Digital Commons Network^™

Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J

Theses and Dissertations (Comprehensive)

A critical problem facing agriculture today is being able to consistently and sustainably provide plants with adequate nutrients for growth. With this problem being exacerbated by the ever-increasing human population, new perspectives and techniques are required to ensure global food security. In order to fully realize potential solutions, however, plant growth and nutrition cannot be exclusively focused upon. The soil-microorganism-plant system is comprised of many interconnected and interdependent processes that together support plant growth: it is upon these processes that the focus must be placed. In this work, the agromineral Spanish River Carbonatite (SRC) is characterized using the framework of …

02. My Career In Prairie Research And Restoration, Peter Schramm

North American Prairie Conference Proceedings

No abstract provided.

What Would The Babel Fish Say?, Monica Gagliano

Animal Sentience

Starting with its title, Key’s (2016) target article advocates the view that fish do not feel pain. The author describes the neuroanatomical, physiological and behavioural conditions involved in the experience of pain in humans and rodents and confidently applies analogical arguments as though they were established facts in support of the negative conclusion about the inability of fish to feel pain. The logical reasoning, unfortunately, becomes somewhat incoherent, with the arbitrary application of the designated human criteria for an analogical argument to one animal species (e.g., rodents) but not another (fish). Research findings are reported selectively, and questionable interpretations are …

Using Linear Mixed Models To Analyze Native And Non-Native Species Abundances In Coastal Sage Scrub, Kaylee Anderson

Scripps Senior Theses

Coastal Sage Scrub (CSS) is a low scrubland plant community native to the coasts of California, housing many threatened and endangered species. Due to the invasion of non-native plants, many areas of CSS have type converted to annual grasslands and the fire frequency has accelerated; fire in turn, may facilitate further invasion, leading to a loss of biodiversity. While many studies document post-fire succession in these communities, pre-fire data are rarely available for comparison, especially data on seedling emergence. I analyzed post-fire recovery of a type-converted grassland community, comparing seedling emergence data for the first and third year after fire …

Exploring The Link Between Foliar Water Uptake Capacity And Climate In Coast Redwood, Yvette M. Ferreira

Cal Poly Humboldt theses and projects

Coast redwood (Sequoia sempervirens D. Don) depends on foliar water uptake from fog and rain to maintain water balance during the dry summer season. As fog and rain decline across the redwood region, understanding how foliar uptake capacity responds to climate has become increasingly important. This study investigated how three peripheral leaf traits that influence foliar water uptake, visible wax coverage, stomatal density, and guard cell length, vary across climatic gradients and how those traits affect uptake across 14 sites in California. Foliar water uptake was quantified using rain-chamber rehydration experiments, climatic predictors were evaluated using least absolute shrinkage …

Identifying Plant Functional Traits To Assist Ecological Intervention In A Drying Landscape, Ana Luiza Muler

Theses: Doctorates and Masters

Mediterranean-type ecosystems (MTEs) are among the most vulnerable to land use and climate change and many attempts are in place to restore these ecosystems. Therefore, it is necessary to assess differences in plants’ ability to withstand water-stress, including biotic interactions. Such knowledge helps us understand community assembly, which is crucial for ecological intervention. This study involved: (1) reviewing the literature on traits that can differentiate functional types; (2) adapting the methodology to measure leaf water potential at turgor loss point (πtlp) for small-leaved species; (3) using these traits to quickly identify water-use strategies of adult …

Cytokinin Acts Through The Auxin Influx Carrier Aux1 To Regulate Cell Elongation In The Root, Ian H. Street, Dennis Matthews, Maria Yamburkenko, Ali Sorooshzadeh

Dartmouth Scholarship

Hormonal interactions are crucial for plant development. In Arabidopsis, cytokinins inhibit root growth through effects on cell proliferation and cell elongation. Here, we define key mechanistic elements in a regulatory network by which cytokinin inhibits root cell elongation in concert with the hormones auxin and ethylene. The auxin importer AUX1 functions as a positive regulator of cytokinin responses in the root; mutation of AUX1 specifically affects the ability of cytokinin to inhibit cell elongation but not cell proliferation. AUX1 is required for cytokinin-dependent changes of auxin activity in the lateral root cap associated with the control of cell elongation. Cytokinin …

Early Seral Mixed-Conifer Forest Structure And Composition Following A Wildfire Reburn In The Sierra Nevada, Erin Alvey

Cal Poly Humboldt theses and projects

Before the era of modern fire suppression, California’s northern Sierra Nevada mixed-conifer and yellow pine forests were self-regulating; recurring short-interval, low-mixed severity wildfires maintained forest structure and composition, which in turn exerted bottom-up controls on subsequent wildfires. As a result of fire suppression, and coupled with the effects of climate warming and other anthropogenic disturbances, the fundamental structure of mixed-conifer and yellow pine forests has shifted. Wildfires may now be increasing in size, severity, and frequency across western North America. However, little is known about the post-fire impacts of repeat wildfire on a forest after a long era of suppression. …

Effects Of Glyphosate On Soybean Nutrition, Endophytic Colonization By Cercospora Cf. Flagellaris And Development Of Cercospora Leaf Blight, Teddy Garcia Aroca

LSU Master's Theses

Glyphosate (Roundup®, Monsanto, Inc., St. Louis, MO) is the most widely used herbicide in the world because of its broad spectrum and its efficacy in controlling annual broadleaf weeds and undesired grasses. The effect of glyphosate on mineral nutrition and plant diseases has been an important topic during the past decade, because of its controversial effects on plant mineral nutrition. In order to test the hypothesis that glyphosate affects soybean mineral nutrition, and therefore predisposes soybean to Cercospora leaf blight, six glyphosate-resistant (GR) soybean varieties were either not treated or treated with glyphosate in field experiments. Plants were then evaluated …

Characterization Of Sulfur Chemistry In Louisiana Coastal Wetland Soils Using X-Ray Absorption Fine Structure (Xafs) Spectroscopy, Negar Dehghani Tafti

LSU Master's Theses

Sulfur is one of the most abundant elements in the environment, which plays a vital role in the growth and functioning of plants and microorganisms. It is found in an extended variety of species in gases, liquid, and solid forms and present in various nature systems. Wetlands are one of the largest global sinks/sources of sulfur. Being existing in a variety of oxidation states, sulfur contributes to biogeochemical cycles of coastal wetlands through involving in humification processes as well as influence on metal sulfide formation and consequently, methanogenesis and greenhouse gas emission. In this study, we have evaluated sulfur chemistry …

Influence Of Silicon On The Development Of Anthracnose Of Grain Sorghum, Sanjay Pokhrel

LSU Master's Theses

To study the effect of Silicon (Si) with and without a fungicide on anthracnose development of sorghum, several experiments were conducted in the greenhouse and field. In the initial study, different Si rates [0 (control), 0 (lime control), 200, 400, 600, 800 kg Si/ha] were used in a low-Si Alfisol to determine if inoculum densities were affected by Si levels. No differences were observed between inoculum densities of 1*105 and 1*106 conidia/ml in affecting anthracnose development in the greenhouse. Anthracnose severity was found to be lowest in plants treated with 800 kg Si/ha, regardless of inoculum density. In another study, …

The Relationship Between Invasive Annual Grasses And Biological Soil Crust Across Eastern Washington, Jarrett B. Cellini

EWU Masters Thesis Collection

Invasive annual grasses cause ecological and economic damage across the western US and are a focal point in restoration and management plans. Managing invasion resistance of natural areas is critical to maintaining their biodiversity and function. Climate change is expected to shift species interactions, including invasive annual grasses, and may alter invasion resistance. One component of invasion resistance is biological soil crust (biocrust), which has been shown to limit Bromus tectorum (cheatgrass) in arid regions. However, biocrust has been less studied in semiarid regions and its effects on other invasive annual grasses, such as Ventenata dubia, have never been studied. …

A Molecular Characterization Of The Fungal Endophytes Within The Needles Of Ponderosa Pine (Pinus Ponderosa), Amy E. Gray

EWU Masters Thesis Collection

"Fungal endophytes (microbial fungi that live in plant tissues without causing disease) are ubiquitous in plants studied to date. Many conifers host endophytes that produce important bioactive secondary metabolites. While the endophytes in Pinus ponderosa roots have been studied, the endophyte communities within the needles are not well characterized by molecular means: thus, the goal of this study was to do so. Needles were sampled at two sites located five kilometers apart along a slight precipitation gradient in Eastern Washington State. Fungal DNA (along with pine DNA) was isolated directly from needles of two ages. Internal transcribed spacer regions of …

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

Mechanisms Of Native Shrub Encroachment On A Virginia Barrier Island, Joseph Thompson

Theses and Dissertations

Species composition, temperature, soil nutrients, and leaf area index (LAI) were recorded across three encroaching Morella cerifera thicket edges and three free- standing shrubs on Hog Island, Virginia to characterize the effect of shrub thickets on the plant community and microclimate. Electron transport rate (ETR) was taken on shrub leaves to determine if microclimate benefits M. cerifera physiology. Species richness was lowest inside shrub thickets. Soil water content and LAI were higher in shrub thickets compared to grassland. Soil organic matter, N, and C were higher inside shrub thickets. Summer and fall maximum temperatures were more moderate in shrub thickets …

Development Of Functional Markers For Resistance To Leaf Scald In Sugarcane, Andres Felipe Gutierrez Viveros

LSU Doctoral Dissertations

Leaf scald, caused by Xanthomonas albilineans, is a major sugarcane disease worldwide. The disease is managed primarily with resistant cultivars obtained through classical breeding; however, the erratic symptom expression hinders the reliability and reproducibility of the selection process. The development of molecular markers associated with incompatible/compatible reaction can overcome this limitation. Suppression subtractive hybridization (SSH) and quantitative trait locus (QTL) mapping were the strategies used to find leaf scald resistance-associated genes and molecular markers in sugarcane. SSH results showed that genes involved in signal perception and transduction, and DNA binding, were highly expressed in the resistant clone LCP 85-384 compared …

Characterization Of Xylella Fastidiosa In Rabbiteye Blueberry, Mary Helen Ferguson

LSU Doctoral Dissertations

Xylella fastidiosa colonizes the xylem of a wide range of plants and causes symptoms in many of them. It was of interest to determine how widespread X. fastidiosa was and what its potential impact might be in rabbiteye blueberry. X. fastidiosa was detected from two of 17 Louisiana orchards from which samples were collected. A yield study was conducted at one of these orchards, and mean yields of X. fastidiosa-positive plants were 55% and 62% less than those of X. fastidiosa-negative plants in 2013 and 2014, respectively. Average berry weight was also lower in X. fastidiosa-positive plants. However, plants that …

Identification Of Genes Associated With Resistance To Brown Rust In Sugarcane And Prevalence Of One Major Gene, Mavir Carolina Avellaneda Barbosa

LSU Doctoral Dissertations

Development of resistant cultivars is the main control measure against sugarcane brown rust caused by Puccinia melanocephala. Durability is uncertain, since the pathogen possesses adaptive ability to overcome host plant resistance. A differential gene expression study utilizing suppressive subtraction hybridization was conducted to improve understanding of brown rust resistance mechanisms in sugarcane. The expression patterns of 11 unigenes representing biosynthetic pathways, defense-related genes, and signaling genes were analyzed in L 99-233, a cultivar exhibiting quantitative resistance, L 01-299, a resistant cultivar with the major resistance gene Bru1, and two susceptible cultivars, Ho 95-988 and L 09-125, at 24 h, 48 …

Effects Of Predator Satiation On Seed Predation In New Roadside Prairie Plantings, Jessica Riebkes

Dissertations and Theses @ UNI

Restoration efforts in the tallgrass prairie ecosystem are inhibited by high seed cost and as little as 10% emergence of planted, pure live seed. This study examined the portion of loss due to seed predation and sought to reduce this predation in new roadside prairie plantings. Studies document the occurrence of predation in several plant communities and across all plant families, but little is known about how to reduce the impact of seed predators, especially in a restoration setting. On three sites where native prairie seed was recently drilled, we attempted to satiate seed predators by broadcasting a supplemental food …

Horticultural Technique For Rearing And Redistribution Of The Sessile Biological Control Agent, Rhizaspidiotus Donacis On Its Host Plant, Arundo Donax, Joseph M. Villarreal, John A. Goolsby, Ann T. Vacek, Adalberto A. Perez De Leon, Alexis Racelis

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Arundo donax, giant reed is an invasive weed in the riparian habitats of the Rio Grande Basin. A biological control program using specialist insects from the native range in Mediterranean Europe, including the arundo scale, Rhi-zaspidiotus donacis has been implemented. The arundo scale is a sessile insect that spends most of its life cycle affixed to its host plant, thus creating challenges for its rearing and redistribution to field sites. A horticultural technique was developed which allowed for rearing of the scale on small, potted A. donax microplants, which could later be transplanted to field sites. Female scale reach maturity …

Impact Of The Biological Control Agent Tetramesa Romana (Hymenoptera: Eurytomidae) On Arundo Donax (Poaceae: Arundinoideae) Along The Rio Grande River In Texas, John A. Goolsby, Patrick J. Moran, Alexis Racelis, Kenneth R. Summy, Maricela Martinez Jimenez, Ronald D. Lacewell

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Five years post-release of the arundo gall wasp, Tetramesa romana, into the riparian habitats of the lower Rio Grande River, changes in the health of the invasive weed, Arundo donax, or giant reed, have been documented. These changes in plant attributes are fairly consistent along the study area of 558 river miles between Del Rio and Brownsville, TX, and support the hypothesis that the arundo wasp has had a significant impact as a biological control agent. Plant attributes were measured prior to release in 10 quadrats at each of 10 field sites in 2007, and measured again …

Population Genetic Structure Of Asclepias Tuberosa In Northwest Iowa: A Comparison Within And Between Remnant Prairies And Commercially Available Seed, Jeff Ploegstra, Brittany De Ruyter, Tony N. Jelsma

Faculty Work Comprehensive List

Isolated in scattered remnants, less than 0.1% of Iowa's original tallgrass prairie remains. The small populations remaining are at risk for reduced genetic diversity, inbreeding depression, and outbreeding depression. In light of these concerns, we used microsatellite analysis to assess the genetic structure of butterfly milkweed (Asclepias tuberosa) populations on prairie remnants in northwest Iowa. We compared remnant populations with a restoration population at Dordt College in Sioux Center, Iowa, and with an Oklahoma seed source. Microsatellites identified for use in common milkweed (Asclepias syriaca) had sufficient polymorphism information content (PIC) across the butterfly milkweed ( …

Small Unmanned Aerial Vehicles (Micro-Uavs, Drones) In Plant Ecology, Mitchell B. Cruzan, Ben G. Weinstein, Monica R. Grasty, Brendan F. Kohrn, Elizabeth C. Hendrickson, Tina M. Arredondo, Pamela G. Thompson

Biology Faculty Publications and Presentations

Premise of the study: Low-elevation surveys with small aerial drones (micro–unmanned aerial vehicles [UAVs]) may be used for a wide variety of applications in plant ecology, including mapping vegetation over small- to medium-sized regions. We provide an overview of methods and procedures for conducting surveys and illustrate some of these applications.

Methods: Aerial images were obtained by flying a small drone along transects over the area of interest. Images were used to create a composite image (orthomosaic) and a digital surface model (DSM). Vegetation classification was conducted manually and using an automated routine. Coverage of an individual species …

Using Detection Dogs And Rspf Models To Assess Habitat Suitability For Bears In Greater Yellowstone, Jon P. Beckmann, Lisette P. Waits, Aimee Hurt, Alice Whitelaw, Scott Bergen

Western North American Naturalist

In the northern U.S. Rockies, including the Greater Yellowstone Ecosystem (GYE), connectivity is a concern because large carnivores have difficulties dispersing successfully between protected areas. One area of high conservation value because of its importance for connecting the GYE to wilderness areas of central Idaho is the Centennial Mountains and surrounding valleys (2500 km2) along the Idaho–Montana border just west of Yellowstone National Park. The current expansion of grizzly bears (Ursus arctos) and other large carnivore populations outside protected areas of Yellowstone National Park and Grand Teton National Park has placed a greater emphasis on potential linkage zones …

Rna Sequencing Analysis Of The Msl2msl3, Crl, And Ggps1 Mutants Indicates That Diverse Sources Of Plastid Dysfunction Do Not Alter Leaf Morphology Through A Common Signaling Pathway, Darron R. Luesse, Margaret E. Wilson, Elizabeth S. Haswell

Biology Faculty Research

Determining whether individual genes function in the same or in different pathways is an important aspect of genetic analysis. As an alternative to the construction of higher-order mutants, we used contemporary expression profiling methods to perform pathway analysis on several Arabidopsis thaliana mutants, including the mscS-like (msl)2msl3 double mutant. MSL2 and MSL3 are implicated in plastid ion homeostasis, and msl2msl3 double mutants exhibit leaves with a lobed periphery, a rumpled surface, and disturbed mesophyll cell organization. Similar developmental phenotypes are also observed in other mutants with defects in a range of other chloroplast or mitochondrial functions, including …

A Novel Transcription Factor In Arabidopsis Thaliana Abiotic Stress Response, Achira S. Weerathunga Arachchilage

LSU New Orleans Theses and Dissertations

Plants respond to environmental stress by altering their gene expression. Under stress conditions some genes are activated and some genes are repressed. Even though a lot of work has been done to understand mechanisms of gene activation under abiotic stress very little information is available on how stress responsive genes are kept repressed under normal growth conditions. Recent work has revealed that plants use transcriptional repression as common mechanism of gene repression. Transcriptional repression is achieved by recruitment co-repressor complexes to the target genes. Recent studies have revealed that the co-repressor LUH complexes with SLK1 and SLK2 to silence Arabidopsis …

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

School of Natural Resources: Dissertations, Theses, and Student Research

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …

Restoration Of A Wet Longleaf Pine (Pinus Palustris) Savanna In Southeast Louisiana: Burning Toward Reference Conditions, Alex K. Entrup

LSU New Orleans Theses and Dissertations

This study quantifies the changes in vegetation composition and structure of a fire-excluded Pinus palustris (longleaf pine) wetland savanna restoration site in southeastern in comparison to a proximate contemporary reference site. The restoration site was invaded by hardwood species and off-site pines, and never underwent extensive soil disturbance. The restoration treatments involved logging across portions of the site and the reintroduction of fire across the entire site. All species present in 10m² quadrats were recorded prior to treatment and throughout the 17 year study at reference and treatment sites. The community composition of both logged and unlogged sites converged …

Extension Agriculture And Natural Resources In The U.S. Midwest: A Review And Analysis Of Challenges And Future Opportunities, Mahdi M. Al-Kaisi, Roger Wesley Elmore, Gerald A. Miller, David Kwaw-Mensah

Department of Agronomy and Horticulture: Faculty Publications

This review addresses key changes in U.S. agricultural extension and future opportunities. Agricultural extension has been a part of the land-grant university (LGU) system for more than 100 years. The Morrill Act of 1862 established the LGU system by authorizing states access to federally controlled land and funding for public institutions offering educational opportunities focusing on agriculture and mechanical arts for farmers and the working class. Current surveys in Iowa reveal changing trends in extension: more than 90% of farmers identified private-sector crop advisers as their primary source for recommendations, whereas more than 80% of those advisors identified Iowa State …

Assessing Foliar Ascorbate Content In A Rice Diversity Panel And In Selected Mapping Population Lines With Varying Levels Of Seedling Cold Tolerance, Sonia Elizabeth Castillo Gonzalez

Student Theses and Dissertations

Rice is economically, culturally, and socially important to many people in the world. Arkansas is the main rice producer in the USA. Climate change continues to increase the incidence of abiotic stresses such as cold, heat, drought, water excess, and soil salinity. These stresses pose a particular challenge to rice cultivation. Rice has lower yields under cold stress, particularly when plants are exposed to cold at the seedling and reproductive stages. Early spring plantings and field irrigation with underground cold water expose rice seedlings to cold stress. Previous studies in Arabidopsis thaliana have shown that lines engineered to have elevated …