Title of Document: THE ROLE OF SPERMIDINE IN THE REGULATION OF DEVELOPMENT AND DIFFERENTIATION IN SPERMATIDS OF

Spermiogenesis in the microspore of the water fern, Marsilea vestita, is a rapid process where a dry microspore containing a single cell undergoes nine successive mitotic divisions to produce 32 spermatids and seven sterile cells. Immediately after the dry microspore is placed into water, cytoplasmic movements precede the first mitotic division; a number of proteins and mRNAs aggregate into zones that later become the spermatogenous initials of the gametophyte. Development is driven by the regulated translation of stored mRNA with little or no new transcription (Hart and Wolniak, 1999). The pattern of translation in the gametophyte is ordered precisely spatially and temporally, which indicates that certain proteins are required in specific locations at specific stages of development. Spermatid differentiation involves the de novo synthesis of 140 basal bodies, the remodeling and condensation of nuclear chromatin and then, nuclear elongation. A complex cytoskeletal structure, the multilayered structure (MLS), is formed at the anterior end of the cell and extends the length of the elongated gamete, and apparently functions in cell and nuclear elongation. This document focuses on the role of kinesin motor proteins and spermidine in the regulation of gametophyt