INFLUENCE OF BENZYLADENINE AND GIBBERELLIC-ACID ON ORGANOGENESIS IN CRIMSON GIANT EASTER CACTUS

Experiments were performed to determine the influence of gibberellic a cid (GA(3)) and benzyladenine (BA) on organogenesis of 'Crimson Giant' Easter cactus [Hatiora gaertneri (Regel) Barthlott] phylloclades cult ured in vitro. The numbers of flower buds and new phylloclades increas ed linearly as BA concentration increased from 0 to 444.1 mu M. GA(3) increased the number of new phylloclades when present in moderate conc entrations (2.9 or 28.9 mu M), but inhibited flower bud formation when present in concentrations as low as 0.3 mu M. The inhibitory effect o f GA(3) on flower bud formation was diminished when the medium was ame nded with BA at 44.4 or 444.1 mu M. Explants cultured in media that co ntained 288.7 mu M GA(3) produced fewer organs (new phylloclades plus flower buds) compared to those cultured in media with 0, 0.3, 2.9, or 28.9 mu M GA(3). BA and GA(3) concentrations also affected the percent age of explants with flower buds and the percentage of explants with n ew phylloclades. This study shows that organogenesis in H. gaertneri c an be controlled by varying the concentrations of BA and GA(3) in the culture medium.