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Species Of Fusarium Causing Root Rot Of Soybean In South Dakota: Characterization, Pathogenicity, And Interaction With Heterodera Glycines, Paul Nyawanda Okello

Electronic Theses and Dissertations

In South Dakota, Fusarium-associated diseases (e.g. seedling diseases, root rot and sudden death syndrome) are emerging threats to soybean production. Several species of Fusarium have been reported to cause these diseases in the soybean producing regions of the United States and in the world. However, little information is available on the species of Fusarium causing soybean root rot in South Dakota and their pathogenicity. Therefore, the objectives of this study were to (1) characterize the species of Fusarium causing soybean root rot in South Dakota; (2) evaluate the cross-pathogenicity of species of Fusarium causing root rot of soybean and corn; …

ทรานสคริปโทมของข้าวพันธุ์พื้นเมืองไทยภายใต้ภาวะเครียดจากความเค็ม, พีรวัธน์ จันทนกูล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ข้าว (Oryza sativa L.) เป็นพืชอาหารสำคัญในภูมิภาคเอเชีย ซึ่งในภาคตะวันออกเฉียงเหนือของไทยนั้นถือเป็นแหล่งผลิตข้าวสำคัญที่มีคุณภาพดีแต่มีผลผลิตต่ำเนื่องจากภาวะดินเค็มที่ส่งผลต่อการเจริญเติบโตและความสามารถในการติดเมล็ด จากการประเมินการตอบสนองต่อภาวะเค็มในกล้าข้าวพบว่าข้าวพันธุ์หลวงประทานซึ่งเป็นข้าวพันธุ์พื้นเมืองไทยแสดงลักษณะการทนเค็ม ดังนั้น จึงทำการศึกษาทรานสคริปโทมที่เวลา 0 3 6 12 24 และ 48 ชั่วโมง หลังจากได้รับภาวะเค็มเพื่อศึกษากลไกการทนเค็มของข้าวพันธุ์นี้โดยใช้เทคนิค 3’-Tag RNA-seq ผลการศึกษาพบว่ามียีนที่แสดงออกอย่างแตกต่างเป็นครั้งแรกภายหลังเผชิญกับภาวะเค็มเป็นเวลา 12 ชั่วโมง ได้แก่ OsRCI2-5 ซึ่งเป็นยีนที่เกี่ยวข้องกับการส่งสัญญาณ และเมื่อเวลาผ่านไป 24 ชั่วโมงพบว่า OsRMC ซึ่งเป็นยีนที่สามารถตอบสนองต่อภาวะเครียดจากความเค็มแสดงออกมาอย่างแตกต่างอย่างมีนัยสำคัญ และเมื่อพืชเผชิญกับภาวะเค็มเป็นเวลา 48 ชั่วโมงพบว่ามียีนที่แสดงออกอย่างแตกต่างอย่างมีนัยสำคัญจำนวน 63 ยีน ซึ่งมีหน้าที่เกี่ยวข้องกับความสามารถในการทนเค็ม ผลการวิเคราะห์โครงข่ายการแสดงออกร่วมของยีนที่ภาวะเค็มทั้ง 63 ยีน จากการคำนวณค่าสัมประสิทธิ์สหสัมพันธ์แบบพลวัตบางส่วน พบว่า OsRCI2-5 และ OsRMC มีการแสดงออกร่วมกับยีนที่ทำหน้าที่ควบคุมการแสดงออกของยีนอื่น ๆ ประกอบด้วย Transcription factor และ Ubiquitin ligase enzyme โดยในภาวะเค็ม OsRMC มีส่วนทำให้มีการแสดงออกมากขึ้นของยีนที่เกี่ยวกับการตอบสนองเพื่อป้องกันตนเองของพืชจากปัจจัยทางชีวภาพ จากการศึกษาเพิ่มเติมเพื่อยืนยันผลกระทบของภาวะเค็มต่อการแสดงออกของยีนที่ระบุได้ ด้วย qRT-PCR ในข้าวพันธุ์ต่าง ๆ พบว่า OsRCI2-5 และ OsRMC เป็นยีนที่พืชตอบสนองต่อภาวะเค็มและเกี่ยวข้องกับกลไกการทนเค็มในข้าวพันธุ์หลวงประทาน

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 …

Enhanced Efficiency Nitrogen Formulation Effect On Grass-Legume Pasture Productivity, Kathryn Marie Payne

Theses and Dissertations--Plant and Soil Sciences

The use of nitrogen (N) fertilizer is generally restricted on mixed species forage systems due to its stimulatory effect on grasses which increases competition with legume species. Reduced legume growth from this competition can compromise forage nutritive value and prospective yields. The controlled-release nature of several enhanced efficiency fertilizer N products holds the potential to improve legume persistence in mixed species pastures while providing supplemental N required by the grass component. The studies contained in this dissertation evaluated the effect of different enhanced efficiency N formulations (ATU, ESN, methylene urea, SuperU, and a 75% ESN: 25% urea blend) and untreated …

Breeding For Tomato Resistance To Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae), Ammar Sami Al-Bayati

Theses and Dissertations--Plant and Soil Sciences

Cultivated tomato plants are extremely susceptible to the two-spotted spider mite Tetranychus urticae Koch. Selection for pest resistance is usually a crucial step required to achieve successful genetic resistance transfer from wild into cultivated tomato genotypes. S. habrochaites LA2329, a wild relative of tomato, is highly resistant to arthropods. Its resistance has been attributed to the presence of a high density of type IV and type VI trichomes and abundant production of 7-epi-zingiberene, a sesquiterpene hydrocarbon. The interspecific backcross hybrids used in this research were derived from the cross between the wild relative tomato, S. habrochaites LA2329, and the cultivated …

Optimizing Cover Crop Rotations For Water, Nitrogen And Weed Management, Cintia Soledad Sciarresi

Theses and Dissertations--Plant and Soil Sciences

Winter cover crops grown in rotation with grain crops can be an efficient integrated pest management tool (IPM). However, cover crop biomass production and thus successful provisioning of ecosystem services depend on a timely planting and cover crop establishment after harvest of a cash crop in the fall. One potential management adaptation is the use of short-season soybeans to advance cover crop planting date in the fall. Cover crops planted earlier in the fall may provide a greater percentage of ground cover early in the season because of higher biomass accumulation that may improve weed suppression. However, adapting to short-season …

The Effect Of Cold Stratification And Perigynia Removal On The Germination Of Three Prairie Carex Species, Christina M. Boeck Crew

Dissertations and Theses @ UNI

Sedges (Carex spp. Linneaus. [Cyperaceae]) are a major component of Midwestern U.S. tallgrass prairie and prairie wetland plant communities, yet they are often lacking in restoration projects because they can be difficult to germinate. Cold-wet stratification and perigynia removal have been shown to increase germination in some Carex species. The germination response of 3 native species, plains oval or shortbeak sedge (C. brevior (Dewey) Mack.), field oval or troublesome sedge (C. molesta Mack.), and prairie or Bicknell’s sedge (C. bicknellii Britton.), was tested to cold-wet stratification (28d) and perigynia removal in stored seed (10 months). Seed treatments …

Influence Of Shaded Conditions On Development Of Asteraceae Species Native To Kansas, Aline Rodrigues De Queiroz

Master's Theses

to the heterogeneity of habitats, all plants are exposed to at least some degree of shade during their lifetime. Reduced light intensity, drops in R:FR ratio, and limited blue light are cues for plants to perceive competition; the shade avoidance syndrome (SAS) is common for grassland species while shade tolerance (ST) is common for forest species when competition is perceived. SAS is characterized by elongation of stems and petioles, reduced branches, decreased leaf area, decreased shoot biomass, and increased number of ramets. ST is characterized by little elongation of stems and petioles, high chlorophyll content and high chlorophyll a/b ratio …

The Effects Of Zinc Nanofertilizers On Tomato Plants, Ketsira Pierre

Honors Undergraduate Theses

Farmers around the world aim to use soil with adequate nutrients to produce sufficient and quality crops to the world's ever-growing population. Unbalanced use of nutrients in the soil will lead to soil deficiency, which is usually seen in South and Southeast Asian countries. This soil deficiency is often due to loss of micronutrient(s) within the soil from farming practices. Micronutrient deficiency affects not only plant growth but human health. Plants grown in nutrient deficient soil produce food with nutrient deficiencies, which affect people dependent on these foods for nutrients (Kathmandu, 2004). Nutrient deficient diseases and disorders like malnutrition are …

Holocene Fire History Reconstruction Of A Mid-Evaluation Mixed-Conifer Forest In The Eastern Cascades, Washington, Zoe Rushton

All Master's Theses

Fire histories of mid-elevation mixed-conifer forests (MEMC) are uncommon, particularly in the eastern Cascades of Washington. As a result, fire regimes and the effects of 20th century fire suppression in these forests are not well understood. In the summer of 2014 a 7.80 meter-long sediment core was extracted from Long Lake, located approximately 45 km west of Yakima, WA, which exists in a grand fir-dominated mixed-conifer forest. Fire activity for the Long Lake watershed was reconstructed using macroscopic charcoal analysis and pollen analysis was used to reconstruct vegetation change through time. Charcoal results show low fire activity in the early …

The Role Of Continuous Flowering Phenology For In Neotropical Plant-Pollinator Interactions For Use In Conservation, Chelsea Renee Hinton

Online Theses and Dissertations

The diversity of mutualistic interactions in the Neotropics exceeds that of all other tropical regions and is posited to result from a unique assemblage of plant species that produce the highest spatio-temporal predictability of food resources. A rare component of the Neotropical flora that contributes largely to the spatio-temporal predictability of food resources is found in understory shrub or tree-let species with a continuous reproductive phenology (i.e. produce fruit and flowers daily during all months of the year). Plant-animal interaction science suggests that plant species with a longer duration of reproductive phenology will accumulate more mutualistic partners over time and …

Impacts Of Plant-Microbe Interactions On Seedling Performance In A Riparian Forest Invaded By Lonicera Maackii, Taylor E. K. Strehl

Masters Theses

Soil microbes have profound impacts on plant growth and survival and can either promote or inhibit plant dominance. Exotic plants are often strongly invasive because they have escaped their natural enemies, potentially including antagonistic soil microbes. I examined how the invasive shrub Lonicera maackii and a common native tree, Acer negundo, responded to soil microbial communities to determine the role of soil microbes in regulating invasion success. This was done by growing both species with microbes from invaded (L. maackii) and uninvaded (A. negundo) soils collected from three locations within a riparian forest. Seedlings were …

Enhancing Water Stress Tolerance In Floriculture Crops, Suejin Park

Graduate Theses, Dissertations, and Problem Reports

Water deficit is one of the major constraints on plant growth and development, causing reduction of crop productivity. To minimize water loss, among many adaptation strategies, plants close their stomata to reduce transpiration. The stomatal closure is regulated by light, internal CO2 concentration, and plant hormones, mainly abscisic acid. Plants’ response mechanisms to water deficit are complex processes involving numerous genes and various signaling pathways. Floriculture crops are often exposed to water deficit during shipping and retailing, and these periods often result in damaged crops and profit loss. Understanding of plant responses to water deficit stress will provide us an …

Optimization Of Engineered Super Donor Strains Of Cryphonectria Parasitica To Reduce Canker Expansion In A Forest Setting, Amy Michelle Metheny

Graduate Theses, Dissertations, and Problem Reports

Chestnut blight, caused by the non-native fungus Cryphonectria parasitica, has decimated American chestnut (Castanea dentata) populations throughout the eastern U.S. over the last century. Biological control of blight, termed hypovirulence, has emerged naturally in the form of a debilitating hypovirus transmitted through hyphal anastomosis among vegetatively compatible C. parasitica strains. Six unlinked vegetative incompatibility (vic) loci regulate hyphal anastomosis and thus, hypovirus transmission, which has limited biocontrol efficacy in genotypically diverse communities. Recently, four of six vic loci have been disrupted to engineer two “super donor” or SD strains. In combining these strains, enhanced transmission …

Plant Hormone Lab Module: Assessing Different Factors To Create The Most Effective Lab, Ahmed El-Kulak

Williams Honors College, Honors Research Projects

The research project focused on evaluating 3 different factors in creating a plant hormone lab module for Principles of Biology II lab. The main hormone of focus was brassinosteroid. In the model plant Arabidopsis thaliana, brassinosteroids promote cell elongation, cell division, root growth, and seed germination. Three goals were established to create the most efficient lab module possible. First, mutant (bes1,bri1) root length was assessed without addition of brassinolide (BL), a synthetic brassinosteroid. Then, ½ MS and ½ MS + 20% sucrose plates were compared to see which media produced the greatest difference in root growth between the mutant lines. …

Where Birds Chill: An Assessment Of The Habitat Preferences Of Birds Overwintering In Hudson Valley Forests, Elizabeth Claire Axley

Senior Projects Spring 2019

Many avian species overwinter in eastern North America; however, studies on bird populations are rarely undertaken during this critical survival time, and little is known as to their habitat preferences and foraging behavior. In this observational study, we performed a survey of birds overwintering in the Hudson Valley’s temperate, primarily-deciduous forests, assessing avian populations’ habitat preferences through the vegetative structural variables surrounding overwintering birds as they forage. Our results suggest that high canopy cover is critically important to predicting overwintering bird occupancy on a microhabitat scale. Moreover, overwintering birds preferentially occupy forest plots not dominated by sugar maples, in spite …

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …

Ecophysiological Responses Of Tropical Woody Species To Ambient And Elevated Temperatures, Kelsey R. Carter

Dissertations, Master's Theses and Master's Reports

Tropical forests cycle one third of Earth’s carbon, yet we are still unsure how tropical vegetation will respond to climate warming. Tropical biomes experience a smaller temperature margin compared to other systems, possibly making them less capable of thermal adjustments. In addition, thermal responses of vegetation have been identified as one of the areas of greatest uncertainty for global carbon models. This dissertation works to quantify tropical forest photosynthetic responses to temperature as well as assessing physiological thermal acclimation of four tropical species. In Chapter, 2 we conducted a meta-analysis to investigate global tropical photosynthetic responses to temperature. We presented …

Seedling Xylem Anatomy Of Two Banksia Species Relative To Availability Of Groundwater, Melissa Karlinski

Theses: Doctorates and Masters

Fluctuating environmental conditions place plants at risk of mortality if they cannot adapt, particularly to warmer temperatures and drier environments. Plants are known to modify their morphology, physiology and anatomy to thrive under these conditions, and xylem anatomy and hydraulic architecture are common traits studied to understand plant adaptations and responses to changeable water availability. However, little is known about the changes to the hydraulic architecture of groundwater dependent plants during their early establishment in water-limited environments. By exposing young seedlings of two Banksia species to contrasting groundwater availability treatments in a glasshouse experiment, it was possible to analyse the …

Going Back To The Soil: An Integrated Approach To Farming., Renée V. Christie

Theses and Dissertations (Comprehensive)

Agricultural productivity is often constrained by nutrient availability; as such, copious amounts of synthetic fertilizers are applied to maintain productivity. However, the intensive use of synthetic fertilizers has reduced the capacity of the soil to carry out crucial roles such as nutrient cycling because of shifts in the microbial community composition and structure. In addition, much of the applied synthetic fertilizers become lost to the environment through run-off, which contributes to soil degradation. With the increasing demand on agricultural systems to provide food and fibre and the adverse impacts of agricultural production on the soil resource, amendments that support soil …

Facilitative And Competitive Tradeoffs Between Morella Cerifera Seedlings And Coastal Grasses, Michael N. Sinclair

Theses and Dissertations

Morella cerifera is a rapidly expanding native shrub on the Virginia barrier islands which displaces other native coastal species and may interrupt normal sediment dynamics. Barrier islands are considered stressful environments with low nutrients, high solar load, and frequent drought and salt exposure; facilitation often dominates in stressful environments according to the Stress Gradient Hypothesis. The objective of this project was to understand the importance of species interactions with grasses on the growth and physiology of M. cerifera at the seedling life stage through both field and lab experiments. Grasses provided ~1.3°C insulation to shrubs during winter freeze events and …

Medicinal Properties Of The Araliaceae, With Emphasis On Chemicals Affecting Nerve Cells, Rana Alharbi

Masters Theses

In recent times, medicinal plants have become the focus of scientists and research. However, many have used traditional medicine to take advantage of plant extracts to treat many diseases, especially neurological diseases. Various central nervous system receptors have been shown to associate with plant extracts influencing the pharmacology and in this manner conceivably assuming a role in human sickness and treatment. For instance, extracts from Cussonia paniculata Eckl. & Zeyh targeted several early nervous and mental disease, and Kalopanax pictus has been traditionally used for the treatment of rheumatoidal arthritis, nerve pain and diabetes mellitus.

In the present study, we …

Morphological And Morphometric Analysis Of Nekemias Arborea And Ampelopsis Aconitifolia (Vitaceae), Sally Rose Gray

Dissertations and Theses @ UNI

Leaf morphology in angiosperms is not constrained by the leaf’s important function of providing energy through photosynthetic reactions. In just one family, Vitaceae, it is easy to observe among it’s over 900 species, various leaf shapes and sizes even among closely related species as well as within individual species. Observation of these leaf forms within species can be used to determine, for example where a vine transitions from the juvenile state to the adult state as well as their relationship to the spatial and temporal patterning of inflorescence initiation. Analysis of two species within the Ampelopsis clade, one that retained …

Haplotype Diversity And Population Genetic Structure Of Antistrophus Gall Wasps Associated With Two Silphium Species And Implication For Host Mediated Speciation, Jiaxin Deng

Masters Theses

Gall making insects form a special feeding guild of phytophagous animals, and by manipulating host plant tissue differentiation, are able to avoid plant chemical defenses and thus have no need for counter defense mechanisms. Host plant selection is crucial to the evolution of these insects because successful gall formation is largely dependent on host plant ability to respond to stimuli. In Illinois and neighboring states, Antistrophus gall wasps associated with the rosin weed (S. integrifolium) and the cup plant (S. perfoliatum) are morphologically indistinguishable and thus have been treated as belonging to single species. However, the wasps from the host …

Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski

Theses and Dissertations (Comprehensive)

Cuscuta is a genus of nearly 200 obligate stem parasites with a nearly cosmopolitan distribution and considerable agricultural and ecological significance. Dodder seeds are considered “unspecialized”, with no morphological adaptations towards particular dispersal vectors; however, the seed coat anatomy has recently suggested an adaptation to endozoochory. This is the first attempt to provide a genus-wide overview of the diversity in morphology and anatomy of Cuscuta seeds, together with an assessment of the water gap and exploration of various form-function relationships. I surveyed 104 species belonging to all four Cuscuta subgenera. Seeds of the species of the first infrageneric dodder …

Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones

Theses and Dissertations (Comprehensive)

With growing concerns about agricultural sustainability and food security, the use of rock fertilizers and agrominerals is receiving renewed interest. A wide variety of geological resources have been proposed as crop nutrient sources, with silicate rocks the predominant focus. Carbonatite rocks are known to weather more readily than silicate rocks; yet, they have received relatively little attention as it is thought their high Ca and Mg contents hinder effective nutrient release. However, there is strong evidence that the nutrients within carbonatite rocks are easily accessible to plants, and that these rocks have noticable effects on crop plant growth. Here I …

Competition Or Facilitation: Examination Of Interactions Between Endangered Sida Hermaphrodita And Invasive Phragmites Australis, Samantha N. Mulholland

Theses and Dissertations (Comprehensive)

Virginia Mallow (Sida hermaphrodita) is a perennial herb of the Malvaceae family that is native to riparian habitats in northeastern North America. Throughout most of its geographical distribution however, it is considered threatened and only two populations are known from Canada. The biology and ecology of S. hermaphrodita are still poorly understood and although few studies have been performed to determine the factors that contribute to the species rarity, it is considered threatened potentially due to the loss of habitat caused by exotic European Common reed (Phragmites australis subsp. australis) invasion. Allelopathic and phytotoxic conditioning of …