Effects of Indoleacetic Acid on Lignification In Wheat Internodes and In Vitro

Abstract

The formation of lignin was determined in wheat internodes incubated with ferulic acid, hydrogen peroxide, and various concentrations of indoleacetic acid (IAA). lAA was found to markedly inhibit lignification in the lower two-thirds of the internode. Experiments which were carried out in vitro utilized the polymerization of free radicals, formed after eugenol had been oxidized by peroxidase and hydrogen peroxide, as a model system for lignification. The polymerization was inhibited considerably by IAA. A mechanism is postulated to explain the effects of lAA.