LONG SHOOT TERMINAL BUD DEVELOPMENT AND THE DIFFERENTIATION OF POLLEN-CONE AND SEED-CONE BUDS IN PINUS-CARIBAEA VAR HONDURENSIS

Bud type differentiation and development were investigated in early and late flowering grated clones of Pinus caribaea Morelet var. hondurensis Barr. & Golf. (Caribbean pine) growing at two sites in the tropical north of Australia. Regardless of the early and late flowering tendencies, pollen and seed-cone buds began to differentiate in middle and late March, respectively. Unlike the cone buds of temperate pines, there was no apparent pause in development between pollination and differentiation. The long shoot terminal bud organogenic sequence resembled that described in temperate pines and led to an episodic, monocyclic shoot growth pattern. The formation of up to several long shoot terminal buds between the onset of seed-cone-bud differentiation and flowering frequently resulted in multiple sets of seed cones.