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Articles 1 - 21 of 21
Full-Text Articles in Life Sciences
Factors Affecting Apothecia Production And Primary Infection By Monilinia Vaccinii-Corymbosi On Vaccinium Angustifolium, Ian Leonard
Electronic Theses and Dissertations
Mummy berry, caused by Monilinia vaccinii-corymbosi (MVC), is a prolific disease of Vaccinium angustifolium (wild blueberry) leading to decreased yield in wild blueberry fields throughout the Downeast (DE) and Midcoast (MC) regions of Maine (ME). This study aimed to identify factors affecting primary inoculum production and infection by MVC on wild blueberry, and what bud stages of wild blueberry are most susceptible to infection. Through common garden (CGE), field and incubation experiments conducted in 2021 and 2022, factors affecting carpogenic germination of MVC pseudosclerotia and relationships between susceptible wild blueberry buds and environmental factors were analyzed. The CGE conducted in …
A Sky Island Perspective: New England Alpine Plant Distributions Across The Region, Andrea Tirrell
A Sky Island Perspective: New England Alpine Plant Distributions Across The Region, Andrea Tirrell
Electronic Theses and Dissertations
Alpine ecosystems around the globe are at risk due to climate change, human disturbance, and habitat loss. New England alpine zones are small and fragmented, which could make them vulnerable to global change. However, the persistence of tundra relics throughout the Holocene suggests the persistence of these communities in microclimate refugia. Assessing the near-term vulnerability of alpine plant communities is challenged by a lack of standardized, repeat surveys and long-term monitoring data, which presents a challenge for the many agencies monitoring New England’s alpine zones. Island biogeography theory predicts that alpine species richness is a function of area, but this …
Determining Effects Of Management Practices On Potato Early Dying And Soil Microbiome And Assessing Risk Of Fungicide Resistance In Verticillium Dahliae, Kedi Li
Electronic Theses and Dissertations
Potato early dying (PED) is a yield-constraining soilborne disease of potato, caused by Verticillium spp. with V. dahliae being the predominant causal agent. Since the pathogen inhabits soil for long periods, PED management aims to reduce the population of V. dahliae in soil. Benzovindiflupyr and azoxystrobin are effective chemicals and frequently used in the control of V. dahliae. In this study, field trials were conducted at Aroostook Farm, Presque Isle, ME in 2019 and 2020. Chemical and biological products have been studied for PED control, and fungicide resistance was also examined. To evaluate fungicide resistance, benzovindiflupyr was characterized on …
Assessing Plant And Lichen Diversity Using Reflectance Spectra, Lance Stasinski
Assessing Plant And Lichen Diversity Using Reflectance Spectra, Lance Stasinski
Electronic Theses and Dissertations
Biodiversity is changing and it is imperative that we continually assess it in order to preserve ecological services that we rely on. Spectral platforms are increasingly being used to assess biodiversity due to the fact that light reflected from an organism’s surface carries much of information about that organism. Despite the promise spectroscopy shows, two gaps in our knowledge remain. First, we do not know how well reflectance spectra can be used to estimate fine-scale diversity – intraspecific genetic and phenotypic diversity – that is fundamental to ecological and evolutionary processes. Second, spectral libraries, used to construct models to estimate …
Evaluating The Current Weed Community In Wild Blueberry Fields And Ipm Strategies For Spreading Dogbane (Apocynum Androsaemifolium), Anthony G. Ayers
Evaluating The Current Weed Community In Wild Blueberry Fields And Ipm Strategies For Spreading Dogbane (Apocynum Androsaemifolium), Anthony G. Ayers
Electronic Theses and Dissertations
Lowbush blueberry (Vaccinium angustifolium) is Maine’s third largest crop (USDA 2020 a). From 2017 – 2019 the three seasons yield average was 27,200 tons were harvested from 19,500 acres for a value of $22,468,000 (USDA 2020 c). Lowbush blueberries are managed on a two-year cycle. Every other year, lowbush blueberry fields are pruned to the ground either through the use of a tractor mounted flail mower or a prescribed burn (Yarborough 2009). Pruning is a necessary part of managing lowbush blueberries as the second-year growth produces the highest yield but steadily declines in subsequent years (Drummond et al. …
Population Structure And Reproductive Biology Of Monilinia Vaccinii-Corymbosi (Reade) Honey In Lowbush Blueberry In Maine, Katherine A. Ashley
Population Structure And Reproductive Biology Of Monilinia Vaccinii-Corymbosi (Reade) Honey In Lowbush Blueberry In Maine, Katherine A. Ashley
Electronic Theses and Dissertations
Lowbush blueberry, Vaccinium angustifolium Aiton, is both an economically and culturally important crop in Maine, being one of the few endemic crops to North America. The fungus Monilinia vaccinii-corymbosi (Mvc) causes mummy berry disease and is a significant pathogen of both highbush (Vaccinium corymbosum) and lowbush blueberries. While impacts of this disease are not regularly documented, it is estimated that 30-50% of the yield in an unmanaged field can be lost because of Mvc. This disease is typically managed with fungicides or burning of the field during years when the field is pruned, however, the impacts to the …
The Dispersal Pattern Of Thekopsora Minima In Wild Blueberry Determined By A Molecular Detection Method, Nghi Nguyen
The Dispersal Pattern Of Thekopsora Minima In Wild Blueberry Determined By A Molecular Detection Method, Nghi Nguyen
Electronic Theses and Dissertations
Blueberry rust caused by Thekopsora minima is a common disease in wild blueberry (Vaccinium angustifolium) and other Vaccinium genera. Understanding the spore dispersal pattern and disease cycle of fungal pathogens in wild blueberry is crucial for the development of a more efficient disease management program. Molecular assays for rapid detection and quantification of Thekopsora minima were developed to be incorporated with a spore trap sampling method and weather data collection to examine spore dispersal pattern and production in three different fields: Blueberry Hill Farm in Jonesboro, East Machias, and Spring Pond in Deblois, Maine, in three years 2014, …
Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos
Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos
Electronic Theses and Dissertations
Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …
Climatic Range Filling Of North American Trees, Benjamin Seliger
Climatic Range Filling Of North American Trees, Benjamin Seliger
Electronic Theses and Dissertations
Understanding the degree to which species distributions are controlled by climate is crucial for forecasting biodiversity responses to climate change. Climatic equilibrium, when species are found in all places which are climatically suitable, is a fundamental assumption of species distribution models, but there is evidence in support of climate disequilibria in species ranges. Long-lived, sessile organisms such as trees may be especially vulnerable to being outpaced by climate change, and thus prone to disequilibrium. In this dissertation, I tested the degree to which North American trees are in equilibrium with their potential climatic ranges using the ‘range filling’ metric, which …
Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach
Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach
Electronic Theses and Dissertations
Pollination of both wild and crop plants is at a crossroads; honey bee populations are experiencing losses at a higher rate than ever before, and some native bee species are declining in abundance to the point of being listed as endangered species. A few examples of these threats include pesticide exposure, habitat loss, and climate change. In response to bee population declines, conservation efforts have been initiated to increase habitat quality for bees by planting pollinator reservoirs or gardens. Plants provide nutrition to bees in the form of pollen and nectar. Several studies have shown links between higher nutritional quality …
The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini
The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini
Electronic Theses and Dissertations
The acreage of pollinator-dependent crops continues to expand across the globe. Simultaneously, honey bee hives – an annually rented commodity that growers rely on – are more expensive every year and in some cases, scarce. In response, pollinator-dependent growers seek alternative pollinators. One approach is installing bee pasture on farms, a strategy that enables systems-based farmers to become in-situ farm-scale habitat managers. This thesis first presents a review of the literature on bee pasture plantings and provides a brief overview of some methods for assessing their impacts on the pollinator community. There are three major gaps in current bee pasture …
Assessing The Biological Condition Of Maine Streams And Rivers Using Benthic Algal Communities, Thomas John Danielson
Assessing The Biological Condition Of Maine Streams And Rivers Using Benthic Algal Communities, Thomas John Danielson
Electronic Theses and Dissertations
The purpose of this study was to test and develop algal methods of evaluating the condition of Maine streams and rivers. The primary objective was to develop a statistical model to predict attainment of Maine's aquatic life criteria for water quality classes A, B, and C. I collected 298 samples of algae on rocks from 193 locations across the state. The major pattern in species composition related to conversion of forests to urban, residential, and agricultural land uses. I calculated preferred environmental conditions of 236 algal taxa for 1) concentrations of nitrogen, phosphorus, and dissolved ions in the water, 2) …
Myriophyllum Heterophyllum Michx. (Haloragaceae): Control And Vegetative Reproduction In Southwestern Maine, Jacolyn E. Bailey
Myriophyllum Heterophyllum Michx. (Haloragaceae): Control And Vegetative Reproduction In Southwestern Maine, Jacolyn E. Bailey
Electronic Theses and Dissertations
Native to the southeastern United States, variable-leaf watermilfoil (Myriophyllum heterophyllum) is an invasive species in the Northeast and has been documented in Maine lakes for twenty years. Variable-leaf watermilfoil is targeted by the Maine Department of Environmental Protection as a species of grave concern as it has aggressively colonized twenty-six water bodies in Maine. This aquatic invasive plant grows in dense mats and outcompetes native vegetation. It is causing both ecological and economic disruption to Maine's lakes and ponds. The plants clog boat motors and deter people from swimming and other water related activities. Allofragmentation and autofragmentation occur …
Systematics Of The Lobulomycetales, A New Order Within The Chytridiomycota, David Rabern Simmons
Systematics Of The Lobulomycetales, A New Order Within The Chytridiomycota, David Rabern Simmons
Electronic Theses and Dissertations
Based on molecular phylogenetic analyses, the polyphyletic order Chytridiales, one of the four orders in the Chytridiomycota, contains several well-supported clades. One species, Chytriomyces angularis, however, does not group within the robust clades of the Chytridiales or any other chytrid order. The light-level morphology and zoospore ultrastructure of this aquatic species also differ from those of the type species of the genus Chytriomyces. I amassed nine additional pure culture isolates of soil-inhabiting chytrids with morphologies or rDNA sequences similar to C. angularis, including two isolates of C. poculatus, and studied the molecular phylogeny of these ten …
Age-Related Trends In Red Spruce Needle Anatomy And Their Relationship To Declining Productivity, Margaret H. Ward
Age-Related Trends In Red Spruce Needle Anatomy And Their Relationship To Declining Productivity, Margaret H. Ward
Electronic Theses and Dissertations
Many species of trees undergo predictable age-related changes in foliar morphology and physiology. Age-related declines in photosynthetic rates, which may lead to decreases in productivity, have been described for numerous species. However, the physiological basis for these phenomena is unclear, as are linkages between agerelated trends in morphology/anatomy and physiology. Photosynthetic capacity in red spruce (Picea rubens Sarg.) may result from increased mesophyll resistance to CO2 uptake in older trees. Additional studies with other species imply that the foliage of older trees may have a lower ratio of photosynthetic to non-photosynthetic tissue and a larger proportion of xylem to leaf …
Development And Light Response Of Leaves Of Metasequoia And Close Relatives, Xiaochun Li
Development And Light Response Of Leaves Of Metasequoia And Close Relatives, Xiaochun Li
Electronic Theses and Dissertations
Metasequoia glyptostroboides is a useful nearest living relative (NLR) of the Eocene fossil Metasequoia. Research on modern Metasequoia might give us some clues about its fossil counterpart. During this study the leaf anatomy of Metasequoia, Glyptostrobus, Sequoia and Taxodium was investigated with light microscopy and transmission electron microscopy. Metasequoia exhibits several characteristics of typical sciaphilic plants, such as slightly arched outer cell walls in the adaxial epidermal cells, strongly arched outer cell walls in the abaxial epidermal cells, mesophyll composed of spongy cells, chloroplasts with well-developed grana not only in mesophyll cells but in both the adaxial and abaxial epidermis. …
Variation In The Severity Of Mummy Berry Disease Among Lowbush Blueberry Clones, Laura Penman
Variation In The Severity Of Mummy Berry Disease Among Lowbush Blueberry Clones, Laura Penman
Electronic Theses and Dissertations
Lowbush blueberry production is important for the economy of Maine and the Maritime provinces, and mummy berry disease, caused by Monilinia vaccinii- corymbosi, often reduces plant stand vigor and fruit production. The severity of mummy berry disease among clones of lowbush blueberry were measured in four fields over a two year period (2001 and 2002). In each of 37 clones,lO flowering stems with and without symptoms of blight were randomly selected at flowering to represent "diseased" and "healthy" stem populations, respectively. The severity of leaf and flower blight and fruit mummification was measured for each of these stems, and the …
Physiology, Enzyme Production, And Zoospore Behavior Of Balrachochytrium Dendrobatidis, A Chytrid Pathogenic To Amphibians, Jeffery Scott Piotrowski
Physiology, Enzyme Production, And Zoospore Behavior Of Balrachochytrium Dendrobatidis, A Chytrid Pathogenic To Amphibians, Jeffery Scott Piotrowski
Electronic Theses and Dissertations
Balrachochytrium dendrobatidis is a pathogen of amphibians that has caused severe population declines on several continents, and little is known about the conditions that favor epidemics. The zoospore activity, temperature, and pH requirements of B. dendrobutidis were investigated to help understand the ecology and transmission of this pathogen. Over 95% of the chytrid's zoospores stop moving in less than 24 hours, and the zoospores swam less than 2 cm before encysting on tryptone agar. B. dendrobutidis zoospores were not attracted to tryptone, gelatin hydrolysate, casamino acids, keratin, gelatin, glucose, or lactose. The chytrid grew and reproduced at temperatures ranging from …
The Occurrence And Characterization Of Hemoglobin From Different Strains Of Genetically Diverse, Free-Living Frankia, Jason Beckwith
The Occurrence And Characterization Of Hemoglobin From Different Strains Of Genetically Diverse, Free-Living Frankia, Jason Beckwith
Electronic Theses and Dissertations
Hemoglobins have been identified in root nodules of many actinorhizal plants. When cultured in vitro, the actinomycete Frankia strain CcI3 produces hemoglobin when grown with or without supplied nitrogen. The cyanobacterium, Nostoc commune, also produces hemoglobin in vitro, although only under nitrogen-fixing, microaerobic conditions, and in less than one fifth of the explored strainslspecies. The objectives of this study were to determine if Frankia strains EANlpec, ArI3, EUNlf, CcI.17, and Cc13, members of diverse genogroups, are capable of producing hemoglobin in vitro, to characterize the oxygen kinetics of the hemoglobin, and to determine the effect of nitrogen, oxygen, and carbon …
Relationships Between Rooting Restrictions, Radial Growth, And Drought Stress With White Pine (Pinus Strobus) Decline In Southern Maine, Megan L. Fries
Relationships Between Rooting Restrictions, Radial Growth, And Drought Stress With White Pine (Pinus Strobus) Decline In Southern Maine, Megan L. Fries
Electronic Theses and Dissertations
Throughout southern Maine there was a noticeable decline and mortality of white pine (Pinus sfrobus) from 1997 through 2000 in dense pole-size stands. The decline was widespread, scattered, and happened simultaneously indicating that it was incited by an abiotic stress. Because only isolated stands showed decline and mortality, site factors likely predisposed trees to injury. Site factors are likely related to the widespread field abandonment that took place throughout southern and central Maine, and led to establishment of pure white pine stands in many areas. Although white pine can regenerate on many sites, some locations will have soil limitations, such …
Study Of Conidia Production And Transmission Of Beauverza Bassiana (Balsamo) Vuill. In Colorado Potato Beetle (Leptinotarsa Decemlineata), Silvia Fernandez
Study Of Conidia Production And Transmission Of Beauverza Bassiana (Balsamo) Vuill. In Colorado Potato Beetle (Leptinotarsa Decemlineata), Silvia Fernandez
Electronic Theses and Dissertations
This work is an investigation of:( 1) mortality of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), under different modes of exposure to the pathogen Beauveria bassiana (Bals.) Vuill., (2) host and environmental factors affecting sporulation, production, and viability of B. bassiana conidia from infected cadavers of CPB larvae, and (3) transmission of the disease in CPB populations. The research leads to an improved understanding of the process of transmission of B. bassiana in CPB populations. This may enhance its use as a biological control agent for this pest insect. The highest rate of mortality of CPB larvae (77 percent) …