Evidence for a translocatable florigenic promoter in mango

Movement of a putative florigenic promoter from leaves to buds was investigated in two cultivars of mango (Mangifera indica L.) over two flowering seasons through examination of the minimum number of leaves on each stem necessary for floral induction and movement of this component over various distances from stem to stem in isolated branches. The minimum number of leaves on individual stems necessary to induce flowering was less than 1/4 of a cross-cut leaf per stem. The putative florigenic promoter moved from donor stems bearing as few as one leaf to induce flowering in five receiver stems located as far down branches as 100 cm from the donor stem. Evidence suggests that movement of the putative florigenic promoter occurs in phloem and that far more of this component is available in trees than is necessary for floral induction of initiating shoots during cool, floral-inductive conditions of the subtropics.