Anther and pollen development are important to plant reproduction processes leading to seed production. The floral bud of the model plant organism, Arabidopsis thaliana, consists of 6 anthers which encase copious amounts of pollen. Within the anther locules, a variety of nutrients are provided to pollen in order to support its development. This study aims to offer a deeper understanding of the role of anther caleosins in the Brassicaceae by investigating the expression, localization, and putative function of the anther-specific caleosin (AT1G23240). Through the use of various molecular and microscopy techniques (e.g., quantitative reverse transcriptase polymerase chain reaction, Western blot analysis, laser confocal microscopy, and transmission electron microscopy), it was determined that AT1G23240 was expressed at late stages of anther development -mainly within the endoplasmic reticulum and tapetosomes of tapetal cells, and the protein was also detected on the pollen coat of mature pollen. This elucidation of anther caleosin expression will help in better understanding its role and significance in the overall plant reproduction process, possibly in pollen-stigma interactions, as well as its potential in biotechnological applications in regards to fertility within key crop kinds of the Brassicaceae family. PREFACEWithin this thesis, techniques such as the qualitative polymerase chain reaction, Western blot analysis, confocal laser scanning microscopy, and transmission electron microscopy were used to elucidate the developmental expression, localization, and potential function of the Arabidopsis thaliana anther-specific caleosin AT1G23240. Figures and text used within this thesis are intended for later submission and publication of my findings.While I carried out the majority of the work within this thesis, I would like to thank the