Shoot Culture of Ocimum sp. and Its Phytochemical Profile

Abstract

The success of the in vitro culture technique is influenced by many factors, including the type of explants, culture medium and exogenous plant growth regulators (PGR). These factors greatly influence the speed and effectiveness of plant regeneration as well as the profile of the phytochemical compounds produced. Therefore, this study aims to determine the effect of the PGR combination on the growth response of in vitro node explants as well as the phytochemical profiles of Ocimum sp. Node explants obtained from 2 weeks old in vitro seedlings were cultured on MS medium with the addition of PGR, namely BAP and Kinetin (0.2 and 5 mg/l) combined with NAA (0.1 and 0.2 mg/l) and synthetic cytokinins alone namely Thidiazuron (TDZ) (1, 3, and 5 mg/l). The growth response of the explants and the potential for regeneration were observed for 8 weeks of culture. Effects of adding activated charcoal (AC) to root media were observed on growth of plantlets aged 2 weeks. Phytochemical profile of In vitro shoot was analyzed using GC-MS and LC-MS to be compared with its profile in in vitro callus tissue. The results showed that MS medium with the addition of a combination of cytokinin and auxin was able to induce shoot regeneration in node explants of Ocimum sp. in vitro. The Kinetin/NAA combination produced better shoot height growth, while the BAP/NAA combination produced a higher leaves number. Thidiazuron at all concentrations was able to induce shoots that were more likely to form rosettes. The addition of AC to the rooting medium did not have a positive effect on the response of shoot and plantlet growth. Chromatographic screening showed different profiles of secondary compounds in the callus and shoot tissues of Ocimum sp. in vitro. Callus composed of actively dividing cells do not produce some of the secondary compounds as produced by in vitro shoots. This shows the difference in the potential of cells or tissues in synthesizing secondary metabolites.