Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Science (BS)
Eric M. Engstrom
The plant hormone ethylene plays many roles in the development and physiology of plants, such as coordination of ripening, wound response, and cell fate specification. The final step of the ethylene biosynthetic pathway is catalyzed by 1-aminocylopropane- 1-carboxylate oxidase (ACC oxidase or ACO). There are five ACO genes in Arabidopsis thaliana, all coding for different isozymes of ACO. The expression domains in the plant and expression levels of all five ACO genes are not well understood. Part of the aim of this thesis is to elucidate the expression domains and levels of the five ACO genes in Arabidopsis using promoter::GUS fusions and quantitative reverse transcription PCR (qRT-PCR) analysis, respectively. The genus Selaginella is part of the lycophyte family of plants. Selaginella species are heterosporous, vascularized, microphyllous plants. The processes of ethylene perception and biosynthesis are poorly understood in Selaginella. The second part of this thesis will focus on the study of ethylene perception in Selaginella apoda and Selaginella moellendorffii. Both S. apoda and S. moellendorffii were exposed to exogenous ethylene for 60 days, after which leaf cell size measurements were made using the scanning electron microscope. Sporangium counts were also performed, looking for sex and positional data on the strobili. In ethylene treated plants, cell sizes in both plants were shown to be significantly smaller. Also, the ratio of megasporangia to microsporangia produced by strobili on S. apoda plants increases dramatically when the plants are grown in ethylene exposure conditions.
Givens, Christopher Stephen, "A Physiological and Evolutionary Study of the Plant Hormone Ethylene" (2010). Undergraduate Honors Theses. William & Mary. Paper 867.
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