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Chemically Induced Phytoextraction Of Lead (Pb) Contaminated Soil By Switchgrass (Panicum Virgatum L.), Austin Gilly

Master of Science in Integrative Biology Theses

Soils contaminated with lead (Pb) from human activities including industrial byproducts create an environmental and human health risk. Phytoextraction through chemical acquisition of Pb in soils offer a potentially cost effective and ecologically driven approach to remediation. Switchgrass (Panicum virgatum L.) is known to have a tolerance for a wide range of heavy metals including Pb. Switchgrass is also able to grow in a wide range of climates. Soil chemistry manipulation, using chelates and plant growth promoters could provide an effective field method for phytoremediation using switchgrass. In this study chemically enhanced phytoextraction using the soil-fungicide Infuse (active ingredient …

Plant Diversity And Nitrogen Addition On Belowground Biodiversity And Soil Organic Carbon Storage In Biofuel Cropping Systems, Jennifer Butt

Boise State University Theses and Dissertations

Bioenergy production may reduce the emission of CO₂ which contributes to climate change, particularly when management strategies are adopted that promote soil carbon (C) sequestration in bioenergy cropping systems. Planting perennial native grasses, such as switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) may be used as a strategy to enhance soil C accumulation owing to their extensive root systems. Fertilizer use may further promote soil C sequestration, because of its positive impacts on plant production and soil C input. However,, the influence of fertilizer addition on soil C accumulation is variable across bioenergy cropping …

Aboveground-Belowground Interactions: Roles Of Soil Biotic And Abiotic Factors On Switchgrass's (Panicum Virgatum) Growth, Defense Against Herbivory And Cell Wall Chemistry., Binod Basyal

Electronic Theses and Dissertations

Plants constantly interact with their biotic and abiotic soil environments. Most terrestrial plants form beneficial associations with soil microbes such as arbuscular mycorrhizal (AM) fungi, which are widely known for their ability to transfer soil phosphorus and nitrogen to the host plants. They help plants tolerate drought stress and improve plant defense against herbivores such as plant-parasitic nematodes (PPNs). This dissertation investigates the role of AM fungi on switchgrass’s (Panicum virgatum) growth, cell wall chemistry, and defense against PPNs using a combination of growth chamber and field studies. Switchgrass is a native warm-season species which is gaining traction as candidate …

Switchgrass (Panicum Virgatum L.) Pollen-Mediated Gene Flow And Transgene Bioconfinement Strategies, Reginald Millwood

Doctoral Dissertations

Switchgrass (Panicum virgatum L.) is a native North American grass under development as a bioenergy feedstock. Genetic engineering has been employed to introduce transgenic traits for economical biofuel production. However, potential transgene movement from switchgrass raises regulatory and environmental concerns. Experimental studies are needed to determine the potential for transgene flow from switchgrass. The aims of this research are to estimate pollen dispersal and pollination distances for transgenic switchgrass, and evaluate genetically engineered male sterility as a transgene bioconfinement strategy. A three-year field experiment was performed to estimate switchgrass pollen dispersal and pollination distances using a modified Nelder wheel design. …

Proteome Characterizations Of Microbial Systems Using Ms-Based Experimental And Informatics Approaches To Examine Key Metabolic Pathways, Proteins Of Unknown Function, And Phenotypic Adaptation, Suresh Poudel

Doctoral Dissertations

Microbes express complex phenotypes and coordinate activities to build microbial communities. Recent work has focused on understanding the ability of microbial systems to efficiently utilize cellulosic biomass to produce bioenergy-related products. In order to maximize the yield of these bioenergy-related products from a microbial system, it is necessary to understand the molecular mechanisms.The ability of mass spectrometry to precisely identify thousands of proteins from a bacterial source has established mass spectrometry-based proteomics as an indispensable tool for various biological disciplines. This dissertation developed and optimized various proteomics experimental and informatic protocols, and integrated the resulting data with metabolomics, transcriptomics, and …

Genetic Diversity, Genetic Variation And Identification Of Quantitative Trait Loci (Qtl) Associated With Biomass Yield And Establishment-Related Traits In Lowland Switchgrass (Panicum Virgatum L.), Cheryl Ontolan Dalid

Doctoral Dissertations

Switchgrass is a warm-season C4 grass used for biofuel production. The primary goal of this study is biomass yield improvement for use as a bioenergy feedstock. The research plan was partitioned into three main objectives: (i) evaluate the genetic diversity among lowland switchgrass populations using microsatellite markers; (ii) assess genetic variation in an Alamo half-sib (AHS) population developed through phenotypic selection; (iii) and identify quantitative trait loci (QTL) associated with biomass yield and establishment related seed traits using a Nested Association Mapping (NAM) population. The genetic diversity study on lowland switchgrass showed significant phenotypic variations (P<0.05) among and within germplasm accessions. The Analysis of Molecular Variance (AMOVA) revealed that among genotypes within populations and among populations explained 84 and 16% of molecular genetic variations. The Principal Coordinate Analysis (PCoA) and cluster analysis separated switchgrass populations according to the ancestral background. The study on genetic variation showed significant variation (P<0.05) among AHS for biomass yield, tillering ability, and spring vigor, suggesting the importance of additive genetic variation in these traits. Results also showed great potential for biomass yield improvement through selection based on family performance. Using 10% selection intensity, parental control of two, and a narrow-sense heritability estimate of 0.11, gain per cycle selection from half-sib family selection is estimated to be 23%. The study on identification of QTLs associated with biomass yield and establishment related traits showed significant variation among NAM families and genotypes within families for biomass yield, seed weight, and germination (P<0.05). A total of 785 significant markers for biomass yield were detected (P<0.05) of which 176 were for seed weight and 131 for germination. Composite interval mapping revealed 21 QTLs for biomass yield across locations in 2 years the highest LOD score of 7.6 detected in chromosome Ia that explained a 12.5% of the phenotypic variation. Two QTLs located in chromosome VIIIb for seed weight explained 5.2% and 4.6% phenotypic variation. One QTL for germination located in chromosome IXa explained 5.2% of the phenotypic variation. The results of these studies will be useful for future breeding efforts in switchgrass and other perennial grasses.

Effects Of Hardwood Control And Switchgrass Intercropping On Breeding Bird Communities And Resource Use In Managed Loblolly Pine Stands In Mississippi, Marian Fuller-Morris

Theses and Dissertations

Managed loblolly pine (Pinus taeda) stands are common in the southeastern United States and provide young forest conditions for early successional breeding birds. Common pine management practices (e.g. hardwood control) and novel practices (e.g. switchgrass [Panicum virgatum] intercropping), may influence breeding bird use. I evaluated breeding bird abundance, diversity, and resource use within loblolly stands treated to control hardwood species, intercropped with switchgrass, and with no additional management. Hardwood control and switchgrass intercropping both decreased hardwoods and shrubs, and increased forbs. Switchgrass intercropping increased some early successional bird abundances. However, diversity was not different among treatments. Switchgrass intercropping increased 13C:12C …

Identification, Characterization, And Genetic Comparison Of Fusarium Species Isolated From Switchgrass (Panicum Virgatum L.), Tamara Annette Collins

Masters Theses

Fusarium spp. are ubiquitous, soilborne and seedborne pathogens that affect over 100 economically important plant hosts annually, resulting in billions of dollars in economic losses. They cause a variety of plant disease symptoms including, crown, root, and stem rots, wilts, and foliar necrosis. Furthermore, they produce harmful mycotoxins that are detrimental to the health of animals and humans. Members of this genus have been isolated from diseased tissues of switchgrass. The objective is to correctly identify and classify Fusarium isolates to species using both classic phenotypic characterization and current genetic technologies of DNA extraction and polymerase chain reaction and create …

Intraspecific Differences In Belowground Associations And Seedling Root Morphology For The Biofuel Crop, Panicum Virgatum., Erin Renee Kinnetz

Electronic Theses and Dissertations

The perennial C₄ grass Panicum virgatum (switchgrass) is a promising bioenergy feedstock. Switchgrass is symbiotic with arbuscular mycorrhizal fungi (AMF). I examined 12 varieties of switchgrass grouped into 2 ecotypes (upland, lowland) to see if they differed in AMF abundance and root colonization using the GLBRC Variety Trials experiment. There was higher root colonization of lowland ecotype. A greenhouse experiment evaluated the role of live soil organisms in seedling establishment of 11 varieties. Live soil increased seedling survival, growth and influenced root morphology. Ecotypes differed in root architecture. Lowland developed a higher specific root length (SRL), a trait associated …

Native Species For Biomass Production And Roadside Habitat In South Dakota, Jacob Foley

Electronic Theses and Dissertations

Native grasses and forbs are being considered for planting along South Dakota roadsides to create a favorable habitat for wildlife while also allowing landowners a source of forage and biomass production. South Dakota is host to 54,900 hectares (145,000 acres) of right-of-way that are managed by the South Dakota Department of Transportation. Approximately 80% of the roadsides are used by landowners for hay production. Species diversity and potential biomass yield were determined for the current roadside vegetation along four transects (SD Highways 14, 34 and 50) and SD I- 29 between White, SD and Elk Point, SD. Smooth bromegrass (Bromus …

Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce

Masters Theses

Panicum virgatum (switchgrass), a perennial grass native to North America, is a leading biomass feedstock candidate for the manufacture of cellulosic ethanol. Switchgrass is considered a viable option for biofuel production due to its cheap production cost and ability to grow on marginal land. Biofuel derived from switchgrass has been shown to be very energy efficient, producing 540% more renewable energy versus nonrenewable energy expended. Switchgrass-derived biofuel is also estimated to have greenhouse gas emissions that are 94% lower than emissions from gasoline (Schmer et al 2008). Biofuels are created through biochemical processes that utilize various enzymes and microorganisms for …

Characterization Of Fusarium Species And Alternaria Alternata, And Their Effects On Switchgrass Health And Chemical Components, Sara Beth Collins

Masters Theses

Panicum virgatum L., readily referred to as Switchgrass, is a perennial warm-season bunch grass, used as an alternative energy source for biofuel production. There is insufficient research on switchgrass pathogens, and is expected that an increase in disease pressure will result as more land is reserved for this perennial crop. The purpose of this research was to identify and characterize pathogenic Alternaria alternata and Fusarium species on Switchgrass (Panicum virgatum L.), and to evaluate their impact on stand establishment and plant health. Molecular identifications of fungal isolates obtained from infected commercial switchgrass seed yielded eight species (A. alternata, …

Modification Of Carbohydrate Active Enzymes In Switchgrass (Panicum Virgatum L.) To Improve Saccharification And Biomass Yields For Biofuels, Jonathan Duran Willis

Doctoral Dissertations

The natural recalcitrance of plant cell walls is a major commercial hurdle for plant biomass to be converted into a viable energy source as alternative to fossil fuels. To circumvent this hurdle manipulation of carbohydrate enzymes active in the cellulose and hemicellulose portions of the plant cell wall can be utilized to improve feedstocks. Production of cellulolytic enzymes by plants have been evaluated for reducing the cost associated with lignocellulosic biofuels. Plants have successfully served as bioreactors producing bacterial and fungal glycosyl hydrolases, which have altered plant growth to improve saccharification. A bioprospecting opportunity lies with the utilization of insect …

Switchgrass Cultivar And Intraspecific Diversity Impacts On Nitrogen Use Efficiency, Aislinn Johns

Boise State University Theses and Dissertations

Bioenergy feedstock production is an important component of the national renewable energy strategy, which is based on biomass supply. Biofuels for ethanol production may be produced in high-input crop production systems, but the efficacy of these systems for increasing net energy yields over its full life-cycle compared to traditional fuels is under debate, because it is now evident that the benefits of feedstock production are maximized only when biofuels are derived from feedstocks produced with much lower life-cycle greenhouse-gas emissions than traditional fossil fuels. To this end, the reduction of agricultural inputs is key to developing an effective biofuel feedstock …

A Simulation Model Of The “Bio-Depot” Concept In The Context Of Components Of Variance And The “Taguchi Loss Function”, Maximilian Platzer

Masters Theses

The research focuses on the simulation, statistical evaluation, costs, and continuous improvement of supply chains for bio-based materials. A significant challenge of using cellulosic feedstocks for biofuel or bioenergy production is the high per unit costs of final products, e.g., biofuels. The goal of the research is to provide practitioners with useful statistical methods and a simulation Excel template for evaluating the variance and costs associated with the supply chain of bio-based products. Statistical Process Control (SPC), components of variance, Taguchi Loss Function, and reliability block diagrams (RBD) are used in this thesis for the evaluation of the supply chain …

Induced Phytoextraction Of Lead From Contaminated Soils By Panicum Virgatum, Enhanced With Edta, Citric Acid, Benomyl, Propiconazole And Nitric Oxide, Adrianna E. Beavers

Master of Science in Integrative Biology Theses

Soil lead (Pb) contamination represents a major environmental and public health risk. Conventional Pb remediation methods are typically expensive and risk further environmental damage. Phytoextraction has emerged as an alternative heavy metal remediation method with the potential for reducing both economic cost and negative environmental effects. For this study, North American native switchgrass (Panicum virgatum) was chosen due to its ability to achieve high biomass yields across a variety of climates and environmental conditions. The switchgrass plants in this study were treated with chemical chelates, fungal suppressants, and nitric oxide (NO) donors with the intent of optimizing Pb …

Assessment Of Early Successional Arthropod And Breeding Bird Response To Intercropping Switchgrass Within An Intensively Managed Loblolly Pine Forest, Craig Daniel Marshall

Theses and Dissertations

Loblolly pine (Pinus taeda) plantations are a common land use of the southeastern United States that have the potential to function as a source of cellulosic biomass for biofuel production. A novel land use practice of intercropping switchgrass (Panicum virgatum) between planted loblolly pines has been developed as a potential method of cellulosic biomass production. I evaluated response of arthropods and breeding birds to intercropping switchgrass within loblolly pine plantations compared to typically managed pine plantations. I detected 13 arthropod orders and 44 breeding bird species during 2014 – 2015. Intercropping switchgrass reduced arthropod diversity and evenness, with richness not …

Senescence Of Native Perennial Warm Season Grasses Senescence Associated Switchgrass Transcriptome, Michaellong Tran

Electronic Theses and Dissertations

Senescence of perennial crops enable continuous harvests after one sowing event. Perennials senesce at adapted rates of their native environments; however, early senescencing crops do not maximize the growing season as nutrient reallocation takes precedence. Chlorophyll degradation and nitrogen reallocation was observed to occur rapidly between mid to late September. Transcriptome analysis on early and late senescencing switchgrass cultivars reveals upregulation of starch metabolism, light reactions, Calvin-Benson Cycle, and anthocyanin synthesis in late senescencing switchgrass. Morphological variations between the two germplasms prolong the growing season of late senescencing switchgrass, maximizing yield. Expression of mRNA as senescence progresses and between the …

Heat And Mass Transfer In Baled Switchgrass For Storage And Bioconversion Applications, Drew F. Schiavone

Theses and Dissertations--Biosystems and Agricultural Engineering

The temperature and moisture content of biomass feedstocks both play a critical role in minimizing storage and transportation costs, achieving effective bioconversion, and developing relevant postharvest quality models. Hence, this study characterizes the heat and mass transfer occurring within baled switchgrass through the development of a mathematical model describing the relevant thermal and physical properties of this specific substrate. This mathematical model accounts for the effect of internal heat generation and temperature-induced free convection within the material in order to improve prediction accuracy. Inclusion of these terms is considered novel in terms of similar biomass models.

Two disparate length scales, …

Storage Of Round And Square Switchgrass Bales: Effect Of Storage Time And Fungal Inoculation On Saccharification Efficiency, Noaa Frederick

Graduate Theses and Dissertations

To produce fermentable sugars from lignocellulosic biomass feedstock, severe pretreatment conditions are needed (either high acid concentration, temperature, or retention times). High severities can produce toxic byproducts which inhibit enzymatic hydrolysis or fermentation. In order to reduce pretreatment severities (and thus increase enzyme and fermentation efficiency), the white-rot fungus Pleurotus ostreastus was seeded into square and round bales of Kanlow switchgrass (Panicum virgastum L.) and left in the field over a period of 9 month. The laccase producing fungus is believed to selectively degrade lignin, a common plant structural polymer, which can function as an enzymatic inhibitor. Samples were taken …

Modifying A Cow-Calf Biophysical Simulation Model For Analyses Of Alternative Enterprises, Jennifer L. Lutes

Graduate Theses and Dissertations

Cow-calf producers in the United States, tasked with providing beef calves for the beef industry, have had a multitude of difficulties to overcome in recent years. Producers in northwest Arkansas were negatively impacted by high hay prices coupled with low beef cattle market prices due to severe drought experienced in portions of 2010, 2011, and 2012. During this time they also faced high grain prices, due to a record low harvest, combined with portions of the corn harvest diverted from human and animal feed to ethanol production. Tight lending policies of this time, reminiscent of the housing market crash in …

Genetic Modification Of Switchgrass (Panicum Virgatum L.) For Improvement Of Plant Architecture, Biomass Productivity And Sugar Release Efficiency For Biofuel, Wegi Aberra Wuddineh

Doctoral Dissertations

Switchgrass (Panicum virgatum L.) is a leading candidate bioenergy crop for sustainable biofuel production. To ensure its economic viability, tremendous improvements in switchgrass biomass productivity and recalcitrance to enzymatic saccharification are needed. Genetic manipulation of lignin biosynthesis by targeting transcriptional regulators of higher level domains of lignin biosynthesis and other complex traits could alter several bioenergy-desirable traits at once. A three-pronged approach was made in the dissertation research to target one plant growth regulator and transcription factors to alter plant architecture and cell wall biosynthesis.

Gibberellin (GA) catabolic enzymes, GA 2-oxidases (GA2oxs), were utilized to alternatively modify the lignin …

Modeling Water Quality For Switchgrass Crop Production: Implications For Bioenergy Sustainability In East Tennessee, Zachariah Tzvi Seiden

Masters Theses

With passing of the US Energy Independence and Security Act (EISA) of 2007, there has been considerable research conducted on the sustainability of bioenergy crop production in the United States; switchgrass has shown particular potential for bioenergy production in East Tennessee. Many studies evaluating the environmental impact switchgrass has on runoff and water quality use the Soil and Water Assessment Tool (SWAT) for watershed modeling. Because SWAT is a lumped watershed model, it evaluates the result of hydrological processes for each hydrologic response unit (HRU), without accounting for the physical interactions between these HRUs. The Water Erosion Prediction Project (WEPP) …

Economic And Environmental Optimization In The Supply Of Switchgrass In Tennessee, Jia Zhong

Masters Theses

The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan.

The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first …

Soil Resource And Production Dynamics Of A Tree-Grass Intercropping System Managed Across Gradients Of Interspecific Competition, Kurt Joseph Krapfl

Theses and Dissertations

Belowground competition presents a threat to the production and sustainability of tree-grass ecosystems. Management scenarios designed to optimize the spatial and temporal distribution of soil resources will improve resource-use efficiency and promote greater co-production. We conducted three experiments to assess competition dynamics between loblolly pine and switchgrass. In a three-year field trial, loblolly pine and switchgrass were intercropped across varying competitive intensities. Interspecific competition decreased loblolly pine annual growth; however, establishing vegetation exclusion zones surrounding pines largely mitigated these effects. Switchgrass yields were less affected by interspecific competition compared to pines and land equivalency ratios indicated that with proper management …

Enhancing The Sustainability Of Integrated Biofuel Feedstock Production Systems, Amanda Joy Ashworth

Doctoral Dissertations

As use of second-generation biofuel crops increases, so do questions about sustainability, particularly their potential to affect fossil energy consumption and greenhouse gas emissions. Nitrogen (N)-fixing legumes interseeded into switchgrass (Panicum virgatum L.) may be an alternative to inorganic fertilizer in forage-feedstock systems. Research herein is divided into four general experiments: I). N replacement and feedstock impacts from legume intercrops and biochar in switchgrass; II). N-fixation rates in intercrop systems; III). impacts of biofuel systems under enhanced climate change; and, IV). projected sustainability of regional switchgrass production. Approaches included: characterization of feedstock/forage quality traits based on legume, biochar and …

Diallel Analysis Of Biomass And Ethanol Yield In Leaves Versus Stems Of Lowland Switchgrass, Alexandria Christina Desantis

Masters Theses

Switchgrass (Panicum virgatum L.) is a warm season perennial grass used widely as a forage crop. This research seeks to address improving biomass yield and predicted ethanol yield through certain traits by the following objectives: (1) differences in average biomass and predicted ethanol yields from leaves versus stems, (2) genetic variance and heritability estimates of biomass and ethanol yield traits (3) general (GCA) and specific combining ability (SCA) among the five parents for biomass and ethanol yield, and (4) correlations between agronomic and morphological traits. Five parents with varying morphological traits were crossed in a diallel design, excluding selfs. …

Phytoextraction Of Lead From Contaminated Urban Soils By Panicum Virgatum Enhanced With Phytohormone, Edta, Benomyl, And Citric Acid Application, Matthew Aderholt

Master of Science in Integrative Biology Theses

Lead (Pb) contamination in soil represents a threat to human health and cleanup efforts often requires expensive or environmentally disruptive techniques. Phytoextraction has gained attention as a possible alternative to traditional remediation methods because of lower cost and minimal soil disruption. Panicum virgatum L. (switchgrass) was chemically enhanced with applications of the soil-fungicide benomyl, chelates (EDTA and citric acid), and phytohormones for phytoextraction of Pb from contaminated urban soils in Atlanta, GA. EDTA is often regarded as the most effective chelate, but has potential problems associated with its use due to long persistence time in soil and possible Pb mobilization …

Methods Of Analysis For Fermentation Science Products Using Various Analytical Techniques, Casey Jay Howdieshell

Online Theses and Dissertations

Fermentation science, the study of microorganisms as they digest food sources to produce usable products for consumption, has been around since the dawn of modern civilization. Historically, the fermentation process has been utilized for the production of alcoholic beverages. More recently, however, the production of bioethanol and biodiesel as a fuel source alternative to classical fossil fuels has gained increased popularity. As with any synthetic process, derivations and optimizations for ideal production are needed. As such, analytical techniques must be implemented to ensure quality control and pinnacle efficiency. This body of work describes analytical techniques providing key qualitative and quantitative …

Switchgrass Cultivar, Harvest Frequency, Fertilizer Source, And Irrigation Effects On Near-Surface Soil Properties In West-Central Arkansas, Alayna A. Jacobs

Graduate Theses and Dissertations

Switchgrass (Panicum virgatum L.) has been identified as a model bioenergy feedstock crop and is expected to become an important feedstock for future renewable fuel generation. Agronomic management combinations that maximize monoculture switchgrass yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management combinations on near-surface soil properties. The objective of this research was to determine the residual near-surface soil property effects of three years (2008 to 2011) of consistent management combinations to maximize switchgrass biomass production, including cultivar (‘Alamo’ and ‘Cave-in-Rock’), harvest frequency (1-cut and 2-cut systems per year), fertilizer source (poultry …