INDOLILACETIC (IAA) AND ABSCISIC (ABA) ACIDS BY GROWING PROCESS OF MAIZE STEM INTERNODES (ZEA MAYS L.)

Abstract

Published data about phytohormonal regulation of growth processes of the stem were analyzed. We investigated the content of free and bound forms of indolilacetic and abscisic acids in the internodes of growing maize stem on the stage of five and seven leaves (active growth), and eleven leaves (cessation of stem growth, the beginning of the panicle flowering period). It was found that the shoot of maize is characterized by high content of free form of indolilacetic acid in the middle and upper internodes formed with physiologically young tissue. A significant concentration of bound forms indolilacetic acid is noted in the lower internodes and in zone of differentiation of individual internode, but rapidly growing internodes contains relatively high amounts of conjugated forms of indolilacetic acid. High concentration of free and bound forms of abscisic acid is marked for the lower internodes. The top internodes contain minimum level of free-form and a substantial amount of bound form. A clear difference it was showed in the balance of phytohormones in growing zones of individual internode. A tissue of elongation zone is the richest of auxi­ne, for this tissue also showed a significant content of free form of abscisic acid.