In coffee, prior to flowering, the xylem does not develop well and almost all the water flux to the bud coming from the leaves is done via the phloem. When the first rains start to fall, probably some alterations in the hormonal
balance occur, leading to a fast development of the xylem,which permits water to enter the flower (Mes 1957; Drinnan and Menzel 1994). Studies with radioactive tracers (tritiated Irrigation and flowering in coffee plants water and 45 Ca), however, showed that in constantly irRegarding the water aspect per se, flowering in coffee has been associated with cycles of water deficit in the plants, which would break dormancy of the totally differentiated floral buds, leading to anthesis in 8 to 12 days. In this model, it is probable that dry periods would be necessary for the uniformity in the maturation of the higher number of rigated plants, xylem development could be slower, probably due to the smaller lumen of the vases, offering higher resistance to water flux to the floral bud (Astegiano et al.1988).