Digital Commons Network^™

Effects Of Blue And Green Light On Plant Growth And Development At Low And High Photosynthetic Photon Flux, Michael Chase Snowden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Research in photobiology dates back over 200 years with studies using primitive light sources. This early research identified photoreceptors and action spectra for specific regions of the light spectrum that are paramount for photosynthesis as well as growth and development that are still topics of interest today.

Photobiological research has become an area of increasing interest since the introduction of light-emitting diodes which allow for evaluating endless combinations of light spectra. Red light-light emitting diodes were the first to be introduced that had an electrical efficiency comparable to existing light sources. The research found that red light alone was not …

Effect Of Blue Light And Temperature On Leaf Expansion, Stem Elongation, And Growth, Tracy A. O. Dougher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Short height and high yield per unit energy in controlled environments are essential to the success of a food production system for spaceflight. Temperature and light quality can be manipulated in controlled environments to reduce plant height and increase yield. Although the effects of temperature on height and yield are well studied at ambient CO₂, temperature effects at elevated CO₂ with a hydroponic root zone are not well characterized. We studied soybean yield and height under two lamp types over a broad range of temperatures. Temperature had little effect on yield or height, but lamp type had …

Ammonium And Nitrate Effects On Growth, Development And Nutrient Uptake Of Hydroponic Wheat, Thomas M. Hooten

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The long-term effects of low and high NH₄⁺/ NO₃^- uptake ratios in a system with rigorous control of pH and nitrogen concentration are poorly understood. In two replicate studies, two cultivars of wheat (Triticum aestivum) were grown to maturity with three NH₄⁺/ NO₃^- ratios in hydroponic solution: 0/100, 25/75, and 85/15%. Nitrogen was controlled at ample levels throughout the 70-d life cycle and pH was controlled at 5.8 ± 0.2. An equimolar ratio of NH₄⁺ to Cl^- was used to facilitate charge balance. Nitrogen consumption …

A Simple Model To Predict Optimal Harvest Time Of Alfalfa Using Near Infrared Reflectance Spectroscopy, Environmental, Morphological, And Growth Parameters, Jody A. Gale

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Knowledge of relationships between nutrient levels, yield, maturity, and environmental influences on alfalfa (Medicago sativa L.) are necessary to estimate when to harvest alfalfa to maximize quality and yield. Objectives were to document the change in nutrient content, yield, and growth stage of alfalfa grown in Utah as it matures and to develop a simple model to predict optimal harvest date. The study involved three locations in major alfalfa producing regions in Utah. Samples were collected from three commonly grown alfalfa varieties between 26 April and 26 September in 1987. Maximum and minimum levels of crude protein (CP) observed were …

The Influence Of Certain Growth Hormones On Plant Growth At Cold Temperatures, Michael D. Salvesen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted to determine the effect of externally applied growth hormones on winter rye (Secale cereale var. cougar). The rye was grown under the snow in a specially prepared tunnel on a mountain side near Logan, Utah. These plants showed a remarkable ability to grow at 0°C. Three growth hormones, kinetin, gibberellic acid (GA), and auxin (indole-3-acetic acid) were externally applied to rye seedlings growing in the tunnel. These seedlings were alter weighed, measured and tested for soluble protein content. The three hormone treatments had no significant effects on the fresh weights or shoot lengths of the …

Photosynthesis, Dark Respiration, And Growth Of Rumex Patientia L. Exposed To Uv-B (280-315 Nm) Irradiance Corresponding To Reduced Atmospheric Ozone Concentrations, William B. Sisson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Net photosynthesis, dark respiration, chlorophyll concentrations and growth were determined for Rumex patientia L. exposed to UV-B radiation corresponding to reduced atmospheric ozone concentrations. The hypothesis of whether reciprocity is maintained in the response of R. patientia to polychromatic UV-B radiation was tested. On the basis of the relationships derived from these studies, a simulation model was developed for the prediction of photosynthesis and growth of R. patientia exposed to UV-B radiation corresponding to any atmospheric ozone reduction.

Photosynthetic rates were found to be depressed after two hours exposure to UV-B irradiance simulating a 0.18 atm·cm ozone column when the …

The Effect Of The Herbicide Glyphosate On The Growth Of Selenastrum Capricornutum, Judith Susan Eisen

Undergraduate Honors Capstone Projects

The herbicide glyphosate (MON-0139), an isopropylamine salt of N- (phosphonemethyl)glycine, was tested to determine its effects on the growth of the fresh water green alga Selenastrum capricornutum. Experiments were carried out to determine algicidal, algistatic, and inhibitory concentrations of the compound.

Concentrations from 5 ppm to 1000 ppm were inhibitory to the growth of the alga, but the effects were algistatic, rather than algicidal. At concentrations from 0.1 ppm to 1.0 ppm the growth of the alga was stimulated by the presence of the herbicide, while at concentrations from 0.001 ppm to 0.05 ppm the effects of the herbicide were …

Some Effects Of The Under Snow Environment On Growth And Carbohydrate Content Of Claytonia Lanceolata Pursh, Bryce D. Bennett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted in a mountain habitat to determine the effects of altered light and temperature upon the natural growth and/or carbohydrate cycles of Claytonia lanceolata during the period of winter snow cover. Treatments included natural control, light exclusion, and temperature alteration by insulation and by heating for a brief period. Monthly measurements were made of soil temperature (upper 12 cm), shoot development, soluble sugar, and soluble starch. The quantity and quality of light penetrating the snow cover was also determined.

About 0.0052% of the available visible light (400-750 nm) penetrated 70 cm of snow and 0.02% penetrated 50 cm …

The Effect Of Limited Moisture Supply At Various Stages Of Growth On The Development And Production Of Hybrid Corn, Ralph E. Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Corn occupies from 25 to 30 percent of the crop land harvested in the United States. In recent years the acreage devoted to corn in this country has been decidedly greater than that devoted to any other cultivated crop. In 1944 its dollar value exceeded the combined values of wheat, barley, rye, grain sorghums, and cotton.

Although South Dakota lies on the northwestern fringe of the corn belt, the corn crop is one of the most important in that state. Corn production in that area is somewhat unstable because of drought. Corn often fails to reach full maturity before the …