Olive floral bud growth and starch content during winter rest and spring budbreak

In the olive (Olea europaea L.), inflorescence and flower differentiation o ccur in the early spring following a period of winter chilling and dormancy of the potentially reproductive buds. We examined the size, structure, and starch content of these buds during winter rest in the field and during fo rcing under standard growth chamber conditions, Basic bud structure and dim ensions remained unchanged during the rest period, but starch content incre ased in the bud's central axis. When cuttings were forced in the growth cha mber, the buds followed a morphogenetic pattern similar to that observed in the field, but the sequence of developmental events could be timed more pr ecisely. The first changes observed were the onset of axis growth and the d ifferentiation of axillary primordia within 3 days of transfer to the growt h chamber. This was followed by the initiation of new nodes, and, at 15 to 18 days, by the first signs of floral differentiation in the terminal and a xillary bud apical meristems. Bud growth and differentiation were accompani ed by a decrease in starch content.