Effects of Steroids on Chrysanthemum in relation to Growth and Flowering

THE physiology of flower initiation has been much investigated for more than half a century. It is now established that in conditions of inductive day length the leaves produce a hormone which induces differentiation in the apical meristem. The chemical nature of the hormone has not yet been definitely established. There have been many investigations of the effect of different organic compounds on plants in relation to flowering. The primary motive has been to look for compounds that could possess “florigenic” activity. Some workers have used various antimetabolites in an attempt to determine whether any of them block the synthesis of the floral stimulus, which could provide some indirect indications as to the nature of the hormone. Antimetabolite investigation has suggested that the flowering hormone may be a steroid or an isoprenoid-like compound 1 . Work on a strawberry variety has shown that unsaponifiable lipid fractions from flowering plants promote flowering in the vegetative ones 2 . The active substance may include vitamin E and certain unidentified sterols. This communication reports the effects of steroids on flowering of chrysanthemum plants in non-inductive conditions.