Plant Sciences Commons^™

An Environmental Approach To Food Safety Assessment Using Artisan Cheese And Fresh Produce As Model Systems, Marie Limoges

Graduate College Dissertations and Theses

This dissertation examined recently issued regulatory standards using cheese and produce as model systems. FDA's 2015 Domestic and Imported Cheese and Cheese Products Compliance Program Guidelines (CPG) E. coli standards on cheese safety, and the extent to which these standards affect domestic and imported cheese commerce, was assessed. Results from FDA's Domestic and Imported Cheese Compliance Program for samples collected between January 1, 2004 and December 31, 2006 were analyzed. Of 3,007 cheese samples tested for non-toxigenic E. coli, 76% (2,300) of samples exceeded 10/g, FDA's target for regulatory activity. In cheese samples containing E. coli levels of 10/g and …

Impact Of A Winter Rye Cover Crop On Edge-Of-Field Nutrient Losses And Corn Silage Production, Keegan Griffith

Graduate College Dissertations and Theses

Cover crops have the potential to reduce environmental impacts of corn production. The objective of this study was to quantify differences in nitrogen (N) and phosphorus (P) loading between corn plots with or without a winter rye cover crop (Secale cerale). Four field plots (30 x 46 m) in Chazy, NY with edge-of-field monitoring were used for the study. Two plots were randomly assigned a rye cover crop treatment and planted with a grain drill at a rate of 112 kg ha-1 after corn silage harvest in 2015 and 2016. Continuous water flows were monitored from surface runoff and tile …

Ecosystem Function Along An Elevational Gradient In Vermont, Emily Page Piche

Graduate College Dissertations and Theses

Living (biotic) and non-living (abiotic) factors drive the function of ecosystems across a variety of scales from the root-soil interface to the watershed. Biotic and abiotic global change pressures such as increasing temperature and invasive species are shifting how ecosystems function. Thus, exploring and understanding how these factors shape function across the landscape is an important research area. For example, climate change both directly and indirectly affects soil microbial functions – such as carbon mineralization and nitrogen transformations – through increasing activity under warming and altering inputs to the soil through species composition changes. Mountains provide a useful tool for …

Evolutionary History Of The Angiosperm Npf1 Gene Subfamily: Duplications, Retention And Functional Implications For Root Symbioses And Development, Giovanna Sassi

Graduate College Dissertations and Theses

ABSTRACT

The success of land plants can be attributed to the evolution of beneficial associations between plant roots and soil microbes. Root-microbe mutualisms extend the range of plant nutrient acquisition delivered through the hyphal network of mycorrhiza, an ancient and widespread plant symbiosis, or by the more recent adaptive innovation of nitrogen-fixing nodule symbioses. A plant’s genetic toolkit governs its selection of beneficial symbionts and the developmental extent of these intimate interactions. However, the evolutionary origins and function for only a few symbiotic signaling components have been explored. The central aim of this dissertation is to resolve the evolutionary events …

Natural Selection For Disease Resistance In Hybrid Poplars Targets Stomatal Patterning Traits And Regulatory Genes., Karl Christian Fetter

Graduate College Dissertations and Theses

The evolution of disease resistance in plants occurs within a framework of interacting

phenotypes, balancing natural selection for life-history traits along a continuum of

fast-growing and poorly defended, or slow-growing and well-defended lifestyles. Plant

populations connected by gene flow are physiologically limited to evolving along a

single axis of the spectrum of the growth-defense trade-off, and strong local selection

can purge phenotypic variance from a population or species, making it difficult to

detect variation linked to the trade-off. Hybridization between two species that have

evolved different growth-defense trade-off optima can reveal trade-offs hidden in either

species by introducing phenotypic and …