Plant Biology Commons^™

Practical Challenges In Delivering Dsrna For Woody Plant Protection, Zachary Bragg

Theses and Dissertations--Entomology

Unprecedented weather events associated with climate change, coupled with extensive anthropogenic stresses, have reduced the effectiveness of traditional forest pest management approaches, which can no longer keep pace with invasive species overwhelming naïve landscapes and native pests experiencing eruptive and expansive outbreaks. Double-stranded RNA-(dsRNA) mediated gene silencing, a type of RNA interference (RNAi), has been coopted for use as a biopesticide against a multitude of agricultural and horticultural pests and could serve as a powerful tool for woody plant protection. While effective initiation of gene silencing and subsequent mortality have been demonstrated in multiple tree pests, effective and efficient methods …

Assessing Endophyte Frequency Distributions And The Effect Of Epichloë Brachyelytri In The Chemotypic And Genotypic Diversity Of Brachyelytrum Erectum, Rachel Ann Sneed

Theses and Dissertations--Plant Pathology

Seed-transmissible epichloid fungal endophytes are best known for their roles as defensive mutualists in cool-season grasses. Historically, the discovery of fungal endophytes was driven by investigations of plant toxicity to livestock, followed by extensive study of their alkaloids and protection against insects and nematodes. Epichloae can produce four classes of alkaloids: ergot alkaloids, lolines (saturated aminopyrrolizidines), indole–diterpenes, and peramine. It is increasingly evident that these hereditary symbionts have much more diverse chemical profiles both in individual populations and between them. To this end, differences in chemotypic profiles of these symbionts may translate to different evolutionary and environmental advantages across plant …

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 …

Wildar Northeast Florida, Kailan Sindelar

UNF Faculty Research and Scholarship

Learn about some of the unique aspects of life in the wetlands and rivers of Northeast Florida and how we study them. In this app players see the memories of a student at the University of North Florida play out in front of them in AR. This app was created with funding the Digital Humanities Institute at the University of North Florida and informed by subject matter experts at the university.

Characterizing New Plant Fossils With Woody Growth From The Battery Point Formation Of Quebec (Canada), Emma T. Casselman

Cal Poly Humboldt theses and projects

The oldest woody growth has been recognized in several Early Devonian (ca. 410-395 Ma) euphyllophytes. Their taxonomic diversity is difficult to evaluate due to a lack of quantitative methods for comparing plants based on secondary xylem anatomy. In turn, this hinders understanding of their implications for the evolution of plant development. To develop metrics that quantify secondary xylem anatomy and allow for conclusive comparisons, I investigated extant taxa and Early Devonian fossil woody taxa. I developed multiple metrics for quantifying tracheid size as a function of position in the secondary xylem and tested them on a dataset of extant gymnosperms. …

Pioneering Plant Metabolomic Library Of Indonesian Plants For Research, Conservation, Capacity Building And Economic Development, Isabel Armas, Ernawati Sinaga, Nonon Saribanon, Noverita, Alvira Noer Effendi, Chairil Rohadi, Hanifa Nur Adilah, Vyacheslav Dushenkov, Ilya Raskin

Publications and Research

Indonesia, one of the world’s most biodiverse countries, is undergoing mass deforestation, exacerbating climate change and leading to accelerated loss of species. This project addressed the urgent need to conserve endangered Indonesian biodiversity. Specifically, the potentially life-saving bioactive compounds harbored within its plants. A group of Indonesian researchers from Universitas Nasional (UNAS) in Jakarta received training in RApid Metabolome Extraction and Storage (RAMES) technology, an ethical, low-impact, field-deployable and cost-effective methodology developed by Rutgers University. The team of Indonesian scientists used this technology to create the first metabolomic library of Indonesian plant species and an easily transportable collection containing 501 …

Quantifying The Ecological Effects Of Salix Fragilis On Riparian Habitat In Kittitas County, Washington, Landon Shaffer

All Master's Theses

Invasive species threaten plant community structure and function globally. Riparian areas, the zone near streams where water influences vegetation, are especially sensitive to invasive species colonization, suffering large-scale shifts in community composition. Salix fragilis (crack willow) is a nonnative riparian species abundant in the lower elevation tributaries of central Washington. Some speculate whether this willow should be listed as invasive in Washington, despite a lack of regional supporting evidence. I studied riparian communities dominated by either S. fragilis or native species in the Kittitas Valley and measured biodiversity, quantified differences in solar attenuation, and compared leaf decomposition rates to learn …

Trinity Transcript Assembly For The Titan Arum, Alveena Zulfiqar, Beenish J. Azhar, Samina N. Shakeel, William Thives Santos, Theresa D. Barry, Dana Ozimek, Kim Delong, Ruthie Angelovici, Kathleen M. Greenham, Craig A. Schenck, G. Eric Schaller

Dartmouth Scholarship

Transcriptome analysis of the titan arum was performed using floral and leaf tissues harvested from “Morphy” and “Morphy Junior,” two titan arums housed in the greenhouse of the Life Sciences Center at Dartmouth College. De novo transcript assembly for the reads obtained by RNA-seq was performed with Trinity-v2.6.6, using the default settings of >95% identity and a minimum assembled contig length of 200 nucleotides, resulting in the assembly of 915,085 transcripts that clustered as 536,644 genes.

See the following publication for details:

Zulfiqar, A., Azhar, B.J., Shakeel, S.N., Thives Santos, W., Barry, T.D., Ozimek, D., DeLong, K., Angelovici, R., Greenham, …

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 …

Turtlegrass (Thalassia Testudinum) Undergoes A Coordinated Hypersensitive Response When Challenged With Pathogenic Labyrinthula Sp., Ava Vasile Larson

UNF Graduate Theses and Dissertations

Infection of the subtropical seagrass Thalassia testudinum Banks ex König by pathogenic Labyrinthula sp. was found to induce lesion progression, alterations to the host’s oxidative metabolism, and production of defense metabolites over the early stages of infection (monitored over a 72-hr time course). By 48-hrs post-infection, host oxygen consumption, internal reactive oxygen concentrations, and caspase-3 proteolytic activity reached their highest levels. The formation of reactive oxygen species (ROS) and nitric oxide (NO) were detected in T. testudinum lesions by use of redox-sensitive probes/substrates and fluorescent imaging. To our knowledge, this work represents the first time NO has been detected in …

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 …

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 …

Investigating Changing Macronutrient Dynamics At A Plant, Microbe And Plant-Microbe Interactions Scale, Emel Kangi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nutrient limitation drives forest ecosystem processes by altering net primary production, belowground (C) investments, and microbial activity. As such, the availability of essential macronutrients, such as nitrogen (N) and phosphorus (P), can severely impact plant growth, microbial decomposition, and the strength of plant-microbial interactions. However, our understanding of plant and microbe responses to changing nutrient availability, and the extent to which nutrient availability affects plant-microbe interactions, remains somewhat limited. Therefore, in this dissertation, I aimed to investigate nutrient limitation on a plant, microbe, and plant-microbe interaction level. First, to connect the phenotypic responses of nutrient-limited plants to key molecular mechanisms, …

Building Better Biofuel Crops: A Field Evaluation Of Transgenic Populus Modified To Improve Feedstock Performance For Bioenergy Use, Molli Elisabeth Coombs

Graduate Theses, Dissertations, and Problem Reports (ETD)

A transition away from fossil fuel use is necessary for the future of energy production, and biofuels are a renewable energy option that can mitigate the impacts of fossil fuels through lowered carbon emissions and possible carbon sequestration. In order to successfully compete with fossil fuels, the production of biofuels must be sustainable and cost effective. Populus species are a biofuel crop used for bioenergy conversion from lignocellulosic biomass that have been proposed for use in feedstock plantations on marginal lands, which would avoid competition with agricultural production. Two challenges of feedstock production being faced are recalcitrance to chemical processing, …

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 …

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.

Role Of Ph And Plant Age On The Selection Of Rhizobial Endophytes In Soybean Root Nodules, Cole Alexander Roman

Graduate Theses/Dissertations

Soybeans form symbiotic relationships with nitrogen-fixing bacteria in their root nodules to acquire most of their nitrogen requirement; nitrogen is often one of the limiting nutrients in the soil. Members of the Bradyrhizobium, Sinorhizobium, Mesorhizobium, and Rhizobium genera can nodulate soybeans. Bradyrhizobium is preferentially selected over other types of rhizobia in varying environmental conditions and is often found in acidic soils. Sinorhizobium is often identified in the root nodules of soybeans in neutral and alkaline soil. So far, the potential role of soil pH on the selection of rhizobial endophytes with soybean root nodules is unknown. Likewise, …

Disturbance-Prone Ozark Streams: Interactions Between Plants And The Stream Environment, Alexis Renea Reifsteck

Graduate Theses/Dissertations

Ozark streams are extremely diverse ecosystems, despite frequent flood disturbance. Plant communities are frequently altered by bed-moving floods but are extremely resilient. We know that land-use, sediments, and nutrients can impact plant communities, but more can be divulged about how plants alter communities and how environmental variables influence plant community composition in disturbance-prone Ozark streams. To address this, I examined two key aspects of Ozark stream ecosystems: the role of American Water Willow, Justicia americana, in structuring aquatic habitats and the factors influencing gravel bar plant community composition. In the first chapter, I investigated how J. americana, a …

Should Crop Sequences In Western Australia Include More Lupins?, Christophe D'Abbadie, Sud Kharel, Ross Kingwell, Amir Abadi Ghadim

Grain and Other Field Crops Research Articles

Reducing greenhouse gas emissions is an increasing priority for Australian grain producers. Could substituting lupins for canola, as a rotational break crop, enable farmers to reduce their emissions by less use of nitrogenous fertilisers?

Aim

This study aims to identify if replacing canola with lupins in rotations at a range of locations in Western Australia’s grainbelt is environmentally and economically attractive.

Methods.

Bio-economic simulation modelling is used to examine the gross margins and emissions associated with replacement of canola by lupins at 14 locations in the grainbelt of Western Australia in variousland use sequences.

Key results

Replacing canola with lupins …