Digital Commons Network^™

A Force Of Nature: Molecular Mechanisms Of Mechanoperception In Plants, Gabriele B. Monshausen, Elizabeth S. Haswell

Biology Faculty Research

The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification …

Functional Analysis Of A Glutathione S-Transferase Gene From Reniform Nematode On Soybean, Jing Hou

All Theses

Nematode glutathione S-transferases (GSTs) have been implicated in plant-nematode interactions as effector proteins with an important role in the establishment of feeding sites. Studies with root-knot nematode in Arabidopsis thaliana suggest that GSTs may protect the nematode against oxidative plant defenses and modulate plant responses to parasitism. Our objective was to study the function of a GST from reniform nematode (Rotylenchulus reniformis) in soybean. We used a virus-induced gene silencing (VIGS) system, utilizing a Bean pod mottle virus (BPMV)-based vector and a partial sequence of gsts-1 from Meloidogyne incognita to silence the putative reniform nematode homolog. The effect of silencing …

Diversity Among Isolates Of Phytophthora Cinnamomi From Ornamental Plants In South Carolina, Simon Schreier

All Theses

Phytophthora cinnamomi is a devastating pathogen that can attack over 900 hosts. It is the most common species of Phytophthora isolated from woody ornamental crops in South Carolina but little is known about variability among isolates of P. cinnamomi that attack these plants. Therefore, 142 isolates of P. cinnamomi recovered from diseased plant samples submitted to the Clemson University Plant Problem Clinic between 1995 and 2011 were characterized for mycelium growth habit, growth rate, mefenoxam sensitivity, mating type, and sporangium morphology. Mycelium growth habit on PARPH-V8 selective medium was classified as aerial, appressed, or dwarf; 87% of isolates had the …

Soybean (Glycine Max) Response To Imazosulfuron Drift And Carryover From Rice (Oryza Sativa), Sandeep Singh Rana

Graduate Theses and Dissertations

In the Midsouth, soybean is often grown in close proximity to rice or in rotation with rice. Herbicides used in rice can injure soybean via drift or carryover. Consequently, field trials were conducted to determine the response of soybean (cv. AG 4703) to imazosulfuron drift and carryover (at Fayetteville, Marianna, Keiser and Pine Tree, AR) from rice. To assess the potential for carryover, soybean was planted into rice fields treated the previous year with imazosulfuron (rotation study). To evaluate in-season sensitivity of soybean to imazosulfuron (tolerance study) relative to halosulfuron, a common sulfonylurea herbicide applied to rice, both imazosulfuron and …

Distribution And Control Of Glyphosate-Resistant Johnsongrass (Sorghum Halepense) In Arkansas Soybean, Dennis Brent Johnson

Graduate Theses and Dissertations

Johnsongrass, once the most persistent and troublesome grass weed of row crops throughout the southern U.S., has previously been confirmed resistant to the acetolactate synthase (ALS) and acetyl-coenzyme A carboxylase-inhibiting herbicides in the Midsouth and has recently evolved resistance to glyphosate in Arkansas. The goal of this research was to establish the geographical distribution of herbicide-resistant johnsongrass in Arkansas and to develop herbicide programs for controlling glyphosate-resistant johnsongrass in Arkansas soybean. Johnsongrass accessions were collected from 14 counties in the Mississippi River Delta region of Arkansas and screened for resistance to four of the most commonly used postemergence herbicides for …

High Yield Soybean Management: Planting Practices, Nutrient Supply, And Growth Modification, Evan Sonderegger

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Growers are constantly seeking ways to improve yield in soybean [Glycine max (L.) Merr.]. There has been much interest in the use of selected alternative practices to maximize soybean yield. These practices include planting soybean at higher than recommended seeding rates, planting soybean in narrow rows, breaking apical dominance to induce branching, application of strobilurin fungicides prophylactically to minimize disease and extend the seed filling period, the use of N fertilizer both in furrow and foliar applied, and the use of seed treatments to promote early stand establishment and health. Field studies were conducted at the University of Nebraska …

Factors Influencing The Distribution And Structure Of Tropical Vascular Epiphyte Communities At Multiple Scales, Carrie Woods

All Dissertations

Understanding the factors that determine species distributions is a central question in ecology. Niche-based theories stress the importance of environmental heterogeneity in influencing species distributions while neutral-based theories emphasize the effects of dispersal limitation. The relative importance of these factors in influencing species distributions may depend on spatial scale - deterministic factors may be more important at small spatial scales where fine-scale habitat factors become more relevant and stochastic factors may be more important at larger spatial scales where dispersal limitation becomes more relevant. I examined the influence of deterministic and stochastic factors on the distribution and structure of vascular …

The Characterization Of Algae Grown On Nutrient Removal Systems And Evaluation Of Potential Uses For The Resulting Biomass, Kristin Hampel

Dissertations

Eutrophication resulting from excess nutrient loads is a major environmental issue that affects surface water quality and causes surplus primary production, thereby reducing dissolved oxygen concentrations. A method for managing nutrients in surface waters involves absorption of excess nutrients by deliberately cultivating benthic algal turf biomass, then harvesting it for a variety of uses, including biofuels, soil amendments, or feed supplements, thus coupling nutrient removal to additional economic drivers.

The goals of this work are to (1) evaluate the composition of algal biomass grown to remove surface water nutrients, (2) compare biomass grown at different geographic locations and in dissimilar …

Quick Start Guide To Soil Methods For Ecologists, Lora Perkins, Robert R. Blank, Scot D. Ferguson, Dale W. Johnson, William C. Lindemann, Ben M. Rau

Natural Resource Management Faculty Publications

Increasingly biologists and ecologists are becoming aware of the vital importance of soil to processes observed above ground and are incorporating soil analyses into their research. Because of the dynamic and heterogeneous nature of soil, proper incorporation of soil analysis into ecological studies requires knowledge and planning. Unfortunately, many ecologists may not be current (or trained at all) in soil science.We provide this review, based on our cumulative >60 years of work in soil science,to help familiarize researchers with essential information to appropriately incorporate soil analyses into ecological studies. Specifically, we provide a brief introduction into soils and then discuss …

B.R. Wells Rice Research Studies 2012, R. J. Norman, K.A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

A R2r3-Myb Transcription Factor From Epimedium Sagittatum Regulates The Flavonoid Biosynthetic Pathway, Wenjun Huang, Haiyan Lv, Ying Wang, Wei Sun, Ming Luo, Shaohua Zeng, Sitakanta Pattanaik, Ling Yuan

Plant and Soil Sciences Faculty Publications

Herba epimedii (Epimedium), a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. The bioactive components in herba epimedii are mainly prenylated flavonol glycosides, end-products of the flavonoid pathway. Epimedium species are also used as garden plants due to the colorful flowers and leaves. Many R2R3-MYB transcription factors (TFs) have been identified to regulate the flavonoid and anthocyanin biosynthetic pathways. However, little is known about the R2R3-MYB TFs involved in regulation of the flavonoid pathway in Epimedium. Here, we reported the isolation and functional characterization of the first …

Systematics, Climate, And Ecology Of Fossil And Extant Nyssa (Nyssaceae, Cornales) And Implications Of Nyssa Grayensis Sp. Nov. From The Gray Fossil Site, Northeast Tennessee, Nathan R. Noll

Electronic Theses and Dissertations

The Late Hemphillian (latest Miocene or earliest Pliocene, 7-4.5 Ma) Gray Fossil Site in northeastern Tennessee is interpreted to represent a lacustrine paleokarst fed by a river or stream. This research focuses on the morphological and systematic relations of Nyssa endocarps (fruit pits) from the fossil site to extinct and extant Nyssa species. A combination of metric and nonmetric traits allows recognition of a new species: Nyssa grayensis sp. nov. This fossil species shares the most similarities with the extant Nyssa ogeche Bartram ex Marshall from southeast North America and the Eocene fossil Nyssa eolignitica Berry from western Tennessee. Affinities …

Genetic Diversity Of Asclepias Tuberosa In Iowa Prairies, Jeff Ploegstra, Michelle Alkema, Kayla Graves, Brittany De Ruyter, Tony N. Jelsma

Faculty Work Comprehensive List

Reduced population size can result in the loss of genetic diversity, which in turn can make organisms more susceptible to environmental challenges. In Iowa less than one percent of the original tallgrass prairie remains, isolated in a few remnant prairies. We are undertaking a long term project to assess the genetic variability in native prairie plants on remnant prairies in Northwest Iowa. We are testing six microsatellite sequences for butterfly milkweed (Asclepias tuberosa) from the Steele Prairie State Preserve, Broken Kettle Grasslands, a private prairie near Cherokee IA, a prairie restoration project on the Dordt College campus and populations from …

Effects Of Varying Spring Hollow Tine Aerification Size And Timing On Bentgrass Greens, Lewis Hubbard Jr

All Dissertations

The desire to maintain optimal turfgrass and surface properties often leads turfgrass managers to minimize impact from cultural practices like hollow tine aerification (HTA). Comprehensive research is essential to developing aerification programs which allow optimal use of turfgrass surfaces without sacrificing overall turf health.
A two-year field experiment was conducted on a 14-year-old U.S. Golf Association (USGA)-specified Crenshaw creeping bentgrass [Agrostis stolonifera L. var palustris (Huds.)] research putting green in Clemson, SC, to evaluate the effects of varying spring HTA size and timing on turfgrass, surface, organic matter (OM), and soil properties.
Spring HTA treatments included 1.2-cm i.d. tines spaced …

A Review Of Apomixis And Differential Expression Analyses Using Microarrays, Jonathan Harris Cardwell

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Apomixis is a complex trait of great interest to the agricultural community, as it has the potential to fix hybrid vigor in many agriculturally significant crops. Although apomixis has been studied extensively morphologically, the genetic and epigenetic factors responsible for apomixis are still very poorly understood. As no apomictic species has been sequenced and annotated, various low-cost tools and techniques are being utilized to begin profiling the trait. These include cross-species microarrays using probe masking, which deletes information from array probes that do not hybridize to the genomic DNA of the cross species. Despite their limitations, these tools are providing …

Thorns Of Native Lower Rio Grande Valley Plants Are Colonized By Potentially Pathogenic Bacteria, Felicia A. Charles

Theses and Dissertations - UTB/UTPA

Epiphytic pathogenic bacteria on the thorns of native LRGV plants may provide a defense mechanism for the plants. To test this, plant thorns were collected from LRGV plant species and aerobic and anaerobic bacteria were isolated in thioglycollate medium. Tests were performed to characterize the bacterial cultures. The 16S rRNA gene was sequenced to allow for species identification. Sixty-nine bacterial cultures were isolated, including gram-positive and gram-negative cell types. All utilized a variety of carbon sources for nutrients and 23% of isolates displayed hemolysis. Bacterial identification included members of the genus Bacillus, Pseudomonas, Serratia, and others. Most were opportunistic pathogens. …

Genome-Wide Association Mapping Identifies Qtls And Candidate Genes For Salt Tolerance In Soybean, Lei Huang

Graduate Theses and Dissertations

Salinity is a common abiotic stress causing soybean yield loss worldwide. Use of tolerant cultivars is an effective and economic approach to coping with this stress. Toward this, research is needed to identify salt-tolerant germplasm and better understand the genetic and molecular basis of salt tolerance in soybean. The objectives of this study were to identify salt-tolerant genotypes, to search for SNPs and QTLs associated with salt tolerance, and to identify candidate salt tolerance genes. A total of 192 diverse soybean lines and cultivars were screened for salt tolerance in the greenhouse based on visual leaf scorch scores after 15 …

Selecting Drought Tolerant Soybean Genotypes Using Qtls Associated With Shoot Ureide And Nitrogen Concentrations, Alejandro Bolton

Graduate Theses and Dissertations

In soybean, nitrogen fixation is more sensitive to drought than other physiological processes like photosynthesis. The sensitivity of nitrogen fixation to drought has been associated with high shoot concentrations of ureide and nitrogen under well-watered conditions. Previous research by Hwang et al. (2013) detected quantitative trait loci (QTLs) in a KS4895 by Jackson population associated with shoot ureide and nitrogen concentrations. The present research evaluated the use of these QTLs in selecting genotypes with drought tolerant nitrogen fixation. Our objectives were to compare actual versus expected phenotype of recombinant inbreed lines (RILs) selected using molecular markers, and to evaluate the …

Abiotic And Biotic Factors Affecting The Japanese Beetle In Arkansas, Bryan Mathew Petty

Graduate Theses and Dissertations

Japanese beetles are a relatively new pest to Arkansas. During my Ph.D. research I investigated the pathogens and environmental factors influencing Japanese beetle populations in the state. The prevalence of various pathogens and parasitoids attacking Popillia japonica were recorded annually from wild populations. Of specific interest was the microsporidian pathogen Ovavesicula popilliae, which I introduced as a biological control agent in the state. Details of the relationship between this pathogen and the Japanese beetle were investigated, including dose response, host range, and spore production. Additionally, annual abundance of the beetle in the region was recorded and tracked over the course …

Study Of Thermotolerance Mechanism In Gossypium Hirsutum Through Identification Of Heat Stress Genes, Jin Zhang

Graduate Theses and Dissertations

ABSTRACT

Heat stress causes major losses to cotton seed and lint yield. Introduction of heat stress tolerance to Arkansas cotton varieties is highly desirable. However, very little is known about the molecular basis of heat stress tolerance in cotton. The present study attempted to identify heat stress tolerance genes in two heat-tolerant cotton cultivars, VH260 and MNH456, originating from Pakistan. Towards this, the expression profile of the cotton orthologs of sevenArabidopsisheat stress tolerance genes was studied in these two cultivars, and compared with the two heat-susceptible cotton cultivars, ST213 and ST4288, originating from Mississippi Delta region. In addition, physiological parameters …

Prerequisites For Biocrops Up-Scaling I: An Assessment Of Seed Propagation Of Oilferous Plant Species With Potential For Biodiesel Production, Agnes Ms Nyomora, Esther P Masomhe

Tanzania Journal of Science

This study assessed the propagation of non- edible oil plant species with potential for biodiesel production on 4 potting media forest, sandy, clay and loamy soil using seeds. Investigation was based on assessment of seed germination capacity, rooting ability and seedling growth rate of six selected plant species Telfairia pedata, Jatropha curcas, Excoecaria bussei, Croton macrostachyus, Croton megalocarpus and Ricinus communis. Completely randomized design (CRD) was adopted for this study using 10 seeds per plot (5L capacity pots) with 4 replications. An ANOVA was conducted to test for the significance of the treatments while Tukey-Kramer Multiple Comparisons test was used …

Prerequisites For Biocrops Up-Scaling Ii: An Assessment Of The Vegetative Method Of Propagation For Oilferous Plant Species With Potential For Biodiesel Production, Agnes Ms Nyomora

Tanzania Journal of Science

The rooting ability of hardwood cuttings from six selected non- edible oilferous plant species with potential for biodiesel production namely Telfairia pedata, Jatropha curcas, Excoecaria bussei, Croton macrostachyus, Croton megalocarpus and Ricinus communis was assessed on 4 different potting media i.e. forest top soil, sandy, clay and loamy soil. The proportion of cuttings that rooted were evaluated for the root numbers, root length, root dry weight, sprouting and callus formation. Complete randomized design (CRD) was adopted for the experiments and each of the species was replicated 4 times using 5 hardwood cuttings per plot (5 L capacity pots). An ANOVA …

The Phaseolus Vulgaris Zip Gene Family: Identification, Characterization, Mapping, And Gene Expression, Carolina Astudillo, Andrea C. Fernandez, Matthew W. Blair, Karen A. Cichy

Agricultural and Environmental Sciences Faculty Research

Zinc is an essential mineral for humans and plants and is involved in many physiological and biochemical processes. In humans, Zn deficiency has been associated with retarded growth and reduction of immune response. In plants, Zn is an essential component of more than 300 enzymes including RNA polymerase, alkaline phosphatase, alcohol dehydrogenase, Cu/Zn superoxidase dismutase, and carbonic anhydrase. The accumulation of Zn in plants involves many genes and characterization of the role of these genes will be useful in biofortification. Here we report the identification and phlyogenetic and sequence characterization of the 23 members of the ZIP (ZRT, IRT like …

A Legume Biofortification Quandary: Variability And Genetic Control Of Seed Coat Micronutrient Accumulation In Common Beans, Matthew W. Blair, Paulo Izquierdo, Carolina Astudillo, Michael A. Grusak

Agricultural and Environmental Sciences Faculty Research

Common beans (Phaseolus vulgaris L.), like many legumes, are rich in iron, zinc, and certain other microelements that are generally found to be in low concentrations in cereals, other seed crops, and root or tubers and therefore are good candidates for biofortification. But a quandary exists in common bean biofortification: namely that the distribution of iron has been found to be variable between the principal parts of seed; namely the cotyledonary tissue, embryo axis and seed coat. The seed coat represents ten or more percent of the seed weight and must be considered specifically as it accumulates much of …

Early Inflorescence Development In The Grasses (Poaceae), Elizabeth Kellogg, Paulo Camara, Paula Rudall, Philip Ladd, Simon Malcomber, Clinton Whipple, Andrew Doust

Biology Department Faculty Works

The shoot apical meristem of grasses produces the primary branches of the inflorescence, controlling inflorescence architecture and hence seed production. Whereas leaves are produced in a distichous pattern, with the primordia separated from each other by an angle of 180◦, inflorescence branches are produced in a spiral in most species. The morphology and developmental genetics of the shift in phyllotaxis have been studied extensively in maize and rice. However, in wheat, Brachypodium, and oats, all in the grass subfamily Pooideae, the change in phyllotaxis does not occur; primary inflorescence branches are produced distichously. It is unknown whether the distichous inflorescence …

Elk (Cervus Elaphus) Seasonal Habitat Selection In A Heterogeneous Forest Structure, Jesse N. Popp, David N.C. Mcgeachy, Josef Hamr

Aspen Bibliography

Seasonal habitat selection by the reintroduced Burwash elk population, approximately 30 km south of Sudbury, Ontario, has been analysed in order to assist in the development of future management. Twenty-five adult females were radio-collared and tracked 1–3 times a week for 3 years. The most prominent patterns included selection of intolerant hardwood forests (trembling aspen, white birch, and balsam poplar) during all seasons, while Great Lakes-St. Lawrence pines (white and red pine dominated stands) were used less than expected based on availability for all seasons. The selection patterns are likely associated with seasonal climatic conditions and forage preferences. Because the …

Identification Of Species Of Botryosphaeriaceae Causing Bot Gummosis In Citrus In California, A.O. Adesemoye, J.S. Mayorquin, D.H. Wang, M. Twizeyimana, S.C. Lynch, Akif Eskalen

Department of Plant Pathology: Faculty Publications

Members of the Botryosphaeriaceae family are known to cause Bot gummosis on many woody plants worldwide. To identify pathogens associated with Bot gummosis on citrus in California, scion and rootstock samples were collected in 2010 and 2011 from five citrusgrowing counties in California. Symptoms observed on citrus included branch cankers, dieback, and gumming. Various fungal species were recovered from necrotic tissues of branch canker and rootstock samples. Species were identified morphologically and by phylogenetic comparison as ‘Eureka’ lemon, ‘Valencia’, ‘Washington Navel’, ‘Fukumoto’, grapefruit, ‘Satsuma’, and ‘Meyer’ lemon. Species were identified morphologically and by phylogenetic comparison of the complete sequence of …

Automated Conserved Non-Coding Sequence (Cns) Discovery Reveals Differences In Gene Content And Promoter Evolution Among Grasses, Gina Marie Turco, James C. Schnable, Brent S. Pedersen, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Conserved non-coding sequences (CNS) are islands of non-coding sequence that, like protein coding exons, show less divergence in sequence between related species than functionless DNA. Several CNSs have been demonstrated experimentally to function as cis-regulatory regions. However, the specific functions of most CNSs remain unknown. Previous searches for CNS in plants have either anchored on exons and only identified nearby sequences or required years of painstaking manual annotation. Here we present an open source tool that can accurately identify CNSs between any two related species with sequenced genomes, including both those immediately adjacent to exons and distal sequences separated by …

Storage Technique Preserves Citrus, Kills Pathogens, Gayle Volk, Jan Suszkiw

Agricultural Research Magazine

Americans consume about 84 pounds of fresh and processed citrus per person each year, with oranges topping the list at 61 pounds annually. The availability of these favored fruits in grocery stores, fresh markets, and other consumer outlets is a testament to growers’ success in managing the ever-present threat of pests and diseases to the nation’s $3.4 billion citrus crop (2011-12), most of which is produced in Florida and California.

A major threat is citrus greening disease, also known as “Huanglongbing.” First detected in Florida in August 2005, citrus greening today is the target of a multifaceted effort by federal, …

Fungi Can Be Friends Or Foes, Amy Rossman, Jo Anne Crouch, Shannon Dominick, Sharon Durham

Agricultural Research Magazine

Fungi are a large and diverse group of organisms. Some fungi, like mushrooms, are edible and considered crops. Others, however, can cause serious diseases of crop and forest plants, and those diseases can have negative effects on local and international economies as well as on the supply of food and other materials that agriculture provides.

The Agricultural Research Service maintains a unique resource—the U.S. National Fungus Collections—for helpful and detailed information about fungi. Accurate knowledge of fungi is critical for controlling the diseases they cause.

North America’s Largest Fungarium

In 1869, the Smithsonian Institution transferred its fungal collection to the …