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Garlic Mustard (Alliaria Petiolata) Management Effectiveness And Plant Community Response, Erin Coates-Connor

Masters Theses

The control and eradication of the invasive biennial herb garlic mustard (Alliaria petiolata) and the restoration of invaded forest habitats present important linked challenges to land managers in North America. Removing garlic mustard by hand and by glyphosate herbicide application have both been used as eradication strategies with mixed results. Each method has advantages and disadvantages, but they are rarely compared for effectiveness and community impact across multiple years of management. Some previous studies have shown improvements in species diversity and plant community composition following management, while others have found no differences. To better understand both garlic mustard …

Small Fruit Phenolics: Phenolic Variations And Related Health Relevance, Susan Cheplick

Doctoral Dissertations

Berries, specifically, strawberries, raspberries, blackberries, and blueberries, are considered an integral part of a healthy plant-based diet. Berries contain high levels of phenolic compounds, which contribute to the health benefits of berry consumption. Many phenolic compounds exhibit high levels of antioxidant activity and other health related benefits, including anti- microbial, anti-inflammatory and cardio-vascular related functional capabilities. Strawberry and raspberry fruit were screened and evaluated for potential in dietary management of type 2 diabetes and related hypertension using in vitro assay models. There were differences between cultivars within each crop related to antioxidant activity. Inhibition of α- amylase, α-glucosidase, and ACE-1 …

The Good, The Bad, And The Ugly: Pollinators As Vectors Of Mummy Berry Disease In Highbush Blueberry, Matthew Boyer

Doctoral Dissertations

Background: Many plants must balance the need for pollination services with mediating the risk of pollinator-vectored pathogens. Vaccinium corymbosum, highbush blueberry, is negatively affected by an insect-vectored, fungal plant pathogen, Monilinia vaccinii-corymosi (MVC), the cause of mummy berry disease, in which the asexual spore mimics pollen grains and is transferred from blighted tissue to flowers via pollinators, resulting in inedible, hardened fruits. Highbush blueberry plants require outcrossed pollen for maximum yield and fecundity. Therefore, yield of blueberry plants rely on a balance between adequate pollination service and disease avoidance. Approach: To explore the relationship between pollinator community and infection …

Apple Disease Forecasting Models: When Climate Changes The Rules, Elizabeth W. Garofalo

Masters Theses

With a changing global climate, plant pathologists must understand the impact aberrant weather events may have on the development of plant diseases. Fungal plant infections are largely dependent on temperature and precipitation, climate parameters that are predicted to change more in this century. Venturia inaequalis causes apple scab, one of the most destructive apple diseases of temperate growing regions. Temperature and precipitation drive apple scab infections and forecast models, which guide growers in efficient, effective fungicide applications. In some recent years in the Northeast, these models have failed to accurately predict when ascospores of this fungus are available to cause …

A Plant Pathology View Of Signaling: A Computational Study Of Fusarium Oxysporum Kinomes And Downy Mildew Resistance In Sweet Basil, Gregory Deiulio

Doctoral Dissertations

This dissertation is composed of two projects that focus on pathogen and plant signaling within the framework of plant pathology. The first project targets protein kinases within the species complex Fusarium oxysporum based on genomic information and tracks their presence/absence and copy number variation across evolutionary time. We have predicted the kinomes of 19 Ascomycete fungi using the kinase annotating software Kinannote. Among Fusaria, kinases related to the perception of the environment, such as Histidine kinases, are proliferated. Similarly, I observed the expansion of Target of Rapamycin (TOR) kinase that regulates cell growth and development in responding to environmental cues. …

Variation And Evolution Of Fruit Ripening Traits In Tomato Species, Ian M. Gillis

Doctoral Dissertations

As angiosperm seeds mature within their ovaries, ovary tissue tends to grow and transform itself into fruit, which aids the success of the seeds. Fruits that are fleshy provide numerous ways to aid in the protection and the dispersal of seeds. First, they keep seeds hidden, encased in hard walls, surrounded by poisons and unpalatable compounds, and second, they undergo developmental changes that facilitate seeds’ release. Tomatoes, a model fleshy fruit, have all these protective traits, and over the course of ripening they become the familiar fruit that is a staple crop around the world. The wild relatives of cultivated …

Grass-Specific Mechanisms Of Iron Uptake: Investigation Of Phytosiderophore Transporters And Discovery Of Novel Iron Deficiency Loci, David Chan Rodriguez

Doctoral Dissertations

Iron-deficiency anemia is one of the most prevalent forms of malnutrition worldwide, affecting 1.62 billion people, with the population in developing countries being the most affected. Iron is equally vital in plants to perform essential functions such as photosynthesis. Crop grasses form part of everyday human nutrition, contribute fundamentally to human caloric intake, and, in some parts of the world, are the primary source of food. Grasses acquire iron from the soil by secreting chelator molecules called phytosiderophores to solubilize iron, making it available to be transported by the Yellow Stripe1 (YS1) transporter. In this dissertation, I studied aspects of …

The Interplay Between Polarity Regulators, Calcium, And The Actin Cytoskeleton During Tip Growth, Carlisle Bascom Jr

Doctoral Dissertations

Plant cell growth is a meticulously regulated process whereby the cell wall is selectively loosened to allow for turgor-pressure driven expansion. The rate of expansion must equal delivery of new material, or the cell will lyse. In many plant cells, this process happens diffusely around the cell. However, a number of plant cells have anisotropic shapes that require exquisite spatial control of secretion. One simple example of anisotropic patterning is tip growth; highly polarized cell expansion utilized by pollen tubes, root hairs, and moss protonemata. Investigating the role various molecules have in tip growth sheds light on how plant cells …

Plants, Parasites, And Pollinators: The Effects Of Medicinal Pollens On A Common Gut Parasite In Bumble Bees, George Locascio

Masters Theses

Declines in several pollinator species are due to a variety of factors, including pathogens. Incorporating pollinator-friendly plant species into wild and agricultural habitats could reduce the stress of pathogens if food sources act medicinally against pathogens. Previous research demonstrated one domesticated sunflower cultivar (Helianthus annuus) can dramatically reduce a gut pathogen (Crithidia bombi) of the common eastern bumble bee, Bombus impatiens. To ascertain the breadth of this medicinal trait, we tested whether pollen from several H. annuus cultivars and four relatives could also reduce C. bombi infections in B. impatiens. We also investigated whether …

Impact Of Oyster Mushroom Mycelium On The Growth Of Kale And Forage Radish, Levi Lilly

Masters Theses

Saprophytic fungi can be paired with companion crops in interplant systems to increase production efficiency. However, fungal species/strain, substrate, and inoculation rate can affect the growth of companion crops. This project investigated the viability of open-field mushroom production by interplanting three strains of Pleurotus ostreatus (Elm A, Elm B, and 8801) with kale (B. oleracea var. acephala) and forage radish (Raphanus raphanistrub sub. sativus), and measured the effect of interplanting on plant yield over two field seasons. In the field, Elm A showed an increase in plant yield at a low inoculation rate and decrease in …

The Impact Of Intraspecific Density On Garlic Mustard Sinigrin Concentration, Mercedes Harris

Masters Theses

Garlic mustard (Alliaria petiolata, Brassicaceae) is a biennial herb that produces glucosinolates, a class of constituent secondary metabolites that defend against herbivores and pathogens allowing it to grow at high densities in invaded regions. The glucosinolate sinigrin is predominant in garlic mustard and aids in its competitiveness as an invasive species. In North America, garlic mustard can grow at high densities and form dense monocultures which may increase its apparency to herbivores and therefore increase its sinigrin production. I measured leaf sinigrin concentration in garlic mustard populations of different densities in the field and in greenhouse experiments to evaluate …

Performance Of Floristic Quality Assessment In Massachusetts Forested Wetlands, Carolyn Gorss

Masters Theses

In order to combat the loss of valuable wetland functions and services, federal, state and tribal governments must have the tools to accurately assess and monitor the condition of wetland ecosystems. One particular method of wetland assessment is Floristic Quality Assessment (FQA), which has been growing in popularity throughout the United States since its creation in the 1970s. FQA relies on vegetative indicators of human disturbance to assess the integrity of an ecosystem. FQA calculations are based on Coefficients of Conservatism (C-scores), professionally-assigned scores ranging from 0-10 that denote a local species' tolerance to anthropogenic disturbance. Despite increasing interest in …

Integrating Cover Crop Mixtures And No-Till For Sustainable Sweet Corn Production In The Northeast, Julie S. Fine

Masters Theses

Fall-planted forage radish (Raphanus sativus L. longipinnatus) cover crops have shown successful weed suppression and recycling of fall-captured nutrients. This research evaluated the nutrient cycling and weed suppressive benefits of forage radish cover crop mixtures to develop an integrated system for no-till sweet corn (Zea mays L. var rugosa) production that improves crop yield and soil health. Treatments included forage radish (FR), oats (Avena sativa L.) and forage radish (OFR), a mixture of peas (Pisum sativum subsp arvense L.), oats and forage radish (POFR), and no cover crop control (NCC). Subplots were assigned to …

Uncovering Tasselsheath3. A Genomic And Phenotypic Analysis Of A Maize Floral Mutant., Thompson Zhang

Masters Theses

In the modern era, maize has become the most successful crop grown in the United States. According to the USDA over 90 million acres of land are planted to corn and 96.2% of the U.S feed grain production is made up of the cereal. Part of the success of maize is due to its floral architecture, and its pollination technique in which the flower opens, exposing stamens containing pollen into the air. A unique organ called the lodicule functions as a release mechanism, forcing the flower to open. Lodicules from grasses and eudicot petals are homologous, yet there is little …

Extractable And Non-Extractable Polyphenols From Apples: Potential Anti-Inflammatory Agents, Makenzi Gennette

Masters Theses

With diet being such a huge factor in the development of diseases, emerging research has supported that apple consumption is a promising candidate for disease prevention due to the high phenolic content it possesses. These polyphenols can be found in two forms: extractable polyphenols (EP) and non-extractable polyphenols (NEP). Polyphenols have been shown to have strong anti-inflammatory and anti-oxidant properties, but up until this point, most researchers focus on EP fractions, while NEP are neglected. After the EP extraction using acetone and acetic acid (99:1) from the Apple Boost powder, three additional extraction methods were conducted on the remaining powder …

Investigation Of Cytochrome P450 Monooxygenases In S. Homoeocarpa For Chlorothalonil Biotransformation, Robert Green

Masters Theses

Sclerotinia homoeocarpa (F.T. Bennett) is one of the most economically important pathogens on high amenity cool-season turfgrasses where it causes dollar spot. Due to decades of over-reliance and repeated chemical treatments, S. homoeocarpa has developed resistance and insensitivity to multiple classes of fungicides. To understand the genetic mechanisms of fungicide resistance, the whole genomes of two strains with varying resistance levels to fungicides, were sequenced. In unpublished data (Sang et al.), a RNA-sequencing analysis revealed three CYP450s that were validated to play a functional role in S. homoeocarpa’s resistance against different fungicide classes. We also identified CYP450 metabolic action …

Investigation Of Fungicide Resistance Mechanisms And Dynamics Of The Multiple Fungicide Resistant Population In Sclerotinia Homoeocarpa, Hyunkyu Sang

Doctoral Dissertations

A filamentous ascomycete fungus Sclerotinia homoeocarpa causes dollar spot, which is the most important disease of turfgrasses in the United States. Despite the increased number of reports of site-specific fungicide resistance and a recent report of multidrug resistance (MDR) in S. homoeocarpa field populations, the genetic mechanisms behind resistance or reduced sensitivity to fungicides remain poorly explained in the fungus. In order to prevent further development of fungicide resistance in the dollar spot pathosystem, a detailed elucidation of mechanisms of site-specific fungicide resistance and MDR is needed. In addition, the previous studies of MDR in fungi mostly focused on efflux …

The Key Question In Symbiotic Nitrogen Fixation: How Does Host Maintain A Bacterial Symbiont?, Onur Oztas

Doctoral Dissertations

The fact that plants cannot use nitrogen in the gaseous form makes them dependent on the levels of usable nitrogen forms in the soil. Legumes overcome nitrogen limitation by entering a symbiotic association with rhizobia, soil bacteria that convert atmospheric nitrogen into usable ammonia. In root nodules, bacteria are internalized by host plant cells inside an intracellular compartment called the symbiosome where they morphologically differentiate into nitrogen-fixing forms by symbiosome-secreted host proteins. In this project, I explained the host proteins required to maintain bacterial symbionts and described their delivery to the symbiosome. I showed that the SYNTAXIN 132 (SYP132) gene …

The Effect Of Management Practices On Bacterial, Fungal, And Nematode Communities On Cool Season Turfgrass, Elisha Allan-Perkins

Doctoral Dissertations

Golf courses comprise 50 million acres in the United States of highly managed turf susceptible to abiotic and biotic stressors. A growing area of interest is utilizing microbes to improve plant growth, increase disease and stress tolerance, and reduce pathogens. In order to develop these new practices, we must gain an understanding of turfgrass microbial communities and how they are affected by management practices. We characterized bacteria, fungi, and nematodes on three golf courses: one organic, one with reduced inputs, and one conventional. We took samples from three management areas on each course representing different management intensities (roughs, fairways, and …

Comparative Transcriptome Analysis Of Wild Tomato Species During Fruit Development, Altynay Zhanayeva

Masters Theses

Fleshy fruits in different species can display large variation in color. A link between fruit color and seed dispersal success is suggested by previous studies showing that high intensity of fruit color increases the visitation rate in seed-dispersing birds. Wild tomato species (Solanum spp.) are excellent model organisms for research on genetic basis of differential fruit color development during the ripening process. Despite polymorphism in fruit color, all tomato species have yellow flowers due to accumulation of carotenoid pigments, which suggests that the carotenoid pathway is intact. Thus, regulatory changes controlling enzymes activity during fruit maturation are likely …

Uncovering The Genetic Basis For Biofuel-Related Traits In Brachypodium Distachyon, Scott J. Lee

Doctoral Dissertations

Biofuels derived from plant biomass present a promising avenue to address the negative aspects of fossil-fuel dependence. The sustainability of biofuel production relies in part on the efficient degradation of lignocellulosic feedstocks. In order to capitalize on the potential of lignocellulosic biofuels, the genes underlying natural genetic variation for conversion efficiency must be determined. We have developed a robust and high-throughput assay to measure feedstock quality using the anaerobic bacterium Clostridium phytofermentans. We have measured biomass accumulation phenotypes and utilized this assay to perform quantitative trait locus (QTL) mapping and a genome-wide association study (GWAS) in the model grass species …

Evaluating The Role Of Glutathione In Detoxification Of Metal-Based Nanoparticles In Plants, Chuanxin Ma

Doctoral Dissertations

The potential risks from metal-based nanoparticles (NPs) in the environment have increased with the rapidly rising demand for and use of nano-enabled consumer products. Plant’s central roles in ecosystem function and food chain integrity ensure intimate contact with water and soil systems, both of which are considered sinks for NPs accumulation. Thus, this dissertation describes three main objectives to comprehensively understand the interactions between plants and NPs and to characterize the role of glutathione (GSH) in detoxification of metal-based NPs in plants at physiological, biochemical, and molecular levels. (1) The effects of cerium oxide (CeO₂) and indium oxide …

Investigate The Interactions Between Silver Nanoparticles And Spinach Leaf By Surface Enhanced Raman Spectroscopic Mapping, Zhiyun Zhang

Masters Theses

Owing to their increasing application and potential toxicity, engineered nanoparticles (ENPs) have been considered as a potential agricultural contaminant that may pose unknown risk to human beings. However, many techniques require invasive and complicated sample preparation procedures to detect and characterize engineered nanomaterials in complex matrices. In the first part of this thesis, we present a non-destructive and label-free approach based on surface enhanced Raman spectroscopic (SERS) mapping technique to qualitatively detect and characterize gold nanoparticles (AuNPs), on and in spinach leaves in situ. We were able to detect the clearly enhanced signals from AuNPs at 15 to 125 nm …

Iron Signaling In Arabidopsis Thaliana, Celina Abundis

Masters Theses

Iron is among the essential micronutrients for all living organisms and is a cofactor for many cellular redox reactions. Although iron is a highly abundant metal element found in the earth’s crust, it is also a limiting factor in plant development when it is present as insoluble ferric oxides. Plants have evolved two strategies to acquire soluble iron referred to as Strategy I and Strategy II. Our lab has focused on the Arabidopsis thaliana double mutant ysl1ysl3. The mutants display a chlorotic phenotype and are unable to correctly respond to iron deficiency.

Grafting is a common method for joining …

Novel Advancements For Improving Sprout Safety, Kyle S. Landry

Doctoral Dissertations

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the …

Chemically Mediated Interactions Between Hosts, Parasitic Plants And Insect Herbivores, Muvari C. Tjiurutue

Doctoral Dissertations

Species interactions, by changing phenotypic traits, can alter the outcome of subsequent interactions. Plant-mediated responses to herbivores have been extensively studied, but little is known about plant-mediated responses involving parasitic plants within a broader community context that also includes herbivores. Because parasitic plants are important components of many ecosystems and can shape community structure, it is important to understand how host-mediated interactions influence parasite preference and success. The goal of this thesis is to examine interactions between hosts, parasitic plants and herbivores mediated by chemical traits. We first examined the effects of dodder (Cuscuta sp.) parasitism on induced defenses …

Understory Plant Community Structure In Forests Invaded By Garlic Mustard (Alliaria Petiolata), Jason Aylward

Masters Theses

ABSTRACT

UNDERSTORY PLANT COMMUNITY STRUCTURE IN FORESTS INVADED BY GARLIC MUSTARD (ALLIARIA PETIOLATA)

MAY 2016

JASON ALLEN AYLWARD, B.S., PAUL SMITH’S COLLEGE

M.S. UNIVERSITY OF MASSACHUSETTS AMHERST

Directed by: Professor Kristina Stinson

Plant invasions represent a significant threat to the structure and function of natural ecosystems. Garlic mustard (Alliaria petiolata) has been identified as a threat to native communities mostly through small-scale studies and focused experiments. In this in situ observational study I examined the effects of garlic mustard invasion on species composition across multiple sites by comparing plant diversity and composition in invaded and adjacent …

Variations In The Invertebrate Communities Of Wild Cape Cod Cranberry Bogs, Barbara Wagner

Masters Theses

As a species domesticated only in the last century, agricultural cranberry plants (Vaccinium macrocarpon) remain little removed from their wild relatives. Thus, it is a potential model species for studies of the earliest stages of domestication; however, there is little available quantitative information on its wild population biology and ecology. As such information is vital to studies of the ecological changes occurring during domestication, the purpose of this study was to consolidate the relevant knowledge available and conduct a preliminary search for patterns in the invertebrate communities of wild bogs. The alpha diversity was found to be greater …

Evaluation Of Spring Frost Control Methods And An Assessment Of Cold Hardiness In Cranberry (Vaccinium Macrocarporn Ait.), Faith Ndlovu

Doctoral Dissertations

The American cranberry (Vaccinium macrocarpon Ait.) is an important temperate woody shrub crop whose fruit has human health benefits. Cranberry acquires cold hardiness in the autumn and loses it in spring, following deacclimation. Frost protection is necessary in cranberry production as a means to reduce bud damage due to low spring temperatures. The objectives of the field studies were to evaluate two methods of sprinkler irrigation for frost protection, the conventional approach consisting of continuous irrigation throughout the night (CON) and intermittent cycling of sprinklers (INT) incorporating cycling on and off throughout the night, by (i) assessing bud damage …

Assessing Kiln-Produced Hardwood Biochar For Improving Soil Health In A Temperate Climate Agricultural Soil, Emily J. Cole

Doctoral Dissertations

Soil quality has become a major factor used in assessing sustainable land management and the overall environmental quality, food security, and economic viability of agricultural lands. Recently, biochar has been touted as having many potential uses as a soil amendment for improving soil quality, specifically improving cation exchange capacity, pH and nutrient availability. However, soil biology also plays a significant role in biogeochemical processes that influence soil health and should be included in a more comprehensive study of soil health. This dissertation describes 4 projects within the same 3-year field study with the cumulative purpose of better understanding the effect …