Biology Commons^™

Clonal Plants' Traits And Responses Following Fire Disturbance In Ponderosa Pine Ecosystems In The Colorado Front Range, Raymond Erskine

Master's Theses

Mountain ecosystems are currently experiencing increasing impacts of disturbances (e.g., wildfire) due to global changes in climate and land use, leading to significant changes in vegetation composition and landscape dynamics. Clonal plants, characterized by their vegetative reproduction strategies, offer a range of ecologically important traits to cope with disturbances. However, clonality is often excluded in studies of post-fire vegetation dynamics in mountain ecosystems, and our knowledge of the ability of clonal plants to respond to differing disturbance regimes is limited. Therefore, I examined the response of understory vegetation following fire disturbance in burned and unburned ponderosa pine stands of the …

Clonal Growth And Trait Variation In The Colorado Front Range: The Influence Of Elevation And Ecosystem, Jordan Conley

Master's Theses

Amid global climate change, exploring adaptive strategies among alpine flora, particularly through clonal growth, becomes critical for biodiversity conservation. This study aims to explore the patterns of dominance and distributions among clonal species across environmental gradients in the Colorado Front Range, employing a trait-based comparative analysis to understand the adaptive strategies of alpine flora and their implications for conservation amid rapid climate change. We focused on two species, studying traits like lateral spread, bud count, and bulbil numbers. Advanced statistical methods such as Permutational Multivariate Analysis of Variance (PerMANOVA) and Multi-Response Permutation Procedures (MRPP) were used to evaluate community compositions …

Ammonium Chemotaxis In Chlamydomonas Reinhardtii, Gabela Nelson

LSU Doctoral Dissertations

Analysis of ammonium chemotaxis in Chlamydomonas reinhardtii is largely hindered, compared to that of phototaxis, despite equal importance on flagellated microalgal physiology. A major contribution of this shortfall is the lack of proper assay method. We developed a simple Petri dish assay method in which light is homogenously exposed while patterns of the cellular migration are tracked with a function of time. Using the method, new findings were revealed. First, this research presented that a strain lacking the eyespot organelle required for light gradient-sensing exhibits similar chemotactic behavior compared to a wild-type strain, suggesting Chlamydomonas sense an ammonium gradient not …

Examination Of Greenhouse Conditions That Influence Scale Infestation Rates On Begonia, Madeline M. Cusick

Honors College Theses

Scale insects are common pests within greenhouse and agricultural settings. I quantified scale infestation on Begonia x Richmondensis, also known as the Dragon Wing begonia, within the Armstrong Campus Greenhouse from March to November of 2023. Six different treatments accounted for variations in sunlight, humidity, and temperature within the greenhouse with the goal of determining the insect’s preferred environmental conditions. Morphological comparisons were also made between host plant Dragon Wing begonia and other begonias present within the greenhouse. Analysis indicated a significant difference in scale presence on replicate plants by zone and sunlight treatments, with more plants hosting at least …

Assessing Endophyte Frequency Distributions And The Effect Of Epichloë Brachyelytri In The Chemotypic And Genotypic Diversity Of Brachyelytrum Erectum, Rachel Ann Sneed

Theses and Dissertations--Plant Pathology

Seed-transmissible epichloid fungal endophytes are best known for their roles as defensive mutualists in cool-season grasses. Historically, the discovery of fungal endophytes was driven by investigations of plant toxicity to livestock, followed by extensive study of their alkaloids and protection against insects and nematodes. Epichloae can produce four classes of alkaloids: ergot alkaloids, lolines (saturated aminopyrrolizidines), indole–diterpenes, and peramine. It is increasingly evident that these hereditary symbionts have much more diverse chemical profiles both in individual populations and between them. To this end, differences in chemotypic profiles of these symbionts may translate to different evolutionary and environmental advantages across plant …

Environmental Biology Masters Capstone, Antonio Gonzalez-Pita

Regis University Student Publications (comprehensive collection)

Human wildlife interactions (HWI) pose a complex challenge for wildlife managers. Human encroachment into wildlife habitat and the growing number of outdoor recreationists are increasing the frequency of contact and conflict, especially in regions such as the Front Range of Colorado. Geographic information systems (GIS), which use a combination of remote sensing and environmental survey data, allow for predictive spatial analyses of where human wildlife interactions are likely to occur. I used publicly reported observations of moose to create spatial predictive maps in a species distribution model framework. Slope and elevation were shown to be the strongest predictors of HWI, …

Ms Environmental Biology Capstone Project, Sarah Luper

Regis University Student Publications (comprehensive collection)

Recreational trails and the presence of invasive species such as Bromus inermis can both disturb grassland community composition. Trails can act as dispersal corridors for plant material, but can also be a source of trampling and compaction. Invasive grasses like Bromus inermis can easily establish in grasslands and decrease species richness by increasing competition. Understanding these effects, this study aims to understand how both the presence of recreational trails as well as the presence of Bromus inermis affect species richness and overall community composition at Two Ponds National Wildlife Refuge. Belt transect sampling took place in fall 2019 and again …

Quantifying The Ecological Effects Of Salix Fragilis On Riparian Habitat In Kittitas County, Washington, Landon Shaffer

All Master's Theses

Invasive species threaten plant community structure and function globally. Riparian areas, the zone near streams where water influences vegetation, are especially sensitive to invasive species colonization, suffering large-scale shifts in community composition. Salix fragilis (crack willow) is a nonnative riparian species abundant in the lower elevation tributaries of central Washington. Some speculate whether this willow should be listed as invasive in Washington, despite a lack of regional supporting evidence. I studied riparian communities dominated by either S. fragilis or native species in the Kittitas Valley and measured biodiversity, quantified differences in solar attenuation, and compared leaf decomposition rates to learn …

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 …

Evidence Of Competitive Release Following Overstory Mortality In A Semi-Arid Piñon-Juniper Woodland, Corrie D. Gonzalez

Biology ETDs

Extreme temperatures and severe drought events have led to widespread tree mortality worldwide. In semi-arid regions of the Southwest United States, these events pose a significant threat to piñon-juniper (PJ) woodlands. We studied the effects of piñon and juniper mortality on the growth and physiology of existing saplings in PJ woodlands by analyzing water status, photosynthetic activity, and tissue chemistry to gain insights into these impacts. Juniper saplings exhibited improved water status and water use efficiency in response to overstory mortality, whereas piñon saplings did not. Additionally, both piñon and juniper saplings exhibited increased photosynthetic rates, increased photosynthetic capacity, and …

Reintroducing Hemp (Rongony) In The Material Palette Of Madagascar: A Study On The Potential Of Hemp Clay Components And Its Impact On Social And Ecological Communities., Henintsoa Thierry Andrianambinina

Masters Theses

When mentioning the word hemp, especially in the local language of Madagascar, the literal translation does not set it apart from marijuana, as they are both called “rongony” - creating the stigma around hemp as the negative stereotype of marijuana. However, the material has been used by the ancestors of Madagascar, as well as across cultures, in its fibrous form to produce fabrication like textile goods and packaging. During colonization, the prohibition of hemp intensified, and since then, any activity related to either of these plants is prohibited and will end in severe punitive measures. This thesis explores the strengths …

The Bellarmine Bee Bed: Organizing A Native Plant Garden Using Feedback From The Local Community, Kate Moran

Undergraduate Theses

Animal pollinators are the cornerstone of healthy ecosystems. Their survival is essential for the persistence of entire food chains: from the flowers they cross-pollinate directly, to the animals who depend on those plants for nutrition. The establishment of pollinator gardens—particularly ones that consist of native plants—is an effective way to enhance their biodiversity, abundance, and well-being.

The main goal of this thesis is to construct a pollinator garden that maximizes the benefits for animal pollinators using feedback from local gardeners. A survey was used to gather information about the popularity and preferences of 40 flowering plants, and after analyzing the …

Effects Of Heavy Metal Uptake On Growth, Chlorophyll Content, And Calcium Oxalate Crystals In Lemna Minor (Duckweed), Olivia F. Miller

Undergraduate Honors Thesis Projects

Lemna minor L., duckweed, is a common aquatic plant used for the phytoremediation of wastewater. Heavy metal contamination poses a significant issue, and numerous studies have been conducted on the efficiency of L. minor’s hyperaccumulation ability of these metals. Calcium oxalate crystals are an important aspect of the growth and development of L. minor, but how they are influenced by the uptake of heavy metal has not been extensively studied. This study aims to determine the effects that lead, cadmium, and copper have on the formation of calcium oxalate crystals, vegetative growth, and chlorophyll a and b content on L. …

Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Terrestrial plant communities are shaped by competition for resources, herbivory, and abiotic processes. Savanna systems represent a dynamic coexistence of contrasting life forms (grasses and trees) shaped by competition and disturbance. The Kentucky Inner Bluegrass Savanna-Woodland (KIBSW) is described as an open woodland of shade intolerant species; however, climatic, and edaphic conditions can support closed-canopy forest. After European pioneer settlement (c1750-1800), over 99% of “savanna-woodlands” have been lost. KIBSW remnants are experiencing a recruitment failure, leading to a dominance shift in tree communities. I researched how tree-grass competition and mammalian herbivory influence KIBSW regeneration and maintenance. The KIBSW does not …

Investigation Of The Function Of Protein Acyl Transferases Using Crispr-Cas9 To Create Null Mutants, Claire E. Christopher

Honors Theses and Capstones

24 Protein Acyl Transferases (PATs) have been identified in the model organism Arabidopsis thaliana. Despite knowing the enzymatic function of these genes (palmitoylation), the specific subcellular pathways, protein targets, and cellular activities of these proteins remain unknown. To investigate the pathways that PAT genes are involved in, deletion mutations were created in several genes and the phenotype of the organisms carrying homozygous mutations was observed. To introduce mutations, the CRISPR/Cas9 system was inserted into the plant’s genome using Agrobacterium tumefaciens to cause deletions in PAT genes of interest. To date, no CRISPR-induced pat mutants have a noticeable phenotype. These …

Propagation, Physiology And Biomass Of Giant Cane (Arundinaria Gigantea) For Conservation And Restoration, Sanjeev Sharm

MSU Graduate Theses

Giant cane (Arundinaria gigantea) is a native species to 22 states in the U.S. The species and its ecosystem are considered critically endangered, and the species has been reduced to 2% of its original extent. The species has a long cultural and conservation history. Large canebrakes were commonly found in Missouri in bottomland forests, stream and riverbanks, and margins of lakes. My research goals were to: 1) examine methods for propagation success from field to greenhouse to field; 2) examine the physiology of cane at one of the few current canebrakes, for greenhouse propagated plants, and field planted …

Investigating Plant Physiological Responses To Global Phylogenetic Diversity Of Glomeromycotina, David Z. Mowbray

Honors Undergraduate Theses

Arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of terrestrial plant species with associations predominantly characterized as mutualistic. In addition to well-documented enhancement of host growth response, more recent analyses have demonstrated the conferral of host benefits under numerous biotic and abiotic stressors. However, much of the established evidence originates from studies involving limited AM fungal diversity. Accordingly, this study sought to evaluate the potential effects of inoculation on plant host physiological traits within a growth chamber environment, investigate potential correlations between host trait responses, & assess the degree of phylogenetic signal observed in trait responses due to the presence of …

Winter Dynamics Of Storm Water Management Ponds And Winter Tolerance In Three Aquatic Plant Species, Patrick Strzalkowski

Theses and Dissertations (Comprehensive)

The vast majority of the research into the performance of stormwater management ponds (SWMPs) has been performed in warm regions or during the warmer seasons in temperate regions. It is presumed that SWMPs are inactive in the winter as any potential stormwater is trapped in snow and ice. The main goal of this thesis was to test this presumption and to study the dynamics and performance of three SWMPs during the winter. Remote water level loggers were installed into the three SWMPs and daily grab samples from the influents and effluents were taken and analyzed for total phosphorus (TP), chloride, …

Genetic Characterization Of Centromere-Mediated Uniparental Genome Elimination In Arabidopsis, Diana Spencer

Electronic Theses and Dissertations

The production of haploids through crossing was first discovered from instances of interspecies crosses in Nicotiana spp. in 1924. Since then, haploid induction crosses has been used to improve plant breeding programs and commercially utilized in a number of crop industries. The generation of doubled haploid instantaneously creates a pure homozygous line, therefore eliminating the need for several generations of inbreeding. There are several pathways to induce haploids in plants: of these methods, centromere-mediated genome elimination pathway engenders the highest haploid induction rate (HIR) with up to 45% in Arabidopsis compared to 15% through phospholipase-mediated haploid induction in maize. Centromere-mediated …

The Emerging Value Of The Viroid Model In Understanding Plant Responses To Foreign Rnas, Junfei Ma

Theses and Dissertations

RNAs play essential roles in various biological processes. Mounting evidence has demonstrated that RNA subcellular localization and intercellular trafficking govern their functions in coordinating plant growth at the organismal level. Beyond that, plants constantly encounter foreign RNAs (i.e., RNAs from pathogens including viruses and viroids). The subcellular localizations of RNAs are crucial for their function. While numerous types of RNAs (i.e., mRNAs, small RNAs, rRNAs, tRNAs, and long noncoding RNAs) have been found to traffic in a non-cell-autonomous fashion within plants, the underlying regulatory mechanism remains unclear. Viroids are single-stranded circular noncoding RNAs, which entirely rely …

Spatiotemporal Transcriptome Diversity And Responses To Salinity Tolerance In The Extremophyte Schrenkiella Parvula, Chathura Wijesinghege

LSU Doctoral Dissertations

Schrenkiella parvula is an extremophyte model related to the most widely studied plant model, Arabidopsis thaliana and Brassica crops in the mustard family (Brassicaceae). It can thrive in highly saline environments where the soil is enriched in Na⁺, K⁺, Li⁺, borates, and chlorides. Understanding how this extremophyte can survive high salinity with genomic adaptations can provide insight into developing stress resilient crops in the future. Gene expression of S. parvula in response to salt has been investigated using shoot and root tissue from mature vegetative-phase plants. However, prior studies have not examined the transcript …

Influence Of Plant Density On Rainfall Interception By Spartina Alterniflora, Hannah K. Longaberger

Honors College Theses

Abstract

Spartina alterniflora is an abundant plant in eastern US and Gulf coast salt marshes; it is important in maintaining a diverse ecosystem. Salt marshes are impacted by rainstorms, which may affect erosion events. This project examined the partitioning of rainfall on single plants of various sizes and on central plants within different canopy densities of S. alterniflora. By calculating the rain stemflow (SF), throughfall (TF), and water adhered to the stem in S. alterniflora, we gained insight to rainfall partitioning with different plant features. My research found no statistically significant relationship between different plant features and SF, TF, …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

University of New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Sodium Mediates Developmentally Plastic Responses In Plants And Herbivores, Luis Santiago-Rosario

LSU Doctoral Dissertations

Sodium plays a crucial role in organismal performance, trophic-level interactions, and eco-evolutionary dynamics. For plants, sodium impacts osmoregulation, growth, and water uptake. For animals, sodium is essential influencing osmoregulatory processes, muscle and neural development, and blood regulation. My dissertation aims to disentangle why sodium mismatch affects resource-consumer interactions and its influence on morphological and behavioral plasticity. First, I identified how sodium impacts plant performance and sodium accumulation strategies. I initially focused my research on understanding how increasing substrate sodium affects plant growth and tissue sodium accumulation strategies in controlled settings using a systematic review approach. I found that saltier plants …

Procedures For Genetic Modification Of Miscanthus X Giganteus, A Biomass Crop, Anjali Arpan

Theses and Dissertations

Development of genetic improvement procedures for the bioenergy crop, Miscanthus × giganteus (M×g; triploid), are desired for trait improvement. Agrobacterium tumefaciens has been used in other Miscanthus spp. for genetic improvement, but not in M×g, nor have more than a few genes been introduced at a given time. Transformation procedures for M×g were developed; studies included use of A.tumefaciens (strain LBA4404) and A. rhizogenes (strain A4) for introduction of seven genes isolated (by other researchers) from Sorghum bicolor involved in sorgoleone biosynthesis (an allelopathic compound), and selectable marker gene neomycin phosphotransferase II. Procedural development included generation of …

The Potential Role Of Phenotypic Plasticity In The Ability Of Hydrocotyle Bonariensis To Occupy Two Different Habitats, Harold Ralph Parsons Iii

Honors College Theses

Phenotypic plasticity is the ability of an organism to change morphology and/or physiology in response to changes in the environment. Hydrocotyle bonariensis is a coastal perennial herb found in both coastal sand dunes and inland coastal plain habitats in Georgia. The purpose of this study was to determine if there were differences in leaf morphology for populations of H. bonariensis in coastal sand dune and inland coastal plain habitats. Leaf morphology and microenvironmental variables were compared between H. bonariensis populations at Tybee Island (TI), GA, representing the coastal sand dune habitat, and Georgia Southern University Armstrong Campus (GSU) in Savannah, …

Climate Change And Conservation Of Milkweed: Evidence Of Extensive Admixture Between Common Milkweed And Poke Milkweed, Elizabeth Davies

Undergraduate Honors Theses

Global climate change can drive many changes in species interactions. One primary way it affects species is by changing climates, causing species to expand their ranges and allowing them to interact with species from whom they were previously isolated. In plants, new species interactions can result in hybridization – the creation of hybrid offspring between two separate species. This hybridization can increase gene flow between the species and lead to introgression, the transfer of genetic material from one species to another through hybrid backcrossing with the parent species. My thesis investigates hybridization in the model system Asclepias (milkweed) by analyzing …

Investigating The Effect Of Longhorned Milkweed Beetle Larval Root Feeding On Resprouting In Common Milkweed, Margaret Donnan

Undergraduate Honors Theses

Clonal reproduction is an important form of reproduction for many plants, and plants can grow clonally through a variety of methods, such as belowground stems, specialized organs, or adventitious buds on their roots (Herben and Klimešová 2020). In plants that reproduce via buds on their roots, researchers have shown that damage to roots can stimulate bud production and sprouting (Bartušková and Klimešová 2010). Common milkweed (Asclepias syriaca) is a root- sprouting perennial plant that receives yearly damage to its roots via the feeding of the larvae of the specialist longhorned milkweed beetle (Tetraopes tetrophthalmus) (Erwin et al. 2013). In this …

A Comparison Of Natural, Living, And Hardened Shorelines Ability To Prevent Coastal Erosion And Maintain A Healthy Ecosystem, Gabrielle Spellmann

Master's Theses

It is important to find a suitable method to protect the U.S. Gulf Coast shoreline, since its’ low elevation and the Loop current make it vulnerable to sea level rise. I focused on two manmade methods, hardened, and living shorelines, of coastal protection for when the natural marsh suffers excess erosion rates. Living shorelines are a suite of shoreline conservation and restoration techniques that usually involve some sort of hardened structure that dampens wave energy so that the native vegetation behind it can take root and stabilize the shoreline. This study looked at six different sites, all containing a natural, …

Screening For Binding Partners And Protein-Protein Interactions Of A Fungal Transcription Factor- Xdr1, Nishadi Punsara Gallala Gamage

Masters Theses

Clarireedia spp. (formerly Sclerotinia homoeocarpaF.T. Bennett) is the causal agent dollar spot, the most economically important turfgrass disease impacting golf courses in North America. The most effective strategy for dollar spot control is repeated application of multiple classes of fungicides. However, reliance on chemical application has led to resistance to four classes of fungicides as well as multidrug resistance (MDR). Fungi are known to detoxify xenobiotics, like fungicides, through transcriptional regulation of three detoxification phases: modification, conjugation and secretion. Little is known, however, of the protein-protein interactions that facilitate these pathways. Following next-generation RNA sequencing of Clarireedia spp., a …