Micropropagation of Ceratopetalum gummiferum, an important Australian cut flower crop

Ceratopetalum gummiferum Sm. 'Albery's Red' (NSW Christmas Bush), a native to eastern Australia, has become an important commercial plant in both the export and domestic markets. A protocol for in vitro culture was investigat ed for rapid clonal. propagation of selected cultivars. Murashige and Skoog medium, supplemented with various concentrations of 6-benzylaminopurine, k inetin, 6(gamma,gamma -dimethylallylamino)-purine or zeatin were examined f or their effects on multiplication. The most successful treatments were 2.2 muM 6-benzylaminopurine and 11.6 muM kinetin which increased shoot number and explant weight. Although zeatin and 6(gamma,gamma -dimethylallylamino)- purine increased shoot length, both failed to increase multiplication rates . However, hyperhydricity was found to be a serious physiological disorder in tissue culture of C gummiferum 'Albery's Red'. Rooting in vitro was also examined with indole-3-butyric acid and naphthalene acetic acid, the most successful being 4.9 mM indole-3-butyric acid. The development of an in viv o rooting protocol, however, may prove to be essential for the commercial p roduction of this plant.