Studies on the Transmission of Floral Effects of Photoperiod and Gibberellin from One Branch to the Other inImpatiens balsamina

Abstract

In two branched plants ofImpatiens balsamina with intact apex and leaves floral buds are induced only in the branch which is either exposed to 8-h (inductive) photoperiods or receives GA3 treatment if maintained under 24-h (non-inductive) photoperiods. GA3 induces floral buds on the treated branch even if the leaves on that branch are removed, showing that while leaves are essential for photoperception, these are not neoessary for GA3 to cause induction. The effect of the inductive photoperiods or GA3 treatments to a branch is not transmitted to the other branch which is treated with water and is maintained under non-inductive photoperiods even when the latter is defoliated but is transmitted if the apioal or both the apical and axillary buds on the branch receiving inductive photoperiods or GA3 treatment are excised. It, therefore, appears that the existence of strong sinks in the form of axillary and apical buds on the treated branch prevents the transmission of photoperiodic as well as GA3 effects to the other branch in this plant.