Regulation of Gibberellin Biosynthesis: The present proposal identified three primary objectives to elucidate the sites of biosynthesis of the plant hormone, gibberellic acid and how the biosynthesis is regulated: 1) to determine the capacity of cell free enzyme systems derived from various tissues and organs of pea seedlings to synthesize the hormone; 2) to characterize the mixed function oxidases affecting the intermediates, kaurene, kaurenol and kaurenoic acid; and 3) to investigate the stimulation of gibberellin synthesis by light in the fungus Gibberella fujikuroi. The regulation of levels of the phytohormone by localization of synthesis, by inhibition or enhancement of enzyme activities and by modulation of enzyme biosynthesis controls plant growth and development. The knowledge will be useful for manipulating plants to make them higher yielding, easier to germinate, more attractive and more predictable in terms of flowering and fruit setting.
