Changes in o-Diphenol Oxidase During Fibre Development in Cotton

Abstract

Quantitative and electrophoretic changes in o-diphenol oxidase (o-diphenol: O2 oxidoreductase, E.C. 1 10,3.1) were studied during the entire period of cotton (Gossypium arboreum L. cv. Sanjay) fibre development. A significant increase in o-diphenol oxidase activity was recorded during the fibre initiation phase and it is suggested that a shift in redox balance towards oxidation may play an important role in fibre initiation. Low o-diphenol oxidase activity during elongation and its high activity during the phase of secondary thickening, together with isoenzyme patterns, suggest an important role of this enzyme in cotton fibre development. The role of o-diphenol oxidase in relation to auxin turnover and redox balance is discussed.