Ph On Soybean And Cotton Insecticide Efficacy, Taylor Davis

Graduate Theses and Dissertations

Insecticide efficacy often varies by location and year. Many factors can influence an insecticide’s efficacy, but an often-overlooked factor is the quality of water in a carrier solution. Water quality includes many parameters, but two important ones are water hardness and pH. Research has shown that water hardness and pH can affect some pesticides. Multiple experiments were conducted to evaluate the impact of water hardness and pH on insecticide efficacy. Experiments were conducted to evaluate the impact of water hardness and pH on the efficacy and residual control of chlorantraniliprole for the control of corn earworm, Helicoverpa zea (Boddie). Leaf …

Environmental And Agronomic Evaluation Of Struvite In Rice Production Systems, Diego Della Lunga

Graduate Theses and Dissertations

Furrow-irrigation constitutes an alternative water regime that has been increasingly adopted in Arkansas. Among the management of nutrients in furrow-irrigated systems, phosphorus (P) represents a substantial challenge. The environmental sustainability of rice (Oryza sativa) production systems needs to be evaluated across different water regimes and fertilizer-P sources. Therefore, the objectives of the following studies were to: i) evaluate season-long carbon dioxide (CO2) and methane (CH4) emissions and global warming potential (GWP) under different tillage treatments [i.e., conventional tillage (CT) and no-tillage (NT)] and at different site positions (i.e., up-, mid-, down-slope) along the predominant slope of a production-scale, furrow-irrigated rice …

Evaluation Of Weed Control Efficacy And Crop Tolerance To Florpyrauxifen-Benzyl Coated Onto Urea, Bodie Lyn Cotter

Graduate Theses and Dissertations

Frequent off-target movement occurrences to soybean [Glycine max (L.) Merr.], rice (Oryza sativa L.) injury, and a lack of barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] control followed the commercial launch of florpyrauxifen-benzyl in 2018. Florpyrauxifen-benzyl is a synthetic auxin, Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Group 4 herbicide used for postemergence weed control in rice and labeled for application at 30 g ae ha-1. Previous research documented that soybean was susceptible to injury following spray applications of florpyrauxifen-benzyl at less-than-labeled rates, and certain varieties of rice are less tolerant to spray-applied florpyrauxifen-benzyl at 30 g ae …

Management Zone Delineation For Variable-Rate Seeding In Production Soybeans, Ujjwal Sigdel

Graduate Theses and Dissertations

Soybean seeding rate (SR) is selected according to planting date, maturity group, soil properties, and yield goal. Even though one SR is applied in most fields, site-specific adjustments with variable-rate seeding (VRS) technology can help optimize production. The project goal was to determine if VRS could be beneficial to soybean producers in Arkansas. The project objectives were to i) assess planter performance and soybean yield response to five seeding rate treatments, ii) characterize the drivers of yield variability, and iii) create a-posteriori prescription maps for VRS. Five SR treatments (185,000, 247,000, 309,000, 370,000 and 432,000 seeds ha-1) were applied using …

Evaluation Of Oxyfluorfen For Use In Roxy Rice, Casey Hunter Arnold

Graduate Theses and Dissertations

Mid-southern U.S. rice (Oryza sativa L.) producers are challenged every year to control problematic barnyardgrass [Echinochloa crus-galli (L.) Beauv.] and weedy rice (Oryza sativa L.) because they have evolved resistance to most labeled herbicides. Oxyfluorfen is a Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Group 14 herbicide that inhibits protoporphyrinogen oxidase within the plant. Currently, there are no HRAC/WSSA Group 14 herbicides labeled for barnyardgrass or weedy rice control in midsouthern rice production. Therefore, oxyfluorfen is being evaluated for barnyardgrass and weedy rice control. Plant breeders at the University of California – Davis were able to breed …

Assessing The Evaporation Method For Soil-Water Retention Curve Development And Comparison Of Soil-Water Characteristics Across Different Tillage Practices In A Furrow-Irrigated Corn (Zea Mays L.) System, Jeferson Prass Pimentel

Graduate Theses and Dissertations

The thesis comprises three studies. The first study in this thesis (Chapter I) focused on a six-year corn field experiment to assess the influence of conservation agricultural practices on soil properties and their long-term effects on water-use efficiency and yield. Non-tillage management did not significantly reduce soil bulk density compared to conventional tillage, as no differences were observed between non-tillage and tillage systems throughout the 6-year experiment. There was no difference in total water-use efficiency among soil management practices in 2018, 2019, 2020, and 2021. Even though in one year of the study, a significant 24 kg ha-1 mm-1 improvement …

Impact Of Copper-Containing Products And Irrigation On Hybrid Bermudagrass (Cynodon Dactylon (L.) Pers X C. Transvaalensis Burtt-Davy), Adam Gore

All Dissertations

Copper (Cu) is an often-seen component in various turf industry products including fungicides, algaecides, and colorants. Though an essential micronutrient in plants, excessive levels of Cu has been shown in various plant commodities to cause phytotoxicity and plant death. With the increasing use of pigments on hybrid bermudagrass [Cynodon dactylon (L.) Pers x. C. transvaalensis Burtt-Davy] putting greens to replace overseeding practices during traditional dormant periods combined with regular applications of fungicide, algaecide and spray additives containing Cu, the objective of this study was to investigate the potential impact of individual and combined copper-containing treatments on hybrid bermudagrass and …

Furthering Indaziflam-Based Management Strategies Of Three Invasive Annual Grasses In Northern Utah, Peter Weston Maughan

All Graduate Theses and Dissertations, Fall 2023 to Present

Indaziflam is an herbicide highly recognized for its potential to effectively control weedy, winter germinating grasses, such as downy brome, as the herbicides prevents seed germination for several years. Unfortunately, most of these studies only capture the first 2-3 years of indaziflam’s 3-5 years soil activity. This thesis sought to better understand indaziflam’s long-term effects by monitoring both a healthy ecosystem and a degraded ecosystem for up to 5 years after indaziflam application. A secondary study was also conducted to better understand the potential of revegetation via reseeding in indaziflam treated soils. The study concluded that indaziflam very little long-term …

Ecology And Management Of Dyer's Woad (Isatis Tinctoria) In Northern Utah, Erin Marie Hettinger

All Graduate Theses and Dissertations, Fall 2023 to Present

Dyer’s woad (Isatis tinctoria L.) is a non-native forb that continues to threaten natural areas throughout Northern Utah and much of the Intermountain West. Once introduced, dyer’s woad can become extremely invasive, decreasing forage quality, and displacing native species. While dyer’s woad is found throughout much of Northern Utah, its range in other states remains limited. If promptly managed, control success in these areas will be much higher and populations may be kept at bay before ecological damage becomes severe.

This project tested the ability of dyer’s woad seedlings to compete with common rangeland grasslands at varied densities as …

Reducing Inputs And Adding Value To Turfgrass Systems Through Clover Inclusion And Plant Growth-Promoting Rhizobacteria Applications, Paige E. Boyle

All Graduate Theses and Dissertations, Fall 2023 to Present

Recently, the US has seen an expansion in the amount of turfgrass land cover (lawns, parks, roadsides, sports fields, and golf courses), as well as an interest in reducing fertilizer, water, and pesticide use in these grass systems. To help maintain quality and function while reducing resource inputs, two promising approaches have emerged: planting clover into lawns and applying plant growth-promoting rhizobacteria.

White clover and grass mixtures have been studied for their ability to cut down on fertilizer usage and provide a uniform, dark green lawn, but other clover types have not been as widely studied and may provide similar …

Bioregenerative Dietary Supplementation: Optimizing Brassica Production For Space Travel Through Light Intensity, Photoperiod, And Harvest Methodology, Ethan W. Darby

Masters Theses

Bioregenerative dietary supplementation, a component of bioregenerative life support, will be necessary for the success of future exploration-length space endeavors. Plants, as autotrophic producers of calories, nutrients, and oxygen, will be indispensable in the development of these systems. Previous work has identified leafy greens from the genus Brassica as promising candidates for in-flight production of necessary human nutrients such as vitamins C, B₁, and K₁, in addition to β-carotene, the primary vitamin A precursor in the human diet. These plants also produce lutein and zeaxanthin, two compounds important in protecting the eye from radiation-induced damage, as …

A Genome Wide Association Study Of Heat Tolerance In Snap Bean (Phaseolus Vulgaris), Morgan Stone

All Theses

Bean production in the United States has decreased while the temperatures have been steadily increasing, reaching new highs each year. Heat stress is detrimental to common bean (also known as snap bean) production. Symptoms of heat stress include decrease in pollen viability, shriveling of pods, and pod abortion making them unmarketable. Pod production of 323 snap bean accessions from a large diversity panel was assessed in a randomized complete block design with field trials at two different times in the spring season. The results show a significant decrease in the number of pods produced per plant and weight of pods …

Establishing And Optimization Of Tissue Culture Work With Erigeron Canadensis, Robert Petursson

Masters Theses

Glyphosate resistance among weed species has been an increasing problem in crop production over the past two decades. Glyphosate resistant Erigeron canadensis (horseweed) has been found on multiple continents and 20 U.S. states. It appears that the resistance is of non-target type, with mechanisms of action that have yet to be elucidated at the gene level. For the first portion of the study, I focused on reproducing the original indirect organogenesis protocol but discovered biotype variability can influence regeneration success. An improved indirect organogenesis method was then developed using the previously published methods that could be used across biotypes. A …

Chemical Investigation Of Dichloromethane Extract Of Aloe Vera Peels: An Agricultural Waste, Nazmul Huda

Theses and Dissertations

Aloe barbadensis Miller, commonly called Aloe Vera, is a widely popular succulent plant species cultivated across subtropical regions worldwide from India to the Tex-Mex border. Besides its historical uses, Aloe juice has garnered attention as a potential remedy for various ailments, particularly in treating various skin conditions and facilitating wound recovery, including obesity, diabetes, hepatitis, Crohn's disease, and ulcerative colitis. Regrettably, the agricultural practice following sap extraction involves discarding Aloe vera peels, constituting agricultural waste. As part of our continuous research on extraction, isolation, separation, and spectral characterization of value-added chemicals present in waste botanicals herein, …

Germination Trends Of American Chaffseed, Schwalbea Americana L., And Factors Affecting First-Year Seedling Development, Trenton Miller

All Theses

Following centuries of exploitation and fire suppression, longleaf pine systems are now the focus of many conservation efforts. Efforts to restore populations of Schwalbea americana L. in longleaf pine savannas have been met with frustratingly low recruitment. While past studies have briefly quantified germination rates for Schwalbea, there have not been any studies yet that truly investigate this plant’s germination requirements. Additionally, there has been little research into characterizing the parasitic relationship between Schwalbea and its various host species. We conducted a germination study in a growth chamber that investigated Schwalbea’s germination rate and time to germinates as …

Rapid Leaf Senescence Symptoms Are Related To Carbohydrate Depletion In Cut Chrysanthemums, And Strategies For The Symptoms Reduction, Shara Ortiz Carvajal

All Theses

Chrysanthemum (Chrysanthemum ×morifolium) is the second-largest exported cut flower worldwide; however, some cultivars exhibit rapid leaf senescence during their first week of vase life. This phenomenon negatively impacts consumer perception of plant quality, and its cause has been unknown. Experiments were performed in Colombia on cut chrysanthemums shipped to the U.S. for vase-life evaluation. After 10 d, the severity of leaf senescence symptoms was recorded. Experiments examined the effect of flower form [disbud (one flower per stem) versus spray (5-10 flowers per stem)], the effect of time of harvest (A.M. versus P.M.), and sugar sources (dextrose, fructose, mannitol, and sucrose) …

Enabling Breeding For Fruitlet Freeze Tolerance In Peach, Ufuk Caglar

All Theses

Climate change is affecting the production of temperate fruit crops, with cold temperatures emerging as a critical abiotic stressor that limits plant growth and performance. Freeze damage, particularly in spring, has resulted in significant economic losses in peach production in the southeastern United States. Research efforts in peach and other Prunus species have primarily focused on studying dormancy-related traits associated with bloom time, such as chill and heat requirement, with fruitlet freeze tolerance not equally represented. Breeding for climate resilience in peach requires a combination of these traits to allow for late bloom via targeted chill requirement and high heat …

The Floral Thermal Environment: Physical, Morphological, And Environmental Determinants, And Their Impact On Plant-Pollinator Interactions, Jennifer Apland

All Theses

Anthropogenic climate change is driving major shifts in global temperatures and increases in extreme temperature events that contribute to reduced survival and species loss. To counteract extreme temperatures, many organisms can undergo geographic range shifts or engage in behavioral thermoregulation (e.g., movement to suitable microhabitats). While plants are sessile and thus subject to highly variable ambient temperatures, they have evolved mechanisms to regulate internal floral temperature. Floral thermoregulation may mitigate thermal stress on pollen and ovules and impact plant-pollinator interactions. These mechanisms for thermoregulation are often highly dependent on ambient temperature and solar radiation as most plants are not endothermic. …

A Robust Agroinfiltration Method, Bryce N. Trull

Masters Theses

Stable transformation of soybean (Glycine max) is a markedly slow and laborious process. Thus, a tool that enables rapid evaluation of genetic elements in planta is critical to advance complex research and genetic engineering in soybean. To that end, a substantially robust agroinfiltration method was innovated in this work. Agroinfiltration is a technique that leverages Agrobacterium-mediated transient transformation to deliver genetic elements to the cells of whole plant tissues, usually leaves. Several factors were found to be relevant to successful soybean leaf agroinfiltration, including genotype, surfactant, developmental stage, and Agrobacterium culture medium. The research represents not only …

Mimicking Biofilms: Photosynthetic Assessments Of C. Reinhardtii In 3 Physical Forms, John Michael Roesgen

Biology ETDs

Oxygenic photosynthesis supports the majority of life on Earth through the capture of energy from sunlight and the assimilation of CO₂ into basic building blocks of cells. Microalgae are fast growing and account for about half of global photosynthesis. In addition, they can be cultivated and their metabolism can be redirected to generate additional useful products ranging from biofuels to pharmaceuticals. However, the efficiency of metabolite production is severely impacted by the slow diffusion of CO₂ through water and the high energetic costs of harvesting microalgae from liquid cultures. Microalgae grow in open water, but they also form …