GROWTH AND DEVELOPMENT OF THE LOWBUSH BLUEBERRY: APICAL ABORTION

Abstract

The semicultivated lowbush blueberry is fire-pruned on a 3- to 4-year cycle. In spring, vegetative growth is accomplished through the development of an axillary bud on an aerial shoot. In a fire-pruned area, the growth is delayed in both its initiation and termination by as much as a month and arises either from axillary buds on the unburned below-ground portions of the aerial stems, or from rhizome seated buds. Shoot growth is terminated by the abortion of the apical meristem and the death of the proximal portions of the axis. Evidence is presented suggesting that the death of the apex is not triggered by an appropriate photoperiod. Further, although it is inherently controlled, it does not follow the production of a specified quantity (relative to clone) of leaf nor vegetative tissue and is not related to the development of a specified (per clone) leaf photosynthetic area. Finally, there is a strong indication that the death of the shoot is speeded by the presence of a high level of auxin.