Plectranthus
amboinicus (Lour.) Spreng is commonly consumed by people in North Sumatra,
Indonesia, as a vegetable, which is commonly called Torbangun. Plant tissue
culture is an alternative method for the mass-production of transplants.
Genetic improvement by somatic cell manipulation such as induction of polyploid
plants is needed to improve biomass production as well as their secondary
metabolite products. This research aimed to conduct in vitro micropropagation
of diploid and tetraploid P. amboinicus on Murashige and Skoog (MS) medium
containing BAP or Kinetin. Shoot tips were used as explants and cultured on MS
medium containing BAP or Kinetin at 0, 0.5, 1 and 2 mg/l given as single
concentration. The experiment used a completely randomized design with four
replications. Each replication consisted of three explants. The results showed
that height of shoots was affected by type of cytokinins. Kinetin at 0.5 mg/l
gave the highest shoots of tetraploid plants significantly different with
addition of BAP both to diploid and tetraploid plants. The number of multiple
shoots and leaves varied in both diploid and tetraploid plants. Root formation
was best on the medium without addition of cytokinins. Both diploid and
tetraploid plantlets had a high survival rate after acclimatization in the
greenhouse
