Optimization of embryogenic-callus induction and embryogenesis of Glycyrrhiza glabra

Abstract

Glabridin is a major biologically active flavonoid isolated specifically from the root of Glycyrrhiza glabra, which has many pharmacological activities. The production of the wild G. glabra was sharply decreased due to immoderate and ruinous utilization. In vitro regeneration via somatic embryogenesis is important for clonal propagation and genetic transformation. In this paper, factors affecting the embryogenic calli and embryo induction, maintenance and multiplication of G. glabra are assessed. The results showed that the explants of hypocotyl give the highest calli formation frequency of 93.3% on Murashige and Skoog (MS) medium containing 2.0 mg/L 6-benzylaminopurine (6-BA) and 0.5 mg/L 2,4- dichlorophenoxyacetic acid (2,4-D). The maximum efficiency of embryo were obtained on MS medium with 0.5 mg/L 6-BA + 0.5 mg/L kinetin zeatin (KT) + 0.1 mg/L indole-3-butyric acid (IBA); the embryos could develop further on medium with 1000 mg/L malt extract (ME). The occurrence of the embryogenic calli and proglobular embryo were studied by histological section, indicating the single cell origin of the embryogensis of G. glabra. With the protocol reported herein, some green embryo-like cultures were obtained, from which shoots were successfully regenerated in the germinated medium after 10 months of subculture.

Keywords: Glycyrrhiza glabra L., callus induction, embryogenesis, cell culture, histological section

African Journal of Biotechnology Vol. 9(36), pp. 5823-5829, 6 September, 2010