Plant Biology Commons^™

The Interaction Of Fire And Grazing In Oklahoma Artemisia Filifolia Shrubland, Stephen L. Winter

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

I. FIRE-RESILIENCY OF A NORTH AMERICAN ARTEMISIA (ASTERACEAE) SHRUB: IMPLICATIONS FOR RESTORATION OF A CRITICAL ECOSYSTEM PROCESS. Conclusions: Unlike most North American Artemisia shrub species, our research suggests that A. filifolia is highly resilient to the effects of fire. Therefore, use of prescribed fires for the restoration and maintenance of ecosystem processes and properties is appropriate in A. filifolia shrublands of the southern Great Plains in North America.

II. RESTORATION OF THE FIRE-GRAZING INTERACTION IN ARTEMISIA FILIFOLIA SHRUBLAND OF THE SOUTHERN GREAT PLAINS, NORTH AMERICA. Synthesis and applications. Vegetation structure in Artemisia filifolia shrublands of our study were readily altered …

Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and ecotypic variation of these prairie clovers is a prerequisite for developing populations suitable for rangeland revegetation in the western USA. DNA sequences of internal transcribed spacer (ITS/5.8S) and trnK/matK were used to study the phylogeny of these species. The species were distinguished …

Analysis Of The Response Of Medicago Truncatula Calcium Oxalate Mutants To Abiotic Stress, Wayra Gabriela Navia-Gine

Graduate Theses and Dissertations

Calcium oxalate crystals are found in most plant species. In Medicago truncatula wild-type A17, crystals accumulate in leaves along the secondary veins and the only role attributed to them so far is defense against chewing insects. Calcium oxalate deficient (cod) mutants were isolated in M. truncatula; the cod mutants include cod5, which completely lack crystals in the leaves and cod6 that accumulates fewer and smaller crystals compared to A17. We analyzed gene expression in the cod mutants and A17 using GeneChip® Medicago Genome Arrays and found important differences in transcriptome between the three genotypes. In particular, we found a gene …

Effects Of Experimental Nitrogen Additions On Plant Diversity In An Old-Growth Tropical Forest, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guoyi Zhou, Yunting Fang

Biological Sciences Faculty Research

Response of plant biodiversity to increased availability of nitrogen (N) has been investigated in temperate and boreal forests, which are typically N-limited, but little is known in tropical forests. We examined the effects of artificial N additions on plant diversity (species richness, density and cover) of the understory layer in an N saturated old-growth tropical forest in southern China to test the following hypothesis: N additions decrease plant diversity in N saturated tropical forests primarily from N-mediated changes in soil properties. Experimental additions of N were administered at the following levels from July 2003 to July 2008: no addition (Control); …

Joint Fire Science Program – Lake Mead National Recreation Area Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis: Quarterly Progress Report, Time Period: July 1 — September 30, 2010, Margaret N. Rees

Fire Science

• Article entitled “Competitive Hierarchy of Native Desert Plants with Red Brome (Bromus rubens): Towards Identifying Invasion-Reducing Species" was revised and re-submitted to the Invasive Plant Science and Management journal.
• Final data collection on soils and nursery plots is complete. Data are awaiting analysis.

Systematic Analysis Of Nutritional Components, Cell Wall Chemical Features And Potential Pathway(S) Of Assimilate Transport In The Developing Pods And Seeds Of Medicago Truncatula, Alka Sharma

Theses and Dissertations

Medicago truncatula is a model species for legume studies. Despite the great advances in the study of M. truncatula and development of a vast array of genetic tools and genomic resources, there is a lack of knowledge regarding the nutrient movement and accumulation in its pods and seeds. This study used a combination of the microscopic analysis, histochemical localization and the fluorescent tracers to identify the cellular course and location of nutrient movement. Temporal histochemical localization revealed that the longer duration of the accumulation of protein bodies and lipid droplets combined with the high hexoses concentration in seed apoplasm might …

Plant Immunity Directly Or Indirectly Restricts The Injection Of Type Iii Effectors By The Pseudomonas Syringae Type Iii Secretion System, Emerson Crabill, Anna Joe, Anna Block, Jennifer M. Van Rooyen, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Plants perceive microorganisms by recognizing microbial molecules known as pathogen-associated molecular patterns (PAMPs) inducing PAMP-triggered immunity (PTI) or by recognizing pathogen effectors inducing effector-triggered immunity (ETI). The hypersensitive response (HR), a programmed cell death response associated with ETI, is known to be inhibited by PTI. Here, we show that PTI-induced HR inhibition is due to direct or indirect restriction of the type III protein secretion system’s (T3SS) ability to inject type III effectors (T3Es). We found that the Pseudomonas syringae T3SS was restricted in its ability to inject a T3E-adenylate cyclase (CyaA) injection reporter into PTI-induced tobacco (Nicotiana tabacum) cells. …

Increased Plant Uptake Of Nitrogen From 15N-Depleted Fertilizer Using Plant Growth-Promoting Rhizobacteria, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

Harmful environmental effects resulting from fertilizer use have spurred research into integrated nutrient management strategies which can include the use of specific microorganisms to enhance nutrient use efficiency by plants. Some strains of plant growth-promoting rhizobacteria (PGPR) have been reported to enhance nutrient uptake by plants, but no studies with PGPR have used ¹⁵N isotope techniques to prove that the increased N in plant tissues came from the N applied as fertilizer. The current study was conducted to demonstrate that a model PGPR system can enhance plant uptake of fertilizer N applied to the soil using different rates of …

Role Of Sabp2 In Systemic Acquired Resistance Induced By Acibenzolar-S-Methyl In Plants., Diwaker Tripathi

Electronic Theses and Dissertations

Plants have evolved an efficient mechanism to defend themselves against pathogens. Many biotic and abiotic agents have been shown to induce defense mechanism in plants. Acibenzolar-S-Methyl (ASM) is a commercially available chemical inducer of local and systemic resistance (SAR) response in plants. ASM functioning at molecular level is mostly unclear. This research was designed to investigate the mechanism of ASM action in plants. It was hypothesized that SABP2, a plant protein, plays an important role in ASM-mediated defense signaling. Biochemical studies were performed to test the interaction between SABP2 and ASM. Transgenic SABP2-silenced tobacco plants were used to determine the …

The Endosymbiotic Relationship Of Leguminosae (Fabaceae) And Rhizobium, Sabrina Mcgee, Dolores Maceda, Maria Bustos, Maryknoll Palisoc, Rachel Dahl

Undergraduate Research Opportunities Program (UROP)

This project will look at The Endosymbiotic Relationship of Leguminosae (Fabaceae) and Rizobioum. Endoysmbiosis Theory is the concept that mitochondria and chloroplasts are the result of years of evolution initiated by the endocytosis, (the process by which cells absorb material through their cell membrane) of bacteria and algae which, instead of becoming digested, became symbiotic.The mitochondria of eukaryotes evolved from aerobic bacteria, probably rickettsias, living within their host cell and the chloroplasts from cyanobacteria, also known as blue-green algae. Endoysmbiosis is a type of symbiosis in which one organism lives inside the body of another and both function as a …

Reestablishing Diversity In Our Hardwood Forests: A Transplant Study Of Five Spring-Flowering Herbs, Danielle Racke

Masters Theses & Specialist Projects

Herbaceous communities are critical to the functioning of forest ecosystems. They recycle nutrients, help prevent erosion, provide critical microhabitats and maintain biodiversity. In the eastern United States, most hardwood forests are growing on land once entirely cleared or used for some form of agriculture. Although some of these forests are nearly 150 years old, they still have depauperate native herbaceous communities when compared to remaining old-growth forests. This long-term depletion may result from dispersal limitation or environmental limitation.

I tested the hypothesis that dispersal was the primary factor contributing to the absence of five spring-flowering herbaceous species in four secondary …

Unique Functionality Of 22 Nt Mirnas In Triggering Rdr6-Dependent Sirna Biogenesis From Target Transcripts In Arabidopsis, Josh T. Cuperus, Alberto Carbonell, Noah Fahlgren, Hernan Garcia-Ruiz, Russell T. Burke, Atsushi Takeda, Christopher M. Sullivan, Sunny D. Gilbert, Taiowa A. Montgomery, James C. Carrington

Department of Plant Pathology: Faculty Publications

RNA interference pathways may involve amplification of secondary siRNAs by RNA-dependent RNA polymerases. In plants, RDR6-dependent secondary siRNAs arise from transcripts targeted by some microRNA (miRNA). Here, Arabidopsis thaliana secondary siRNA from mRNA, and trans-acting siRNA, are shown to be triggered through initial targeting by 22 nt miRNA that associate with AGO1. In contrast to canonical 21 nt miRNA, 22 nt miRNA primarily arise from foldback precursors containing asymmetric bulges. Using artificial miRNA constructs, conversion of asymmetric foldbacks to symmetric foldbacks resulted in production of 21 nt forms of miR173, miR472 and miR828. Both 21 and 22 nt forms associated …

Temporal And Spatial Assessment Of Evaporation, Transpiration, And Soil Moisture Redistribution, Brian M. Bird

UNLV Theses, Dissertations, Professional Papers, and Capstones

At a native stand of creosote bush (Larrea tridentata) in North Las Vegas, a rainfall simulation study was conducted over a 12 month period from October 2005 to October 2006. Simulated rainfall occurred during the winter, spring, summer, and fall periods. Rainfall simulation systems were positioned on each of 12 plots, each containing a single creosote bush. Simulated rainfall events occurred at night with multiple short pulses designed to maximize infiltration while minimizing ponding. Yearly simulated rainfall amounts were set at 0, 15, 30 and 60 cm (replicated three times) and were approximately 0, 1.5, 3.0 and 6.0 times the …

Heterokaryotic Nuclear Conditions And A Heterogeneous Nuclear Population Are Observed By Flow Cytometry In Phytophthora Infestans, Mursel Catal, Louis King, Pavani Tumbalam, Prissana Wiriyajitsomboon, William W. Kirk, Gerard C. Adams

Department of Plant Pathology: Faculty Publications

A simple and reliable method for preparation of whole nuclei of a common oomycete, Phytophthora infestans, is described for laser flow cytometry. The ease of preparation, the absence of detectable debris and aggregates, and the precision in determinations of DNA content per nucleus improve interpretation and understanding of the genetics of the organism. Phytophthora infestans is the pathogen that causes potato and tomato late blight. The genetic flexibility of P. infestans and other oomycete pathogens has complicated understanding of the mechanisms of variation contributing to shifts in race structure and virulence profiles on important agricultural crops. Significant phenotypic and …

Alteration In Lignin Biosynthesis Restricts Growth Of Fusarium Spp. In Brown Midrib Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen, Scott E. Sattler

Department of Plant Pathology: Faculty Publications

To improve sorghum for bioenergy and forage uses, brown midrib (bmr)6 and -12 near-isogenic genotypes were developed in different sorghum backgrounds. The bmr6 and bmr12 grain had significantly reduced colonization by members of the Gibberella fujikuroi species complex compared with the wild type, as detected on two semiselective media. Fusarium spp. were identified using sequence analysis of a portion of the translation elongation factor (TEF) 1-α gene. The pathogens Fusarium thapsinum, F. proliferatum, and F. verticillioides, G. fujikuroi members, were commonly recovered. Other frequently isolated Fusarium spp. likely colonize sorghum asymptomatically. The χ2 analyses showed that the …

Joint Fire Science Program – Lake Mead National Recreation Area Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis: Quarterly Progress Report, Time Period: May 1 — June 30, 2010, Margaret N. Rees

Fire Science

• Article entitled “Competitive Hierarchy of Native Desert Plants with Red Brome (Bromus rubens): Towards Identifying Invasion-Reducing Species" was submitted to the Invasive Plant Science and Management journal.
• Maintained nursery plots and added installment of nitrogen treatment.
• Took measurements in nursery (competition) plots and harvested biomass.

Following Tetraploidy In Maize, A Short Deletion Mechanism Removed Genes Preferentially From One Of The Two Homeologs, Margaret R. Woodhouse, James C. Schnable, Brent S. Pedersen, Eric Lyons, Damon Lisch, Shabarinath Subramaniam, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Previous work in Arabidopsis showed that after an ancient tetraploidy event, genes were preferentially removed from one of the two homeologs, a process known as fractionation. The mechanism of fractionation is unknown. We sought to determine whether such preferential, or biased, fractionation exists in maize and, if so, whether a specific mechanism could be implicated in this process. We studied the process of fractionation using two recently sequenced grass species: sorghum and maize. The maize lineage has experienced a tetraploidy since its divergence from sorghum approximately 12 million years ago, and fragments of many knocked-out genes retain enough sequence similarity …

Vittatidera Zeaphila (Nematoda: Heteroderidae), A New Genus And Species Of Cyst Nematode Parasitic On Corn (Zea Mays), Ernest C. Bernard, Zafar A. Handoo, Thomas O. Powers, Patricia A. Donald, Robert D. Heinz

Department of Plant Pathology: Faculty Publications

A new genus and species of cyst nematode, Vittatidera zeaphila, is described from Tennessee. The new genus is superficially similar to Cactodera but is distinguished from other cyst-forming taxa in having a persistent lateral field in females and cysts, persistent vulval lips covering a circumfenestrate vulva, and subventral gland nuclei of the female contained in a separate small lobe. Infective juveniles (J2) are distinguished from all previously described Cactodera spp. by the short stylet in the second-stage juvenile (14-17 mm); J2 of Cactodera spp. have stylets at least 18 mm long. The new species also is unusual in that …

Botanical Report Of Tierra Redonda Mountain Blm Area Of Critical Environmental Concern, San Luis Obispo County, California (W120˚59’41”; N35˚45’59”)., Anthony Baniaga, Andrew Theo Fitanides

Biological Sciences

The purpose of this document is to report the results of a botanical survey of a portion of the Tierra Redonda Mountain Area of Critical Environmental Concern. The survey was conducted for the Bureau of Land Management, and executed between October 2009 and June 2010. Tierra Redonda Mountain is the type locality for the Tierra Redonda formation, and has weathered to form steep slopes of exposed chaparral and protected woodlands. Four general community types were found; foothill woodland, chaparral, southern coastal scrub and dune scrub. Alliances determined by The Manual of California Vegetation (2nd ed.) were: Quercus douglasii Woodland, Quercus …

Good Agricultural Practices For Food Safety Of Fresh Produce, Laurie Hodges

Department of Agronomy and Horticulture: Faculty Publications

What are the guiding principles of food safety for fresh produce?

• Once contaminated, removing or killing pathogens on produce is very difficult.

• Preventing microbial contamination at all steps, from production to distribution, is strongly favored over treatments to eliminate contamination that may have occurred.

• Document the implementation of prevention programs, and educate workers at all levels of the agricultural and packing environments on food safety.

Key Signatures of a Credible Food Safety Program

The following is a condensed checklist of practices and conditions that reduce the potential for fresh produce to be exposed to pathogenic microbes. Review …