(Aminooxy)acetic acid inhibits petunia growth and gibberellin- and cytokinin-stimulated growth in bioassays

Abstract

(Aminooxy)acetic acid (AOA) was applied to greenhouse-grown petunias and was used in bioassays for three plant growth hormones so that its growth regulator properties could be studied. In greenhouse studies foliar sprays of 4.8–12 mm AOA inhibited vegetative growth of petunia seedlings (Petunia xhybrida Vilm. ‘White Flash’). When gibberellin A 3 (GA3) was applied to shoot tips previously treated with AOA, plant growth was stimulated, but there was no AOA x GA3 interaction. Some changes in petunia leaf morphology induced by AOA were reversed by GA3. AOA inhibited elongation of corn coleoptile segments (Zea mays L. B73 x Mol7) whether or not 10 μm indole-3-acetic acid (IAA) was present, but there was no AOA x IAA interaction. AOA reduced lettuce hypocotyl (Lactuca sativa L. ‘Grand Rapids’) elongation induced by GA3 and radish cotyledon (Raphanus sativus L. ‘Champion’) expansion induced by benzyladenine (BA). We propose that AOA interferes with postsynthetic metabolism of plant hormones during cell elongation induced by GA3 and cell expansion induced by BA.