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Full-Text Articles in Life Sciences

Misregulation Of Genomic Imprinting Drives Abnormal Seed Development In Hybrid Monkeyflowers (Mimulus), Taliesin Kinser May 2017

Misregulation Of Genomic Imprinting Drives Abnormal Seed Development In Hybrid Monkeyflowers (Mimulus), Taliesin Kinser

Dissertations, Theses, and Masters Projects

Genomic imprinting is the preferential expression of one allele over the other. It is an epigenetic phenomenon that occurs in the placentas of mammals and the endosperm of angiosperms. Endosperm, like placentas, is a nutrient rich tissue that supports the growing embryo within the seed. All grains are predominantly composed of this tissue. It is the product of a second fertilization event, resulting in both maternal and paternal alleles. Some alleles are regulated differentially, resulting in imprinted genes. There are both paternally expressed imprinted genes (PEGs) and maternally expressed imprinted genes (MEGs) in the endosperm. In general PEGs tend to ...


The Influence Of Environmental Factors And Resource Availability On Zostera Marina Flowering Intensity, Andrew J. Johnson Jan 2015

The Influence Of Environmental Factors And Resource Availability On Zostera Marina Flowering Intensity, Andrew J. Johnson

Dissertations, Theses, and Masters Projects

Sexual reproduction and the production of seeds are important for the resilience of all angiosperm species. For clonal species, such as the seagrass Zostera marina, resource allocation is complicated because these species reproduce both asexually and sexually, and the factors contributing to allocation to these two processes remains unknown. The goal of this study was, therefore, to investigate the importance of critical light, nutrient, and rhizome resources on Z.

marina sexual reproduction and flowering intensity. To evaluate the importance of sediment nutrients on Z. marina flowering intensity two distinct field manipulative experiments and one field survey were initiated: 1. Sediments ...


The Roles Of Dispersal And Predation In Determining The Seedling Recruitment Patterns Of A Zostera Marina System, Stephen R. Manley Jan 2014

The Roles Of Dispersal And Predation In Determining The Seedling Recruitment Patterns Of A Zostera Marina System, Stephen R. Manley

Dissertations, Theses, and Masters Projects

Seed dispersal and seed predation are two important processes in the early life history of plants. The interaction between these two processes influences the population recruitment from a parent plant. These mechanisms have been studied extensively in terrestrial plants and have resulted in various models to describe plant recruitment (e.g. Janzen-Connell, Hubbell, McCanny). However, seed dispersal and predation may also influence the population recruitment of marine angiosperms, such as Zostera marina (eelgrass). The objectives of this study were to determine: 1.) the patterns of seed dispersal as a function of distance from the seed source, 2.) the predation pressure ...


The Fruits Of Their Labors: Exploring William Hamilton's Greenhouse Complex And The Rise Of American Botany In Early Federal Philadelphia, Sarah Jane Chesney Jan 2014

The Fruits Of Their Labors: Exploring William Hamilton's Greenhouse Complex And The Rise Of American Botany In Early Federal Philadelphia, Sarah Jane Chesney

Dissertations, Theses, and Masters Projects

This dissertation explores the world of early American botany and the transatlantic community of botanical enthusiasts from the perspective of William Hamilton, gentleman botanical collector in late eighteenth and early nineteenth century Philadelphia. Drawing on both existing documentary sources and three seasons of archaeological excavation at The Woodlands, Hamilton's country estate on the west bank of the Schuylkill River, I analyze both the physical requirements of botanical collecting as well as the more nuanced social, cultural, and economic elements of this trade and its early modern participants.;The personal experiences of individual participants in this exchange are often traced ...


The Effects Of Salinity Pulses Of Varying Duration And Intensity On Three Freshwater Submerged Aquatic Vegetation Species, Rebecca Wright Jan 2012

The Effects Of Salinity Pulses Of Varying Duration And Intensity On Three Freshwater Submerged Aquatic Vegetation Species, Rebecca Wright

Dissertations, Theses, and Masters Projects

No abstract provided.


The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore Jan 2011

The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore

Dissertations, Theses, and Masters Projects

No abstract provided.


Vascular Flora Of The Totuskey Creek Watershed, Richmond County, Virginia, Christopher W. Johnstone Jan 2008

Vascular Flora Of The Totuskey Creek Watershed, Richmond County, Virginia, Christopher W. Johnstone

Dissertations, Theses, and Masters Projects

No abstract provided.


Investigation Of Relationships Between Short-Term Photosynthetic Performance And Long-Term Growth Of Zostera Marina, Elizabeth Amy Lewis Jan 2004

Investigation Of Relationships Between Short-Term Photosynthetic Performance And Long-Term Growth Of Zostera Marina, Elizabeth Amy Lewis

Dissertations, Theses, and Masters Projects

No abstract provided.


Vegetation Dynamics Of A Tidal Freshwater Marsh: Long-Term And Inter-Annual Variability And Their Relationship To Salinity, Sarah B. Davies Jan 2004

Vegetation Dynamics Of A Tidal Freshwater Marsh: Long-Term And Inter-Annual Variability And Their Relationship To Salinity, Sarah B. Davies

Dissertations, Theses, and Masters Projects

No abstract provided.


Microevolutionary Processes In Chesapeake Bay (Virginia, Usa) Eelgrass, Zostera Marina L, Jennifer Michelle Rhode Jan 2002

Microevolutionary Processes In Chesapeake Bay (Virginia, Usa) Eelgrass, Zostera Marina L, Jennifer Michelle Rhode

Dissertations, Theses, and Masters Projects

Eelgrass (Zostera marina L.) is the northern hemisphere's dominant marine angiosperm, a species with both ecological and economic importance. Initial allozyme surveys of eelgrass populations in Chesapeake Bay (Virginia, USA) revealed substantial amounts of geographically-partitioned genetic variation, which could be the result of nonselective demographic processes, including founder events and drift. However, strong spatial variation in the environment and in eelgrass morphology suggests that differential adaptation of isolated beds to local environmental conditions could also produce these patterns. This dissertation used three sets of studies to investigate microevolutionary processes might produce the observed variation among Chesapeake eelgrass beds: (1 ...


Effects Of Light And Salinity Stress On Vallisneria Americana (Wild Celery), Gail T. French Jan 2001

Effects Of Light And Salinity Stress On Vallisneria Americana (Wild Celery), Gail T. French

Dissertations, Theses, and Masters Projects

No abstract provided.


Spatial And Temporal Variation In Plant Communities Of Three Tidal Salt Marshes Along The York River, Virginia, Rosemary E. Laird Jan 2001

Spatial And Temporal Variation In Plant Communities Of Three Tidal Salt Marshes Along The York River, Virginia, Rosemary E. Laird

Dissertations, Theses, and Masters Projects

No abstract provided.


Plant Species Of The Virginia Coastal Plain Flora That Are Disjunct From The Mountains: Their Distribution, Abundance And Substrate Selectivity, Leah E. Mcdonald Jan 2000

Plant Species Of The Virginia Coastal Plain Flora That Are Disjunct From The Mountains: Their Distribution, Abundance And Substrate Selectivity, Leah E. Mcdonald

Dissertations, Theses, and Masters Projects

No abstract provided.


Ecological Dispersal Mechanisms, Reproductive Ecology, And The Importance Of Scale In Zostera Marina In Chesapeake Bay, Matthew C. Harwell Jan 2000

Ecological Dispersal Mechanisms, Reproductive Ecology, And The Importance Of Scale In Zostera Marina In Chesapeake Bay, Matthew C. Harwell

Dissertations, Theses, and Masters Projects

Previous knowledge of the seed ecology of the clonal seagrass Zostera marina L. (eelgrass) suggests that sexual reproduction is not very important to the population dynamics of eelgrass; however, researchers have hypothesized long-distance dispersal for nearly a century. From a bay-wide sampling effort, viable eelgrass seeds in the seed bank were found throughout most of the lower and middle Chesapeake Bay, but abundance of seeds was highly variable. Lower seed-bank densities were found in middle Chesapeake Bay, the region with slow recovery of eelgrass populations. From natural and artificially created eelgrass populations, regional environmental conditions were found to have a ...


Systematic And Population Genetic Analyses Of Northern Vs Southern Yellow Lady's Slippers (Cypripedium Parviflorum Vars Parviflorum, Pubescens, And Makasin): Inference From Isozyme And Morphological Data, Lisa Ellen Wallace Jan 1997

Systematic And Population Genetic Analyses Of Northern Vs Southern Yellow Lady's Slippers (Cypripedium Parviflorum Vars Parviflorum, Pubescens, And Makasin): Inference From Isozyme And Morphological Data, Lisa Ellen Wallace

Dissertations, Theses, and Masters Projects

No abstract provided.


The Vascular Flora Of The Carrotoman River Watershed, Lancaster County, Virginia, Troy W. Weldy Jan 1995

The Vascular Flora Of The Carrotoman River Watershed, Lancaster County, Virginia, Troy W. Weldy

Dissertations, Theses, and Masters Projects

No abstract provided.


Phylogenetic Implications Of Sporogenesis Ultrastructure In The Genus Bossiella (Corallinales, Rhodophyta), Kimberly Joy Karnas Jan 1995

Phylogenetic Implications Of Sporogenesis Ultrastructure In The Genus Bossiella (Corallinales, Rhodophyta), Kimberly Joy Karnas

Dissertations, Theses, and Masters Projects

No abstract provided.


An Ultra Structural Study Of Sporogenesis, Vegatative Morphology, And Host-Parasite Interactions In Choreonema Thuretii (Corallinales, Rhodophyta), Elizabeth Anne Lapointe Jan 1995

An Ultra Structural Study Of Sporogenesis, Vegatative Morphology, And Host-Parasite Interactions In Choreonema Thuretii (Corallinales, Rhodophyta), Elizabeth Anne Lapointe

Dissertations, Theses, and Masters Projects

No abstract provided.


Measurement Of In Situ Eelgrass Community Metabolism In Standing And Flowing Waters: Methods And Models, William James Seufzer Jan 1994

Measurement Of In Situ Eelgrass Community Metabolism In Standing And Flowing Waters: Methods And Models, William James Seufzer

Dissertations, Theses, and Masters Projects

No abstract provided.


Reproductive Strategies In Asclepias Syriaca And Apocynum Cannabinum, Mariellen J. Soltys Jan 1994

Reproductive Strategies In Asclepias Syriaca And Apocynum Cannabinum, Mariellen J. Soltys

Dissertations, Theses, and Masters Projects

No abstract provided.


The Vascular Flora Of The Tar Bay And Powell Creek Watersheds, Prince George County, Virginia, Mark Eugene Mort Jan 1994

The Vascular Flora Of The Tar Bay And Powell Creek Watersheds, Prince George County, Virginia, Mark Eugene Mort

Dissertations, Theses, and Masters Projects

No abstract provided.


The Role Of Predation On Zostera Marina L (Eelgrass) Seed Abundance, James Fishman Jan 1994

The Role Of Predation On Zostera Marina L (Eelgrass) Seed Abundance, James Fishman

Dissertations, Theses, and Masters Projects

No abstract provided.


Growth Response Of Eelgrass (Zostera Marina L) To Root-Rhizome And Whole Plant Exposure To Atrazine, Arthur C. Schwarzschild Jan 1993

Growth Response Of Eelgrass (Zostera Marina L) To Root-Rhizome And Whole Plant Exposure To Atrazine, Arthur C. Schwarzschild

Dissertations, Theses, and Masters Projects

No abstract provided.


A Vegetational Analysis Of Interdunal Swale Communities Of False Cape State Park, Currituck Spit, Virginia, Heather A. Jones Jan 1992

A Vegetational Analysis Of Interdunal Swale Communities Of False Cape State Park, Currituck Spit, Virginia, Heather A. Jones

Dissertations, Theses, and Masters Projects

No abstract provided.


Adaptive Significance Of Ray Florets In Asteraceae, Gail Taber Steele Jan 1992

Adaptive Significance Of Ray Florets In Asteraceae, Gail Taber Steele

Dissertations, Theses, and Masters Projects

No abstract provided.


Sediment Inorganic Nitrogen Stocks And Root-Rhizome Ammonium Uptake By Eelgrass (Zostera Marina L) In The Lower Chesapeake Bay, Christopher P. Buzzelli Jan 1991

Sediment Inorganic Nitrogen Stocks And Root-Rhizome Ammonium Uptake By Eelgrass (Zostera Marina L) In The Lower Chesapeake Bay, Christopher P. Buzzelli

Dissertations, Theses, and Masters Projects

No abstract provided.


Vegetation Ecology Of Tidal Freshwater Swamps Of The Lower Chesapeake Bay, United States Of America, Richard D. Rheinhardt Jan 1991

Vegetation Ecology Of Tidal Freshwater Swamps Of The Lower Chesapeake Bay, United States Of America, Richard D. Rheinhardt

Dissertations, Theses, and Masters Projects

Woody and herbaceous vegetation were sampled in 23 tidal swamps along a tidal freshwater tributary of lower Chesapeake Bay. Four vegetative categories were ordinated with Detrended Correspondence Analysis (DECORANA). Species distribution patterns of each strata were compared with respect to edaphic factors, a wetness index, and mean water table depth. Woody species are restricted to hummocks (topographic highs). Hummocks drain as quickly as the tide drops and so are partially inundated for only short periods each day. Although low in canopy diversity, tidal swamps are floristically rich in herbaceous and woody understory species, ranking them among the most speciose in ...


Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles Jan 1990

Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles

Dissertations, Theses, and Masters Projects

Dissolved nutrient concentrations and invertebrate grazing activity regulate epiphytic biomass. Because epiphyton may limit light and carbon at leaf surfaces and the consequent productivity of submerged macrophytes, factors which influence epiphytic biomass may indirectly affect macrophyte abundance. I measured the simultaneous effects of water column nutrients (ambient or 3x ambient concentrations of nitrogen and phosphorus) and grazing (presence or absence of epifaunal community) on epiphyton and macrophytes seasonally in eelgrass (Zostera marina L.) microcosms on lower Chesapeake Bay. Grazing was more important than nutrients in controlling accrual of total epiphytic biomass, although effects on epiphytic components varied; numbers of diatoms ...


The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett Jan 1990

The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett

Dissertations, Theses, and Masters Projects

No abstract provided.


Vascular Flora Of Northwestern Highland County, Virginia, Theresa Alee Theodose Jan 1989

Vascular Flora Of Northwestern Highland County, Virginia, Theresa Alee Theodose

Dissertations, Theses, and Masters Projects

No abstract provided.