In vitro Propagation and Caulogenesis of Dracaena draco Plants

Dracaena draco is a monocot from family Asparagaceae. The dragon tree is a subtropical plant and features many botanic and Mediterranean gardens worldwide. D. draco has been categorized as vulnerable in Europe and endangered worldwide in the IUCN Red List of Threatened Species (IUCN, 1998). The aim of this study is to develop an efficient protocol for rapid in vitro propagation and caulogensis of D. draco Plants via enhanced axillary bud proliferation from single nodal explants cultured on full strength MS medium, 30g/l sucrose, 4g/l gelrite augmented with various concentrations of plant growth regulators as BA, NAA, IBA and their combinations. In general, the present study concluded that the best results for the initiation stage were recorded on MS medium fortified with NAA and BA at 2.00 and 1.00 mg/l, respectively. Meanwhile, supplemented medium with BA and NAA at 4.00 and 1.00 mg/l, respectively, gave rise to the best results for the multiplication stage. Regarding rhizogenesis stage, the best results were recorded when the neoformed shoots of the multiplication stage were divided singly and cultured on MS medium plus IBA and NAA at 1.00 and 0.50 mg/l, respectively which led to the highest mean number of roots formed per propagule. For callus induction, the internodal segments cultured into MS medium supplemented with BA and NAA at 0.50 and 2.00 mg/l, respectively, gave rise to the best results for the percentage of explants formed callus and callus size. Concerning the percentage of direct organogenesis and number of shoots formed per explants best results obtained from BA and NAA at 0.250 mg/l and 0.00 mg/l, respectively.Neoformed plantlets were acclimatized ex vitro and in vivo vigorously in a mixture of perlite and peat moss at (1:1) or (2: 2) or (2:3) and (3:3) consecutively, in addition to fixed volume (1 portion) of sterile sand; which resulted in the highest mean value of survival percentage/plant (100%) and showed true-to-type plants ex vitro.