Activation-tagging is a powerful functional genomics technique used to identify plant genes and their functions. The random introduction of gene enhancers into the plant genome results in the overexpression of nearby genes, thus the gene responsible for a mutant phenotype can be determined based on the location of the enhancers. In a screen for activation-tagged Arabidopsis lines with aberrations in trichome morphology, a mutant (named P330) with unbranched trichomes was identified. In this thesis, the actin- encoding gene ACT11 was found to be upregulated by T-DNA pSKI015 in P330. Additionally, this line also produces a second mutant phenotype, characterized by a significant reduction in seed set. The findings presented in this thesis build upon previous work that has shown ACT11 is strongly expressed in reproductive organs (such as pollen and ovules) and rapidly elongating tissues in Arabidopsis. The role of actin has been characterized in Arabidopsis trichome morphogenesis, however much remains unclear about actin dynamics in sexual reproduction. Our investigation on the effects of increased ACT11 expression adds to our understanding of these processes and also provides the framework for future studies into trichome morphogenesis and sexual reproduction in flowering plants. / Thesis (Master, Biology) -- Queen's University, 2014-06-24 15:14:59.429