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- All Subjects: Foliar spray
- Creators: Henderson, Mark
- Creators: Johnson, Melissa
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
Honors colleges have offered an academically rigorous option for growing numbers of diverse students. This study took place at a large, public university that required undergraduate students to complete a thesis to graduate from the honors college. In 2017, 97% of students who began the honors thesis prior to senior year completed it. Thus, the aim of this study was to help more students begin the honors thesis process early.
Thesis Launch was a six-week intervention that was designed to provide support for students in the critical early steps of thesis work such as brainstorming topics, examining professors’ research interests, reaching out to professors, preparing for meetings with potential thesis committee members, and writing a thesis prospectus. Thesis Launch offered web-based resources, weekly emails and text message reminders, and was supplemented by in-person advising options.
A mixed methods action research study was conducted to examine: (a) students’ perceptions of barriers that prevented beginning thesis work; (b) self-efficacy towards thesis work; (c) how to scale the intervention using technology; and (d) whether participants began the thesis early. Quantitative data was collected via pre- and post-intervention surveys, journals, and prospectus submissions. Qualitative data came from student interviews, journals, and open-ended questions on the surveys.
Quantitative data showed that after students participated in Thesis Launch, they had higher self-efficacy to work with professors, perceived fewer barriers to thesis work, and greater proportions of students began thesis work early. The qualitative data were complementary and showed that participants overcame barriers to thesis initiation, built self-efficacy, preferred an online intervention, and began thesis work early. Findings also showed that a primarily technology-based intervention was preferred by students and showed promise for scaling to a larger audience.
Thesis Launch provided a framework for students to begin work on the honors thesis and have mastery experiences to build self-efficacy. Strategies that fostered “small wins” and reflective efforts also assisted in this aim. Participants accomplished tasks tied to thesis work and customized their personal thesis timelines based on work begun during Thesis Launch. Finally, a discussion of limitations, implications for practice and research, and personal reflection was included.
Thesis Launch was a six-week intervention that was designed to provide support for students in the critical early steps of thesis work such as brainstorming topics, examining professors’ research interests, reaching out to professors, preparing for meetings with potential thesis committee members, and writing a thesis prospectus. Thesis Launch offered web-based resources, weekly emails and text message reminders, and was supplemented by in-person advising options.
A mixed methods action research study was conducted to examine: (a) students’ perceptions of barriers that prevented beginning thesis work; (b) self-efficacy towards thesis work; (c) how to scale the intervention using technology; and (d) whether participants began the thesis early. Quantitative data was collected via pre- and post-intervention surveys, journals, and prospectus submissions. Qualitative data came from student interviews, journals, and open-ended questions on the surveys.
Quantitative data showed that after students participated in Thesis Launch, they had higher self-efficacy to work with professors, perceived fewer barriers to thesis work, and greater proportions of students began thesis work early. The qualitative data were complementary and showed that participants overcame barriers to thesis initiation, built self-efficacy, preferred an online intervention, and began thesis work early. Findings also showed that a primarily technology-based intervention was preferred by students and showed promise for scaling to a larger audience.
Thesis Launch provided a framework for students to begin work on the honors thesis and have mastery experiences to build self-efficacy. Strategies that fostered “small wins” and reflective efforts also assisted in this aim. Participants accomplished tasks tied to thesis work and customized their personal thesis timelines based on work begun during Thesis Launch. Finally, a discussion of limitations, implications for practice and research, and personal reflection was included.
ContributorsEardley, Trisha Lynn (Author) / Buss, Ray (Thesis advisor) / Henderson, Mark (Committee member) / Johnson, Melissa (Committee member) / Arizona State University (Publisher)
Created2019