Abstract
Callus formation and organ differentiation were studied in tubular florets cultured in vitro of chrysanthemum and cineraria. The basal medium was the one modified from Murashige and Skoog (1962). Callus formation and organ differentiation varied according to combinations and concentrations of growth substances. One of the best media for plantlet induction contained 10-7M 2, 4D in combination with IBA, IAA and 6-BAR of each 10-5M. Cultivar differences in callus differentiation were observed. One cultivar exhibited mainly root differentiation and other cultivars produced leaves and stems. 6-BAR pretreatment for cut shoot promoted callus development of florets and stimulated root differentiation in medium containing only IBA or IAA. Plantlets differentiated from callus subcultured in a medium containing 10-5M each of IAA, 6-BAR and inosine and lacking 2, 4D. However, though callus development was promoted, no differentiation of organs was observed from callus subcultured in a medium containing 10-5M each of 2, 4D and 6-BAR. However individuals of chrysanthemum derived from culture showed usual chromosome counts, few exceptional variations in leaf shape and flower color had appeared.
