Matching Items (2)
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- All Subjects: Biofertilizers
- All Subjects: Water
- Genre: Academic theses
- Creators: Steele, Kelly
Description
Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. The dry biomass and cellular extracts of Scenedesmus dimorphus were applied as a biofertilizer, a foliar spray, and a seed primer to evaluate seed germination, plant growth, and crop yield of Roma tomato plants. The dry biomass was applied as a biofertilizer at 50 g and 100 g per plant, to evaluate its effects on plant development and crop yield. Biofertilizer treatments enhanced plant growth and led to greater crop (fruit) production. Timing of biofertilizer application proved to be of importance - earlier 50 g biofertilizer application resulted in greater plant growth. Scenedesmus dimorphus culture, growth medium, and different concentrations (1%, 5%, 10%, 25%, 50%, 75%, 100%) of aqueous cell extracts were used as seed primers to determine effects on germination. Seeds treated with Scenedesmus dimorphus culture and with extract concentrations higher than 50 % (0.75 g ml-1) triggered faster germination - 2 days earlier than the control group. Extract foliar sprays of 50 ml and 100 ml, were obtained and applied to tomato plants at various extract concentrations (10%, 25%, 50%, 75% and 100%). Plant height, flower development and number of branches were significantly enhanced with 50 % (7.5 g ml-1) extracts. Higher concentration sprays led to a decrease in growth. The extracts were further screened to assess potential antimicrobial activity against the bacterium Escherichia coli ATCC 25922, the fungi Candida albicans ATCC 90028 and Aspergillus brasiliensis ATCC 16404. No antimicrobial activity was observed from the microalga extracts on the selected microorganisms.
ContributorsGarcia-Gonzalez, Jesus (Author) / Sommerfeld, Milton (Thesis advisor) / Steele, Kelly (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2014
Description
For the past 30 years wildlife biologists have debated the need of pronghorn antelope (Antilocapra americana) to drink freestanding water (free water). Some have suggested that pronghorn may feed at night to increase preformed water (plant moisture) intake, thus decreasing their dependence on free water. Pronghorn diet composition and nutrient intake is integral to understanding water available to pronghorn through preformed and metabolic sources. The dual purpose of this study was to determine plant composition of pronghorn diets, and to examine whether night feeding provides a water allocation advantage by testing for differences between day and night and modeling free water requirements during biologically critical seasons and years of different precipitation. I determined species composition, selected nutrients, and moisture content of American pronghorn diets on Perry Mesa, Arizona in March, May, June and August of 2008 and 2009. I used microhistological analysis of fecal samples to determine percent plant composition of pronghorn diets. I used forage samples to evaluate the nutrient composition of those diets for moisture, crude protein and structural carbohydrates, and to calculate metabolic water. I used calculations proposed by Fox et al. (2000) to model free water requirements and modified the equations to reflect increased requirements for lactation. Diet analysis revealed that pronghorn used between 67% and 99% forbs and suggested fair range conditions. Preformed water was not significantly different between night and day. Night feeding appeared to be of marginal advantage, providing an average potential 9% preformed water increase in 2008, and 3% in 2009. The model indicated that neither male nor female pronghorn could meet their water requirements from preformed and metabolic water during any time period, season or year. The average free water requirements for females ranged from 0.67 L/animal/day (SE 0.06) in March, 2008 to 3.12 L/animal/day (SE 0.02) in June, 2009. The model showed that American pronghorn on Perry Mesa require access to free water during biological stress periods.
ContributorsTluczek, Melanie (Author) / Miller, William H. (Thesis advisor) / Brown, David E. (Committee member) / Steele, Kelly (Committee member) / Arizona State University (Publisher)
Created2012