Vegetative propagation of K. galanga Linn (Zingiberaceae) cannot fulfill the current demand for planting material and tissue culture offers an alternative means for mass propagation. Experiments were carried out on propagation of plants through direct organogenesis and comparison of larvicidal activity and phytochemicals present in rhizome of natural and tissue cultured plants in order to confirm the potential use of tissue cultured plants as an alternative to natural plants in commercial scale productions. In vitro shoot induction was optimized with rhizomee bud explants grown on MS medium supplemented with 2.0 mg/L Benzyl amino purine (BAP) and 0.5 mg/L IAA (Indole-3-acetic acid). MS medium supplement with 1.0 mg/L IAA and 0.2 mg/L Indol-3-butric acid (IBA) was identified as the best medium for root induction. Rooted plantlets were acclimatized successfully (100%) in a mixture of soil: sand: compost (1: 1: 1). Hexane found to be a better solvent for extraction of phytochemicals over methanol and the 50% hexane extract showed the highest larvicidal activity against the fourth instar larvae of A. aegypti. GC-MS analysis revealed the existence of the nine key compounds in both samples tested confirming the possibility of using tissue cultured plants as a substitute for natural plants in medicinal purposes.
Gyrinops walla (Gaertn.) (Thymelaeaceae) is a slender tree which grows in wet zone regions in Sri Lanka. Potentiality of production of resinous natural product, agarwood, which used in perfumery and medicine manufacturing, grant a great demand for this species in worldwide. In vitro micropropagation technique may be a practicable solution to provide healthy planting materials in commercial scale, in order to overcome the problems caused to the natural population due to
overexploitation. Thus, using leaf disc explant, possibilities of mass propagation through in vitro techniques was explored in in vitro study. Explants were surface sterilized using 0.2% carbendazim, 10% sodium hypochlorite (Clorox) and 70% ethanol each followed by two successive washings in sterile distilled water. Murashige and Skoog (MS) basal medium supplemented with varied
concentrations of different plant growth regulators, 6-benzylaminopurine (BA and
naphthaleneacetic acid (NAA) were tested for induction of calli from leaf discs. Out of different growth regulator combinations, rapid callus growth was observed in MS medium supplemented with 1.0 mg/L BA and 3.0 mg/L NAA within six weeks. Calli obtained were yellowish, compact and callus induction was mainly observed along the midrib. Calli obtain could either be used for mass
propagation, through indirect organogenesis or for establishment of plant cell culture to obtain secondary metabolites. From the results obtain, it could be concluded that callus initiation is feasible through leaf disc explant.
Keywords: Gyrinops walla, in vitro micropropagation, callus formation, plant growth regulators,
leaf disc explant