Botany Commons^™

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 …

Characterizing The Germination Process And Establishing Best Practices For Seed Propagation Of Tamaulipan Thornscrub Species For Habitat Restoration, Saroj Dhakal

Theses and Dissertations

Tamaulipan thornscrub is an imperiled plant community of southern Texas and northeastern Mexico. Given its importance for biodiversity conservation, stakeholders have been involved in restoration programs using seedlings grown from wild seeds. However, stakeholders often report that insufficient seedling supply is a challenge. To address knowledge gaps in seed germination behavior limiting seedling production, this study was conducted on 18 Tamaulipan thornscrub species, identified by growers as difficult to germinate. Seeds of all studied species are orthodox except Amyris texana, which have recalcitrant properties. Nine species have physical dormancy that was successfully addressed with mechanical and/or chemical scarification. Other species …

Patterns Of Fire History And Vegetation Changes In The Last 5000 Years: A Paleoecological Study Of Iquitos, Annabel Zwarts

Theses and Dissertations

The vegetation of the Amazonian rainforest is hypothesized to have been shaped by pre-Columbian activities, such as burning and palm management to various extents. Management of palms is hypothesized to have caused some of the most useful species to become hyperdominant in Amazonia. This study investigated the extent to which human activities over the past 5000 years affected palm abundances in mature lowland rainforests near Iquitos, Peru. I used phytoliths and charcoal from soil cores to determine the history of local floras, and modern palm surveys to compare modern phytolith occurrence with modern vegetation. Because pre-Columbian activity clustered along the …

Applicability Of Using Bio-Receptive Concrete For Building Facades In Egypt, Gina Roupheil

Theses and Dissertations

The significant increase in carbon dioxide emissions caused by the construction industry is detrimental to our planet. This is rapidly increasing with the urbanization of cities that is gradually taking its toll on the available green spaces, which help in balancing such emissions. Recently, researchers have been trying to make use of bio-receptivity to create biomaterial systems that could be spread on building envelopes and support the growth of small plant species and microorganisms to establish on. Out of those materials, comes the concrete as a promising material for bio-colonization.

Within this context, this study aims at investigating the applicability …

Facilitative And Competitive Interactions Among Dune Grass Species In Monoculture And Polyculture Communities, Anne M. Sciolino

Theses and Dissertations

Coastal dunes are natural barriers between land and sea and are imperative to the protection and preservation of inland ecosystems and human infrastructure. However, due to global warming, seal level rise, and coastal development, coastal dunes are under constant threat of destruction. Restoration efforts have been implemented to rebuild the protective function of dunes through the planting of dune building grasses. Dune grasses build and maintain these vital sand dunes. However, little is known about facilitative and competitive relationships among the grasses. In order to maximize restoration efforts, research is needed to better understand the biotic interactions among restorative grass …

Investigating The Role Of Plant Traits And Interactions In Emergent Wetland Nutrient Removal, Andrew Ryan Sample

Theses and Dissertations

Increasing wetland restoration in the Lower Mississippi Alluvial Valley has been identified as a method to reduce nutrient loading in the Gulf of Mexico. Wetlands have historically been used to treat water through processes facilitated by wetland plants, and relatively few species and plant traits have been identified as important in carrying out these processes. This study focuses on some of those species and traits and aims to identify species differences and plant traits that may be important for wetland nutrient mitigation. Chapter I provides background information on nutrient pollution, wetland biogeochemical mechanisms for nutrient sequestration, and the focal species …

Csi Botany: Dna Barcode “Fingerprints” Identify Cryptic Urban Flora, Luis R. Vega

Theses and Dissertations

As short genomic markers, DNA barcodes can play a role in conservation by identifying cryptic species and hybrids when morphological approaches fall short. Here we present our application of barcodes to the identities of two wetland taxa as part of an ongoing floristic inventory of Van Cortlandt Park (VCP), Bronx, NY. Previous barcode data by Marriott et al. (2018) identified the VCP lake water lily as the exotic Nymphaea alba, rather than the native N. odorata as historically described. In addition, cattails in the park were historically identified as the native Typha latifolia and the exotic T. angustifolia …

Taxonomic And Phylogenetic Diversity Of Pitcher Plant Bogs In Georgia's Coastal Plain, Melanie Flood

Theses and Dissertations

Diversity studies via floristic survey and taxonomic metrics have proven essential for discerning community composition and biodiversity, however, phylogenetic analyses are necessary to reveal underlying evolutionary change and potential community assembly patterns. Pitcher plant bogs are highly diverse, highly understudied habitats that contain numerous listed and at-risk plant and animal species of Georgia.

In this study I investigated the taxonomic and phylogenetic diversity of pitcher plant bogs by asking the following questions:

1) What is the taxonomic diversity of pitcher plant bogs,

2) What is the dispersion of phylogenetic diversity within bog habitats, and

3) Does taxonomic and phylogenetic diversity …

Quantifying Contributions Of Climate, Geography, And Gene Flow To Divergence: A Case Study For Three North American Pines, Constance E. Bolte

Theses and Dissertations

Long-lived species of trees, especially conifers, often display weak patterns of reproductive isolation, but clear patterns of local adaptation and phenotypic divergence. Discovering the evolutionary history of these patterns is paramount to a generalized understanding of speciation and the processes that confer population persistence versus those that compromise adaptive potential under rapidly changing environments. Forest trees have long generation times and low migratory potential making them especially vulnerable to population fragmentation and reductions of genetic diversity due to insufficient tracking of niche optima and adaptational lags. Within clades of the genus Pinus, evolutionary histories appear to be riddled with hybridization …

It Takes A Muscle: Wholes, Holes, And Other Voids, Saar Shemesh

Theses and Dissertations

IT TAKES A MUSCLE¹

In the BELLY of the BEAST, the HUMAN

in the deep end of a SWIMMING POOL

in a GRAVE, looking up/out from within

at the base of a CRATER, ABYSS, PIT

the room as a CRADLE, INCUBATOR

architecture as MOTHER MOULD.²

____________________________

¹ Title is borrowed and abbreviated: Spectral Display, “It Takes A Muscle To Fall In Love,” 1982.

² For what American-English delineates as ‘mold,’ British-English uses ‘mould’ and is more specific in its technicality. The former doesn’t distinguish in spelling between mold (fungus) and mold (mould). I’m not particularly a fan of …

Algal Biodiversity Survey Of The Middle Chattahoochee River Using Dna Metabarcoding, Amanda Howell

Theses and Dissertations

Aquatic plants play vital roles in water systems by providing ecological services, and one group that is understudied is algae. Algae play a crucial role in water systems as bioindicators and primary producers. They can be challenging to identify with the naked eye, so researchers have been using DNA metabarcoding, where DNA belonging to specific taxa can be isolated and identified from water samples. The objective of this study was to conduct an algal biodiversity survey on the middle Chattahoochee River system in Georgia. Water samples (1L) were filtered and sent to RTL Genomics for sequencing and processing; the data …

Exploring Interactions Of Phyllosphere Epiphytes With Plant Pathogenic Bacteria Pseudomonas And Xanthomonas On Tomato, Ashley D. Turner

Theses and Dissertations

Recent studies have indicated the importance of resident microflora of plants in contributing towards overall plant health. Among difference components of the plant microbiome, Methylobacterium and Sphingomonas have been recognized as common residents of the phyllosphere for many host plants, however their role in disease control needs to be further investigated. The purpose of this study was to conduct experiments investigating the effectiveness of phyllosphere Methylobacterium and Sphingomonas isolated from red clover against common tomato phyllosphere bacterial pathogens, Pseudomonas syringae pv. tomato and Xanthomonas perforans. Additionally, this study uses X. perforans wild-type and X. perforans type VI secretion system …

The Origin And Evolution Of Flower Characters In Angiosperms With A Case Study On The Genetic Basis Of Zygomorphic Corolla Development In Bee And Hummingbird Pollinated Species Of Schizanthus (Solanaceae), Ghadeer Bukhari

Theses and Dissertations

This Ph.D. dissertation investigates two main projects separated into two chapters, one for each. The first chapter explores the evolution of flowering plants (angiosperms), a macro-scale study. The second project is on a micro-scale that focus on exploring the genes that regulate the similarities and the differences of flower morphology reflecting their different pollination syndromes in two species of Schizanthus (Solanaceae), i.e., S. pinnatus, a bee-pollinated flower, and S. grahamii, a hummingbird- pollinated flower.

In the first chapter, I used floral diagrams to study the origin and the evolution of floral traits in angiosperms, a new set of morphological data …

Plant-Pollinator Associations In An Eastern Serpentine Savannah And The Effects Of Overbrowsing, Allyson Richins

Theses and Dissertations

Chapter 1: Native plant response to deer overbrowsing in a serpentine savannah

Plants are particularly vulnerable to physical disturbance in low productivity areas, due to a high cost of replacing lost plant tissue. In the eastern United States, serpentine grasslands are fragmented ecosystems with high concentrations of rare endemic plant species, low concentrations of soil nutrients, and uncontrolled deer overpopulation. This study assessed functional responses of native angiosperms in a rare eastern serpentine savannah to selective deer browsing. Plant count, flower count, floral area, vegetative area, and plant height of 10 serpentine plant species were compared inside and outside of …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

An Evaluation Of The Medicinal Plants Of Andros Island, Bahamas, Vivian Pedrozo

Theses and Dissertations

The earliest civilizations have been using plants as their foundation for healing and medicinal traditions for thousands of years. The use of plant medicinals, more commonly known as “bush medicine” on Andros Island, has been rapidly decreasing due an increased presence of western medicine and increased population pressures from urbanization that are threatening local biodiversity hotspots. Ethnobotany is not only important from a conservation standpoint but is also used to preserve traditional knowledge of herbal medicinals and applications, the people of Andros continue to rely on bush medicine, mainly in the form of teas to help manage health related problems. …

Chamaecrista Fasciculata In Tallgrass And Sand Prairies: The Potential For Differential Responses, Robert W. Philips

Theses and Dissertations

Successful establishment of a diversity of native species has become an important goal for restoration site managers to achieve, however as seed sources for a species may occur in habitats with different abiotic and biotic characteristics. Consequently, seeds from different sources may vary in their success in a restoration. Chamaecrista fasciculata, a native prairie species, occurs in two divergent prairie types - tallgrass and sand prairies. Tallgrass prairies have a moist soil with dense vegetation; in contrast, sand prairies have a well-drained sandy soil with sparse vegetation. I propose differential selection acting on populations in these prairie types would affect …

Floral Symmetry Genes Elucidate The Development And Evolution Of Oil-Bee Pollinated Flowers Of Malpighiaceae And Krameriaceae, Farahnoz N. Khojayori

Theses and Dissertations

Specialization on insect and animal pollinators is thought to be the driving force for the evolution of floral traits. Specifically in the New World (NW), the oil-bee pollination syndrome has led to the convergence of floral characters in two distantly related families of core eudicots, Malpighiaceae and Krameriaceae. Both families display a flag-like structure that establishes a zygomorphic flower and floral oil rewards in epithelial elaiophores. These traits work concomitantly to attract and reward female oil-bees that help fertilize these flowers and in return receive oils. The underlying genetics of floral zygomorphy were studied in several clades of core eudicots, …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

Mechanisms Of Native Shrub Encroachment On A Virginia Barrier Island, Joseph Thompson

Theses and Dissertations

Species composition, temperature, soil nutrients, and leaf area index (LAI) were recorded across three encroaching Morella cerifera thicket edges and three free- standing shrubs on Hog Island, Virginia to characterize the effect of shrub thickets on the plant community and microclimate. Electron transport rate (ETR) was taken on shrub leaves to determine if microclimate benefits M. cerifera physiology. Species richness was lowest inside shrub thickets. Soil water content and LAI were higher in shrub thickets compared to grassland. Soil organic matter, N, and C were higher inside shrub thickets. Summer and fall maximum temperatures were more moderate in shrub thickets …

Evaluating The Evolutionary And Genetic Relationships Of The Andean Orchids Of Northwestern Ecuador, Kylie Bucalo

Theses and Dissertations

DNA barcoding is a molecular based technique used to separate and identify individual species. Here we establish a DNA Barcode library for the orchid flora of an Andean cloud forest in Northwestern Ecuador. The library contains 135 matK and 136 rbcL DNA Barcodes representing over 33 Orchidaceae genera. Sequence analysis shows percent species resolution was higher for matK (98.8%) than rbcL (70.24%), with a large portion of the unresolved species for the rbcL loci coming from taxonomically complex genera in the subtribe Pleurothallidinae. Neighbor Joining (NJ) trees revealed that the orchid flora of Siempre Verde is divided taxonomically into …

Factors Constraining The Reproductive Output Of Baptisia Alba Macrophylla, Ashley Morgan Hembrough

Theses and Dissertations

Baptisia alba macrophylla, a native, herbaceous perennial legume, produces inflorescences with a large number of flowers, yet matures relatively few fruits. We hypothesized that the number of seeds matured by B. alba macrophylla is maximized based on resource availability at each stage of development, but this optimal number is further compromised by extrinsic factors including pollen limitation and pre-dispersal seed predation by the weevils Apion rostrum and Tychius sordidus. To test this hypothesis, we conducted a field experiment at two sites: (i) the John English Prairie, located in Hudson, IL, and also (ii) the Sugar Grove Nature Center and Funks …

Latitudinal Gradient Facilitates Adaptive Population Differentiation Of Campanulastrum Americanum (American Bellflower), Marisa L. Naciuk

Theses and Dissertations

Local adaptation is characterized by higher reproductive fitness by individuals present in their native habitats relative to nonlocals. This study utilized Campanulastrum americanum as a model for assessing whether an environmental gradient can facilitate local adaptation. In particular, I determined if a latitudinal gradient across eastern United States has influenced the phenology and reproductive fitness of five northern and four southern C, americanum populations. These populations were reciprocally transplanted into two common garden sites positioned in the most northern and southern extent of the species distribution: Hastings, MI and Columbus, GA. I observed adaptive population differentiation of northern and southern …

Dispersal: A Multidisciplinary Investigation Of Plant Life, Alexandra E. Arzt

Theses and Dissertations

Using plants as a basis for exploring the interstices between the human and nonhuman, this thesis investigates ideas of awareness, intelligence, deep time, animism, and the fluctuating human perception of the agency of Nature. It outlines environmental art practices since the 1950s involving vegetal life. In addition, the paper provides a critical analysis of plant perception of Jakob von Uexküll’s work and theories of vital materialism and “critical plant studies” while noting recent studies in plant neurobiology. In my work, plants become active participants via their movement, seeding, and smell. This study takes the form of imitation, purposeful symbiosis, anthropomorphism, …

Effects Of Genetic Modification Of Phosphoinositol Pathway On Light Signaling And Secondary Metabolism In Tomato Plants, Mohammad Alimohammadi

Theses and Dissertations

Inositol- (1,4,5) triphosphate (InsP3) is known as an important signaling factor and a regulator of plant responses to environmental and stress conditions. Overexpression of the InsP 5-ptase gene is found to enhance tolerance of transgenic tomato plants to abiotic stress and the induction of lycopene synthesis in InsP 5-ptase transgenic plants. Here, we demonstrated that the genetic reduction of InsP3 affected the overall phosphoinositol pathway, flavonoid metabolism, and light signaling in InsP 5-ptase transgenic plants. Transgenic plants that overexpress the InsP 5-ptase gene demonstrate an increase in the expression of major light signaling transcription factors (LeHY5, SIMYB12, LeELIP). We found …

Regulation Of Growth And Stress Tolerance In Tomato Plants By Expression Of A Dominant-Negative Version Of Erecta Gene From Arabidopsis Thaliana, Hector Ernesto Villagarcia

Theses and Dissertations

Receptor kinases are the main group of signal recognition structures in plants. The large number and diversity of these receptors suggest that they perform major roles in a complex regulatory network of growth, development, and physiological responses. The ERECTA gene is a leucine-rich, receptor-like kinase that affects plant growth rates, stomatal patterning, transpiration efficiency, bacterial pathogen resistance, inflorescence and floral organ morphology, and leaf polarity. The ability to manipulate the ERECTA pathway in members of the Solanaceae family can reveal fundamental mechanisms including regulation of fruit and tuber development. This knowledge may enable changes in plant architecture and growth rates …

Effect Of Increased Carbon Dioxide Levels On Urushiol Production In Toxicodendron Radicans And Toxicodendron Toxicarium, Meredith Gilbert

Theses and Dissertations

It is hypothesized that global warming is at least partially due to increased greenhouse gases, one of which is carbon dioxide. An increase in atmospheric carbon dioxide has been shown to stimulate higher rates of plant productivity, including the production of plant toxins like urushiol. Urushiol, a secondary plant compound produced in members of the Anacardiaceae family, causes dermatitis in sensitive individuals. An increase in urushiol production could increase the reactivity of certain individuals to plants like poison oak and poison ivy. To determine how elevated levels of atmospheric carbon dioxide would effect urushiol production, 16 samples of poison ivy …

The Vascular Flora Of Saline County, Arkansas, Charles Theodore Witsell

Theses and Dissertations

The vascular flora of Saline County, Arkansas was collected from March 2002 to November 2007 resulting in a total of 1,510 taxa (52% of the known flora of Arkansas), representing 165 families, 617 genera, and 1,457 species. Of these, 241 (15.9%) are non-native and 99 (6.6%) are of state conservation concern. Of these, 20 taxa (1.3%) are considered to be of global conservation concern (G1-G3). Twenty-seven habitats and plant communities are qualitatively described from the county. Of these, shale barrens, igneous glades, pine flatwoods, swamp lakes and floatant marshes, channel scar depression ponds, high-gradient stream channels, and bluffs and talus …