Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 5 of 5

Full-Text Articles in Life Sciences

Molecular Identification And Characterization Of Viral Pathogens Infecting Sweet Cherry, Aaron J. Simkovich Oct 2020

Molecular Identification And Characterization Of Viral Pathogens Infecting Sweet Cherry, Aaron J. Simkovich

Electronic Thesis and Dissertation Repository

Stone fruits are a valuable crop grown worldwide, however pathogens such as viruses threaten fruit production by reducing tree health and fruit yield. In an orchard within the Niagara region of Ontario, symptoms typical of viral infection such as chlorosis and leaf deformation were seen on sweet cherry (Prunus avium L.) trees. Next generation sequencing was performed on symptomatic and asymptomatic leaves and four viruses were identified. On the tree displaying the most severe symptoms, Prune dwarf virus (PDV), was the only virus detected. A survey conducted during this work showed 42% of cherry trees on a single …


Floral Traits And Carbon Dynamics Of Cucumber In Response To Climate Change, Sarah Josina Mcdonald Aug 2020

Floral Traits And Carbon Dynamics Of Cucumber In Response To Climate Change, Sarah Josina Mcdonald

Electronic Thesis and Dissertation Repository

Pollination by animals is an important ecosystem service that contributes to the reproduction of many angiosperms. Climate change may alter this mutualism by affecting floral traits that are important to pollinators. Using Cucumis sativus, I tested the effects of experimentally elevated temperature and CO2 concentration on flowering onset, flower number, flower size, and floral rewards. Additionally, to better understand plant carbon balance and investment in reproduction, I measured biomass partitioning and leaf carbon fluxes of plants under their growth conditions. Carbon dynamics were similar across treatments, and plants grown under high [CO2] and temperature showed similar …


Investigating The Role Of Carbon Stress In The Mortality Of Tamarack Seedlings Under A Warming Environment, Bridget K. Murphy May 2020

Investigating The Role Of Carbon Stress In The Mortality Of Tamarack Seedlings Under A Warming Environment, Bridget K. Murphy

Electronic Thesis and Dissertation Repository

Climate warming is increasing the frequency of climate-induced tree mortality events. While drought combined with heat is considered the primary cause of this tree mortality, little is known about whether high temperatures alone can induce mortality, or whether rising CO2 will increase survival. I grew tamarack in two experiments combining warming (0-8 ˚C above ambient) and CO2 (400-750 ppm) to investigate whether high growth temperatures led to carbon limitations and mortality. Using glasshouses, +8 ˚C warming with ambient CO2 (8TAC) led to 40% mortality despite thermal acclimation of respiration. Dying 8TAC seedlings had lower needle carbon concentrations …


Soybean Root Exudates Increase The Physiological Diversity Of Bacteria In Cadmium-Treated Soil, Leily Kazemi Movahed Feb 2020

Soybean Root Exudates Increase The Physiological Diversity Of Bacteria In Cadmium-Treated Soil, Leily Kazemi Movahed

Electronic Thesis and Dissertation Repository

Three soybean cultivars with contrasting retention of cadmium (Cd) in the root were grown in Cd-spiked nutrient solution and used to determine that symplastic compartmentalization of Cd in roots is probably responsible for retention of Cd in roots. Roots of the low Cd-accumulator AC Hime treated with 30 mM Cd exuded up to 10-fold higher concentrations of citric, succinic, fumaric and malic acids into the hydroponic solution when compared to control; concentrations of the same organic acids from the high Cd-accumulator Westag 97 increased by up to 3-fold. The same cultivars were grown in Cd-spiked soil and the physiological profiles …


Microrna156: A Short Rna With A Major Role In Abiotic Stress Tolerance In Alfalfa, Biruk Ayenew Feyissa Feb 2020

Microrna156: A Short Rna With A Major Role In Abiotic Stress Tolerance In Alfalfa, Biruk Ayenew Feyissa

Electronic Thesis and Dissertation Repository

The highly conserved plant microRNA156, miR156, affects various aspects of plant development and stress response by silencing SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors. Our understanding of the role of miR156 and its mode of action in alfalfa’s (Medicago sativa L.) response to drought and flooding is still elusive, and thus this study was aimed at filling this gap in knowledge. Physiological parameters, metabolite and transcriptional analyses showed an interplay between miR156/SPL13 and WD40-1/DFR to mitigate drought stress. Low to moderate levels of miR156 overexpression suppressed SPL13 and increased WD40-1 to fine-tune the DIHYDROFLAVONOL-4-REDUCTASE (DFR) level for …