Effects of Indoleacetic Acid and Other Oxidation Regulators on in Vitro Peroxidation and Experimental Conversion of Eugenol to Lignin.

Problems of lignin formation have long occupied the attention of investigators, however, neither the physiological nor chemical mechanisms involved in lignification is known in detail. Nevertheless, a considerable body of knowledge has accumulated through the investigations of Freudenberg, Nord, Brown, Wardrop, and others (4, 5, 6, 10, 13, 15, 23), especially on the biochemistry, histochemistry, and enzymology of lignification. Investigations using model systems have contributed information on precursors, their transformations, (10, 17, 21) and biophysical factors in formation of lignin polymers (18). Although phenylpropane dehydrogenation polymers formed in model systems are not identical with specific lignins, they belong to this group of natural products (1, 3). Indoleacetic acid (IAA) may regulate lignin formation. It inhibits lignification and other peroxidations in model systems (18, 19, 21) yet indirectly promotes xylem regeneration (11), presumably by inducing formation of vascular peroxidase (7, 8, 12). Antioxidant activity has been found in organic nitrogen compounds, including IAA, which possess mobile electronic systems (16, 19, 20) and provides a new experimental approach to the study of hormones and regulatory processes. Our object is presenting evidence for the oxidation-regulating properties of several substances of biochemical interest, and the evaluation of antioxidants as possible factors in lignification.