Life Sciences Commons^™

Changes In The Barley Stem Proteome In Response To Drought During Grain Filling, Mohammed Al Slamh

Dissertations and Theses @ UNI

Drought is the major environmental factor that limits crop yield worldwide. Crops are particularly vulnerable to drought at the reproductive stage. In cereals, grain filling during drought depends on the contribution of current photosynthesis products from the leaf and spike and carbohydrates stored mainly in the stem and remobilized to the grain. Even though stem reserve is an important source for grain filling, changes in the proteome of barley stem under drought have not been studied. Also, the molecular events associated with differential stem reserve remobilization under drought are not well understood. In this study, barley plants were exposed to …

Understanding Morphological Responses Of Typha (Cattail) Species To Nutrient Pollution, Anna Marie Shapiro

Dissertations and Theses @ UNI

In the Midwestern United States, Typha x glauca is a hybrid of the native Typha latifolia and the non-native Typha angustifolia. Typha x glauca is considered invasive, and it is dominating Typha latifolia when they co-occur. Wetlands in the Midwest face nutrient pollution, due to fertilization used within the agricultural industry. Wetlands are nutrient sinks, which store the increased levels of nitrogen and phosphorus. These nutrients are known to increase Typha growth. Within this thesis, it was hypothesized that an increase of nitrogen in the wetland may increase the width of Typha leaves, making it difficult to distinguish the …

Seed Mix Design, Planting Time, And First-Year Mowing Management To Improve Multifunctionality And Cost-Effectiveness Of Tallgrass Prairie Reconstructions, Alec James Glidden

Dissertations and Theses @ UNI

The conversion of the Midwestern United States’ tallgrass prairies to agriculture has resulted in extensive habitat loss and degradation and a decline in the provisioning of ecosystem services. To restore these services the United States Department of Agriculture created the Conservation Reserve Program (CRP) which provides incentives to agricultural landowners to implement conservation practices designed to meet goals pertaining to single ecosystem services. We studied the effects of seed mix design, planting time, and first-year management on the multifunctionality and cost-effectiveness of prairie reconstructions. We established research plots planted with one of three seed mixes either in the dormant (fall) …

Community Diversity Influences Selection On Nutrient Resorption In Panicum Virgatum, Michael J. Lashbrook

Dissertations and Theses @ UNI

Panicum virgatum L. (switchgrass) is a bioenergy crop shown to conserve and recycle nutrients through a process known as nutrient resorption. While there are many studies looking at various aspects of nutrient cycling in switchgrass, it remains unclear whether selection is acting upon increased nutrient resorption in this species. Further, there are no phenotypic selection studies coupling empirical sexual and asexual reproduction data.

A field study and a modeling study were conducted to determine phenotypic selection on nutrient resorption and the influence of resorption on asexual reproduction in switchgrass. For the field study of phenotypic selection, I hypothesized selection favors …

The Systematics Of Physaria Sensu Stricto From Wyoming And Surrounding Areas, Jason Ratcliff

Dissertations and Theses @ UNI

Two genera of Brassicaceae – Lesquerella and Physaria – were recently united on the basis of monophyly. Classically, these genera have been distinguished based on morphology with 'traditional” Physaria species having doubly inflated (didymous) fruits. Molecular data consisting of ribosomal internal transcribed spacer (ITS) DNA sequences indicate Physaria has evolved from the larger Lesquerella genus, thus making Lesquerella a paraphyletic grouping as previously described. A revised treatment of the combined Physaria recognized 106 species within the genus, of which 26 taxa occur in Wyoming. Of the Wyoming taxa, those traditionally described as belonging to Physaria (i.e.Physaria sensu stricto) have …

Carbon Sequestration And Weedy Invasion In Crp Fields, Destiny Danielle Magee

Dissertations and Theses @ UNI

The Conservation Reserve Program (CRP) aims to provide ecosystem services in landscapes dominated by agriculture by converting previous agricultural fields into reconstructed prairies and wetlands. The main priorities of the program include reducing soil erosion and improving water quality, but the perennial vegetation in the fields can also provide other benefits such as increased carbon sequestration and biodiversity. These additional benefits of the program are not closely monitored, though these benefits are potentially equally valuable to the targeted program benefits. This study compared soil carbon in CRP fields and a subset of corn fields in order to determine the impact …

Productivity And Community Composition Change In Prairie Biomass Feedstocks, Kathleen Loretta Madsen

Dissertations and Theses @ UNI

With increasing concerns of climate change and resource usage, there is a growing interest in diverse prairie biomass as a form of alternative energy. In this study, we look at four potential biomass feedstock treatments that were chosen specifically to target high biomass yields and consist of native Iowa tallgrass prairie species. The four feedstocks consist of a one-species monoculture of C₄ switchgrass (Panicum virgatum L.), a 5-species mixture of C₄-grasses, a 16-species mixture of C3 and C₄-grasses, forbs, and legumes, and a 32-species mixture of C3 and C₄-grasses, sedges, forbs, and …

Evaluation Of The Csr1-2 Allele From Arabidopsis Thaliana Cs3102 As An Imazapyr Herbicide Resistance Marker For Biolistic Transformation Of The Shoot Apical Meristem, Amanda J. Stump

Dissertations and Theses @ UNI

Plant genetic engineering requires a marker gene to differentiate transformed cells. To test the csr1-2 allele as a selectable marker for the shoot apical meristem (SAM), we cloned a genomic fragment from Arabidopsis thaliana mutant CS3102 which contained the coding sequence and promoter. We then evaluated the utility of this allele on two model systems, Arabidopsis and tobacco, with soybean as the positive control. Initial dose-response experiments were conducted using a seedling plate assay to determine the lethal dose of imazapyr. For the mutant Arabidopsis thaliana CS3102, a concentration of 500 μM imazapyr was required to overcome the resistance phenotype …

The Effect Of Cold Stratification And Perigynia Removal On The Germination Of Three Prairie Carex Species, Christina M. Boeck Crew

Dissertations and Theses @ UNI

Sedges (Carex spp. Linneaus. [Cyperaceae]) are a major component of Midwestern U.S. tallgrass prairie and prairie wetland plant communities, yet they are often lacking in restoration projects because they can be difficult to germinate. Cold-wet stratification and perigynia removal have been shown to increase germination in some Carex species. The germination response of 3 native species, plains oval or shortbeak sedge (C. brevior (Dewey) Mack.), field oval or troublesome sedge (C. molesta Mack.), and prairie or Bicknell’s sedge (C. bicknellii Britton.), was tested to cold-wet stratification (28d) and perigynia removal in stored seed (10 months). Seed treatments …

Morphological And Morphometric Analysis Of Nekemias Arborea And Ampelopsis Aconitifolia (Vitaceae), Sally Rose Gray

Dissertations and Theses @ UNI

Leaf morphology in angiosperms is not constrained by the leaf’s important function of providing energy through photosynthetic reactions. In just one family, Vitaceae, it is easy to observe among it’s over 900 species, various leaf shapes and sizes even among closely related species as well as within individual species. Observation of these leaf forms within species can be used to determine, for example where a vine transitions from the juvenile state to the adult state as well as their relationship to the spatial and temporal patterning of inflorescence initiation. Analysis of two species within the Ampelopsis clade, one that retained …

The Effects Of Mycorrhizal Inoculant And Micronutrients On Early Plant Establshment During A Tallgrass Prairie Reconstruction, Christopher L. Barber

Dissertations and Theses @ UNI

Symbiotic relationships between mycorrhizal fungi and land plants are one of the most widespread examples of symbiosis on Earth yet there is still much to discover about their ecological impacts.

Prairie reconstructions are often done on highly disturbed sites such as reclaimed cropland, turf grass, and road rights-of-way. Disturbed soils often lack adequate quantities of both mycorrhizal fungi and micronutrients. I hypothesized that inoculated seeds with mycorrhizal spores or micronutrient seed treatments will aid in the early establishment of a tallgrass prairie.

To test this hypothesis four treatments (T1 control, T2 mycorrhizal, T3 micronutrient, and T4 mycorrhizal and micronutrient) were …

The Effects Of Nutrient Resorption, Photosynthetic Rate, And Leaf Longevity On The Success Of Typha × Glauca, Clarissa Marie Ruiz

Dissertations and Theses @ UNI

The hybrid cattail Typha × glauca is invasive in the Midwestern United States, and outcompetes wetland natives and its parent species, Typha angustifolia and Typha latifolia under high nutrient conditions. Typha × glauca’s large size and copious litter production are the main factors known to contribute to its success, although research is lacking on physiological processes that contribute to its nitrogen use efficiency.

Nitrogen resorption was investigated as a mechanism of dominance in Typha × glauca. Due to nitrogen resorption being a nutrient conservation strategy, nitrogen resorption should be high in areas of low nitrogen availability. Since nitrogen …

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 …

Butterfly And Floral Community Dynamics At A Native Prairie Agrofuel Research Site, Benjamin J. Hoksch

Dissertations and Theses @ UNI

Agrofuel production in the Midwest has historically relied upon monoculture food crops (Zea mays and Glycine max) that do little to support biodiversity or maintain soil and water quality. The University of Northern Iowa’s Tallgrass Prairie Center is investigating the feasibility of establishing and harvesting diverse mixes of native prairie vegetation for use as a sustainable agrofuel. In 2009 48 research plots were established on three soil types, on land with a >30 year history of row crop production in Black Hawk County, IA. Each plot was seeded with one of four native prairie agrofuel crops: (1) Switchgrass1, (2) Grasses5 …

A Comparison Of The Effects Of Burning, Haying And Mowing On Plants And Small Mammals In A Tallgrass Prairie Reconstruction, Ryan Allan Neuhaus

Dissertations and Theses @ UNI

Fire is an effective management tool for reconstructed prairies. However, due to safety concerns, road departments and other prairie managers are sometimes reluctant to use fire. Therefore, alternative techniques to manage reconstructed prairie, such as mowing or haying, need to be considered. The goal of this study is to determine if mowing and/or haying can be used to manage vegetation in lieu of fire for prairie reconstructions. This study examines the effects of four management techniques on plant and small mammal species in a tallgrass prairie reconstruction. No management, mowing, haying, and burning were replicated six times using a split …

Variation In Mineral Content Of Prairie Forb Species And Content Changes Over Winter Related To Slagging Potential, Jennifer Nyla Wahl Rupp

Dissertations and Theses @ UNI

Coal fired power plants are responsible for more than 75 percent of the energy produced in Iowa. Burning coal releases large amount of carbon dioxide and other chemical compounds into the atmosphere.

A variety of types of biomass, including prairie vegetation, are being proposed as biofuel alternatives for electrical generation. Tilman et al. (2006) determined that biofuels from mixtures of prairie vegetation of increasing diversity provide more usable energy, reduce greenhouse gases and produce less agriculture pollutants. The Prairie Power Project of the Tallgrass Prairie Center is testing four mixtures of prairie species for maximum production of biomass. A primary …

Biodiversity And Ecosystem Function And The Design Of Tallgrass Restorations For Biomass Production, Dustin Robert Jon Graham

Dissertations and Theses @ UNI

Biodiversity and ecosystem function research (BEF) suggests species richness may provide high levels of ecosystem functions. However, few studies have applied a BEF perspective of restoration, which utilizes biodiversity to achieve increases in ecosystem functions. In this study, we test the application of the BEF perspective of restoration in the design of tallgrass prairie plantings as a biomass crops. Specifically, we examine the effects of planted species richness on biomass production, resistance to disturbance, and resistance to invasion by weeds.

Four seed mixes which range in species richness (1, 5, 16 and 32 species) were established in four, field-scale (0.33-0.55 …

Tracking Above- And Below- Ground Seed Persistence And Mortality In A Native Tallgrass Prairie Restoration, Carmen Pellish

Dissertations and Theses @ UNI

The large cost of seed and low seedling establishment rates make restoring native tallgrass prairies expensive and difficult. Tallgrass prairie restorations typically achieve seedling emergence rates of only 10%. This begs the question of what happens to the remaining 90% of seeds that do not emerge as seedlings. This thesis sought to assess or quantify the importance of seed predators and death by microorganisms or to senescence on seed survival and seedling establishment within a newly planted native tallgrass prairie restoration under typical restoration conditions. I hypothesized that small vertebrate seed predators would play be detrimental to overall seedling emergence …

Development Of Leaf Shape And Vein Homologies In Five Species Of The Genus Ipomoea (Convolvulaceae), Austin William Jones

Dissertations and Theses @ UNI

Angiosperm leaves are extremely variable in form while predominantly maintaining the function of the primary photosynthetic organ of the plant. Changes in leaf form can result from myriad physiological processes which may be influenced by ecology, physical stimuli, phylogeny, or other factors. In studying the development of divergent leaf forms among closely related species, conserved morphological elements may be identified that are not apparent in the mature form. The genus Ipomoea (Convolvulaceae) contains over 600 species and a wide range in leaf shapes. Five species, I. purpurea, I. coccinea, I. sloteri, I. quamoclit, and I. cairica show a range in …

Succession Of An Iowa Sand Prairie Into An Adjoining Old-Field, Susan Jill Kirt

Dissertations and Theses @ UNI

Native plant succession studies were conducted in 2000 and 2001 at the Cedar Hills Sand Prairie northwest of Cedar Falls, IA. The study site consisted of a remnant sand prairie with an adjoining old-field that had been undergoing secondary succession since the mid-1970s. Vegetation was sampled over a 100 m transect of the remnant prairie and a 200 m transect of the old-field. The transect was sub-divided into 50 m subsites to examine progression of native species into the old-field. To analyze changes in vegetation, the similarity of the sub-sites were compared for percent canopy cover and number of species …

The Use Of Aflp To Detect Genetic Differentiation Within And Among Populations Of Two Prairie Plant Species: Panicum Virgatum And Coreopsis Palmata, Christopher Andrew Hilker

Dissertations and Theses @ UNI

The degree of genetic diversity within any species is crucial to its survival with respect to environmental stresses and its ability to adapt. As native Iowa prairie plant populations continues to diminish, genetic diversity within the state becomes crucially important for restoration, reconstruction, and conservation efforts. This study seeks to determine the degree of genetic variation within native Iowa populations of Panicum virgatum (switchgrass) and Coreopsis palmata (prairie coreopsis, tickseed, prairie tickseed). Plants were obtained directly from the tallgrass prairie, from native seed plantings, and from greenhouse grown cultivated varieties (switchgrass). Amplified Fragment Length Polymorphisms (AFLP) provided genetic fingerprints of …

The Use Of Rapd To Detect Genetic Variation In Populations Of Liatris Aspera Michx., Duane Joseph Kitchen

Dissertations and Theses @ UNI

The tall grass prairie is one of the most degraded and fragmented ecosystems on earth. Interest in conserving, restoring, and reconstructing tallgrass prairie began early in the 1900s, and has increased dramatically since the 1960s. Early restoration and reconstruction efforts relied primarily on seed collected from prairie remnants near the planting site, but with the increase in prairie planting efforts came a greater demand for large quantities of affordable, viable seed of native prairie species. Following an increase in the use of cultivated varieties (cultivars) of seed, concerns over the loss of genetic integrity of local populations and low genetic …

Effects Of Sludge Application On Prairie Establishment, Brenda Joan Durbahn

Dissertations and Theses @ UNI

Native prairie in Iowa has all but disappeared since the development of agricultural land by European settlers over the past 165 years. Reconstructing prairie is one way to replace some of the acreage that was lost. A byproduct of settling an area is the generation of garbage and other wastes. Currently there is a surplus of sludge, the waste product of waste water treatment facilities. This material is usually disposed of in landfills, used on agricultural land or reclamation projects.

A small area of prairie was reconstructed on the top of a closed portion of the Black Hawk County Solid …

Inactivation Of Soybean Peroxidase During Sodium Azide Oxidation: A Comparative Study, Mohamed Yehia Zakaria Aboul Eish

Dissertations and Theses @ UNI

Azide ion is a mechanism-based inactivator of a number of peroxidases. However, there are often variations in the manner in which inactivation occurs. Soybean Peroxidase (SBP) is found in the plant's seed coat. Unlike many other peroxidases, a single enzyme rather than several isozymes are produced thus making more simple the purification and characterization of the enzyme. In this research it was shown that, as with other peroxidases, SBP is inactivated by azide during turnover. During azide oxidation SBP forms a ferrous-NO intermediate. In this respect, SBP is similar to the lignin peroxidases from Phanerochaete chrysosporium which also form ferrous-NO …

Macrophyte-Macroinvertebrate Interactions In A Lentic Ecosystem And The Effect Of Fluridone Treatment To Control Myriophyllum Spicatum L., Gregory J. Moeller

Dissertations and Theses @ UNI

Myriophyllum spicatum L. is an exotic macrophyte that can become pestiferous in lentic ecosystems. Two field studies were conducted to investigate: 1) epiphytic macroinvertebrates associated with M. spicatum and native macrophytes; and 2) epiphytic macroinvertebrate community response to fluridone treatment for M. spicatum control.

In the first study evaluating epiphytic macroinvertebrates associated with M. spicatum and native macrophytes, triplicate samples were collected at three sites in both Auburn and Zumbra Lakes, Minnesota, USA. One site in each lake contained primarily M. spicatum, the second site contained M. spicatum and native vegetation, and the third site was dominated by native …

The Effects Of Herbicides On Microbial And Mycorrhizal Populations In Native Prairie, Corn, And Non-Native Prairie Vegetation, Using The Biolog Technique, Susann E. Ahrabi-Fard

Dissertations and Theses @ UNI

Soil bioremediation has primarily focused on the use of free living, actively growing microorganisms to degrade toxic organic substances. Recently, however, plants and rhizosphere activity, including mycorrhizal fungi have been increasingly studied to determine the role that consortial assemblages may play in bioremediation. While the enhanced absorbtion of nutrients, water, and minerals by mycorrhizal fungi has been well documented, less is known about their role in the degradation of soil contaminants. Using the Biolog plate technique, microbial communities were characterized in Native Prairie, Corn, and Non-Native Prairie vegetative strips prior to, and after two applications of Acetachlor, Alachlor, and Atrazine. …

Multivariate Analysis Of The Carex Brevior Group In Iowa, Scott C. Zager

Dissertations and Theses @ UNI

In Iowa, the most troublesome sedges to identify are Carex brevior, C. festucacea, C. molesta, C. normalis, C. tenera, and C. tenera var. echinodes. These taxa form the C. brevior group--part of an even larger aggregate of species associated with C. straminea. Their morphological features are indistinct and intergrade into one another. Botanists have had difficulty classifying members of this aggregate for nearly 200 years. Some authors have viewed the taxa as separate species, others as polymorphic forms of a single species. Much of the contention has centered upon the variation of taxonomic characters used to delimit and distinguish species. …

Gas Exchange Of Four Viburnum Species, Lisa Gayle De Berg

Dissertations and Theses @ UNI

In the natural environment, a plant's gas exchange and water use efficiency characteristics in response to environmental stresses such as vapor pressure deficit, temperature, light intensity, and water potential may vary according to physiological and morphological species differences, leaf types (deciduous or evergreen), and habitat types (northern and southern). In the field, laboratory, and growth chamber, the effect of vapor pressure deficit, temperature, and light intensity on gas exchange characteristics was investigated for four woody shrub species from the genus Viburnum. The species under investigation include: y. rhytidophyllum (northern evergreen), y. awabuki (southern evergreen), y. dentatum (northern deciduous), and y. …

Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney

Dissertations and Theses @ UNI

The native vegetation of Iowa was primarily tallgrass prairie and currently exists only in small isolated parcels, including some remnants occurring in roadsides. Roadside prairie remnants are important for historical, environmental, aesthetic, scientific, and economic reasons. Information about factors influencing the occurrance of roadside prairie vegetation could be useful to roadside vegetation managers in development of initial vegetation surveys and subsequent to restoration of roadside prairie vegetation.

This study was conducted to determine what factors most affected the percent coverage of prairie graminoids in roadsides; particularly soil moisture availability, drainage, soil disturbance, and availability of a prairie seed sources. Prairie …

A Survey Of The Vascular Flora Of Black Hawk County, Iowa, Karen E. Van Norman

Dissertations and Theses @ UNI

Black Hawk County, located in the east-central part of the state of Iowa, is a political subdivision of 570 square miles. The topography of the county is the result of glaciation, erosion and deposition, causing gently rolling plains. The Cedar and the Wapsipinicon rivers transect the county from the northeast to the southwest. With their tributaries, these rivers comprise a natural drainage network which has enhanced agricultural practices throughout the county.

The vascular flora of the county was surveyed in the field during the growing seasons of 1982 and 1983. Over 1500 voucher specimens were collected. Data were also compiled …