Digital Commons Network^™

Understanding The Role Of Early-Stage Seed Development On Final Seed Weight By Linking Seed Physiology, Transcriptomics, And Environments In Soybean (Glycine Max (L.) Merr.), Ashwini Shivakumar

Theses and Dissertations--Plant and Soil Sciences

Soybeans, which are widely grown in the United States, are used as food, animal feed, and industrial oil. The rise in plant-based diets highlights the high protein content and versatility of soybean. Understanding seed development is crucial for increasing yield. Soybean seed development includes three phases: lag, seed-filling, and maturation. Post-fertilization, the seed undergoes cell division in the lag phase, forming the embryo, endosperm, and seed coat. The embryo absorbs the endosperm and develops into two cotyledons. During the seed-filling phase, cotyledon cells accumulate starch, proteins, and lipids. During maturation, seeds dry out and become quiescent. Studies indicate that the …

Carbon Allocation To Growth And Storage In Pinus Ponderosa During And Following Experimental Carbohydrate Limitation, Ella M. Keefer

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Understanding how plants allocate carbohydrates to growth and storage in the face of drought and other stresses that reduce carbohydrate availability is crucial to predict ecosystem responses to future stress events. Growth is critical for resource acquisition while storage of carbohydrates is critical as a safeguard during stress. Despite this, how plants allocate carbohydrates to growth and to non-structural carbohydrate (NSC) storage under drought and carbohydrate limitation is poorly understood. We examined how carbohydrate limitation, with and without drought, affects carbon allocation to growth versus stored NSCs. We found that under carbon limitation and depletion of stored NSC, NSC storage …

A Cytosine Analogue 5-Azacitidine Improves The Accumulation Of Licochalcone A In Licorice Glycyrrhiza Inflata., Xiaoling Ma, Ningxin Jiang, Jingxian Fu, Yuping Li, Lijun Zhou, Ling Yuan, Ying Wang, Yongqing Li

Plant and Soil Sciences Faculty Publications

Licochalcone A (LCA) is a characteristic compound of Glycyrrhiza inflata with anti-inflammatory, antioxidant and antitumor activities. However, G. inflata produces LCA in low quantities that does not meet the market demand. In this study, we found that DNA methylation inhibitor 5-azacitidine (5-azaC) successfully improved the LCA contents in G. inflata seedlings. Transcriptome analysis revealed a series of differentially expressed genes (DEGs), including transcription factors such as MYB, ERF, WRKY, and some structural genes related to flavonoid biosynthesis. However, whole genome bisulfite sequencing (BS-seq) results showed little effect of the 5-azaC treatment on the alteration of DNA methylation on these genes, …

The Mechanism Of Sperm (Pro)Nuclear Migration In Plants And Animals, Yilin Zhang, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

Gamete nuclear migration is a critical process during fertilization in flowering plants, yet its molecular mechanisms remain poorly understood. Recent studies have highlighted the essential role of cytoskeletal elements, particularly F-actin, in directing sperm nuclear migration, contrasting with the microtubule-driven migration in animals. We summarize the process of sperm nuclear migration in plants and the involvement of Class XI myosin XI-G in Arabidopsis, along with the ROP8-SCAR2 pathway’s ARP2/3-independent mechanism for F-actin nucleation. We also provide a comparative overview of examples from sea urchins, C. elegans, mice and yeast contrasting these mechanisms with those in plants. Finally, we …

Examining The Effects Of Artemisia Annua On Neuro2a Cells, Wesley Lim

Honors Undergraduate Theses

Artemisia annua L. is a well-known medicinal herb used in Traditional Chinese Medicine for many centuries and contains artemisinin, which exhibits antimalarial properties [1] and is a potential treatment for SARS-CoV-2 [2]. However, the neurological effect of A. annua and its compounds are poorly understood. We hypothesize that A. annua extracts and artemisinin will provide protection against oxidative stress in mouse neuronal Neuro2A cells. Superoxide dismutase 1 (SOD1) is an anti-oxidant enzyme that protects against oxidative damage [3]. Growth Arrest and DNA Damage-inducible 45 alpha (Gadd45a) is involved in DNA repair and is a common biomarker for DNA damage[4]. SOD1 …

Sweetening The Deal: Enhancing Flower Production And Quality For Native Pollinators In Urban Landscapes, Yaelle Esther Reeve

Honors Undergraduate Theses

Urban landscapes can support pollinator conservation, but traditional landscape designs lack the diverse mixtures of native plants needed to support native pollinators. Although native plants support pollinators and can survive with less water and fertilizer than non-native landscape plants, they do not always grow well under modified urban soil conditions and irrigation regimes. A better understanding of the factors influencing flower production and the quality of native plants is needed if we are to design landscapes that support pollinator conservation. This study focused on how flower production and quality in different native plants responded to compost and irrigation treatments. The …

A Gis Tool For Optimal Forage Species Selection, David B. Hannaway, Christopher Daly, Michael D. Halbleib, Linda Brewer, Sophie Baur, Chelsea Clark, Emilie Krecklow, Scott Bassett

IGC Proceedings (1977-2023)

To determine appropriate forage species for US ecoregions, geographic information technologies (GIS) are being used to create climatic and soil factor maps. Excel spreadsheets and RStudio are used to create response functions of forage species to minimum and maximum temperature, annual precipitation, soil pH, soil salinity, and salinity. National forage data and expert opinion will evaluate quantitative tolerances, seasonal yield profiles, and pollinator suitability. These maps and agronomic and livestock use information will be shared with forage specialists and farmers to provide alternatives for improved perenniality, increased diversity, and system circularity. Future work will include development and evaluation of climate …

Hop Cone Drying For The Small Grower: Temperature And Airflow Considerations, Stacy A. Adams, David M. Mabie, Michael F. Kocher, David Jones

Department of Agronomy and Horticulture: Faculty Publications

Small hop growers without nearby processors for cone stripping and drying must attempt to do so on their own farm. Challenges exist for self-built drying systems, including drying capacity, processing speed, airflow direction, and maintaining quality during drying. Research-based recommendations are given for optimal temperature, sizing of drying vessel, maximum cone depth, and influences associated with airflow on processing uniformity and cone quality are presented.

Life Cycle Greenhouse Gas Emissions In Maize No-Till Agroecosystems In Southern Brazil Based On A Long-Term Experiment, Guilherme Rosa Da Silva, Adam J. Liska, Cimelio Bayer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Brazilian agriculture is constantly questioned concerning its environmental impacts, particularly greenhouse gas (GHG) emissions. This research study used data from a 34-year field experiment to estimate the life cycle GHG emissions intensity of maize production for grain in farming systems under no-tillage (NT) and conventional tillage (CT) combined with Gramineae (oat) and legume (vetch) cover crops in southern Brazil. We applied the Feedstock Carbon Intensity Calculator for modeling the “field-to-farm gate” emissions with measured annual soil N₂O and CH₄ emissions data. For net CO₂ emissions, increases in soil organic C (SOC) were applied as a proxy, …

Evaluation Of Winter Cereal Cover Crops Across Nitrogen Management Strategies In No-Till Corn Production, Robert Nalley

Theses and Dissertations--Plant and Soil Sciences

Rye (Secale cereale L.) is the most popular winter cereal cover crop utilized before corn, but wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) may provide a comparable value due to their similar fibrous root systems. Despite the benefits associated with winter cereal cover crops, drawbacks are possible for the subsequent corn crop. A field study was conducted with three site-years in Kentucky to measure the impact of the three winter cereals across nitrogen (N) management strategies. Wheat produced the most biomass compared with barley or rye cover crops. Wheat and rye needed approximately 100 more …

From Code To Crops: Harnessing Bioinformatics And Artificial Intelligence (Ai) In Agricultural Omics, Lakshay Anand

Theses and Dissertations--Plant and Soil Sciences

Global agricultural faces numerous challenges, such as climate change, resource limitations, novel pests and diseases, increasing costs, and the ever-increasing human population. To tackle these challenges, we need innovative strategies that combine new technologies and data analytics approaches to enhance agricultural output, promote sustainable methods, and optimize resource allocation. The key to this innovation lies in understanding the complex molecular web within plants that governs their growth, defense, and adaptability mechanisms. By mastering this molecular network, we can cultivate crops that are more resilient, sustainable, and suitable for different climatic terrains. Moreover, studying the symbiotic relationship between plants and microorganisms …

The Effects Of Potassium Fertilization Regime On High Tunnel Tomato Production, Sapana Pandey

Theses and Dissertations--Plant and Soil Sciences

A two-year field experiment (2022-2023) was conducted at the University of Kentucky Horticulture Research Farm in Lexington, KY to study the effects of potassium (K2O) fertilization rates on tomato yield and ripening disorders in determinate and indeterminate varieties (‘BHN-589’ and ‘Big Beef’, respectively). In the first year, K2O rates representing the soil test result-based commercial recommendation (0 lbs/acre) and sequentially greater rates (150, 300, and 450 lbs K2O/acre) were applied. In the second year, K2O rates were increased based on lack of fruit quality response and were 0, 300, 600, and 900 lbs K2O/acre. Leaf tissue nutrients, tomato yield, and …

Surveys, Field Studies, And Laboratory Incubation Experiments To Improve Alfalfa Production In The Mid-South, William Fleming

Theses and Dissertations--Plant and Soil Sciences

The objective of the alfalfa survey was to determine the role of soil fertility in the alfalfa yield plateau. Soil samples at depths of 10, 15, and 30 cm and tissue samples were collected from 114 alfalfa stands across Kentucky and surrounding states. Results indicate that soil fertility is likely contributing but not driving the alfalfa yield plateau. The main objective of the polyhalite incubation study is to determine if POLY4 was soluble enough to support potassium (K) and sulfur (S) for plant growth. The design of the study included four fertilizer treatments, three soil types, and four incubation times. …

Identifying Physiological, Morphological, And Genetic Drivers Of Key Intermediary Phenotypic Traits Associated With Stalk Lodging Resistance Within Genetically Diverse Maize Germplasm And Sorghum, Norbert Bokros

Theses and Dissertations--Plant and Soil Sciences

Maize stalk lodging reduces grain yields due to the permanent breakage or deformation of stalk tissue before grain harvest. To reveal new insights into the complex problem of maize stalk lodging, this dissertation will examine three primary objectives. First, the direct, diurnal influence of turgor pressure will be shown to have only marginal effects on stalk bending strength, a key trait associated with stalk lodging resistance. Up to a dozen individual stalks, grown to physiological maturity within the same field, were tested using a DARLING testing device. In parallel, stalk turgor status as measured by leaf water potential and turgor …

The Effect Of Spring And Winter Killed Cover Crops On Soil Physical Properties And Soil Organic Carbon, Danielle Doering

Theses and Dissertations--Plant and Soil Sciences

Maintaining soil organic carbon (SOC) and healthy soil physical structure in agroecosystems is crucial to sustainable production. To assess medium term impacts of cover crops on soil health in the top 90 cm, we conducted a field experiment in central Kentucky with varying levels of winter cover: spring and winter kill cover crops, weedy and bare winter fallows. After eight years of cover crop use, some soil physical properties improved: 35% greater mean weight aggregate diameter at 0-30 cm with spring kill covers and 5.2% more C held within large aggregates for both cover crop treatments compared to winter fallow. …

The Roles Of Mrna Polyadenylation Factors In Plant Growth And Development, Lichun Zhou

Theses and Dissertations--Plant and Soil Sciences

Messenger RNA polyadenylation, the process wherein the primary RNA polymerase II transcript is cleaved and a poly(A) tract added, is a key step in the expression of genes in plants. Polyadenylation is mediated by a complex (the polyadenylation complex, or PAC) that consists of between 15 and 20 subunits. To learn the roles of PAC in regulation of the polyadenylation in plants, I conducted a survey of variability in the plant PAC. For this, I drew upon a database of naturally-occurring variation in numerous geographic isolates of Arabidopsis thaliana. The results show that many subunits of the PAC are …

Weedy Rice Resistance To Imidazolinone Herbicides And Control With Glyphosate, Juan C. Velasquez, Veronica Hoyos, Nilda Roma-Burgos, Guido Plaza

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Background

Weedy rice (Oryza sativa L.) is a serious competitor of rice, causing severe yield losses. It contaminates and reduces the quality of harvested grain.

Objective

(1) evaluate the response of Colombian weedy rice accessions to glyphosate and the mixture of imazamox + imazapyr (F-IMIs) at commercial rates; (2) determine the resistance level of one morphotype of weedy rice putatively resistant to the F-IMIs from the objective (1).

Methods

Ten weedy rice accessions were evaluated for response to F-IMIs (imazamox + imazapyr 49.5 and 22.5 g a.i. ha-1, respectively) and glyphosate (960 g a.e. ha-1). One putative ALS-resistant and …

Contents, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Development And Evaluation Of A Retrofittable Variable Rate Applicator Controller, Ahmed Abdalla

Electronic Theses and Dissertations

The need to optimize resource utilization while increasing crop productivity is paramount. This research proposes a Low-cost Retrofittable Variable Rate Applicator Controller (VRAC) that aims to leverage the adoption of Variable Rate Technologies. The controller operates via the Raspberry Pi platform, a Global Positioning System (GPS), a stepper motor drive, and an anti-slip wheel encoder. The VRAC allows precise, on-the-fly control of variable-rate application of farming inputs. It utilizes GPS with 10 cm accuracy to pinpoint geographic coordinates in real-time. A wheel encoder measures traveling speed with a slip-resistant wheel design for precise RPM readings. The Raspberry processes the data, …

Monarch Butterfly (Danaus Plexippus) Oviposition Preferences And A Survey Of Fungal Pathogens On Native Milkweeds (Asclepias) Of The Northern Great Plains, Grace Damiano

Electronic Theses and Dissertations

North American monarch butterfly (Danaus plexippus) populations are experiencing significant declines due to habitat loss caused by land use changes. Much of the American Midwest where milkweed, the only host plant of the monarch butterfly, was once much more abundant has been converted to a predominantly agricultural landscape. There are nineteen species of milkweed native to the northern Great Plains region occupied by South Dakota, North Dakota, and Minnesota. Some of these milkweed species may be preferable to monarch butterflies for different reasons, including morphological factors such as stem length, species-level chemical factors, and temporal factors. As monarch …

Competition Between Bradyrhizobium Strains For Soybean Nodulation, Lilia Ernestina Montanez Hernandez

Electronic Theses and Dissertations

Biological Nitrogen Fixation (BNF) has surged as a natural strategy to provide available nitrogen to crops by taking advantage of diazotrophs, microorganisms that can reduce atmospheric nitrogen to ammonia. Soybean, a major crop, greatly benefits from BNF by forming endosymbiotic relationships with rhizobacteria from the genus Bradyrhizobium, which culminates in the formation of specialized organs called nodules, where nitrogen fixation occurs. This is known as Symbiotic Nitrogen Fixation (SNF). Inoculation of soybean fields with high nitrogen fixing Bradyrhizobium strains to stimulate SNF is being used as a strategy to increase crop productivity and nitrogen content. However, in North America, SNF …

Early Season Biomass And Weather Enable Robust Cereal Rye Cover Crop Biomass Predictions, Alexandra M. Huddell, Brian Needleman, Eugene P. Law, Victoria J. Ackroyd, Muthukumar V. Bagavathiannan, Kevin Bradley, Adam S. Davis, Jeffrey A. Evans, Wesley Jay Everman, Michael Flessner, Nicholas Jordan, Lauren M. Schwartz-Lazaro, Ramon G. Leon, John L. Lindquist, Jason K. Norsworthy, Lovreet S. Shergill, Mark Vangessel, Steven B. Mirsky

Department of Agronomy and Horticulture: Faculty Publications

Farmers need accurate estimates of winter cover crop biomass to make informed decisions on termination timing or to estimate potential release of nitrogen from cover crop residues to subsequent cash crops. Utilizing data from an extensive experiment across 11 states from 2016 to 2020, this study explores the most reliable predictors for determining cereal rye cover crop biomass at the time of termination. Our findings demonstrate a strong relationship between early-season and late-season cover crop biomass. Employing a random forest model, we predicted late-season cereal rye biomass with a margin of error of approximately 1,000 kg ha⁻¹ based on …

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 …

Benthic And Epibenthic Invertebrate Assemblages Associated With Estuarine Submerged Aquatic Vegetation Differ Between Native And Invasive Plants, Marissa Hall, Kathryn O'Shaughnessy, Bethany Kiley, Ashley Mcdonald, Taber Faurie, Zoey Hendrickson, Anna Reimer, Samantha Smith, Charles Martin

Gulf and Caribbean Research

Estuarine submerged aquatic vegetation (SAV) provides vital habitat for macroinvertebrate communities that support diverse food webs and subsequent ecosystem services. Invasive SAV, however, has the potential to alter estuarine food webs through competition with native SAV, resulting in different associated biological communities. In the Mobile-Tensaw Delta (Alabama, USA), the invasive Eurasian milfoil, Myriophyllum spicatum, is fast becoming the dominant SAV, out-competing native SAV such as wild celery, Vallisneria americana. This study investigated the above- and belowground macroinvertebrate assemblages associated with these SAV habitats. We found significantly different assemblages between the SAV, with V. americana supporting more even and …

Integrating Early Season Clover Cover Crops As A Living Mulch In Broccoli And Transitional Organic Winter Squash Production In Eastern South Dakota, Alexis Rose Barnes

Electronic Theses and Dissertations

Managing weeds, improving soil health, and reducing the use of plastic mulch continue to be priorities for South Dakota vegetable farmers. Farmers have expressed an interest in integrating cover crops into their farm systems. Clover cover crops used as a living mulch within and along cash crop rows may aid in weed suppression, nitrogen fixation, and prevent soil erosion. However, prior research has shown challenges of incorporating living mulch due to yield decreases. Research conducted in 2022 and 2023 in eastern South Dakota investigated the effects of four clover and four in-row soil management treatments on broccoli and organic winter …

Utilizing Soil Sensors To Assess Soil Health And Investigating Cover Crops Impact On Methane Emission, Shailesh Pandit

Electronic Theses and Dissertations

Soil health is influenced by climate change, cultural practices, topography, crop rotations, cover crops, soil parent materials, and soil biota. Interactions between these factors can improve or reduce soil health. This thesis investigates two topics, using soil sensors to provide a rapid assessment of soil health, and the impact of cover crops on soil biological activity and greenhouse gas emissions. Chapter 1 explores the use of two types of sensors to measure apparent electrical conductivity (ECa) and provides examples on the use of these sensors. Even though both sensors measure ECa using different processes, they provide useful information about temporal …

Nitrogen Fertilizer Placement And Rate Impacts Sunflower Seed Yield, Oil And Protein Content, Rojina Kafle

Electronic Theses and Dissertations

South Dakota accounts for about 36% of the total US commercial sunflower production and nitrogen is a major input. Costs related to N fertilizer demand economically optimum N rates. This study investigated the impact of the N fertilizer placement method (broadcast vs band) and rate (0, 28, 56, 84, 112, 140 kg N ha-1) on leaf chlorophyll content, head diameter, seed yield, seed oil, and protein concentration of three sunflower hybrids in 2022 and 2023. The experiment was conducted at Brookings (eastern SD- conventional till, 66 cm rainfall) using an oil-type hybrid and at central SD sites (no-till, 57 cm …

A Soil-Plant-Atmosphere Continuum Model To Simulate Seedling Response To Water Stress, Michael Kurt Kendree Jr.

Graduate Student Theses, Dissertations, & Professional Papers

Most current ecohydrologic models simplify the hydraulics that are at play in plant-water relationships by assuming that the water content within the plant is static. In reality, plants have a relative water content that varies with time in response to environmental stresses. To some extent, variations in plant relative water content are regulated by changes in the osmotic potential of water within plant cells, which contributes to the resilience of plants during periods of water shortage. We present a model that simulates plant water transport and storage within the soil-plant-atmosphere continuum. The model incorporates the role of osmotic regulation in …

Evolutionary Origins Of Secondary Growth - The Periderm Perspective: Integrating Evidence From Fossils And Living Plants, Madison A.K. Lalica

Cal Poly Humboldt theses and projects

Periderm is a structural feature with roles in protection of inner plant tissues and wound healing. Knowledge of periderm occurrences in the fossil record and living lineages outside the seed plants is limited and its evolutionary origins remain poorly explored. Here, I review the known taxonomic distribution of canonical periderm (typical ontogenetic stage) and wound periderm (self-repair mechanism). To this sparse body of data I add new observations and experiments on living plant lineages and new occurrences from the fossil record. One of the latter, documented in the new early euphyllophyte species Nebuloxyla mikmaqiana, joins the oldest known periderm …

Interactions Between New Zealand Mud Snails (Potamopyrgus Antipodarum) And Toxic Cyanoabacteria (Anabaena) In Baduwa’T (Mad River), Humboldt County, California, Cecilia F. Kennelly

Cal Poly Humboldt theses and projects

Invasive species in freshwater systems are circulated around the globe, wreaking havoc on natural communities. The New Zealand mud snail (Potamopyrgus antipodarum) is a very successful aquatic invader that has established populations in freshwater streams, lakes, and rivers around the globe. The goal of this project was to evaluate the interactions of invasive New Zealand mud snails (NZMS) and toxic cyanobacteria Anabaena in the Mad River in Humboldt County, California. These two species of concern are found in similar habitats along the river, but their whether NZMS consume Anabaena or affect toxin production is unknown. First, I conducted …