Life Sciences Commons^™

Severe Drought Impacts Female Pheasant Physiology In Southwest Nebraska, Jessica A. Laskowski, Gwen C. Bachman, Joseph J. Fontaine

The Prairie Naturalist

In 2012, Nebraska experienced one of the worst droughts since the 1930s, accompanied by abnormally high temperatures. We studied the impacts of the 2012 summer drought on female ring-necked pheasant (Phasianus colchicus) body condition and baseline and stress-induced corticosterone concentrations (CORT). We hypothesized that drought conditions would reduce pheasant body condition, increase chronic stress resulting in elevated baseline CORT levels, and down-regulate pheasant stress response to acute stressors, resulting in reduced stress-induced CORT concentrations. In southwestern Nebraska, we captured female pheasants in 2012 (pre-drought) and 2013 (post-drought). Pheasants had poorer body condition after the drought. Although female CORT measures were …

Impact Of Preemergent Herbicides, Mowing Height, And Fertilization On Centipedegrass Root Architecture And Drought Tolerance, Mike J. Adams

LSU Master's Theses

Mowing, N fertilization and the application of preemergence herbicides (PRE) are cultural practices performed on centipedegrass to improve overall turf quality. It is posited that increasing mowing height and application of fertilizers can lead to greater turfgrass rooting and increase drought survival; while the application of PRE is reported to potentially have negative impacts on rooting. At two locations in Louisiana, studies examining the effects of these practices on centipedegrass rooting and drought tolerance were conducted.

In the first 11-week study conducted, centipedegrass was treated with dithiopyr, pendimethalin, prodiamine, simazine, or indaziflam at the manufacturers’ labeled rates. During the 11-wk …

Genomic And Physiological Approaches To Improve Drought Tolerance In Soybean, Avjinder Kaler

Graduate Theses and Dissertations

Drought stress is a major global constraint for crop production, and improving crop tolerance to drought is of critical importance. Direct selection of drought tolerance among genotypes for yield is limited because of low heritability, polygenic control, epistasis effects, and genotype by environment interactions. Crop physiology can play a major role for improving drought tolerance through the identification of traits associated with drought tolerance that can be used as indirect selection criteria in a breeding program. Carbon isotope ratio (δ13C, associated with water use efficiency), oxygen isotope ratio (δ18O, associated with transpiration), canopy temperature (CT), canopy wilting, and canopy coverage …

The Impact Of Climate And Elevation On The Growth And Mortality Of Piñon Pine, Alice M. Fretz

Biology ETDs

The Southwestern United States is currently experiencing severe drought, resulting in the mortality of many tree species. Piñon-juniper woodlands are an extensive biome in the Southwest, and are highly vulnerable to extended periods of drought that lead to tree mortality. Specifically, Pinus edulis populations are decreasing due to increasingly arid conditions. I used dendrochronology to investigate how tree growth rings of Pinus edulis reflect severe drought in living and dead trees. I also investigated how severe drought affects Pinus edulis along an altitudinal gradient. Tree core samples were taken from currently living and dead trees, as well as from trees …

Performance And Recovery Of Turfgrasses Subjected To Drought And Traffic Stresses, R. Braun, D. Bremer, J. Hoyle, N. Bloedow

Kansas Agricultural Experiment Station Research Reports

This study is an effort to determine effects of drought and traffic in turfgrasses. During a 41-day summer drought in 2015 and 2016, warm-season (C4) grasses were more affected by traffic than cool-season (C3) grasses when percent green cover and turf quality were measured. This was because the non-trafficked plots in C4 grasses maintained higher percent green cover and turf quality throughout the drought due to better drought-stress tolerance than the C3 grasses. Regardless of traffic treatment or mowing height, C4 grasses maintained higher percent green cover and visual turf quality than C3 grasses during drought and recovery periods. There …

Climate Influences The Content And Chemical Composition Of Foliar Tannins In Green And Senesced Tissues Of Quercus Rubra, Sara M. Top, Caroline M. Preston, Jeffrey S. Dukes, Nishanth Tharayil

Open Access Publishing Fund

Environmental stresses not only influence production of plant metabolites but could also modify their resorption during leaf senescence. The production-resorption dynamics of polyphenolic tannins, a class of defense compound whose ecological role extends beyond tissue senescence, could amplify the influence of climate on ecosystem processes. We studied the quantity, chemical composition, and tissue-association of tannins in green and freshly-senesced leaves of Quercus rubra exposed to different temperature (Warming and No Warming) and precipitation treatments (Dry, Ambient, Wet) at the Boston-Area Climate Experiment (BACE) in Massachusetts, USA. Climate influenced not only the quantity of tannins, but also …

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Stott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tree fruit crops are of high value, but use a lot of water. Precision irrigation has the potential to save water while simultaneously improving crop quality. The timing and method of precision water stress in various tree fruit crops has been widely studied. However, in order to successfully employ precision irrigation methods in orchards, an accurate measurement of tree water status is required. Currently, stem water potential is the preferred indicator. However, this measurement is tedious and cannot be automated. Because measurements must be taken near solar noon (approximately 1:30 PM MDT in the summer in northern Utah), the number …

Effect Of Drought On Resin Production In Woody Stems Of Rhus Ovata, Sydney T. Adams, Melody Young, Moriah Hall

Seaver College Research And Scholarly Achievement Symposium

Resin production in stems of woody plants is generated from resin canal secretions and is thought to play a significant role in protection from fungal infection and spread. This may be one of several factors associated with fungal infection and fungal induced dieback in plants during severe water stress or drought. We set out to determine if reduction in resin production in a chaparral shrub, Sugar Bush (Rhus ovata), was associated with severe drought in southern California. We hypothesized that dehydrated R. ovata would produce less resin than hydrated plants. Our null hypothesis was that there is no …

A Realistic Meteorological Assessment Of Perennial Biofuel Crop Deployment: A Southern Great Plains Perspective, Melissa Wagner, Meng Wang, Gonzalo Miguez-Macho, Jesse Miller, Andy Vanloocke, Justin E. Bagley, Carl J. Bernacchi, Matei Georgescu

Andy VanLoocke

Utility of perennial bioenergy crops (e.g., switchgrass and miscanthus) offers unique opportunities to transition toward a more sustainable energy pathway due to their reduced carbon footprint, averted competition with food crops, and ability to grow on abandoned and degraded farmlands. Studies that have examined biogeophysical impacts of these crops noted a positive feedback between near-surface cooling and enhanced evapotranspiration (ET), but also potential unintended consequences of soil moisture and groundwater depletion. To better understand hydrometeorological effects of perennial bioenergy crop expansion, this study conducted high-resolution (2-km grid spacing) simulations with a state-of-the-art atmospheric model (Weather Research and Forecasting system) dynamically …

A Vascular Flora Of The Kiavah Wilderness, Scodie Mountains, Kern County, California, Erika M. Gardner

Aliso: A Journal of Systematic and Floristic Botany

Congress designated the Kiavah Wilderness in 1994 under the California Desert Protection Act. It is located in the Scodie Mountains in Kern County, ca. 24 km (15 mi) east of Lake Isabella and 24 km (15 mi) west of Ridgecrest, and encompasses a total of 137 mi² (354 km²) with elevations ranging from 1000 to 2200 m (3500–7294 ft). The Wilderness is ecologically important because it occurs in a transition zone between two floristic provinces, the Sierra Nevada of the California Floristic Province and the Mojave Desert of the Desert Province. It is of cultural significance because …

The Role Of Tre6p And Snrk1 In Maize Early Kernel Development And Events Leading To Stress-Induced Kernel Abortion, Samuel W. Bledsoe, Clémence Henry, Cara A. Griffiths, Matthew J. Paul, Regina Feil, John E. Lunn, Mark Stitt, L. Mark Lagrimini

Department of Agronomy and Horticulture: Faculty Publications

Background: Drought stress during flowering is a major contributor to yield loss in maize. Genetic and biotechnological improvement in yield sustainability requires an understanding of the mechanisms underpinning yield loss. Sucrose starvation has been proposed as the cause for kernel abortion; however, potential targets for genetic improvement have not been identified. Field and greenhouse drought studies with maize are expensive and it can be difficult to reproduce results; therefore, an in vitro kernel culture method is presented as a proxy for drought stress occurring at the time of flowering in maize (3 days after pollination). This method is used to …