XVI International Botanical Congess

Addition of 0.5-10 mM cerium nitrate (Ce) or lanthanum nitrate (La) significantly increased the percentage of plants bolted. Addition of low concentration of Ce in combination with La induced early flowering (1 day). Plants growing on the medium with Ce and La (0.5 to 10 mM), singly or in combination, produced significantly higher number of flowers per plant than the control. Addition of 0.1 to 0.6 mM TRIA induced early flowering (2 days) and significantly increased the average number of flowers produced per plant. Addition of low concentration of Ce or La (0.1 to 2.5 mM) in the presence of 0.3 mM TRIA had no significantly promotive effect on flowering. Addition of low concentrations of Ce and La (0.1 to 1.0 mM) in the presence of 0.3 mM TRIA significantly promoted flowering: the first date to flowering was 2-3 days earlier and the total time for 90% flowering was 4 days earlier than the control. The early flower initiation coincided with a significant increase in the Isopentenyl adenosine concentration 14 days after seed germination.