Reduction in gibberellins content
favouring floral bud formation has been reported previously by
Abdel Rahim et al.and Chen in mango, Chen in lychee and Koshita et al. in citrus, and it may related to
reduction in internodal length or accumulation of carbohydrates
favoured by declining gibberellin contents. Kulkarni and
Protacio et al. reported reduction in internodal length by
paclobutrazol as the result of reduction in gibberellins. Decline
in the gibberellin is an important contributor to floral bud initiation, and this is well substantiated by the studies of Tomer and Oosthuyse that gibberellic acid application reduced
markedly the floral bud initiation and also prevented carbohydrate
accumulation. Further, not all gibberellins have similar role to play in the induction of floral buds.
While decline in GA1 may be important in preparing the buds for
floral induction and those of GA3, GA4 and GA7 might act in floral bud initiation. It was found that total gibberellins in buds were
negatively correlated with w suggesting a role of gibberellins in
maintenance of plant water balance. Similar observations in mango
have been reported by Pongsomboon et al. It is worthy to mention that the side chain in the cytokinin molecule is obtained from isoprenoid pathway leading to gibberellin biosynthesis, thus