Effect of 6-benzylaminopurine (BAP) in different basal media on shoot multiplication of Aquilaria hirta and detection of essential oils in the in vitro shoots

Aquilaria hirta, locally known as 'chandan' or 'chandan bulu', is used interchangeably with Aquilaria malaccensis (karas) to produce gaharu. With the decline in the A. malaccensis populations, harvesting of this precious wood has begun to extend to A. hirta. There is also an increasing interest to plant karas trees and related species. Therefore, a rapid propagation method is necessary to meet the increasing demand for planting materials as well as for conservation purposes. In this paper, we reported on the effect of 6-benzylaminopurine (BAP) in different basal media, Murashige and Skoog (MS) (1962) and woody plant medium (WPM) on shoot multiplications of A. hirta using nodal segments from young seedlings of A. hirta as explants and the chemical analyses of essential oils present in the in vitro shoots. The MS medium supplemented with 0.1 mg/l BAP was the most effective for multiple shoot formation in A. hirta, producing an average of 6.1 shoots per culture, which is significantly higher than other treatments. New shoots produced attained a length of 0.4 to 1.8 cm within 25 days in both MS and WPM basal media. The highest length of new shoots was obtained in WPM containing 0.1 mg/l BAP. Analysis of the oils by gas chromatography (GC) and gas chromatography-mass spectrometry (GCMS) revealed the presence of beta-caryophyllene in trace amounts. Other compounds detected were tetradecanal, hexadecanoic acid, methyl linoleate, linoleic acid, isophytol and phytol acetate.