Micropropagation of licorice (Glycyrrhiza glabra L.) by using intermediate nodal explants

Abstract

Plant tissue culture techniques are useful for producing a large number of disease-free plant material. The aim of the present study was to determine the optimal nodal explant type (terminal, intermediate and basal) and cytokinins (6-benzyladenine and thidiazuron [TDZ] at concentrations of 0 to 3 mg L -1 ) for bud break and axillary shoot proliferation of Glycyrrhiza glabra L. The intermediate nodal explants were effective for the establishment of G. glabra aseptic culture when compared with terminal or basal nodal explants. The highest bud break (89%) and axillary shoot proliferation (eight shoots) were observed when the intermediate nodal explants were cultured on MS medium supplemented with 2 mg L -1 TDZ for 30 d. The best rooting medium was MS medium supplemented with naphthalene acetic acid (NAA) compared with indole acetic acid; NAA at 6 mg L -1 yielded 78% rooting and an average of 6.3 roots per plantlet. The regenerated plantlets were acclimatized, with a survival rate of 77.7%, when transferred to ex vitro conditions and showed no morphological abnormalities. Thus, the high percentage of bud break and rate of shoot proliferation and successful acclimatization established a simple and efficient micropropagation of G. glabra.