Plant Sciences Commons^™

Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry

Electronic Theses and Dissertations

Climate change is a threat to global forest ecosystems. In the northeastern United States, forest trees are facing rising temperatures and increasingly inconsistent moisture regimes. In addition to long-term changes in climate conditions, there is concern about the potential for more frequent and intense climate extremes, which can have severe and rapid negative effects on tree physiology and growth. Further, climate extremes may co-occur to produce a greater magnitude of effect than the sum of their parts, with a prominent example being hot droughts, which are increasing in occurrence and severity. The impact of these and other extreme climate interactions …

Long-Term Influence Of Commercial Thinning On Spruce-Fir Forests, Bishnu H. Wagle Mr.

Electronic Theses and Dissertations

This study investigates long-term influences of pre-commercial thinning (PCT) and commercial thinning (CT) treatments in spruce-fir forests, a key forest type in northeastern North America. Utilizing repeated measurements from replicated experimental research sites (n=15) in Maine, both stand- and tree-level responses to contrasting CT with and without prior PCT (NoPCT) have been quantified. In addition, an in-depth economic analysis, exploring the impact of different thinning treatments, associated costs, merchantability specifications, varying timber and carbon prices, and discount rates, on net present value (NPV) has been carried out using both measured and projected data. Thinning treatments at nine PCT sites combined …

Mp: 766 Roadside Rights-Of-Way As Pollinator Habitat: A Literature Review, Brianne Du Clos

Miscellaneous Publications

Pollination of crops and naturally-occurring flowering plants is a critical ecosystem service provided by managed and unmanaged animal pollinators. Insects are the most studied pollinators, particularly managed honey bees, unmanaged wild bees, and butterflies. Bees and butterflies thrive in early-successional habitat featuring grasses, exposed soil, wildflowers, and shrubs, which is consistently found within transportation and utility rights-of-way (ROW). However, intensive management of ROW can reduce the amount of high-quality pollinator habitat; such practices include frequent mowing, broadcast herbicide use, and planting non-native cool season grasses. Here, we review peer-reviewed academic and non-peer reviewed gray literature describing ROW management practices and …

Deconstructing The Art Of Physical Weed Control, Jordan W. Parks

Electronic Theses and Dissertations

Farmers adjust physical weed control (PWC) tools to optimize efficacy based on observations of weeds, the crop, and soil conditions. These many variables make PWC research challenging. To study PWC tool settings more closely, we constructed a soil bin with a mobile tool carriage inside of a heated glasshouse. The soil bin was 2 m wide by 12 m long by 1 m high, with a tool carriage that can operate at 0.4 to 19.0 km h^-1. Tool angle, spacing, depth, and speed can all be precisely adjusted from the tool carriage and control panel. The goal of …

Influence Of Biochar As A Soil Amendment On Soil Water Content And Wild Blueberry Physiology, Abigayl Novak

Electronic Theses and Dissertations

Maine wild (or lowbush) blueberries (Vaccinium angustifolium Ait.) continue to face challenges imposed by climate change. Reduced frequency of precipitation and increased drought conditions have negatively impacted this crop since it resides in sandy soils with limited retention of water and nutrients. The wild blueberry plants growing in water- and nutrient-poor sandy soils are likely to have poor resilience to drought, resulting in a decline in berry yield during drought years. Thus, there is an urgent need to find a drought management solution for wild blueberries. Compared with other drought management practices, such as irrigation systems, mulching, and adopting drought-resistant …

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 …

Effects Of Lobster Shell Meal As A Soil Amendment On Verticillium Wilt And Potato Growth, Ross Sousa

Honors College

Potatoes (Solanum tuberosum L.) are the most valuable crop in the state of Maine. Despite the crop’s success in the state, potato growers still face the challenges of various abiotic and biotic stresses, including diseases such as potato early dying, caused by the soilborne fungal pathogen, Verticillium dahliae. The disease has been controlled by soil fumigation and fungicides. As an alternative method, organic byproducts, such as lobster shell meal (LSM) or compost, can be used. The benefit of using LSM is thought to occur through the promotion of beneficial chitinolytic soil microbes which can degrade LSM. The derivatives …

Extraction And Characterization Of Antifungal Compounds Produced By Lowbush Blueberry Plants In Response To Monilinia Vaccinii-Corymbosi Infection, Sophia Suriano

Honors College

Maine’s wild blueberries are a vital economic and ecological resource for growers, consumers, and researchers alike. Fungal diseases like Monilinia vacciniicorymbosi (MVC) reduce the yield of berries from infected plants by killing plant tissues and damaging fruit. Understanding what blueberry plants use to defend themselves against fungal pathogens can give a greater insight into increasing plant immunity as a whole. This project aims to better understand the wild blueberry antifungal defense response. I extracted bioactive compounds from the healthy leaves of low severity and high severity disease-affected plants and separated the molecules with thin layer chromatography (TLC). Aspergillus sp. acted …

Improving Use Of Soil Health Practices In Kansas: A Study Of Barriers To Adoption And Novel Incentive Programs, Sara Kelemen

Electronic Theses and Dissertations

As climate change continues to affect agroecosystems, farm resilience will become increasingly important. To feed a growing global population, the future of agriculture must be secure and ultimately, sustainable. Use of soil health practices can increase farm resilience through improved provision of ecosystem services. Not only does this benefit the farm agroecosystem, it can also improve also agronomic outcomes while also improving landscape scale ecological conditions. It can also can have positive impacts on profitability. The benefits to use of soil health practices are well documented, yet rates of adoption in the United States remain relatively low. Therefore, research must …

Genetic Characterization Of Centromere-Mediated Uniparental Genome Elimination In Arabidopsis, Diana Spencer

Electronic Theses and Dissertations

The production of haploids through crossing was first discovered from instances of interspecies crosses in Nicotiana spp. in 1924. Since then, haploid induction crosses has been used to improve plant breeding programs and commercially utilized in a number of crop industries. The generation of doubled haploid instantaneously creates a pure homozygous line, therefore eliminating the need for several generations of inbreeding. There are several pathways to induce haploids in plants: of these methods, centromere-mediated genome elimination pathway engenders the highest haploid induction rate (HIR) with up to 45% in Arabidopsis compared to 15% through phospholipase-mediated haploid induction in maize. Centromere-mediated …

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 …

An Overview Of The Potential Effect Of Climate Change On American Pine Marten, Jordyn Morel

Honors College

The impacts of climate change are only increasing, and yet not all those impacts have been studied on certain species. The American pine marten Martes americana (Turton, 1806) is one of the species potentially vulnerable to climate change. They are an important component of biodiversity as they hunt a variety of small mammals and feed on numerous plants. Martens are also important prey to many winged and terrestrial species. In Maine, they are an umbrella species that co-occur with eleven other species and their presence is also a good indicator of a healthy forest environment. I conducted a literature review …

The Impact Of Glycine Betaine Applications On Drought Response In Wild Blueberries, Abigail Fisher

Honors College

Wild blueberries are an economically important crop for Maine, and with warming temperatures leading to increased periods of drought and increased soil moisture deficits, it is important to find new ways to combat the effects of drought. In this study, we aimed to look at the effect of foliar-applied glycine betaine applications on wild lowbush blueberries in both field and greenhouse experiments. The product being tested was Bluestim, a foliar-applied product containing >96% pure glycine betaine sold by Biobest. The product is claimed to work as an osmoprotectant allowing the plant to maintain turgor pressure and protect enzymes and macromolecules …

Genetic Sources Of Resistance To Potato Blackleg Soft Rot Caused By Dickeya Dianthicola, Lucas K. Heroux

Electronic Theses and Dissertations

Solanum tuberosum L. is the world's most important non-cereal food crop, capable of producing more food per land unit on less water than any other crop. Only rice, wheat, and maize are produced in larger quantities than potato. The potato tuber, a modified stem turned storage organ is nutrient dense and a staple in diets across the world. The potato crop is expected to grow and contribute significantly to the global food supply. However, potato production has increasingly been threatened by unfavorable environmental conditions, and susceptibility to pest and disease. Perhaps the most famous of all the Irish Potato Famine …

Using Soil Testing Data To Examine Organic Carbon Changes During The Past 27 Years In Maine Agricultural Soils, Andrew Chase

Electronic Theses and Dissertations

Agricultural soils may act as a source or a sink for carbon (C) in the global C cycle. With rising atmospheric CO2 levels, C sequestration in soils may play an important role in climate change mitigation. Soil organic carbon (SOC) also contributes to key aspects of soil health and fertility, such as aggregation, water-holding capacity, microbial biomass, and nutrient mineralization. Although SOC may be calculated from estimates of soil organic matter (SOM) obtained by loss-on-ignition (LOI), factors such as sample clay concentration and combustion temperature introduce error into estimates of SOM. We explored the potential for an extensive collection of …

Quantifying Spatial Heterogeneity Of Wild Blueberries And Crop Water Stress Monitoring Using Remote Sensing Technologies, Kallol Barai

Electronic Theses and Dissertations

The wild blueberry is one of the major crops of Maine, with significant economic value and potential health benefits. Due to global climate change, drought impacts have been increasing significantly in recent years in the northeast region of the USA, causing significant economic losses in the agricultural sectors. It has been predicted to increase further in the future. Changing patterns of the elevated atmospheric temperatures, increased rainfall variabilities, and more frequent drought events have made the wild blueberry industry of Maine vulnerable, suggesting the adoption of novel approaches to mitigate the negative impacts of global climate changes. Also, wild blueberry …

Lawrence Kaplan (14 April 1926-6 March 1918), Emily Kaplan

Andean Past

This is an appreciation of the life and work of archaeobotanist Lawrence Kaplan, a specialist in domesticated beans.

Implementing Landscape Design Principles To Improve Green Spaces And Promote Ecotherapy On A College Campus, Jessica Hutchinson

Honors College

As students in Maine are subject to harsh winters and a disconnectedness due to the pandemic, the creation of an ecotherapy focused garden may benefit the community at the University of Maine. Mental health is a rising concern within the United States, where anxiety has been the most frequent in students at 62.7% from a survey conducted by the Center for Collegiate Mental Health (Son et al., 2020). Ecotherapy is the practice of holistic psychology where healing is derived from interactions with the surrounding ecosystem (Summers and Vivian, 2018). Through literature review and gardening, this creative project provides a green …

Mp765: Creating The Orono Bog Boardwalk: A Facility For Education, Research, And Recreation, Ronald B. Davis

Miscellaneous Publications

A memoir by Dr. Ronald Davis detailing the creation of the Orono Bog Boardwalk. The Orono Bog Boardwalk is a premier destination in the Bangor/Orono area for persons wishing to experience the beauty and fascinating plants and animals of a Maine bog. The 1-mile boardwalk loop trail begins at the forested wetland edge in the Bangor City Forest, and after 800 feet crosses the Orono town line into the portion of the Orono Bog owned by the University of Maine. Along the way the boardwalk passes through a wide range of changing vegetation and environments on its way to the …

Hawkweed In Maine Lawns, Donna Coffin

Garden & Yard

In Maine, hawkweed is not on the state’s invasive plant list, although it is in other states. Hawkweed can be a concern to homeowners with lawns that get infested with it. It can also be a problem where the grass is not thriving due to low fertility, dry soils, or compaction. It can also be a problem in pastures and hayfields. Hawkweed does have a few redeeming qualities for pollinators. Beauty is in the eye of the beholder. If you don’t mind seeing these little yellow or orange flowers spring up above your grass and you are in low maintenance …

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

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 …

Functional Diversity In Blueberries And Their Responses To Extreme Drought, Pratima Pahadi

Electronic Theses and Dissertations

Climate change is expected to lead to novel climate conditions with an increase in frequency and severity of drought across many places around the globe including the north-eastern (NE) United States. Therefore, experimental studies that test the impacts of changing environmental conditions over long time scales or experimental studies that mimic these conditions are crucial to understand the potential impact on crops in this region. Wild lowbush blueberries and highbush blueberries are two important crops in NE USA. In this study, the leaf functional, structural, nutrient traits across genotypes of wild blueberries (Vaccinium angustifolium and V. myrtilloides) at …

The Role Of Red Raspberry (Rubus Idaeus) On Inflammation, Lipid Metabolism, And Endothelial Dysfunction As Related To The Metabolic Syndrome, Natalie Vandenakker

Electronic Theses and Dissertations

Metabolic syndrome (MetS) is major public health concern. Diet can play a major role in the prevention and/or progression of the MetS. At 8 weeks of age, male obese Zucker rat (OZR) and their lean littermates (LZR) were placed on a control or an 8% w/w whole red raspberry (WRR)-enriched diet for 8 weeks. Circulating levels of inflammatory cytokines and their gene expression in the liver and adipose tissue were evaluated. Several lipid markers were measured in the plasma, liver and adipose tissue. The expression of eight genes related to lipid metabolism were evaluated, both in liver and adipose tissue. …

Tree Responses To Moderate And Extreme Drought In The Northeastern United States, Ruth A. Van Kampen

Electronic Theses and Dissertations

Climate change is expected to lead to novel drought conditions in the Northeastern United States. Therefore, experimental studies that mimic these conditions are crucial to understand the potential impact on forests. Further, recent large scale dendrochronological studies suggest that spring and summer droughts may immediately impact tree growth while fall droughts may cause delayed impacts on growth the following growing season. Therefore, in this study, we investigated the impacts of six-week-long spring, summer, and fall droughts on the physiology and intra-annual growth on 288 saplings of six tree species native to the Northeastern United States. These species (deciduous broadleaf angiosperms, …

Characterization Of Dickeya Dianthicola And Pectobacterium Parmentieri Causing Blackleg And Soft Rot On Potato, Tongling Ge

Electronic Theses and Dissertations

Potato blackleg and soft rot (PBSR), which can be caused by Dickeya spp. and Pectobacterium spp., is a serious problem worldwide. The recent outbreak of PBSR in the Northeastern USA, caused primarily by D. dianthicola, has resulted in significant economic losses since 2015. This seedborne disease is highly associated with and therefore spread by seed tuber distribution. To understand how the outbreak occurred and where the pathogen originated, a total of 1204 potato samples were collected from 11 northeastern states from 2015 to 2020. All the samples were processed for bacterial isolation and DNA extraction. Dickeya dianthicola and P. …

Analysis Of Conifer Terpenes And Their Effect On The Feeding Habits Of Browntail Moth (Euproctis Chrysorrhoea) Larvae, Hunter Merchant

Honors College

The browntail moth (BTM; Euproctis chrysorrhoea)is a non-native, invasive species that has recently become a serious human health and environmental concern in Maine. BTM caterpillars possess microscopic toxic hairs that cause a poison-ivy-like rash on the skin and have been known to cause respiratory discomfort when inhaled. This invasive species is an herbivorous insect that causes harm to its host tree through defoliation during its larval life stage. BTM larvae weave overwintering webs on branch tips, generally at the tops of hardwood trees. Due to their toxic hairs and where they establish their overwintering webs, the species population is …

Tips For Growing Houseplants In Maine, Donna Coffin, Rebecca Long, Matt Wallhead

Garden & Yard

This newly revised and expanded fact sheet series addresses the basics of keeping houseplants. It will help you diagnose common problems with your houseplants, such as insects and diseases; overwatering or underwatering; improper lighting, temperature, or humidity; and insufficient pot size (root-bound). The series addresses how to start new plants from old plants, and also the unique challenges of growing houseplants in Maine, including the use of artificial light.

• Caring for Houseplants in Maine
• Dealing with Houseplant Problems
• Controlling Insects and Disease in Houseplants
• Growing Houseplants Under Artificial Light
• Creating New Plants from Old
• FAQs About Houseplants in Maine

Pyramiding Approaches For Potato Disease Resistance Breeding, Kristen M. Brown-Donovan

Electronic Theses and Dissertations

This study establishes the start of late blight genetic profiles for varieties and clones used as potato breeding material across the United States,and a Mendelian use of marker-assisted selection is employed to estimate allele dosage.

Potato is the fourth most important staple crop worldwide, with both high nutritional and economic values. Breeders seek improvements for many traits related to yield, dry matter, and surface and internal defects. Resistances to several diseases are also desired traits that breeders try to incorporate into their programs. The advent of DNA-based genetic technologies help breeding programs facilitate faster selection, including the use of marker-assisted …

Microsite Requirements For Successful Regeneration In Lowland Northern White-Cedar (Thuja Occidentalis) Forests, Jeanette Allogio

Electronic Theses and Dissertations

Declines in stands of northern white-cedar (Thuja occidentalis L., hereafter cedar) have been observed as both shifts in species composition and reductions in cedar densities, particularly those stands in lowland sites (Curtis 1946, Boulfroy 2012). While several factors inhibiting cedar regeneration have been identified, a thorough understanding of the conditions that best promote regeneration is lacking. Our objectives for the first chapter were to characterize the site conditions associated with successful regeneration in lowland cedar stands and to describe how spatial patterns of various cedar size classes relate to site preference and to regeneration dynamics. These objectives were achieved …