Studies on the mechanism of leaf formation in crop plants: IV. A presence of auxin in lamina joints rice plants

Abstract

In the previous papers14)15)16)17)18), the anatomical aspects of the extension of lamina joints and the accentuating actions of the extension by auxin and gibberellin were revealed. The given knowledges made it attractive to speculate that some native auxins might act in this region when the cells in adaxial side were elongated by gravity. In this paper, first, the lamina-joint test is established as an assay for evaluation of existence of auxin- and gibberellin-like substances in plant extracts. The procedure was follows: after the leaf segments having lamina joint were floated in distilled water for 24 hours, they were incubated in the test solutions of 1 ml for 48 hours at 30°C in darkness, and the angular degrees between laminae and sheaths were estimated (Tables 1, 2 and Fig. 1). Auxins were extracted by n-hexane and acetonitrile, and purified by means of chromatography with ammonium isopropanol. The auxin activity was estimated by the lamina-joint method mentioned above. It became evident that auxin activity locates in the methanol extracts of the lamina joints in adult rice as well as cabbage leaves (Fig. 3 and 4). © 1962, CROP SCIENCE SOCIETY OF JAPAN. All rights reserved.