Plant Biology Commons^™

Discovering The Genetics Underlying Speciation Traits In Heuchera (Coral Bells), Tajinder Singh

Honors Theses

Hybridization is a key evolutionary mechanism for generating biological diversity, ultimately shaping diversification and adaptation of plant lineages in natural and agroecosystems.  Our understanding of the frequency, distribution, and significance of hybridization is rapidly increasing, but the external driving forces that dictate why certain species hybridize, and others do not remain obscure. The physical traits that shape gene flow and trait sharing among species are likely to be among the key factors that directly control hybridization. Gene flow in most plants is mediated by pollinating insects and thus by pollination syndromes, which are suites of floral traits that have evolved …

Pleistocene Glacial Effects On North American Phylogeographic Patterns, Noah Garland, Ingrid Jordon-Thaden

Scholars Week

The biodiversity of alpine ecosystems are grossly underestimated, in turn threatening habitat loss. Much work is needed in this respect to better understand the process of speciation and extinction in these environments, given the threat of global climate change. We are testing hypothesis regarding rapid radiation of plant lineages both into and out of refugia in the context of dispersal during post-glacial and inter-glacial periods, focusing on the phylogeny of trans-Beringian alpine plant species by observing circumpolar lineages extending into southern portions of the North American Cordillera, the Rocky Mountains and the Intermountain Region.  Focal taxa include species of Draba …

Testing The Intermediate Disturbance Hypothesis On Anthropogenic Pressure In Central Alabama, Gavin Terrell

Theses

Biodiversity is fundamental to maintaining ecosystem structure and function globally. Prior to the late 20th century, ecological theory generally predicted that biodiversity would be highest in systems experiencing minimal disturbance. However, Joseph H. Connell challenged this view with the Intermediate Disturbance Hypothesis (IDH), which posits that species diversity peaks at intermediate levels of disturbance and declines under conditions of both low and high disturbance. Although widely cited, the applicability of the IDH to natural systems remains debated, particularly in the context of anthropogenic disturbances and when diversity is measured beyond species richness alone.

This study evaluated the predictions of the …

Alabama Prairie Reconstruction: Comparing Management Pathways For A Southeastern Landscape, Cecelia R. Geyer

Theses

Southeastern prairies are highly biodiverse yet increasingly threatened by land-use change, fire suppression, and habitat fragmentation. These disturbance-dependent systems rely on periodic fire and grazing to maintain plant diversity and ecosystem function. This study evaluates prairie restoration strategies by testing predictions from the Intermediate Disturbance Hypothesis and the Patch Mosaic Burn Hypothesis. The study site was divided into three treatments: prescribed burned only (B), prescribed burned with mowing (BM) to simulate grazing, and an undisturbed control (C). A standardized mix of native plant seeds was broadcast across all treatments. Ecosystem health and function were evaluated using plant community diversity and …

Asimina Triloba (L.) Dunal: The Complete Story Of America’S Forgotten Fruit, Autumn M. Howard

The Cardinal Edge

Asimina triloba, commonly known as the pawpaw, is a unique and historically significant native fruit tree of the eastern United States. This research paper explores the taxonomy, botanical description, distribution, habitat requirements, ecological interactions, economic importance, and reproductive biology of A. triloba. The species is distinguished by its tropical-flavored fruits, adaptation to temperate climates, and reliance on clonal reproduction and specific insect pollinators. While offering promising opportunities for sustainable agriculture and riparian restoration, A. triloba faces challenges related to limited seed dispersal, susceptibility to certain pests and diseases, and the presence of neurotoxic compounds. Despite its historical importance …

Weather Conditions Associated With Citrus Canker Incidence Caused By Aw Strain In The Lower Rio Grande Valley Of South Texas, Amit Sharma, Teresa Patricia Feria-Arroyo, George Yanev, Madhurababu Kunta

School of Integrative Biological & Chemical Sciences Faculty Publications

Citrus canker, caused by bacterium Xanthomonas citri subsp. citri (Xcc), affects the citrus industry by making the fruit unmarketable due to unsightly lesions on the fruit. Citrus canker caused by a relatively new AWstrain of Xcc was reported on the citrus trees in the residential areas of the Lower Rio Grande Valley (LRGV) of South Texas. Xcc AW has a limited host range, predominantly affecting limes and a few other citrus species. Previous work has reported prevailing environmental conditions that influence the incidence and spread of the citrus canker caused by the Asiatic A strain. However, no information is available …

Investigating Microbe-Mediated Temperature Tolerance In Lemna Minor, Matthew Thomas Farbaniec

Honors Theses and Capstones

Temperature limits plant growth and survival more than many other environmental variables, and increases in the frequency of extreme hot or cold weather events pose significant challenges for plant growth and crop yields. Previous studies have shown that bacteria, fungi, and other microorganisms associated with plants ( i.e., the plant microbiome) can influence host response to temperature stress. These same microbes have their own temperature tolerances. We investigated whether microbial temperature tolerance correlates with plant resilience using an aquatic plant model, Lemna minor, and isolates derived from its microbiome. Microbial isolates were assessed at −10°C, 4°C, and 32°C for …

Analysis Of Alternative Oxidase In Non-Angiosperm Plants, Anissa M. Francis

Theses and Dissertations (Comprehensive)

Alternative oxidase (AOX) is a mitochondrial terminal oxidase that provides an alternative pathway for electron transport, allowing plants to maintain respiratory flexibility under environmental stress conditions. While AOX has been extensively studied in angiosperms (flowering plants), little is known about its distribution and conservation in non-angiosperms. Based on gaps identified in the literature, this thesis investigated the distribution of AOX across non-angiosperm plant lineages. Although AOX is present in many green algae and is therefore considered to be an ancient protein that originated before the existence of non-angiosperm plants, it remains unclear whether the protein is uniformly distributed across these …

A Novel 3d Imaging Approach To Study Evolutionary Innovations In Solanaceae Inflorescences, Devin L. Jackson, Joonseog Kim, Wenheng Zhang Dr.

Undergraduate Research Posters

Understanding the relatedness of angiosperms and the evolution of their inflorescence remains challenging, as these structures are highly modified and prone to convergent evolution. The current research describing inflorescence architecture, whether genetically or morphologically focused, typically relies on text based explanations, 2D images, or 3D based models created with CAD modeling software. This creates a disparity in the reader's understanding of these models since descriptions rely heavily on the author's interpretation of the inflorescence. The goal of our study is to bridge this disconnection by producing anatomically and color-correct 3D inflorescence models using Solanaceae flowers that readers can explore directly, …

From Theory To Ecosystems: Exploring Biodiversity And Ecosystem-Function In Pitcher Plant (Darlingtonia Californica) Microbial Communities, Gavin Sutter

Cal Poly Humboldt theses and projects

The relationship between biodiversity and ecosystem-function (BEF) has been a central focus of ecological research for the last three decades, yet the role of space in shaping BEF relationships remains relatively unknown. Research has shown that community diversity and composition can strongly influence productivity, nutrient cycling, and decomposition, but much of this work treats communities as spatially isolated, leaving open how dispersal and other spatial processes shape BEF at broader scales. To begin addressing this gap, I used microbial communities inhabiting Darlingtonia californica pitcher plant leaves to evaluate how spatial organization and successional change shape biodiversity and ecosystem-functioning. I quantified …

Sex In Plants: Birth, Death, And Trying To Survive In Changing Climates, Elena M. Meyer

Theses and Dissertations

Plant mating systems are key determinants of fitness. Angiosperms exhibit a wide variety of reproductive strategies, including self-fertilization (or selfing), outcrossing, and mixed mating. It has been estimated that up to 43% of plant species are capable of selfing, and selfing has been hypothesized to provide reproductive assurance where opportunities for mating may be limited, such as in marginal environments. However, questions regarding the overall distribution of selfing rates across angiosperms, the maintenance of mixed mating in the face of inbreeding depression, and the impact of self-fertilization on diversification rates remain incompletely resolved. Here, we explore the dynamics of self-fertilization …

Seagrass Persistence In The Indian River Lagoon And Lake Worth Lagoon, Florida, Kelly Kibler, Melinda Donnelly, Vincent Encomio, Madison Giuntoli, Manisha Thenuwara, Brice Bennett, Laura Andrade Barron, Mariam Sonbol, Wynter Raine Seppala, Namritha Ramakrishnan, Jennifer Jordan Báez, Beth Orlando, Irene Arpayoglou, Melissa Meisenburg

Indian River Lagoon Shorelines

The spatial dataset: UCF_seagrasspersistence_IRL_LWL.shp was created with support from the Indian River Lagoon National Estuaries Program and Florida Sea Grant. These projects cumulatively led to creation of a living shoreline restoration prioritization model and hydrodynamic habitat suitability models for 1,550 km (963 miles) of estuarine shorelines in Indian River Lagoon (IRL) and Lake Worth Lagoon (LWL). The dataset presented herein represents persistence of seagrass throughout waters of the IRL and LWL.

Living Shoreline Prioritization And Hydrodynamic Habitat Suitability Models For Restoration In The Indian River Lagoon And Lake Worth Lagoon, Florida, Kelly M. Kibler, Melinda J. Donnelly, Vincent Encomio, Madison Giuntoli, Manisha Thenuwara, Brice Bennett, Laura Andrade Barron, Mariam Sonbol, Wynter Raine Seppala, Namritha Ramakrishnan, Jennifer Jordan Báez, Beth Orlando, Irene Arpayoglou, Melissa Meisenburg

Indian River Lagoon Shorelines

The spatial dataset: UCF_shorelinemodel_IRL_LWL.shp, was created with support from the Indian River Lagoon National Estuaries Program and Florida Sea Grant. These projects cumulatively led to creation of a living shoreline restoration prioritization model and hydrodynamic habitat suitability models for 1,550 km (963 miles) of estuarine shorelines in Indian River Lagoon and Lake Worth Lagoon.

The dataset presented herein includes:

1. shoreline data from >15,000 transects collected in the field,
2. shoreline wave climate data created through hydrodynamic modeling and frequency analysis of historic data,
3. categorization of potential risk for shoreline boat wake impact,
4. persistence of seagrass within 210 m of the shoreline, …

The Effects Of Plastic Mulch And Irrigation On Hemp Chemistry And Leaf Endophytes, Allison Rietman, Connor Morozumi, Robert C. Pearce, Natalie Christian

Journal of Agricultural Hemp Research

As an emerging crop, cultivation techniques for industrial hemp (Cannabis sativa L.) are still being developed and optimized. For example, irrigation and plastic mulching are some management practices that have been touted for their benefits in improving crop quality. Both techniques ensure ample water availability, which has often been attributed to improving hemp cannabinoid and terpene composition. In this study, we examined how supplemental irrigation implemented in a plastic mulch system influenced the cannabinoid and terpene profiles of one cultivar of CBD hemp, Lifter. We grew industrial hemp in field with plastic mulch and applied regular irrigation to one group …

Optimizing Plant Nutrient Uptake: Cost Function Sensitivity Analysis Of The Fun Model, Gabriel Alpay, Joshua B. Fisher, Renato K. Braghiere, Edward R. Brzostek, Gabriella R. Dauber, Kara Allen, Rosemary A. Fisher

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

This study explores the cost functions of the Fixation & Uptake of Nutrients (FUN) model, which aims to optimize the amount of carbon used when plants acquire their necessary nutrients from the soil to maximize nitrogen (N) and phosphorus (P) uptake while minimizing the carbon cost. Specifically, we aimed to quantify the sensitivity of FUN outputs to the parameters belonging to the cost of nitrogen and phosphorus uptake functions by arbuscular mycorrhizal and ectomycorrhizal fungi. We present three dimensions of sensitivity analysis: (1) adjusting all parameters at the same time; (2) keeping one parameter constant while varying the other; and, …

Does Green Stem Photosynthesis Affect Plant Drought Tolerance And Recovery In Avocado?, Nadia A. Valverdi, Paula Guzmán-Delgado, Gregory R. Goldsmith, Eleinis Ávila-Lovera

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Woody plants with green stems may have advantages over non-green-stemmed plants in that extra photosynthetic carbon gain has the potential to improve plant drought tolerance and aid drought recovery. However, most studies relating to green stem photosynthesis and drought tolerance have been conducted on non-horticultural plants under natural growing conditions. We investigated whether avocado green stem photosynthesis enhances drought tolerance and recovery. We applied light exclusion and drought treatments to 3-year-old potted trees of cultivars ‘Hass’ and ‘Fuerte’. Measurements of soil moisture, midday stem water potential, stem photosynthesis, bark chlorophyll concentration, concentration of sugars + starch and stem hydraulic conductivity …

Plant Reproductive Strategies Shift In Response To Restoration Using Beaver Dam Analogs, Laurel F. Martinez

Biology ETDs

As riparian communities become increasingly degraded, restoration treatments are being implemented in streams to recover ecosystem functions. In the Jemez Mountains, beaver dam analogs (BDAs) are used to restore degraded streams by connecting the floodplain and increasing the extent of anoxic soil conditions. These environmental disturbances are expected to alter how riparian plants recruit, particularly their allocation to seed-based and vegetative regeneration strategies. We investigated whether BDAs and associated changes in soil water filled pore space (WFPS) affected riparian plant recruitment. We investigated the number of flowering stems as a proxy for seed-based regeneration and rhizome length and mass as …

Bridging Prairie Restoration And Regenerative Agriculture With Compost Tea, April Hersey

2025 Symposium

Inland Pacific Northwest prairie is an endangered ecosystem that has been reduced by conversion to agriculture. There is growing interest in the role of soil microorganisms in prairie ecosystems, which may be crucial for restoration of the plant community through interspecies interactions within the soil near plant roots. One method for improving soil microorganism community composition is compost tea: enriched liquid compost extract. Compost tea is used in regenerative agriculture to improve crop yields and protect against pathogens, ostensibly through the activity of the added compost microbes. While research has supported compost tea application in regenerative agriculture, it has not …

Advancing Mitochondrial Dna Visualization And Dynamics In Plants: Application Of The Mt-Hi-Ness Fluorescent Marker, Madeleine H. Faber

Honors Program: Senior Projects (Public)

Mitochondrial DNA (mtDNA) plays a crucial role in cellular energy production and inheritance, yet its dynamics and exchange remain poorly understood in plant systems due to limitations in visualization techniques. Traditional visualization methods such as exogenous DNA stains and fluorescent protein markers present challenges in specificity and live-cell imaging. To address this challenge, we adapted the MT-HI-NESS fluorescent marker, originally developed for mammalian cells, for use in plant mitochondrial studies. Using Arabidopsis thaliana as a model system, we employed mitochondrial targeting sequences (IVD and AOX) to ensure accurate localization and to confirm mtDNA binding specificity. The validation process included fluorescence-based …

Crispr-Induced Mutagenesis Of Arabidopsis Thaliana Gene Apetala3, Hazel Frans, Tara Phelps-Durr

SACAD: Scholarly Activities

This project aims to create CRISPR-CAS9 mutations in the APETELA3 (AP3) gene of the model plant Arabidopsis thaliana. AP3 is a class B gene critical to the petal and stamen development of Arabidopsis flowers. AP3 is defined in a MADS domain, which binds directly to DNA and may be responsible for the expression of the CaRG-box genes. AP3 works in conjunction with PISTILLATA (PI), AGAMOUS (AG), APETALA1 (AP1), and SEPALLATA (SEP) genes to specify the development in the second and third whorls of the flower. While several alleles of AP3 already exist, these alleles are strong alleles that knockout gene …

Variation In Response To Phosphorus Among Sweetpotato (Ipomoea Batatas L.) Cultivars, Jeffrey Cole Denis Gregorie

LSU Doctoral Dissertations

Phosphorus (P) is essential for plant growth and is often a major limiting nutrient in agriculture. In sweetpotato (Ipomoea batatas), studies on the role of P on storage root yield have been limited because of the lack of response and inconsistent results across cultivars and years. Growing evidence shows that current phosphate (Pi) fertilizer rates can be reduced while maintaining productivity. Newly published molecular evidence shows differential expression of phosphate starvation response genes among sweetpotato cultivars, further supporting the hypothesis of cultivar-specific Pi sensitivity. The research herein sought to characterize root system architecture and yield response to Pi …

Dataset Supporting "Functional Trait Responses Of Alternanthera Philoxeroides To Increasing Salinity: Stress Tolerance, Avoidance And Escape Strategies Support Invasiveness With Sea Level Rise, Brenda J. Grewell*, Blanca Gallego-Tévar, Jesús M. Castillo, Caryn J. Futrell, Rebecca E. Drenovsky, Nathan E. Harms, Paul D. Pratt

Alligator Weed Salinity Exp for NeoBiota

No abstract provided.

Spatial Analysis Of American Chestnut (Castanea Dentata) Distribution And Ecology In Kentucky’S Federal Lands, Jacob Raymond Pease

Murray State Theses and Dissertations

Anthropogenic factors have been the cause of the decline of tree species across the globe. From unsustainable logging and development to disease and improper management, threats to forests have taken their toll. The American chestnut (Castanea dentata) was once an integral basal tree species in Appalachian forests, but chestnut blight drove the species to functional extinction by the mid-1900s. The recent creation of genetically modified chestnuts gives hope for future restoration of the species throughout its historical range. Despite blight resistance, effective restoration will require optimal site selection for finding and planting chestnuts, which will maximize limited resources. …

Physiological Responses And Plant Trait Interactions With Coastal Dune And Swale Development, Emily C. Riffe

Theses and Dissertations

Vegetation is crucial to coastal ecosystems experiencing climate change and storm-induced disturbance. Plant species interact with the physical environment and are considered “ecosystem engineers.” Sand dunes and barrier islands are at the forefront of climate change impacts as they are barriers that protect landward habitat and communities. Nature based solutions are utilized to protect infrastructure on developed coastlines. Understanding how dominant plant species interact with and alter the physical environment enhances our understanding of the mechanisms of change and consequences to the system. The goal of this research was to quantify physiological and functional trait differences in dominant species found …

Characterizing The Targeting Of Toc159 Receptors To The Chloroplast Outer Envelope Membrane And Their Role In The Assembly Of Distinct Toc Complexes, Michael Fish

Theses and Dissertations (Comprehensive)

Global agriculture and food security face challenges from climate change, population growth, and other human-driven pressures. Enhancing our understanding of plant biology, particularly chloroplast function, is critical for improving crop yield and stress resilience. As the sites of photosynthesis and key regulators of plant responses to environmental cues, chloroplasts depend on the precise import of thousands of nuclear-encoded proteins to maintain their biogenesis and function. While much is known about the core translocon components in the chloroplast outer envelope membrane that form the TOC complex, the mechanisms underlying their targeting, assembly, and regulation remain incompletely understood.

Plastids, including chloroplasts, evolved …

Npr1 As A Temperature-Sensitive Regulator Of Pipecolic Acid-Mediated Plant Systemic Immunity, Spencer Tout

Theses and Dissertations (Comprehensive)

Healthy plant development requires balancing both abiotic (e.g. climate) and biotic (e.g. pathogen) challenges, which intercept important signaling pathways in plants. For example, climate change-associated elevated temperature can negatively modulate various aspects of plant immunity, including the production of central immune signals salicylic acid (SA) and N-hydroxypipecolic acid (NHP). Since SA and NHP signaling both require the master immune co-activator protein NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), it is important to investigate NPR1 as a potentially temperature-regulated molecular hub. Although the NPR1 gene is not transcriptionally downregulated at elevated temperatures (28° C vs. 23° C), little is known about …

Restoration Of Giant River Cane (Arundinaria Gigantea) In Southwest Missouri, Lyndsey D. Rightnowar

Graduate Theses/Dissertations

Giant river cane (Arundinaria gigantea), a native bamboo species, once dominated riparian landscapes across the southeastern United States but has declined to approximately 2% of its historic range. This study evaluated restoration techniques for giant cane in southwest Missouri by examining the influence of rhizome source (putative genotype), planting type, and restoration site on restoration success. I compared two planting types: greenhouse-to-field (G2F) transplanting, where rhizomes were first propagated in the greenhouse before planting, and field-to-field (F2F) transplanting, where rhizomes were directly transplanted from source canebrakes to restoration sites. Rhizomes were collected from four existing canebrakes in Taney …

“Nice To See You”: Addressing Plant Awareness Disparity With Locally Specific Ecological And Cultural Plant Education, Cecilia Muecke

Pomona Senior Theses

Plants form the basis of life on Earth. However, due to the phenomenon of plant awareness disparity, a self-perpetuating cycle whereby plants are overlooked on an individual and global level ensues. Lack of plant awareness leads to a lessened emphasis on plants in sustainability and conservation as well as biology education, resulting in negative impacts on biodiversity and food security. The severity of plant awareness disparity is dependent on cultural context, and Indigenous and/or traditional societies are less likely to experience plant awareness disparity because of they are typically more connected to plants for their everyday needs. Native plants are …

Frozen Green Leaves As Potential Nutrient Subsidies In North American Mangrove Ecosystems, Katelyn Overstreet, Emily M. Dangremond, Ilka C. Feller

Biological Sciences Faculty Publications

Avicennia germinans, the black mangrove, has shifted its range limit northward, and increased in abundance in the Southeastern United States. In January 2018, a 3-day freeze event caused substantial defoliation of green leaves in A. germinans near its northernmost range limit in St. Augustine, FL. During their recovery, plants that lost their leaves grew similarly to plants fertilized with nitrogen, leading to the hypothesis that freeze-killed green leaves (frozen green) may have acted as a fertilizer. To assess the value of frozen green litter as a nutrient subsidy, we performed an experiment in which A. germinans seedlings were grown …

Responses Of Native And Invasive Aquatic Vegetation To Changes In Water Depth In An Ozark Spring-Fed Pond, Daphne Miles

Graduate Theses/Dissertations

Spring-fed aquatic ecosystems in the Ozark Highlands are characterized by stable water depths, clear water, and diverse aquatic vegetation (filamentous algae, submerged, floating, and emergent plants). Sudden changes in water depth can impact aquatic vegetation dynamics but the impacts of prolonged changes are poorly understood. I investigated seasonal and annual changes to aquatic vegetation abundance in a spring impoundment during and after a two-year period of low water depth that was caused by a broken outlet below an artificial dam. Water depth was significantly lower in 2020 and 2021 (low water years), compared to 2022 and 2023 (high water years). …