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Articles 1 - 20 of 20
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Quantifying The Variability In Heavy Metal Concentrations In Produce Grown In Metals-Rich Soil, Harris Lowell Byers
Quantifying The Variability In Heavy Metal Concentrations In Produce Grown In Metals-Rich Soil, Harris Lowell Byers
Theses and Dissertations
Childhood Pb exposure is associated with a multitude of poor health outcomes. In food-insecure areas, growing fresh produce in residential backyard gardens is one option for parents; however, commonly grown crops are known to accumulate Pb in consumable tissues when grown in metals-rich soils. A variety of produce representing a continuum of consumable tissues were grown in soils collected from two residential vegetable gardens, a former metal foundry, and commercial topsoil purchased from a local hardware store. The concentrations of heavy metals in crop tissues were measured with custom wavelength dispersive X-ray Fluorescence (WD-XRF) spectroscopy and portable energy dispersive X-ray …
A Seascape Genetics Approach To Studying Genetic Differentiation In The Bull Kelp Nereocystis Luetkeana, Lily G. Gierke
A Seascape Genetics Approach To Studying Genetic Differentiation In The Bull Kelp Nereocystis Luetkeana, Lily G. Gierke
Theses and Dissertations
The brown alga Nereocystis luetkeana is a foundation species found from Alaska to California. In the Salish Sea, N. luetkeana is declining, but little is known about its population structure. We explored N. luetkeana 1) allelic dissimilarity and richness using seven microsatellite markers, and 2) tested models of gene flow in the Salish Sea using a hydrodynamic transport model. Our results suggest that the N. luetkeana distribution is comprised of four genetic co-ancestry groups that are geographically coherent, apart from the separation of the Strait of Georgia/Puget Sound by the Strait of Juan de Fuca. Our model supported that environmental …
Exploring Primitive Legume Symbiosis Using Chamaecrista Fasciculata As A Model, Zachary E. Zawada
Exploring Primitive Legume Symbiosis Using Chamaecrista Fasciculata As A Model, Zachary E. Zawada
Theses and Dissertations
Legumes form symbiotic associations with diazotrophs collectively termed “rhizobia” leading to the formation of nodules and N2-fixation and contribute significant amounts of fixed N to agricultural and natural environments. The mechanisms of nodulation and N2-fixation are extensively studied using model legumes that belong to the Papilionoideae, in which nodulation is widespread and advanced. In contrast, very little is known about the mechanisms of nodulation and N2-fixation in in basal Caesalpinioideae subfamily in which nodulation is rare. The nodulating caesalpiniod legume Chamaecrista fasciculata is widespread in North America and is suggested as a complementary model to study legume nodulation because of …
Dissection Of Floral Organ Development And Sterility In Sorghum Bicolor, Ashley R. Smith
Dissection Of Floral Organ Development And Sterility In Sorghum Bicolor, Ashley R. Smith
Theses and Dissertations
Sorghum bicolor is a drought resistant cereal grain commonly grown for use in food, feed, fiber, and fuel production. Due to its versatility and modest sized genome it is poised to become an increasingly important research organism within the C4 plants. Sorghum produces spikelet pairs with one fertile sessile spikelet and one to two sterile pedicellate spikelets. One major area of interest in sorghum production is maximizing seed yield. While the importance of the grain is obvious there are several large gaps in the study of sorghum that prevent researchers and growers from maximum productivity. The first gap is that …
Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson
Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson
Theses and Dissertations
Communication between the male and female gametophyte is vital to successful fertilization during sexual reproduction in plants. One of the proteins known to be important for communication between the male and female gametophyte is LORELEI (LRE). Several studies have shown that there are defects in pollen tube guidance and synergid degeneration, however this is the first study that shows that cell wall thickness in the female gametophyte may also be affected. Previous confocal studies have documented that LRE is present both in the filiform apparatus and found in puncta throughout the cytoplasm. This study confirmed this, but our studies suggest …
Of Fire, Mammals, And Rain: Mechanisms Of Plant Invasions, Tara Boyce Bishop
Of Fire, Mammals, And Rain: Mechanisms Of Plant Invasions, Tara Boyce Bishop
Theses and Dissertations
Biological invasions are driving environmental state changes on a global scale. Exotic plant species must be successful at passing several abiotic and biotic filters to establish and disrupt the native plant community assembly. Understanding where exotic plants are on a regional scale and being able to characterize how exotic plants are generally interacting with their environment is crucial information for exotic species management (chapter 1). In the western United States human-related activities are augmenting the spread of exotic plant species by increasing the ignitions of wildfire. Wildfire can lead to nutrient pulses through the removal of intact native communities and …
Bottom-Up Controls (Micronutrients And N And P Species) Better Predict Cyanobacterial Abundances In Harmful Algal Blooms Than Top-Down Controls (Grazers), Scott Andrew Collins
Bottom-Up Controls (Micronutrients And N And P Species) Better Predict Cyanobacterial Abundances In Harmful Algal Blooms Than Top-Down Controls (Grazers), Scott Andrew Collins
Theses and Dissertations
The initiation, bloom, and bust of harmful Cyanobacteria and algae blooms (HAB) in lakes are controlled by top-down and bottom-up ecological controls. Excess phosphorous and nitrogen inputs from anthropogenic sources are primary to blame, but eukaryotic grazers may also promote or curb Cyanobacteria dominance. We tracked shifts in bacterial composition, lake chemistry, and eukaryotic grazing community weekly or bi-weekly through spring and summer and modeled the causes of specific Cyanobacterial species blooms and busts across three lakes in Utah, USA, with differing lake trophic states. Regardless of trophic status, all three lakes experienced blooms of varying composition and duration. Aphanizomenon …
Investigating The Potential Of Weeds As Host Reservoir For Plant Parasitic Nematodes In South Texas, Habraham F. Lopez
Investigating The Potential Of Weeds As Host Reservoir For Plant Parasitic Nematodes In South Texas, Habraham F. Lopez
Theses and Dissertations
Presence and geographical distributions of three damaging nematode pest (R. reniformis, M. incognita, T. semipentrans) have been recorded in the LRGV. With year-round growing seasons, weed pest are a real problem for many LRGV growers. With some growers leaving the field fallow until planting season, these places can serve as potential host reservoirs for plant parasitic nematodes (PPN). This study examined the potential of weeds as host reservoirs for plant parasitic nematodes in the LRGV. Results demonstrated the presence of 5 of the 12 economically important plant parasitic nematode genus and demonstrated a difference in distribution of nematodes …
Whole-Genome Assembly Of Atriplex Hortensis L. Using Oxfordnanopore Technology With Chromatin-Contact Mapping, Spencer Philip Hunt
Whole-Genome Assembly Of Atriplex Hortensis L. Using Oxfordnanopore Technology With Chromatin-Contact Mapping, Spencer Philip Hunt
Theses and Dissertations
Atriplex hortensis (2n = 2x = 18, 1C genome size ~1.1 gigabases), also known as garden orach, is a highly nutritious, broadleaf annual of the Amaranthaceae-Chenopodiaceae family that has spread from its native Eurasia to other temperate and subtropical environments worldwide. Atriplex is a highly complex and polyphyletic genus of generally halophytic and/or xerophytic plants, some of which have been used as food sources for humans and animals alike. Although there is some literature describing the taxonomy and ecology of orach, there is a lack of genetic and genomic data that would otherwise help elucidate the genetic variation, phylogenetic position, …
Use Of Plant Growth Regulators To Expand The Period Of Sagebrush Seed Germination And Reduce The Risk Of Restoration Failure: Laboratory Trials, Chelsea Elizabeth Keefer
Use Of Plant Growth Regulators To Expand The Period Of Sagebrush Seed Germination And Reduce The Risk Of Restoration Failure: Laboratory Trials, Chelsea Elizabeth Keefer
Theses and Dissertations
Seed germination during unhospitable environmental conditions can be a major barrier to direct seeding efforts in dryland systems. In the sagebrush steppe, Artemisia tridentata Nutt. ssp. wyomingensis and Artemisia arbuscula are important shrub species that are being used in restoration, but seeding success is highly sporadic due to inter-annual and intra-seasonal weather variability. Altering and expanding the period of germination, as a form of bet-hedging, may improve plant establishment. Our objective was to determine if we could expand the period of germination using plant growth regulators (PGRs) applied in a conglomerated seed coating treatment. In a laboratory study, the seed …
Hydrologic And Biologic Responses Of Anthropogenically Altered Lentic Springs To Restoration In The Great Basin, Leah Nicole Knighton
Hydrologic And Biologic Responses Of Anthropogenically Altered Lentic Springs To Restoration In The Great Basin, Leah Nicole Knighton
Theses and Dissertations
Water is a limited and highly valued resource in the semi-arid Great Basin. Surface water sources are often small and widely spaced apart, comprising only 1-3% of the surface area of the overall landscape. Despite their small size, these springs and surrounding wet meadows have a substantial effect on the surrounding environment. Springs provide drinking water, forage and cover for livestock and wildlife, habitat for diversity of plant species and a resource for human-related activities. In recent years, many of these springs have become dewatered due to diversions of groundwater for municipal water and agriculture, and climatic shifts in precipitation …
Landsat Collections Reveal Long-Term Algal Bloom Hot Spots Of Utah Lake, Rachel Shanae Tate
Landsat Collections Reveal Long-Term Algal Bloom Hot Spots Of Utah Lake, Rachel Shanae Tate
Theses and Dissertations
Harmful algal blooms (HABs) and nuisance algal blooms (NABs) are a worldwide phenomenon with implications for human health and safety. HABs occur when algae or bacteria grow in high enough densities to harm animals and humans. A primary component of harmful algal blooms is cyanobacteria, which are aquatic, photosynthesizing microorganisms that produce toxins at high concentrations. Cyanobacterial biomass has increased worldwide in recent decades, raising concern about the future of fresh- and marine-water systems in a changing climate. Understanding the patterns and conditions of past algal blooms can provide useful insights for managing future blooms. Remote sensing can enhance our …
A Metagenomic Approach To Understand Stand Failure In Bromus Tectorum, Nathan Joseph Ricks
A Metagenomic Approach To Understand Stand Failure In Bromus Tectorum, Nathan Joseph Ricks
Theses and Dissertations
Bromus tectorum (cheatgrass) is an invasive annual grass that has colonized large portions of the Intermountain west. Cheatgrass stand failures have been observed throughout the invaded region, the cause of which may be related to the presence of several species of pathogenic fungi in the soil or surface litter. In this study, metagenomics was used to better understand and compare the fungal communities between sites that have and have not experienced stand failure. Samples were taken from the soil and surface litter in Winnemucca, Nevada and Skull Valley, Utah. Results show distinct fungal communities between Winnemucca and Skull Valley, as …
The Genome Of Cañahua: An Emerging Andean Super Grain, Hayley Jennifer Mangelson
The Genome Of Cañahua: An Emerging Andean Super Grain, Hayley Jennifer Mangelson
Theses and Dissertations
Chenopodium pallidicaule, known commonly as cañahua, is a semi-domesticated crop grown in high-altitude regions of the Andes. It is an A-genome diploid (2n = 2x = 18) relative of the allotetraploid (AABB) Chenopodium quinoa and shares many of its nutritional benefits. Both species contain a complete protein, a low glycemic index, and offer a wide variety of nutritionally important vitamins and minerals. Due to its minor crop status, few genomic resources for its improvement have been developed. Here we present a fully annotated, reference-quality assembly of cañahua. The reference assembly was developed using a combination of established techniques, including multiple …
The Effects Of Dixie Harrow Treatments On Greater Sage-Grouse Resource Selection And The Nutritional Value Of Sagebrush During Winter, Jason Alan Wood
The Effects Of Dixie Harrow Treatments On Greater Sage-Grouse Resource Selection And The Nutritional Value Of Sagebrush During Winter, Jason Alan Wood
Theses and Dissertations
Sagebrush (Artemisia spp.) is an important source of food and cover for many animals, especially during winter months. Understanding how wildlife species respond to sagebrush management actions can help improve conservation planning. Dixie harrow is a method of improving spring/summer habitat for many herbivores by reducing sagebrush cover to stimulate the growth of grasses and forbs. These treatments, however, may influence the quantity and quality of sagebrush available to greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) during winter. We evaluated the effects of Dixie harrow on sage-grouse resource selection during winter (Chapter 1) and on the nutritional value of sagebrush (Chapter …
Impacts Of Novel Fire And Herbivory Regimes On Snow-Waterresources And Resilience Of Aspen Forests, Jordan Daniel Maxwell
Impacts Of Novel Fire And Herbivory Regimes On Snow-Waterresources And Resilience Of Aspen Forests, Jordan Daniel Maxwell
Theses and Dissertations
Human activities and expansion have created novel disturbance patterns across Earth’s landscapes. Disturbance is an ecological interruption after which ecosystem recovery or transition into a new state can occur, affecting biodiversity, ecosystem functioning, and theavailability of ecosystem services. Fire and herbivory are two of the most widespread forces of disturbance which shape ecosystems globally. In temperate forest ecosystems, fire affects forest composition, which influences the diversity and resilience of ecosystems (chapters 1 and 2) and forest canopy structure, which is important to snowpack accumulation and the availability of water resources (chapters 3 and 4). In chapter one, the effects of …
Evaluating Nitrogen And Carbon Differences In Standing Litter From Normal And Prematurely Senesced Bromus Tectorum Plants, Alexa Lunt Jensen
Evaluating Nitrogen And Carbon Differences In Standing Litter From Normal And Prematurely Senesced Bromus Tectorum Plants, Alexa Lunt Jensen
Theses and Dissertations
Bromus tectorum, an invasive winter annual, has displaced native vegetation throughout the western United States. Bromus tectorum litter influences nutrient cycling near the soil surface as well as plant establishment. Failed seed production of B. tectorum occasionally occurs in the field, with plants exhibiting weak flowering culms that turn straw-colored in spring when normal plants are green or purple in color. Because annual grasses transport most soluble carbon (C) and nitrogen (N) to reproductive organs, seed production failure results in significantly different fates for these nutrients compared with normal plants. As part of larger efforts to understand events leading to …
Evaluating Fungal Pathogen Inoculum Loads In Field Seed Banks, Taryn Lori Williamson
Evaluating Fungal Pathogen Inoculum Loads In Field Seed Banks, Taryn Lori Williamson
Theses and Dissertations
Quantification of soilborne pathogen inoculum loads is important in both agricultural and wildland settings. Quantitative Polymerase Chain Reaction (qPCR) methods using SYBR Green chemistry have been shown to be useful for quantifying fungal inoculum loads in environmental samples. The purpose of this study was to develop a method to quantify fungal pathogen inoculum loads in soil seed banks using a qPCR method with SYBR Green chemistry. The invasive annual grass Bromus tectorum was chosen for this seed bank study. There were three objectives: 1) to design target-specific primers for three fungal pathogens known to be important in Bromus tectorum seed …
Facilitative And Competitive Tradeoffs Between Morella Cerifera Seedlings And Coastal Grasses, Michael N. Sinclair
Facilitative And Competitive Tradeoffs Between Morella Cerifera Seedlings And Coastal Grasses, Michael N. Sinclair
Theses and Dissertations
Morella cerifera is a rapidly expanding native shrub on the Virginia barrier islands which displaces other native coastal species and may interrupt normal sediment dynamics. Barrier islands are considered stressful environments with low nutrients, high solar load, and frequent drought and salt exposure; facilitation often dominates in stressful environments according to the Stress Gradient Hypothesis. The objective of this project was to understand the importance of species interactions with grasses on the growth and physiology of M. cerifera at the seedling life stage through both field and lab experiments. Grasses provided ~1.3°C insulation to shrubs during winter freeze events and …
Planting Density Effects On The Growth Of Dune Grasses., Audrey Kirschner
Planting Density Effects On The Growth Of Dune Grasses., Audrey Kirschner
Theses and Dissertations
Coastal dune vegetation plays a key role in dune formation and stabilization through sediment trapping and erosion control. To restore degraded dunes, revegetation of dune building species is critical. Planting density has been found to effect growth of marsh species, with closer plantings alleviating stress through facilitation. As coastal dunes are high stress environments, it is expected that dune species may also exhibit facilitative interactions based on the Stress Gradient Hypothesis. Therefore, planting grasses in clumped configurations may lead to more successful dune revegetation. The objective of this research was to determine how planting density affects the growth of two …