Micropropagation, encapsulation, and conservation of Decalepis salicifolia, a vanillin isomer containing medicinal and aromatic plant

An efficient in vitro propagation and synthetic seed production protocol was established for the conservation of Decalepis salicifolia (Bedd. ex Hook.f.) Venter, an endemic and critically endangered ethnomedicinal species. Murashige and Skoog (MS) media supplemented with 2.2 mu M BAP and 5.7 mu M IAA produced shoot tip proliferation with an average shoot length of 5.81 +/- 0.03 cm in 3 wk. Axillary bud proliferation was found to be best in 11.1 mu M BAP with an average of 3.5 +/- 0.06 shoots per explant. Shoot tip and nodal explants were encapsulated in sodium alginate and their regeneration was achieved following storage at 4 degrees C up to 12 wk. Successful rooting was obtained in modified MS medium with low nitrate and high sucrose concentration. Quarter strength MS media containing 2.5 mM each of NH4NO3 and KNO3 along with 8% sucrose produced an average number of 12.4 +/- 1.18 roots with an average length of 4.3 +/- 0.08 cm. The in vitro derived rooted plants were successfully hardened (92.8%) and established in field with 100.0% survival rate. Inter-simple sequence repeat (ISSR) markers proved the genetic fidelity among the in vitro grown plant showing 99.5% similarity with the mother plant. Micropropagation derived acclimatized plants produced 2-hydroxy-4-methoxybenzaldehyde in amounts similar to seed-derived field-grown plants of the same age. The in vitro propagation protocol developed for D. salicifolia can be utilized to reduce exploitation pressure from their natural habitats and augment ecorestoration, conservation, and cultivation of this critically endangered and industrially valuable plant. The synthetic seeds technique will serve as propagules in ex situ gene banks, as well as supports cost-effective germplasm conservation.