Life Sciences Commons^™

Revealing The Native Status Of Conyza Bonariensis: Specialization Of Insect Herbivores Associated With Conyza And Erigeron Spp. (Asteraceae) In Louisiana, Texas, And Mississippi, Carlos Wiggins

LSU Master's Theses

Flaxleaf fleabane [Conyza bonariensis (L.) Cronquist] (Asterales: Asteraceae) is an annual herb which grows up to 1.0 m in height and is native to South America. Due to introduction and subsequent development of herbicide resistance, C. bonariensis has become a major agricultural weed in Australia. The purpose of this study was to catalog herbivorous insects associated with local populations of C. bonariensis in Louisiana, Texas and Mississippi in order to establish comparisons with the Australian fauna and identify potential biological control agents. Leaves, roots, stems, and flowers of C. bonariensis were inspected for signs of insects and pathogens. Results …

Evaluating Consumers’ Perception Of Gluten-Free/Clean-Label Muffins, Vanesa Chicaiza

LSU Master's Theses

The gluten-free-natural-ingredient (GF/NCL) product demand is globally increasing and driven by the growing prevalence of celiac-diseases. Nevertheless, the quality of GF product is often inferior compared to wheat-flour counterparts due to the removing of gluten, which, compromises the appearance, structure, and nutritional value. The addition of fiber into GF/NCL products has been considered to improve nutritional values while maintaining quality attributes. According to the US-FDA, a product containing ≥2.5 grams of fiber/serving can be claimed as a “good-source-of-fiber.” However, adding dietary fiber to baked products affects their qualities, and hence possibly lowering product acceptability.

The main objective of this research …

Effects Of Freshwater Input On Nutrient Loading, Toxic Cyanobacteria Bloom Development And Cyanotoxin Production In Lake Pontchartrain Estuary, Louisiana, Callie L. Snow

LSU Master's Theses

Estuaries in the northern Gulf of Mexico (GoM) are undergoing profound alterations due to changes in climate and implementation of coastal restoration activities and these may lead to the increasing frequency of harmful algal blooms (HABs). The introduction of large volumes of nutrient-rich, fresh Mississippi River water into nutrient-poor Lake Pontchartrain Estuary is known to substantially change the chemistry and ecology of the estuary, and warm temperatures paired with the persistent nutrient loading into the estuary supports the proliferation of potentially toxic cyanobacteria blooms (CyanoHABs). Throughout 2019, a long-term opening of the Bonnet Carré Spillway (BCS), initially from February to …

Hemp Microgreen Mineral Content, Cannabinoids, Total Phenolics, And Antioxidants, Cheston T. Schayot

LSU Master's Theses

Hemp (Cannabis sativa) L. microgreens were grown to 7 and 12 days with and without supplemental lighting and/or fertilizer. The principal macronutrient found in hemp microgreens was nitrogen (N), followed by potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca), and sulfur (S). The principal micronutrient found in hemp microgreens was iron (Fe), followed by manganese (Mn), zinc (Zn), boron (B), and copper (Cu). Hemp microgreens were similar to other commonly grown microgreen species in minerals except for P and Mg, where they could potentially be an excellent source, and Zn, where they fell below previously reported amounts. The …

Response Of Roseau Cane (Phragmites Australis) To Two Biotic Stresses: Hyalopterus Pruni And Bipolaris Yamadae, Heather E. Cizek

LSU Master's Theses

Roseau cane (Phragmites australis) is considered an invasive plant because of its ability to replace native plant species. However, in Louisiana it plays an important role protecting coastal infrastructure and being part of the marsh ecosystem in the lower Mississippi River Delta. In recent years, Roseau cane has been affected by a die-off, a problem that has also been reported in some European countries. Possible biotic and abiotic factors that have been associated with the die-off include scale insects, climate change, pollution, salinity levels, and pathogens.

In this research, the individual and combined effect of a foliar disease …

Regional Expansion And Evaluation Of Potential Chemical Control For Invasive Apple Snails (Pomacea Maculata) In Southwest Louisiana, Julian M. Lucero

LSU Master's Theses

The integration of monitoring and chemical control is an efficient strategy for managing invasive apple snails, Pomacea maculata, in the rice (Oryza sativa L.) and crawfish systems of southwest Louisiana. However, their current distribution, expansion rates, and susceptibility to chemical control methods in this area are not well known. This study evaluated the expansion of P. maculata in southwest Louisiana and assessed potential chemical control for P. maculata among toxicity assays using various application rates. The effects of potential chemical control were also assessed on a non-target species, the red swamp crawfish (Procambarus clarkii). P. maculata …

Brood Abundance And Invertebrate Availability In Crop-Dominated Landscapes In The Prairie Pothole Region, Catrina V. Terry

LSU Master's Theses

The Prairie Pothole Region (PPR) is the most important region for ducks in North America, producing over half the ducks on the continent, and it is a priority landscape for wetland and grassland conservation. Agricultural expansion has changed the PPR, and the majority of grasslands and potholes have been converted into row-crops. The loss of nesting habitat has directly caused nest success to decline. Most of the remaining wetlands are surrounded by row-crops, and are considered lower quality because they receive runoff of sediment and chemicals, which may decrease primary forage for young ducklings as well as inhibit wetland vegetation. …

The Predictive Influence Of Challenging Behavior On Parent Stress In Young Children With Autism Spectrum Disorder, Paige Weir

LSU Master's Theses

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication, restricted interest, and repetitive patterns of behavior. Individuals with ASD also exhibit challenging behaviors that affect parent and caregiver stress directly. However, researchers have not yet examined the predictive influence of specific challenging behaviors on parent stress, particularly in young children (i.e., infants and toddlers) with ASD. Therefore, the current study expands existing literature by a) investigating the influence that challenging behaviors of young children with ASD have on parent stress and b) examining the unique contribution that each behavior (i.e., aggressive/disruptive behavior, stereotypy, and self-injurious …

Willingness Of Non-Industrial Private Forest Landowners To Obtain A Private Versus Public Consultation, Erika Largacha

LSU Master's Theses

Promoting conservation practices among family forests landowners play a critical role to enhance forest health and ecosystem services. Several certification programs recognize such efforts, but participation among landowners varies based on their characteristics, program requirements, and incentives. One crucial step of certification is to obtain a forest management plan, but acquisition among landowners remains extremely low. Several studies suggest connecting landowners with foresters as the key element towards the adoption of forest management plans. Because foresters are typically employed by public forestry agencies or as private self-employed consultants, landowners' willingness to work with either may differ. As far as we …

Corn Nitrogen Management Under Different Tillage Systems, Akshara Athelly

LSU Master's Theses

Adoption of no-tillage (NT) and cover crops (CC) significantly effect soil physicochemical properties and nutrient cycling that necessitates modified nutrient management to maximize crop yields. Two field experiments were conducted to evaluate N-sources Urea Ammonium Nitrate (UAN), urea, and urea+ N-stabilizer (urea+ stab) and N-split applications 100%N at V2 (S1), 25%N at V2+75%N at V6 (S2), 25%N at V2+ 50%N at V6+ 25%N at VT (S3) in a sandy loam soil and three CC wheat (Triticum aestivum), hairy vetch (Vicia villosa) , and radish (Raphanus sativus) and their combinations along with three N-rates ( …

Using Uav Technology Paired With Multispectral Cameras To Assess Crown Rust Epidemics In Oats, Turner A. Graham

LSU Master's Theses

Crown rust, caused by Puccinia cornonata f. sp. avenae, is a common disease of oats (Avena sativa) found virtually everywhere oats are cultivated. This disease has caused yield losses of 10 to 40% worldwide. Early detection is important for effective management. A more recently utilized technology in agriculture is unmanned aerial vehicles (UAVs). UAVs, or drones, equipped with cameras are now being used as a resource to take images of fields to identify pests and other issues that may be occurring. Normalized differentiated vegetative index (NDVI) is a numerical indicator used to determine the vegetative health of …

Evaluating Substrate Stratification Practices For Enhanced Water Resource Management In Nursery Production, Kristopher S. Criscione

LSU Master's Theses

The nursery and greenhouse industries have continued to increase in production and sales over the past two decades. This increase in horticultural production necessitates a greater demand for finite natural resources, specifically water. Sustainable water resource management will be critical to the success and continual growth of the nursery industry. Strategic irrigation scheduling and innovative substrate management practices can improve nursery resource efficiency. Soilless substrates were originally utilized by the industry to increase substrate air-filled porosity, to ensure adequately drained container systems. Thus, the implementation of these soilless substrates can lead to an inefficient use of water and fertilizer. Substrate …

Consumers' Perception Of Food Containing Insect Protein Affected By Serving Condition And Questionnaire Protocol, Yupeng Gao

LSU Master's Theses

Edible insects are a new sustainable protein source compared to meat. Western consumers show aversion to the prospect of insects as food due to unfamiliarity, food neophobia, and negative emotions. This dissertation research explored consumers’ emotional perception of insect-based food products presented under different testing conditions and examined the influence of other people’s emotional expressions towards consumers’ purchase decisions. To identify and rate emotion intensities, tests were conducted using three presenting formats including text, image, and an actual product; all of which were applied for both cookies containing insects and without insects. In addition to these presenting formats, news of …

Ontogeny And Resource Use Of Invasive Lionfish, Pterois Volitans, In Shallow Water Habitats Surrounding Summerland Key, Emily Shallow

LSU Master's Theses

The invasive red lionfish, Pterois volitans, has been shown to considerably reduce reef biomass via predation and competition in non-native ranges. Primary maintenance of lionfish is through human removal (e.g., culling), which does not sufficiently control the population due to deep-water spawning, recolonization of recently culled reefs, and ontogenetic migrations to mesophotic waters. Here, I investigated the diets and primary energy pathways during ontogeny in lionfish from the Florida Keys using stomach contents and stable isotope (δ¹³C and δ¹⁵N) analysis to better understand their role in the trophic food web. Additionally, isotopic overlap between lionfish …

A Modular Open-Technology Device To Measure And Adjust Concentration Of Sperm Samples For Cryopreservation, Nikolas C. Zuchowicz

LSU Master's Theses

Repositories for aquatic germplasm can safeguard the genetic diversity of species of interest to aquaculture, research, and conservation. The development of such repositories is impeded by a lack of standardization both within laboratories and across the research community. Protocols for cryopreservation are often developed ad hoc and without close attention to variables, such as sperm concentration, that strongly affect the success and consistency of cryopreservation. The wide dissemination and use of specialized tools and devices can improve processing reliability, provide data logging, produce custom hardware to address unique problems, and save costs, time, and labor. The goal of the present …

Blue Carbon In South Florida's Mangroves: The Role Of Large Roots And Necromass, Zoë I. Shribman

LSU Master's Theses

Blue carbon sequestration and storage in mangroves largely result from belowground biomass allocation in response to flooded anaerobic soil conditions and nutrient availability. Biomass allocation to belowground roots is a major driver of mangrove soil formation and organic matter accumulation leading to blue carbon storage potential. Belowground biomass sampling in mangroves is labor intensive, limiting data availability on biomass stocks, particularly for large roots (>20 mm diameter) and necromass (dead roots). The mangrove nutrient model (NUMAN) uses mostly literature values to parameterize a soil cohort approach to simulate depth distribution of root mass and organic carbon concentration. We evaluated …

Influence Of Planting Date, Maturity Group, Harvest Aids And Fungicide Application On Soybean (Glycine Max (L.) Seed Quality, Ana Priscila Campos

LSU Master's Theses

Field studies evaluated the influence of planting date, maturity group, and harvest timing on soybean yield and seed quality at the LSU AgCenter Northeast (NERS), Macon Ridge, and Dean Lee Research Stations in 2018-2020. In addition, the influence of harvest aid and fungicide application on seed quality impact from delayed harvest and environment was investigated at NERS in 2019 and 2020 in both field and environmentally controlled growth chambers. Soybean yield was maximized when maturity group IV and V soybean varieties were planted between Mid-April and Mid-May. Earlier and later planting dates did not result in maximized yield. Planting date …

Understanding The Etiology Of Taproot Decline Of Soybean Caused By Xylaria Necrophora, José E. Ortiz Solórzano

LSU Master's Theses

Taproot decline (TRD) of soybean is caused by Xylaria necrophora. However, the mechanisms by which it infects soybean and produces symptoms are unknown. Symptoms of TRD include foliar interveinal chlorosis and necrosis and root necrosis, yet X. necrophora appears to be restricted to the roots. While Xylaria species are predominantly wood decomposers, a few are pathogens. More importantly, they produce secondary metabolites (SMs) with multiple bioactivities, including phytotoxicity and antimicrobial activity. Preliminary experiments suggested that X. necrophora was producing SMs responsible for TRD symptoms. We evaluated cell-free culture filtrates (CFs) for phytotoxicity on soybeans, testing for changes in chlorophyll …

Phragmites Australis Dieback In The Mississippi River Delta: Chemical Profiles Of Soil Types And Restoration Potential, Herie Lee

LSU Master's Theses

Since 2016, there has been widespread dieback of P. australis in the Lower Mississippi River Delta (hereafter referred to as Lower MRD, which is defined as the Birds Foot Delta) with relatively little to no signs of recovery. The cause of the current dieback is not fully understood. This thesis explores P. australis with emphasis on chemical profile characterization of different soil types and its effects on plant growth and the potential for restoration in the Lower MRD.

In chapter 2, I characterized the chemical profiles of soils collected from healthy and dieback stands of Phragmites, and from newly …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

Investigating Local Adaptation To Hypoxia Stress In The Eastern Oyster Through Comparative Transcriptomics, Heather Nichole Smith

LSU Master's Theses

Climate change represents one of the most important challenges to biodiversity, therefore it is important to understand the mechanisms that allow species to respond to rapid environmental change. Here, we compared two populations of eastern oysters, Crassostrea virginica, from the Gulf of Mexico to study the mechanisms underlying hypoxia tolerance. Using a common garden experiment and comparative transcriptomics, we identified sets of genes involved in the hypoxia response and found differences in both the timing and baseline expression of hypoxia-responsive genes between tolerant and sensitive populations, consistent with a scenario of local adaptation. These genes include the signaling transcription factor …

Effects Of Plant Spacing Variability And Non-Uniform Emergence On Corn Yield, Justin Dufour

LSU Master's Theses

Plant spacing variability and non-uniform emergence in corn (Zea mays L.) is not uncommon in Louisiana corn fields. Variation in planting depth, non-uniform surface crop residue distribution in no-tillage systems, microsite variation in the seed bed condition, and seed vigor are major factors responsible for non-uniform emergence. Also, planters with low precision in seed placement and careless planting operations can cause non-uniform spacing. Two studies were conducted to quantify the effects of plant spacing variability and non-uniform emergence on grain yield in corn. Six plant spacing treatments at 47,770 plants ha^-1 were evaluated. Uniform spacing, seed skip, double …

Evaluation Of Cool-Season Annuals Effect On Soil Health In Warm-Season Perennial Pastures In Southestern Us., Paola C. Muela Negrete

LSU Master's Theses

Perennial grass crops represent approximately 8 million hectares of the land area of the humid lower southeastern United States. These forage crops receive high rates of fertilizer, especially nitrogen (N), and near monoculture remains have often been treated with repeated applications of herbicides. Pasture management is crucial to improve soil properties in pasturelands. Common pasture management practices include introducing cool-season multispecies in warm-season pasture systems and forage harvest frequency of pasture systems. It is known that cool-season multispecies in warm-season pasture systems ensure cattle feeding during winter season and have beneficial effects on soil microbial biomass, soil organic matter (SOM), …

Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija

LSU Master's Theses

Spring-fed arid wetlands support high biological productivity and are hotspots for endemism and distribution of rare plants, making them areas of high conservation value. These systems are driven by complex interactions among groundwater discharge and the geomorphic and climatic features of the setting, which provide gradients of edaphic conditions, particularly soil moisture and salinity that influence the presence and abundance of rare plant communities. However, spring-fed arid wetlands are at particular risk of increases in salinity and drier hydrological regimes due to anthropogenic activities. Such alterations to abiotic conditions may jeopardize the distribution and abundance of rare plants by exceeding …

Seasonal Variation In The Feeding Ecology Of Yellowfin Tuna (Thunnus Albacares) From The Northern Gulf Of Mexico, Mitchell Shay Lovell

LSU Master's Theses

Highly migratory fishes (e.g., tunas, billfishes, and sharks) play a significant role in the structure and function of open-ocean ecosystems and a better understanding of the food web dynamics that support their populations is essential to improve management and conservation. Here, I use complementary approaches (stomach contents, DNA barcoding, & stable isotopes) to examine seasonal variability in the feeding ecology of sub-adult (70 – 100 cm; n = 371) and adult (100 – 160 cm; n = 206) yellowfin tuna (Thunnus albacares) from the northern Gulf of Mexico over a one-year period (April 2019 – March 2020). Stomach …

Characterization Of Resistance To Two Crambid Stem Borers Among Louisiana Sugarcane Cultivars, Leonardo D. Salgado

LSU Master's Theses

Cultivar resistance is a key management strategy for the stem borer complex (Lepidoptera: Crambidae) in Louisiana sugarcane, but mechanisms of resistance are not well understood. This research evaluated the potential mechanisms of cultivar resistance to Diatraea saccharalis and Eoreuma loftini among commercial sugarcane cultivars and experimental clones through a series of field screenings, greenhouse trials, and diet incorporation assays. The stem borer resistant standard HoCP 85-845 and cultivar L 01-299 were among the cultivars with the lowest borer injury levels in both field and greenhouse trials. Cultivars HoCP 00-950, L 12-201, and HoCP 14-885 were among the most heavily injured …

Isolation Of Foliar Fungi From Roseau Cane (Phragmites Australis) In Coastal Louisiana, David M. Galo Espinal

LSU Master's Theses

Roseau cane (Phragmites australis) is a wild plant with an extensive root system that is useful in areas vulnerable to soil erosion. In Louisiana, this plant plays an important role protecting the coastal infrastructure of the lower Mississippi River delta (MRD). Currently, P. australis growing in the MRD is being affected by a die-off, which has been associated with several biotic and abiotic factors.

Plant pathogenic fungi is a biotic factor that negatively affect plant growth. Therefore, foliar fungi were isolated from plants growing in one die-off affected area (MRD) and two non-affected areas (Pecan Island and Manchac) …

Environmental Perception In Colombia's Páramo Protected Areas, Juliana Delgado

LSU Master's Theses

This thesis analyzes the gap between farmers' environmental perceptions in Téquita, a small village in Colombia, and the definition of protected areas has led to a conflict for the use of natural resources. I examine if the protected area's policies have dealt with the social and ecological issues in the páramos and recognized the social construction of the landscape, farmers' identities, and their interpretations about work and land. The case study focuses on Güina High Mountain in the Guantiva-La Rusia páramo complex, which recently the Colombian government declared as a protected area. In light of anthropologist Tim Ingold's meaning of …

Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam

LSU Master's Theses

Eastern oysters (Crassostrea virginica) provide valuable ecosystem services and support a productive commercial industry in the northern Gulf of Mexico. Declining abundance from water quality changes and other factors drives development of management and restoration strategies focused on a comprehensive, metapopulation approach. Identifying oyster resource zones based on water quality combined with selective breeding of oysters adapted to specific conditions provides strategies to support aquaculture development and ensure resilient oyster populations and high production. Using 2015-2019 satellite-derived continuous salinity and temperature data for coastal Louisiana, this work created maps defining oyster resource zones supportive of (1) broodstock sanctuary …

Penguins Past And Present: Trace Elements, Stable Isotopes, And Population Dynamics In Antarctic And Sub-Antarctic Penguins And Seals, Allyson K. Kristan

LSU Master's Theses

Antarctica and the sub-Antarctic are remote regions where the impacts from climate change and anthropogenic activities are increasingly apparent. Previous studies show that the Antarctic is warming and has been affected by anthropogenic contaminants. Marine predators such as penguins and seals are commonly used in these regions as sentinels of ecosystem health as predator tissues can be used as non-invasive proxies of diet, population trends, and contaminant exposure. This thesis includes two separate studies which investigate the influence of climate change and human activity on Antarctic and sub-Antarctic ecosystems. First, Adelie penguin (Pygoscelis adeliae) eggshell samples were collected …