Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"plant quality"”.
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Species-level Compensatory Responses Buffer Drought and Nitrogen Eutrophication Impacts on Plant-Arthropod Interactions in Species-Rich Grasslands
How drought and nitrogen deposition impact plant-arthropod dynamics is unclear due to interactions between water and nitrogen availability and plant quality for herbivores. Drought and eutrophication can increase plant quality (i.e., foliar nitrogen), the former doing so via physiological changes. …
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Local Variation in the Chemical Defence of European Pine Sawfly (Neodiprion sertifer): Effects of Host Tree Chemistry and Social Environment
… that sequesters resinous acids from the host plant for its antipredator defence. It is also a social insect that feeds and defends cooperatively in a group during the larval stage. In this master’s thesis, I studied the variation in chemical defences from three different natural populations of …
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Nutrient regulation by an omnivore and the effects on performance and distribution
… between the ability of Conocephalus to locate plant and prey resources and the effect that these resources have on omnivore performance (Chapter 3). I found that Conocephalus aggregates in areas of high plant quality but that their numbers do not correspond to areas of high prey density. …
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Nutrition and Plant Growth Regulator Rates for High Quality Growth of Containerized Spiderwort (Tradescantia virginiana L.)
… to determine fertilizer and PGR rates for high quality growth of Spiderwort in a greenhouse production setting. The first experiment screened three plant growth regulators (PGRs) at ascending rates on three T. virginiana cultivars. The most effective rates for height suppression were …
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The effect of aphids in parasitoid-caterpillar-plant interactions
… the relationships between herbivores, their host plants and their parasitoids. However, the relationships between parasitoids and herbivore hosts have typically been studied in isolation of other herbivore species. I examined how the outcomes of species interactions change when multiple …
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The Interaction of Arvicoline Rodents and Sheep in Norwegian Alpine Rangeland
… by large mammals can have significant impacts on plant community composition, species diversity, and nutrient cycling and may also affect densities of small mammals. I used a set of experimental treatments to evaluate the impact of sheep, arvicoline rodents, and fertilization on rangeland in the …
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Tall Fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) Cultivar Performance in the Central California Coastal Region
… heights of five and 10 centimeters and evaluated plant quality based on stand density, leaf texture, and genetic plant color. In the first year of the study, although there were some differences, there were no continual patterns that proved one cultivar to be better or worst than the others. Lower …
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Documenting the Patterns and Ecological Impacts of a Densovirus on Melissa Blue Butterflies (Lycaeides melissa) and Beyond
… species that utilizes members of the Fabaceae plant family for oviposition and larval diet, with records of recent expansion to roadside alfalfa ( Medicago sativa ). Specifically, I investigated whether viral prevalence and load were influenced by factors such as host plant diet or adult …
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Temporal variation in fruit-feeding forest butterfly communities in Sabah, Borneo.
… as well as via indirect effects on larval host plant quality.
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Regulation of Growth and Branching of Containerized Penstemon x mexicali Cultivars
… of this research are to analyze the effects plant growth regulators and pinching practices have on the growth habit of Penstemon x mexicali Pikes Peak Purple and Red Rocks and to produce more marketable containerized Penstemon. A preliminary study analyzed the effects branching agent PGRs had …
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TRACKING PLANT VIRUS INFECTIONS THROUGH MULTIPLE DIMENSIONS: A SEARCH FOR SOURCES OF NONPERSISTENT VIRUS VECTORS AND RESERVOIRS AT LOCAL AND REGIONAL SCALES
… result from a virus-induced reduction in pumpkin plant quality, thereby reducing abundance of a colonizing species within the field. Other virus-mediated effects in pumpkins could reduce aphid attraction to pumpkin fields as well, such as modification of the olfactory stimuli detectable by …
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The use of rockdust and composted materials as soil fertility amendments
… to investigate the impact these materials had on plant yield, plant nutrient content, soil chemistry and soil microbial communities in direct comparison with chemical fertilizer and farmyard manure. There were annual applications of compost, manure and chemical fertilizer in spring with one …
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Factors Affecting Within-plant Variation of Cotton Fiber Quality and Yield
… lint price per pound is determined by its fiber quality profile. Cotton quality is defined by a set of standardized properties (length, strength, elongation, uniformity, color, trash, and micronaire) collected on every United States bale. Each cotton fiber is the remnant of a single cell which …
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A Re-examination of Reproductive Arrest in the Monarch Butterfly, Danaus plexippus.
… as changes in photoperiod, declining host plant quality, and temperature (Goehring and Oberhauser 2002), and in another study simply as temperature (James 1982). This study was conducted to examine cool temperature as the stimulus for the induction of reproductive arrest and to correctly …
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Flowering Control and Production of Strobilanthes dyerianus Mast. (Persian Shield)
… dyerianus is a popular bedding and container plant. A problem in production is that over-wintered stock plants often flower. Once the plant becomes reproductive, stem elongation slows and floral buds arise from every node, rendering the plants useless for propagation. The objectives of this …
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Liming Characteristics of a High-Calcium, Dry Flue Gas Desulfurization By-product and its Effects on Runoff Water Quality
… application to a managed grassland on runoff, plant, and soil quality. Liming characteristics were determined by measuring the calcium carbonate equivalence (CCE), degree of fineness (DOF) and calculating the effective neutralizing value (ENV). The DFGD by-product was land-applied to a managed …
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Herbivore movement and spatial population dynamics in a heterogeneous landscape
… of landscape structure (e.g., patch geography or quality) that might influence dispersal among patches. Furthermore, there has been little exploration of the mechanisms underlying effects of the matrix on the spatial ecology of species. In this dissertation, I examine how the movement and …
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Impact of Light Pollution on Species Interactions
… between insect herbivores and their host plants by examining the entire life cycle of nocturnal Lepidoptera (moths). Ultimately, I found that light pollution induces an ecological trap for moths.</p> <p>I evaluated the importance of light pollution in structuring moth communities by …
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Effects of nitrogen source and level on the growth and composition of Sinningia speciosa Lodd
… fertilizer that can be applied without reducing plant quality under different light and temperature conditions. In one group of experiments, plants were supplied modified Hoagland's solutions in which the N source and level were varied. Shoot dry weight of gloxinias grown in an organic medium in …
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Quality management system to improve conveyor system performance : Lethabo Power Station as case study
… Power Station experienced a number of ash plant conveyor failures that resulted in production loss and plant damages. This study was aimed at determining the root causes of the failures (technical, management system and process) that led to conveyor unreliability. The problem was verified …
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