Involvement of Hormonal Balance in the Control of the ‘Bullhead’ Malformation in Baccara Rose Flowers

Open Access
Publisher Website
Google Scholar
Abstract
Gibberellin activity is much lower and cytokinin activity is higher in the flowers of roses grown at a relatively low temperature and in ‘pbullhead’ malformed flowers which appear in such conditions, compared to ‘normal’ flowers grown at higher temperatures. Injection of gibberellin into the receptacle of flowers grown at low temperature prevents the symptoms of malformation. Injection with cytokinin of those flowers had no effect, but addition of BA1 to GA injection abolishes the malformation-preventing effect of the gibberellin. Cytokinin treatment of plants grown at higher temperatures causes proliferation of the nectary and promotes appearance of adventitious florets which are characteristic symptoms of malformed flowers. The level of auxin is higher in higher temperatures, but there was no effect on the development of flowers at the various temperatures by applying auxin. The involvement of hormonal balance in the abnormal development of rose flowers is discussed.