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 investigated for rapid clonal propagation of selected cultivars. Murashige and Skoog medium, supplemented with various concentrations of 6-benzylaminopurine, kinetin, 6(γ,γ-dimethylalrylamino)-purine or zeatin were examined for their effects on multiplication. The most successful treatments were 2.2 γM 6-benzylaminopurine and 11.6 γM kinetin which increased shoot number and explant weight. Although zeatin and 6(γ,γ-dimethylalrylamino)-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 vivo rooting protocol, however, may prove to be essential for the commercial production of this plant.