After differentiation, the floral bud develops, growing continuously up to its entrance in the dormancy period, when it reaches from 4 to 8 mm and accumulates an external layer of wax. At this point, there is no accumulation of
dry mass and the vascular connection between floral bud and the plant is done almost exclusively by the phloem. It is also in this stage that all the structures related with flower fertilization are formed, and the flower is now considered to
be mature. The factors leading to bud dormancy in coffee are still unknown, and environmental conditions and biochemical factors involved in plant metabolism are considered as possible influences (Barros et al. 1978). It was suggested that this dormancy could be related to flower protection against a period of water stress since under field conditions, floral bud dormancy coincides with the dry season (Rena and Maestri 1984). The influence of low temperatures detected in this season on the flowering process was considered to be of minor importance (Barros et al. 1978) and according to the same authors the problem is to ascertain whether the bud growth arrestment is imposed by the environment or is at true dormancy due to intrinsic conditions.