The effect of 6-benzylamino purine on axillary bud growth of Ilex crenata Thunb. 'Rotundifolia'

Abstract

The effects of 6-benzylamino purine (BA) concentration and timing of BA application at various phases of bud development of Ilex crenata Thunb. 'Rotundifolia' were studied.

Foliar applications of BA at 800 ppm to unbranched rooted cuttings enhanced axillary bud development resulting in well branched Iiners. Axillary bud development of rooted cuttings was enhanced when applications were made when buds were swelIing preceding a flush of growth. Applications made prior to bud swelling or made during a flush of growth were ineffective in stimulating additional axillary bud development. Combined applications of BA at 800 ppm to liners preceding two successive flushes of growth resulted in a 68% increase in total numbers of shoots per plant over control plants. Applications of BA at 600 ppm and 800 ppm to individual shoots resulted in swelling of the terminal 4-5 cm section of treated stems and development of a red pigment followed by growth of numerous axillary shoots on the stem produced by the apical bud. Applications of BA at 1000 ppm and 1200 ppm to individual shoots acted as chemical pinching agents inhibiting apical buds. Leaves on shoots which developed from liners treated with BA at 1200 ppm were 46% smaller than those on control plants. These suppressed leaves contained 60% fewer upper epidermal cells than leaves of control plants, and average epidermal cell size was 24% larger than those of control plants.