Fresh weight, dry weight, and macronutrient content of corollas, ovaries, and styles were measured during the development and senescence of several wild-type and transgenic Petunia x hybrida plants. Flowers of age-related senescence exhibited growth, maintenance, and senescence phases during development. Flowers terminated by pollination-induced senescence exhibited only growth and senescence phases. Fresh and dry weight of Mitchell, V26, and SAG12-IPT corollas followed patterns previously observed in climacteric flowers. SAG12-IPT, a cytokinin overproducing plant, exhibited a prolonged maintenance phase compared to V26. A temporary increase in fresh weight, dry weight, and macronutrients of Mitchell corollas occurred at the expected onset of the ethylene climacteric of the flowers. Increases in ovary fresh weight, dry weight, and select macronutrient contents were concomitant with decreases in these same measurements of corollas, although corolla remobilization contributed only small amounts to the growth of ovaries during age-related and pollination-induced senescence. ACKNOWLEDGMENTS I would first like to extend my gratitude to Dr. Sven Verlinden and Dr. Barton Baker for giving me the opportunity to participate in this program in order to expand my knowledge of horticulture. I would also like to recognize Dr. Todd West and Dr. John Balasko for their contribution as committee members. Thanks to the staff at the WVU Greenhouse, particularly Susan Myers, for her encouragement and assistance throughout the research. Last, but not least, a tremendous thanks to my colleague, Mihaela Iordachescu, for her guidance, leadership, and support during my stay here at WVU. iii TABLE OF CONTENTS I. CHAPTER ONE: Introduction……………………………………... p. 1 II. CHAPTER TWO: Age-Related Senescence Introduction………………………………………………………… p. 18 Materials and Methods……………………………………………... p. Results……………………………………………………………… p. Discussion………………………………………………………….. p. 27 Graphs and Tables………………………………………………….. p. III. CHAPTER THREE: Pollination-Induced Senescence Introduction………………………………………………………… p. 51 Materials and Methods…………………………………………….. p. Results……………………………………………………………… p. Discussion………………………………………………………….. p. 54 Graphs and Tables………………………………………………….. p. IV. Literature Cited………………………………………………………. p. iv CHAPTER ONE: Introduction Flower longevity Flowers are the structures responsible for sexual reproduction, and thus play a crucial role in the perpetuation of the earth's most abundant group of plants, the angiosperms (Rubinstein, 2000). Angiosperms, or flowering plants, dominate the landscape and are believed to have existed as early as 140 million years ago (Sun et al., 1998). Flower size can be as small and simple as those on the Wolffia plant or as large and complex as those of the odoriferous Titan Arums. The angiosperm flower is composed of several organs, each of which performs many different functions leading to successful reproduction, such as production of pollen, pollination, and the development and dispersal of viable seeds (Larsen et a...