A GROWTH INHIBITOR FROM THE ROOTS OF CHRYSANTHEMUM MORIFOLIUM RAMAT. AND ITS INFLUENCE UPON THE GIBBERELLIC ACID RESPONSE

Abstract

The growth-reducing factor in old chrysanthemum soil previously reported in Ontario was found to inhibit growth by reducing number of internodes and internode length. A further effect was the reduction in number of flower buds. Gibberellic acid applications could offset growth reductions but enhanced reduction in floral number. Factors that could inhibit growth of wheat coleoptile sections could be extracted from chrysanthemum roots and buds. A methanolic root extract, after being subjected to paper chromatography with 80% isopropanol, slightly inhibited the growth of chrysanthemums. This inhibiting factor was in the same region of the chromatogram as the factor which inhibited the growth of wheat coleoptile sections. The response to the growth reducing factor is compared with that to naphthalene acetic acid.