Life Sciences Commons^™

Effects Of Understory Vegetation And Litter On Plant Nitrogen (N), Phosphorus (P), N∶P Ratio And Their Relationships With Growth Rate Of Indigenous Seedlings In Subtropical Plantations, Jun Wang, Dafeng Hui, Hai Ren, Zhanfeng Liu, Long Yang

Biology Faculty Research

Establishing seedlings in subtropical plantations is very important for forest health, succession and management. Information on seedling nutrient concentrations is essential for both the selection of suitable indigenous tree species to accelerate succession of the established plantation and sustainable forest management. In this study, we investigated the concentrations of nitrogen ([N]), phosphorus ([P]), and N∶P ratio in leaves, stems and roots of seedlings of three indigenous tree species (Castanopsis chinensis, Michelia chapensis and Psychotria rubra) transplanted with removing or retaining understory vegetation and litter at two typical subtropical forest plantations (Eucalyptus plantation and native species plantation). We also measured the …

Characterization Of The Alternative Oxidase From The Psychrophilic Green Alga Chlamydomonas Sp. Uwo241, Michael Sj Inman

Electronic Thesis and Dissertation Repository

The alternative oxidase (AOX) was studied in the psychrophilic green alga Chlamydomonas sp. UWO241. AOX is the sole component of the alternative pathway of mitochondrial electron transport and is present in all plant and algal species. In silico analysis of the deduced protein sequence of the cloned AOX cDNA showed that the UWO241 protein has lower amounts of proline and higher amounts of lysine and tryptophan compared to the AOX sequence of the mesophilic alga C. reinhardtii. These changes have been seen in other studies of cold-adapted enzymes. Interestingly, unlike C. reinhardtii, AOX transcript abundance in UWO241 …

Effects Of Excitation Pressure On Variegation And Global Gene Expression In Arabidopsis Thaliana, Rainer Bode

Electronic Thesis and Dissertation Repository

I assessed the effects of photosystem II excitation pressure on chloroplast biogenesis and leaf sectoring in the Arabidopsis thaliana variegated mutants im, spotty, var1, var2, chs5 and atd2. The plants were grown under varying degrees of excitation pressure induced by growth at increasing irradiance at different temperatures and the extent of variegation was quantified throughout the plant’s development. I found that the degree of variegation was positively correlated with excitation pressure, regardless of whether high light or low temperature was used to induce increased excitation pressure in all the mutants tested. This was irrespective of …

Toward Target 2 Of The Global Strategy For Plant Conservation: An Expert Analysis Of The Puerto Rican Flora To Validate New Streamlined Methods For Assessing Conservation Status, James S. Miller, Gary A. Krupnick, Hannah Stevens, Holly Porter-Morgan, Brian Boom, Pedro Acevedo-Rodríguez, James Ackerman, Duane Kolterman, Eugenio Santiago, Christian Torres, Jeanine Velez

Publications and Research

Target 2 of the 2020 Global Strategy for Plant Conservation (GSPC) calls for a comprehensive list of the world's threatened plant species. The lack of such a list is one of the greatest impediments to protecting the full complement of the world's plant species, and work to achieve this has been slow. An efficient system for identifying those species that are at risk of extinction could help to achieve this goal in a time frame sensitive to today's conservation needs. Two systems that efficiently use available data to assess conservation status were tested against a provisional International Union for Conservation …

Increasing Atmospheric Nitrogen Deposition: Implications For Tallgrass Prairie Restoration, Jennifer M. Mcphee

Electronic Thesis and Dissertation Repository

Continued intensification of agriculture and combustion of fossil fuels will increase rates of atmospheric nitrogen (N) deposition over the next century. N is typically a limiting resource for terrestrial plants, and many species are adapted to low-N conditions. Increased N availability can affect both plant biomass and species composition, often favouring N-demanding, adventive species. These effects can be adverse in the context of ecological restoration, where the end product often relies on establishing a particular community composition. I used a field experiment in Norfolk County, Ontario, to examine how N addition affects species composition and plant productivity of a tallgrass …

Census And Mapping Of Chorro Creek Bog Thistle In Reservoir Canyon, San Luis Obispo, Ca, Tyler Michael Lutz

Biological Sciences

Chorro Creek bog thistle (Cirsium fontinale var. obispoense) is a federally endangered variety of Fountain thistle endemic to western San Luis Obispo County. The U.S. Fish and Wildlife Service knows of nineteen populations, many with multiple colonies. A population was discovered in the Reservoir Canyon Natural Reserve in 2001, but has not been monitored or described since the time of its discovery. In fall of 2013, a census of the population was performed, the four colonies were mapped, and a floristic survey was conducted. A field experiment was initiated to determine if reducing the riparian canopy coverage can …

Forage News [2013-12], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Thank You Kentucky Farmers
• Forages at KCA
• Forage Variety Reports Now Available
• Southern Forages Translated Into Spanish
• Small Ruminant Grazing Conference to be held in Lexington on February 1, 2014
• AFGC Annual Conference - Memphis, TN
• 34th Kentucky Alfalfa Conference
• Updated Analysis on Fungicides and Alfalfa

Development And Application Of A Gis-Based Long Island Sound Eelgrass Habitat Suitability Index Model, Jamie M.P. Vaudrey, Justin Eddings, Christopher Pickerell, Lorne Brousseau, Charles Yarish

Department of Marine Sciences

The primary objectives of the Eelgrass Habitat Suitability Index Model (EHSI Model) are to assist in the evaluation of sites being considered for eelgrass restoration efforts in the Long Island Sound (LIS) area and to identify areas where water quality issues reduce or eliminate the potential for natural eelgrass colonization. To achieve this goal, geospatial processing of data available from the Long Island Sound area was conducted using ArcGIS v10.0 including the 3D Analyst and Spatial Analyst extensions. The result is a series of maps presented in this report and a GIS-based model available for users to interact with the …

Arkansas Soybean Performance Tests 2013, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/or marketing seed within the State, and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

The Effects Of Salinity On Pythium Disease Of Rice And Soybean, Terea Jeanette Stetina

Graduate Theses and Dissertations

Increasing salinity is an important factor limiting agricultural productivity worldwide. In addition to direct effects on growth and yield, diseases also may be affected. This study characterized the effects of soil salinity on seedling disease of soybean and rice caused by Pythium spp. Controlled environment experiments on soybean used two cultivars which differed in chloride tolerance and soil treated with a CaCl₂ solution to create a range of electrical conductivity (EC) levels. For soybean, soil was either not infested or infested with Pythium sylvaticum or P. aphanidermatum (pathogenic to soybean), or P. oligandrum (not pathogenic to soybean). Twenty-one days …

Effects Of Rain And Simulated Rain On Deoxynivalenol Levels In Grain And Chaff Of Winter Wheat With Fusarium Head Blight, Manoj Kumar Pun

Graduate Theses and Dissertations

Wheat grain affected by Fusarium head blight (FHB) contains the mycotoxin deoxynivalenol (DON) that is harmful to humans and animals. Reducing the amount of DON in grain is the goal of management practices for FHB so it is important to understand the factors affecting DON in grain. Some studies on the effects of late-season moisture found increases in DON while others found decreases due to leaching. The objectives of this study were to determine effects of late-season rain and misting on DON concentration in wheat spike tissues and to quantify the amount of DON leached from spikes. Field experiments were …

Southeast South Dakota Experiment Farm Annual Progress Report: 2013, Agricultural Experiment Station

Agricultural Experiment Station and Research Farm Annual Reports

The 2013 season brought some welcome relief from the drought of the previous year. Our yields were much improved, averaging 175 bushel per acre for corn and 50 bu/ac for soybeans . Several new developments were undertaken at the farm in the 2013 season. We established an area for research where grazing is integrated with crop production – so we now have some scope to conduct research looking at the effects of how grazing crop residues, cover crops and annual forages impacts crop productivity and soil health. Working with Chris Hay from the Ag. and Biological Systems Engineering Dept. at …

Arabidopsis Serk1 And 2 Regulate Anther Development As Co-Receptors Of Ems1, Yao Wang

Theses and Dissertations

In flowering plants, male reproductive cell differentiation, one of the most critical events in the early stage of sexual reproduction, occurs during anther development. In the model plant species Arabidopsis, anther development in each lobe results in the differentiation of five highly organized cell layers with unique identities, including the central male reproductive cells and four somatic cell layers. These features make the Arabidopsis anther an ideal system in which to investigate the mechanisms of cell fate determination and differentiation. Previous studies have demonstrated that a leucine-rich repeat receptor-like kinase (LRR-RLK), EXCESS MICROSPOROCYTES1 (EMS1/EXS1), plays an important role during Arabidopsis …

Leaf Anatomy And Systematics Of Polygaleae (Polygalaceae), Heather Wilber

Undergraduate Honors Theses

Polygalaceae are comprised of approximately 1000 species found worldwide in a variety of habitats. Over half of the species in the family were traditionally grouped into the polyphyletic genus Polygala and need resolution. Leaves from 21 species in 13 genera within tribe Polygaleae were field collected or taken from specimens at the Missouri Botanical Garden Herbarium (MO) to find phylogenetically useful characteristics of the foliar anatomy. The leaves were rehydrated using concentrated ammonium hydroxide, embedded in paraffin, and sectioned at 10 μm thickness using a rotary microtome. To observe epidermal features, rehydrated leaves were also cleared using 3% potassium hydroxide. …

The Imperative Of Conserving California's Foothill Oak Woodlands, Lauren Phillips

Social Sciences

No abstract provided.

Evaluating Economic Impacts Of Switchgrass Harvest Time, Nathanial Elsworth Cahill

Graduate Theses and Dissertations

This thesis deals with cost of production for cellulosic energy crops of switchgrass, miscanthus, and energy sorghum. The first chapter explains the rationale for development of decision support software called Energy Crop Analysis & Planning (ENCAP) and Switchgrass Harvest Date, Yield, Nutrient Removal Estimator (SHYNE). The second chapter examines harvest date implications on yield, nutrient removal, opportunity cost of modified sale dates, and post-harvest storage losses. This harvest date analysis leads to a profit maximizing harvest date from the perspective of the producer. While this harvest date may be optimal for the producer, biorefineries may be interested in sourcing switchgrass …

Remote Estimation Of Nitrogen And Chlorophyll Contents In Maize At Leaf And Canopy Levels, Michael Schlemmer, Anatoly A. Gitelson, James S. Schepers, Richard B. Ferguson, Y. Peng, J. Shanahan, Donald Rundquist

Department of Agronomy and Horticulture: Faculty Publications

Leaf and canopy nitrogen (N) status relates strongly to leaf and canopy chlorophyll (Chl) content. Remote sensing is a tool that has the potential to assess N content at leaf, plant, field, regional and global scales. In this study, remote sensing techniques were applied to estimate N and Chl contents of irrigated maize (Zea mays L.) fertilized at five N rates. Leaf N and Chl contents were determined using the red-edge chlorophyll index with R2 of 0.74 and 0.94, respectively. Results showed that at the canopy level, Chl and N contents can be accurately retrieved using green and red-edge Chl …

Optimal Copper Supply Is Required For Normal Plant Iron Deficiency Responses, Brian M. Waters, Laura C. Armbrust

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible …

Sources Of Variability In Agronomic Weed Seed Predation: Time, Space, Habitat, And Hyperpredation, Sonja K. Birthisel

Electronic Theses and Dissertations

Weed seed predation is an ecosystem service that benefits farmers by decreasing seedbank inputs, thereby reducing weed pressure in subsequent growing seasons. Seed predation can be considerable, but is highly variable. Sources of variability may include time, space, habitat, and trophic interactions such as hyperpredation. Two experiments were conducted to measure the impacts of these sources of variability on weed seed predation rates in Maine mixed vegetable agroecosystems.

Chapter One of this thesis describes a series of landscape-level field experiments conducted to quantify the effects of time, space, and habitat on seed predation rates. Seed assays, with and without vertebrate …

Optimizing Systems For Cold-Climate Strawberry Production, Tiffany L. Maughan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Producing fruits and vegetables in the Intermountain West can be challenging due a short growing season, extreme temperatures, and limited availability of irrigation water. This is particularly true of strawberries, where commercial production is limited due to late fall and early spring frosts that shorten the growing season. With the increasing demand for local produce as urban populations grow and as consumer buying habits change, growers are looking for ways to overcome these climatic challenges. High tunnels are one option growers can use. High tunnels are similar to greenhouses, but less expensive to construct and to maintain. Another way to …

Molecular And Biochemical Mechanisms Of Pathogenesis In The Maize Foliar Pathogen Cercospora Zeae-Maydis, Winfred-Peck Dorleku

Graduate Theses and Dissertations

GLS is a serious foliar disease of maize, a major staple crop grown commercially in the USA for both human and animal feed production, and increasingly, for ethanol production. The disease is caused by two Cercospora species, C. zeae-maydis and C. zeina, both of which infect maize in the USA and in other parts of the world, with yield losses potentially greater than 50%, depending on local conditions. In culture, C. zeae-maydis produces a phytotoxic, host non-specific perylenequinone, cercosporin, and abscisic acid (ABA), for which there is no known pathological or physiological function in the fungus. Experimental evidence indicates …

Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith

Graduate Theses and Dissertations

Sustainability in agriculture is paramount to assuring continued production from our most naturally fertile soils. Storing carbon (C) in soil as organic matter through sustainable agricultural management practices can both remove atmospheric C and improve soil quality. The objective of this study was to evaluate the long-term effects of water management (irrigation and dryland), residue management [burn and no-burn, conventional (CT) and no-tillage (NT)] and residue/fertility level (high and low) on soil respiration and aggregate stability in a wheat- (Triticum aestivum L.) soybean [Glycine max (L.) Merr.], double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta …

Mechanisms For Regulation Of Plant Kinesins, Anindya Ganguly, Ram Dixit

Biology Faculty Publications & Presentations

Throughout the eukaryotic world, kinesins serve as molecular motors for the directional transport of cellular cargo along microtubule tracks. Plants contain a large number of kinesins that have conserved as well as specialized functions. These functions depend on mechanisms that regulate when, where and what kinesins transport. In this review, we highlight recent studies that have revealed conserved modes of regulation between plant kinesins and their non-photosynthetic counterparts. These findings lay the groundwork for understanding how plant kinesins are differentially engaged in various cellular processes that underlie plant growth and development.

A Seasonal, Density-Dependent Model For The Management Of An Invasive Weed, Esther Shyu, Eleanor A. Pardini, Tiffany M. Knight, Hal Caswell

Biology Faculty Publications & Presentations

The population effects of harvest depend on complex interactions between density dependence, seasonality, stage structure, and management timing. Here we present a periodic nonlinear matrix population model that incorporates seasonal density dependence with stage-selective and seasonally selective harvest. To this model, we apply newly developed perturbation analyses to determine how population densities respond to changes in harvest and demographic parameters. We use the model to examine the effects of popular control strategies and demographic perturbations on the invasive weed garlic mustard (Alliaria petiolata). We find that seasonality is a major factor in harvest outcomes, because population dynamics may …

Evaluation Of Three Nest Searching Methods For Ring-Necked Pheasant, Jeffery W. Stackhouse, Kevin K. Sedivec, Benjamin A. Geaumont

The Prairie Naturalist

Ring-necked pheasant (Phasianus colchicus) are a highly sought after game bird and as such, much research has been conducted regarding their ecology (Warner 1981, Trautman 1982, Johnson and Knue 1989). Perhaps the most investigated aspect of pheasant ecology is the species’ reproductive season (e.g. Linder et al. 1960, Dumke and Pils 1979, Leif 1994) with many studies focusing on nesting habitat (Baskett 1947, Clark et al. 1999). Results from previous research have acknowledged the difficulty associated with locating pheasant nests in their preferred cover types (Hanson 1970, Evrard 2000). Studies of pheasant nesting ecology have been based on …

Salamander Colonization Of Chase Lake, Stutsman County, North Dakota, David M. Mushet, Kyle I. Mclean, Craig A. Stockwell

The Prairie Naturalist

Salt concentrations in lakes are dynamic. In the western United States, water diversions have caused significant declines in lake levels resulting in increased salinity, placing many aquatic species at risk (Galat and Robinson 1983, Beutel et al. 2001). Severe droughts can have similar effects on salt concentrations and aquatic communities (Swanson et al. 2003). Conversely, large inputs of water can dilute salt concentrations and contribute to community shifts (Euliss et al. 2004).

Chase Lake is a large, shallow, alkaline lake in east-central North Dakota most famously known for supporting one of the largest breeding colonies of the American white pelican …

How Important Is A Quality Manuscript Review?, Christopher N. Jacques

The Prairie Naturalist

Temperatures are finally starting to cool a bit (for those of us in the northern Great Plains region) and Thanksgiving break is just around the corner.

I offer my reflections in the spirit of encouraging each of you to take a break from your professional obligations and spend time with friends and family enjoying nature and everything it has to offer this fall.

A Northward Range Extension Of The Hispid Cotton Rat (Sigmodon Hispidus) In Missouri, Cody W. Thompson, Elmer J. Finck

The Prairie Naturalist

The hispid cotton rat (Sigmodon hispidus) is a widely distributed rodent with a geographic range extending from north-central Mexico to southern Nebraska and central Virginia and from southeastern Arizona east to Florida (Carleton et al. 1999, Peppers and Bradley 2000, Wilson and Reeder 2005) with isolated populations in Arizona (Bradley et al. 2012) and California (Clark 1972). Range expansions for the species have been well documented (Clark 1972, Farney 1975, Benedict et al. 2000, Wright et al. 2010, Wills et al. 2011). The majority of these range expansions have occurred across the Central Plains during the 20th century …

Use Of Seeded Exotic Grasslands By Wintering Birds, Andrew D. George, Timothy J. O'Connell, Karen R. Hickman, David M. Lesliee Jr.

The Prairie Naturalist

Despite widespread population declines of North American grassland birds, effects of anthropogenic disturbance on wintering habitat of this guild remain poorly understood. We compared avian abundance and habitat structure in fields planted to the exotic grass Old World bluestem (Bothriochloa ischaemum; OWB) to that in native mixed-grass prairie. During winters of 2007–2008 and 2008–2009, we conducted bird and vegetation surveys in six native grass and six OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. We recorded 24 species of wintering birds in native fields and 14 species in OWB monocultures. While vegetation structure was similar between field …

Whooping Cranes Consume Plains Leopard Frogs At Migratory Stopover Sites In Nebraska, Keith Geluso, Brad T. Krohn, Mary J. Harner, Michael J. Assenmacher

The Prairie Naturalist

Whooping cranes (Grus americana) currently consist of a single, wild population that migrates annually from breeding grounds at Wood Buffalo National Park, Canada, to wintering grounds on and around the Aransas National Wildlife Refuge along the Texas coast, USA (NRC 2005). This population reached a low of less than 20 individuals in 1941 (Allen 1952) but has rebounded to over 250 individuals (Chavez-Ramirez and Wehtje 2012, Gil-Weir et al. 2012). Whooping cranes migrate approximately 4,000 km each spring and autumn, traversing much of the North American Great Plains (Lewis 1995) and periodically landing along rivers, wetlands, and other …