Vegetative cutting and in vitro propagation of the tree waratah, Alloxylon flammeum P. Weston and Crisp (family Proteaceae)

Abstract

Alloxylon flammeum is a rare and threatened Australian rainforest species that features spectacular red flowers and contrasting dark green foliage giving it potential as a cut flower crop. It also has potential as a rootstock for difficult to grow tree waratah species. There is, however, little published information on the propagation of Alloxylon spp. Here we show that A. flammeum can be propagated by vegetative cuttings and in vitro. The most commercially viable option is to propagate by cuttings using 8000 mg indole-3-butyric acid/L under intermittent mist with a root zone temperature of 24 ± 2˚C. Pre-treatment of A. flammeum stock plants with gibberellin (A4 and A7) spray before initiation into culture increased the success of initiation. The use of tip material resulted in minimal explant contamination and 1% sodium hypochlorite for 15 min was adequate for surface disinfection of material. Well elongated shoots were multiplied using 6-benzyladenine and 6-dimethylallyaminopurine (isopentyladenine), whilst thidiazuron-cultured shoots were numerous but short and unusable.