Modification of Plant Architecture in `Crimson Giant' Easter Cactus with Benzyladenine

Abstract

Investigations were performed to determine the effects of timing of application and concentration of BA on the vegetative growth of Easter cactus [Rhipsalidopsis gaertneri (Regel) Moran `Crimson Giant']. BA was applied to rooted phylloclades at 27, 37, and/or 47 days after propagation (DAP) at 200 to 1000 mg·liter-1. At 80 DAP, the number and cumulative length of secondary (2°) phylloclades (those developing from the rooted phylloclade) of BA-treated plants exceeded those of the controls. Number and cumulative length of 2° phylloclades increased linearly with increasing BA concentration. At 316 DAP, there were no differences between BA-treated plants and controls in numbers of 2° and apical (terminal) phylloclades. BA also was applied to plants at either 95 or 187 DAP. Treatments included 10, 50, 100, and 200 mg BA/liter and an unsprayed control. Number of new phylloclades (those developing after treatments) and percentage of old phylloclades with new phylloclades increased linearly in response to increasing BA concentration. Relative to the controls, one application of BA at 50, 100, or 200 mg·liter-1 resulted in a ≈50% to 400% increase in total dry weight of new phylloclades accompanied by a ≈4% to 30% decrease in total dry weight of old phylloclades. Branching of mature plants, i.e., with three to five tiers of phylloclades, was significantly affected by timing of application and concentration of BA. BA may be useful for modifying plant architecture of Easter cactus to increase flowering and product marketability. Chemical name used: N- (phenylmethyl) -1H- purine-6-amine[benzyladenine (BA)].