ABSTRACT
Scrophularia venutlis L., a biennial plant, and Scrophularia alata, Gilib. a perennial plant, are both of a rosette type when vegetative, and require, in their natural habitat, a cold winter period for spring flowering. Flowering inhibition was related to a delay or suppression of stem elongation. In S. alata, B-9 strengthens the vernalizing effect of chilling. Associated with high temperatures, it reduces stem elongation and suppresses flower initiation according to the dose of chemical and with a 5-week temperature treatment. Suppression of flowering is overcome by an additional high temperature period. Under highly vernalizing conditions, the same dose of B-9 advanced flower initiation. The B-9-treated plants during a vernalization of 9 weeks flowered simultaneously with untreated plants receiving a longer duration of chilling: 11 weeks. B-9 probably reinforced vernalization by inducing the start of internodal elongation which was the necessary condition for flowering in this plant.
