Life Sciences Commons^™

Phenotypic Responses Of Sagebrush To The Southwestern North America Megadrought: A Genotype-By-Environment (Gxe) Approach, Kara A. Navock

Boise State University Theses and Dissertations

The Southwestern North America megadrought is an extreme climate event. Artemisia tridentata (big sagebrush) is the dominant, keystone species of sagebrush-steppe ecosystems in arid and semi-arid habitats of western North America. I conducted a genotype-by-environment (GxE) experiment on two putative genotypes (drought-tolerant, G1 and drought-sensitive, G2) and two cytotypes, diploid (2x) and tetraploid (4x), to determine the phenotypic responses of big sagebrush seedlings to drought. For three chlorophyll fluorescence parameters, my results indicate a complex set of factors influence sagebrush responses to drought, including canalization, adaptive phenotypic plasticity, cryptic genetic diversity, and GxE interactions. Variation in leaf temperature profiles of …

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

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 …

Drought In Temperate Mesic Regions Leads To Micro-Density Anomalies In White Pine, Elise Miller

CSB/SJU Distinguished Thesis

Wood density and wood volume determine the amount of carbon fixed by trees; however, while we are beginning to understand normal seasonal variation in wood density, anomalies are common, and their drivers are poorly understood. In conifers, wood density normally increases continuously throughout the season, but intra-annual fluctuations in wood density can occur and have been linked to climatic events. The causes of these fluctuations in density at the micro-scale (hereafter micro-density anomalies) are still debated.

Mesic regions are experiencing more droughts, but micro-density anomalies are rarely studied in these ecosystems. This study examined micro-density anomaly distribution within the boles …

Seed Source Regions Drive Fitness Differences In Invasive Macrophytes, Morgane B. Gillard, Rebecca E. Drenovsky, Gabrielle Thiébaut, Michèle Tarayre, Caryn J. Futrell, Brenda J. Grewell

2020 Faculty Bibliography

Premise Worldwide, ecosystems are threatened by global changes, including biological invasions. Invasive species arriving in novel environments experience new climatic conditions that can affect their successful establishment. Determining the response of functional traits and fitness components of invasive populations from contrasting environments can provide a useful framework to assess species responses to climate change and the variability of these responses among source populations. Much research on macrophytes has focused on establishment from clonal fragments; however, colonization from sexual propagules has rarely been studied. Our objective was to compare trait responses of plants generated from sexual propagules sourced from three climatic …

Solar Dimming Decreased Maize Yield Potential On The North China Plain, Qingfeng Meng, Baohua Liu, Haishun Yang, Xinping Chen

Department of Agronomy and Horticulture: Faculty Publications

Solar dimming has been increasing in rapidly developing regions (China and India) and threatening food security. Although previous studies have summarized the ef- fects of climate change-associated increases in temperature on agriculture, few have examined the effects due to solar dimming. Here, we analyzed the effects of solar dimming on maize on the North China Plain (NCP). It is reported that solar dimming intensified and maize yield potential decreased since the 1960s. The total decrease in solar radiation for the whole maize growing season of this period was 17%, and solar dimming explained 87% of the decrease in yield potential. …