Plant Sciences Commons^™

The Evolution And Development Of Awns In The Grass Subfamily Pooideae, Erin L. Patterson

Doctoral Dissertations

This research focuses on a specific example of replicated evolution: the grass awn. Awns are typically extensions of the lemma, but may also appear on glumes or paleas. The lemma is a leaf-like organ on the exterior of the grass flower, the glumes are a pair of bracts subtending the basic unit of grass inflorescences, the spikelet, and the palea is the floral organ opposite the lemma. Awns are often described as "hair-" or "bristle-" like, but appear in many different shapes. Many awns are “twisted & geniculate", in which the awn has two sections, a lower twisted column, and …

The Use Of Biological Soil Health Indicators To Quantify The Benefits Of Cover Crops, Alexander Wu

Masters Theses

Soils provide many essential functions that support the world. With a decline in soil health, these functions also decrease in efficiency, and can threaten the health of billions of people around the world. Typically, soil health tests do not use biological indicators, however microbes drive and perform vital functions to increase soil health. One way to increase soil health is through the use of cover crops to reduce soil erosion during fallow periods, increasing soil organic matter, as well as collecting nutrients from soil into their biomass. These cover crops are then terminated through various methods such as herbicides, disk …

Modulation Of Plant Immunity During The Establishment Of The Nitrogen-Fixing Symbiosis, Miriam Hernandez-Romero

Doctoral Dissertations

Nitrogen is essential for plant tissue growth but is often a limited resource in soils. Many legumes overcome this limitation by entering a symbiotic association with soil microbes, called rhizobia, which provide nitrogen to the plant while rhizobia receive fixed carbon. To successfully form a symbiosis, the host and symbiont exchange a series of molecular signals. One major obstacle during this interaction is the host's innate immune system, which becomes active upon rhizobial detection. It is therefore the main focus of this thesis to identify the mechanisms that modulate host immunity. In the subsequent chapters, we focus on a rhizobial …

Appendix 1. Database Of Eicat Impact Assessment Summaries For 169 Potential Sleeper Invasive Plants In The Northeast United States, Ayodelé C. O'Uhuru, Bethany A. Bradley, Toni Lyn Morelli, Justin Salva

Data and Datasets

Environmental Impacts Classification of Alien Taxa (EICAT) assessments for 169 introduced, established plants in the Northeast (states of CT, MA, ME, NH, NY, RI, VT) that could become invasive with climate change.

Taxonomic Relationships Of Established Plant Species In The Conterminous United States, Daniel Buonaiuto, Annette Evans, Mathew Fertakos, William Pfadenhauer, Justin Salva, Bethany Bradley

Data and Datasets

Invasion status of non-native vascular plants established in the conterminous United States and their phylogenetic relationships to other invaders at multiple taxonomic resolutions.

Remember Your Roots: Biogeographic Properties Of Plants' Native Habitats Can Inform Invasive Plant Risk Assessments, William Pfadenhauer, Michael Nelson, Britt Laginhas, Bethany Bradley

Organismic and Evolutionary Biology Graduate Student Publication Series

Aim: Reducing the effects of invasive plants is best accomplished by predicting which species will invade and preventing their introduction. To do this, risk assessments rely on a variety of plant traits and biogeographic properties to predict potential invasiveness. However, the relative importance of these traits and properties is unknown. Determining which biogeographic properties contribute the most to predicting invasiveness could improve the accuracy and reduce the time needed to complete future risk assessments. Here, we provide a comprehensive analysis and ranking of the biogeographic properties that best differentiate invasive and noninvasive plant species.

Location: Conterminous United States.

Methods: We …

Drone Preflight Checklist, Ryan Wicks, Giverson Mupambi

Cranberry Station Fact Sheets

No abstract provided.

Historical Plant Sales (Hps) Database: Documenting The Spatiotemporal History Of Plant Sales In The Conterminous U.S., Matthew Fertakos, Evelyn M. Beaury, Neil R. Ford, Nicole L. Kinlock, Denise W. Adams, Bethany Bradley

Data and Datasets

The purpose of this database was to extract, standardize, and geocode the historical trade of vascular and non-vascular plant taxa sold in the horticultural industry of the conterminous United States. The HPS database aims to serve as a resource for analysis of contemporary patterns of introduced and invasive plants as well as for identifying opportunities to expand native plant sales in horticulture. Key data sources that make up this database include the Biodiversity Heritage Library's Seed and Nursery Catalog Collection, and the book Restoring American Gardens by D.W. Adams.

Assessing Warm-Season Annual Grasses To Increase Forage Inventory, Andrea Marroquin

Masters Theses

Summers are expected to continue to increase in heat/dryness in the Northeast, causing issues pertaining to forage production during the summer to worsen. Many pastures grow cool season grasses, even during the summer. These grasses enter a dormant period and slowdown in production during the months of July and August, leading to what is referred to as “summer slump”. Some farms grow corn silage during the summer, and while corn silage is a valuable crop, its cultivation often does not support soil biology. This research addresses solutions for both summer slump foraging and more sustainable silage. Summer annuals grow more …

Evaluation Of Semiochemicals For Attractiveness To Multiple Tortricid (Lepidoptera) Pests In Apple Orchards, Ajay P. Giri

Masters Theses

Tortricid moths (Lepidoptera) are known for their outstanding olfaction capabilities that allow them to detect, process, and respond to chemical information emitted by host or non-host plants. Such an ability to filter out odors from the complex mixture to locate their host has allowed researchers and integrated pest management (IPM) practitioners to develop and implement semiochemically-based pest control strategies. The major goal of this study was to evaluate, under field conditions, the response of male and female oriental fruit moth (OFM), codling moth (CM), redbanded leafroller (RBLR) and three lined leafroller (TLLR) to experimental kairomone lures in commercial apple orchards …

Root Growth Dynamics In Response To Moderate Temperatures, Maura J. Zimmermann

Doctoral Dissertations

Temperature can impact growth in plants though both physical and biological means. Plants physically respond to temperature by scaling their enzyme reaction rate to temperature, such as seen in the redox reactions of photosynthesis. Biologically, a plant can respond to temperature more specifically, such as adjusting its flowering time. Recently, the Baskin lab discovered that cell division in the root of the model plant Arabidopsis thaliana is temperature acclimated (Yang et al., 2017). Between the non-extreme temperatures of 15 and 25˚C cell division and growth zone length are constant. While the rate of cell division increases with temperature, the number …

Investigation Of Basil Downy Mildew Pathogen Survival, New Pathotype Development And Sources Of Quantitative, Kelly S. Allen

Doctoral Dissertations

Basil downy mildew (BDM) caused by the oomycete pathogen Peronospora belbahrii, threatens sweet basil (Ocimum basilicum) production worldwide. Chemical and cultural control options for BDM are limited, and resistant cultivars have only recently become available for commercial production. To address this challenging agricultural disease, this research investigates BDM epidemiology, occurrences of new pathotypes, and molecular plant-pathogen interactions leading to host resistance or susceptibility. A reproducible low-resource inoculation protocol was developed to harvest P. belbahrii inoculum and propagate BDM for further research. The survival of P. belbahrii sporangia was examined using an in vitro assay to assess germination …

Diterpene Synthases Of The Rice Blast Fungus: Phylogenetic Analysis And Biochemical Characterization, Ayousha Shahi

Masters Theses

Plant-pathogenic fungi harbor various specialized metabolites including diterpenoids that function as hormones and virulence factors. The fungus Magnaporthe oryzae is the causal agent of rice blast disease and can infect over 50 grass species. We demonstrate that the rice blast fungus encodes two diterpene synthases that produce normal pimara-8,15-diene and manoyl oxide scaffolds. Phylogenetic analysis of diterpene synthases among rice blast pathotypes showed functional conservation of the two core diterpene synthases amongst all pathotypes and suggests further expansion in select grass species. These insights into the blast fungal terpenome may inform efforts to counteract deleterious phytopathogens in crucial food crops.

The Influence Of Cover Crop Termination Strategies And Supplemental Nitrogen On Sweet Corn Yield And Nitrogen Use Efficiency, Sachina Sunuwar

Masters Theses

Cover crops are instrumental in nutrient management and soil health. A field experiment was conducted from fall 2020 to summer 2021 to evaluate the efficiency of different cover crop termination techniques and supplemental nitrogen on sweet corn yield, ear quality and nitrogen use efficiency. The four termination types are herbicide and disk tillage (HDT), herbicide no-till (HNT), cultivation disk till (CDT), and roller crimped no-till (RCNT). These termination types were each divided into four different nitrogen treatment: 0%, 33%, 67% and 100% of the recommended doses (145 kg haˉ¹). Sweet corn yield was highest and % unfilled tip was lowest …

Songbird-Mediated Insect Pest Control In Low Intensity New England Agriculture, Samuel J. Mayne

Masters Theses

Global agricultural intensification has caused large-scale wildlife declines, but agricultural lands that maintain natural habitats can support healthy wildlife populations and receive significant ecosystem services from these natural communities. However, how on-farm biodiversity results in beneficial ecosystem services is highly variable and is reported to differ among taxa and guilds. One group that has attracted attention for their potential beneficial role in reducing pest abundance are birds. Understanding the role of bird communities and individual species in pest control could be important for managing farms under a low intensity agroecological framework. In New England, farmers are increasingly applying low intensity …

Screening For Binding Partners And Protein-Protein Interactions Of A Fungal Transcription Factor- Xdr1, Nishadi Punsara Gallala Gamage

Masters Theses

Clarireedia spp. (formerly Sclerotinia homoeocarpaF.T. Bennett) is the causal agent dollar spot, the most economically important turfgrass disease impacting golf courses in North America. The most effective strategy for dollar spot control is repeated application of multiple classes of fungicides. However, reliance on chemical application has led to resistance to four classes of fungicides as well as multidrug resistance (MDR). Fungi are known to detoxify xenobiotics, like fungicides, through transcriptional regulation of three detoxification phases: modification, conjugation and secretion. Little is known, however, of the protein-protein interactions that facilitate these pathways. Following next-generation RNA sequencing of Clarireedia spp., a …

The Spatial Distribution Of Invasive Plant Presence, Abundance, And Impact, Evelyn M. Beaury

Doctoral Dissertations

Across the globe, native ecosystems are increasingly threatened by the spread and negative impacts of non-native, invasive plants. While many hypotheses explore what contributes to the damage caused by invasive species, few studies have tested these hypotheses at the macroscale. My dissertation addresses this knowledge gap by synthesizing thousands of vegetation surveys from ecosystems across the United States. I leverage existing, as well as explore new macroecological methods to deepen our understanding of the spatial ecology of plant invasions. My dissertation also asks how effective management and policy has been at reducing plant invasions. The primary introduction pathway for invasive …

Genetic And Environmental Regulation Of Plant Growth, Kirk J-M Mackinnon

Doctoral Dissertations

Field grown crops are continually exposed to a variety of external stimuli that influence plant responses. Light, temperature, and water availability interact to affect many economically important traits including growth rate, size, and lifespan. My research is focused on the intersection of genetic and environmental factors influencing plant growth. Specifically, I am interested in elucidating the regulation of rhythmic genes in response to photo- and thermocycles and identifying novel candidate genes associated with growth and drought traits. Understanding the gene regulatory networks that mediate time-of-day signaling is vital to identifying candidate genes across the pan-genome associated with traits of interest.

Community Assembly And Stress Response Of Grassland Phyllosphere Bacteria, Emily Bechtold

Doctoral Dissertations

Grasslands are an important ecosystem with potential to help stabilize food security and reduce greenhouse gas levels. As global temperatures rise, weather patterns are predicted to drastically change. The resulting increase in intensity, duration, and frequency of drought in important grassland areas will not only affect agricultural production, but also increase grassland susceptibility to fire, disease, and soil erosion. Thus, developing ways to sustainably promote grassland health and production is essential to increase food security and reduce environmental strain. Microbes in the phyllosphere, or aerial surface of plants, promote host fitness through phytohormone and nutrient production, increased stress tolerance, and …

Plants, Pipettes And Pcr, Elizabeth Vierling

Science and Engineering Saturday Seminars

Plants are amazing organisms that provide us with food, building materials, the pleasure of gardens, as well as providing the foundation of critical world ecosystems. Although they may look like they are just stuck in one place and doing not more than growing, they have many, many complex ways in which they respond to the environment. The goal of this STEM Ed session will be to discuss ways that plants can respond to the environment with hands on exercises and exploration of possible classroom activities. Participants will engage in state-of-the art methods of testing plant DNA composition using the polymerase …

The Role Of Low-Molecular Weight Fungal Metabolites In Eutypa Dieback Grapevine Trunk Disease, Dana Sebestyen

Masters Theses

Eutypa dieback, one of several grapevine trunk diseases (GTDs), is of serious concern to the grape industry globally. This disease is caused by the fungus Eutypa lata but it is often seen in consortia growth with Phaeoacremonium minimum and Phaeomoniella chlamydospora. It is vital to understand the mechanisms for how this disease functions to develop control measures to combat it. Brown rot fungi are able to use a complex of low molecular weight (LMW) metabolites to induce a Fenton reaction to deconstruct woody tissue. These metabolites are part of a chelator mediated Fenton (CMF) chemistry that produces reactive oxygen …

Can Volunteers Learn To Prune Trees?, Ryan W. Fawcett

Masters Theses

Volunteer pruning programs are becoming an important tool in helping municipal arborists manage the urban forest. To find if volunteers can learn to prune trees well, the ability of volunteers to prune small trees after receiving training was assessed in three different ways, a written exam, a pruning prescription assessment, and a pruning cut assessment. Volunteers were assigned to either an indoor, lecture-based training or an outdoor, hands-on training session. After the training volunteers were asked to complete a written exam to gauge their understanding of the curriculum. Volunteers were then asked to perform a pruning prescription on small street …

The Characterization Of Traits Associated With Freezing Tolerance In Perennial Ryegrass, Rachael Preston Bernstein

Doctoral Dissertations

Plants are constantly subjected to adverse environmental conditions that alter their growth and productivity, with an estimation that approximately 50% of annual average crop yields are reduced due to abiotic stresses. Freezing stress causes desiccation and ice damage in plants and is becoming more important as temperatures and unpredictable weather patterns increase. Normally, plants acclimate to cold temperatures as winter approaches and deacclimate as temperatures warm in the spring. Cold acclimation in fall is required for plants to build up their cellular defenses against desiccation and intracellular ice formation, while deacclimation is the process in which plants metabolize protective compounds …

Dynamic Evolution In The Leucine-Rich Repeat Receptor-Like Kinase (Lrr-Rlk) Family Of Receptors, Jarrett Man

Doctoral Dissertations

Cells in multicellular organisms must gauge their environmental conditions, including neighboring cells, during development. In plants, the Leucine-Rich Repeat Receptor-like Kinases (LRR-RLKs) encode a family of membrane-bound receptors that transduce such cell-to-cell signals and are required for many aspects of plant development. Very little is known about the function of most of these genes, and the evolutionary history of the family is difficult to infer because of its size and complexity. Several factors contribute to this difficulty, including genetic redundancy, challenging bioinformatic detection, exceptionally large family size, and high copy number variation among species. In this dissertation, I characterize some …

Trait Variation And Long-Term Population Dynamics Of The Invasive Alliaria Petiolata (Garlic Mustard) Across Three Microhabitats In Its Invaded Range, Laura Hancock

Masters Theses

Long-term population dynamics across heterogeneous environments can be a major factor in determining species’ ability to expand their ranges and persist in novel environments. Whether and how the relative performance of populations in different microsites over time impacts invasion into new microsites is poorly understood. Though largely restricted to disturbed semi-shaded microhabitats in its home range, the invasive herb Alliaria petiolata (garlic mustard) successfully invades intact forest understories – a novel microhabitat – in its introduced range, where it is known to impact above and below ground community composition. To test the hypothesis that source-sink metapopulation dynamics may be promoting …

Data For « Does Invasion Science Encompass The Invaded Range? A Comparison Of The Geographies Of Invasion Science Versus Management In The U.S. », Lara Munro, Bridget Griffin, Brittany Laginhas, Bethany Bradley

Data and Datasets

Data collected from English-language articles published between 1999-2018 on the ten most studied invasive plants in the United States.

Green Stormwater Infrastructure For The Town Of Maynard, Ma, Angie J. Gregory

Sustainability Science Working Papers

Green Infrastructure refers to ecosystem service solutions that provide human benefit. In the context of Stormwater Management, GI benefits address regulatory compliance measures related to stormwater runoff pollutant capture and flood mitigation on site, while providing co-benefits. Inherently distributive, non-exclusive, and non-rival in nature, Green Infrastructure as publicly owned infrastructure can provide restoration while generating capacity for community resilience. Comprehensive public and private investments will equitably advance public health and safety through this method. This paper will present the use of GI for satisfying compliance for MS4 permits for municipalities and implementation at residential and commercial scale with comprehensive review …

Understanding Food And Climate Change: A Systems Perspective, Megan Brockelbank

Sustainability Education Resources

Climate change will profoundly affect our lives in many ways, even down to the very food we eat. Food is essential for survival and our complex food system, and all that depends on it, face a big threat with climate change. Throughout the semester we will explore the links between the food system and our changing climate with an emphasis on systems thinking. In science we tend to segregate, looking at just one part of a system, while systems thinking looks at the whole picture. Using this approach, we will think critically about how to build a more resilient food …

Winter Malt Barley Growth, Yield, And Quality Following Leguminous Cover Crops In The Northeast United States, Arthur Siller, Heather Darby, Alexandra Smychkovich, Masoud Hashemi

Data and Datasets

There is growing interest in malt barley (Hordeum vulgare L.) production in the Northeast United States. This crop must meet high quality standards for malting but can command a high price if these quality thresholds are met. A two-year field experiment was conducted from 2015–2017 to evaluate the impact of two leguminous cover crops, sunn hemp (Crotalaria juncea L.) and crimson clover (Trifolium incarnatum L.), on subsequent winter malt barley production. Four cover crop treatments –sunn hemp (SH), crimson clover (CC), sunn hemp and crimson clover mixture (SH+CC), and no cover crop (NC) – were grown before …

Natural Genetic Diversity In Tomato Flavor Genes, Lara Pereira, Manoj Sapkota, Michael Alonge, Yi Zheng, Youjun Zhang, Hamid Razifard, Nathan K. Taitano, Michael C. Schatz, Alisdair R. Fernie, Ying Wang

Biology Department Faculty Publication Series

Fruit flavor is defined as the perception of the food by the olfactory and gustatory systems, and is one of the main determinants of fruit quality. Tomato flavor is largely determined by the balance of sugars, acids and volatile compounds. Several genes controlling the levels of these metabolites in tomato fruit have been cloned, including LIN5, ALMT9, AAT1, CXE1, and LoxC. The aim of this study was to identify any association of these genes with trait variation and to describe the genetic diversity at these loci in the red-fruited tomato clade comprised of the wild ancestor Solanum pimpinellifolium, the semi-domesticated …