...............................................................................................................................3 Acknowledgements..............................................................................................................4 List of Tables .......................................................................................................................7 List of Figures ......................................................................................................................8 Chapter 1 Gravitropism....................................................................................................9 The Gravitropic Pathway .......................................................................................10 Perception ..................................................................................................10 Auxin Redistribution..................................................................................13 Response ....................................................................................................16 Signal Transduction ...................................................................................17 Research Focus ......................................................................................................22 Bibliography ..........................................................................................................25 Chapter 2 Characterization of the GPS2 Gene ..............................................................31 Materials and Methods.............................................................................................32 Plant Material, Growth Conditions, and DNA Extraction.........................32 Thermal Asymmetric Interlaced Polymerase Chain Reaction ..................32 Cloning of the PCR Product ......................................................................36 Constructs ..................................................................................................38 Agrobacterium Transformation .................................................................43 Floral Dip and Arabidopsis Transformation ..............................................43