UBC Theses and Dissertations
The single cell suspension culture of the licorice plant, Glycyrrhiza glabra Wu, Chiu Hui
The cells of the licorice plant, Glycyrrhiza glabra, were cultured as a "single cell" suspension. Their growth behaviour, yield and metabolic products were studied. The suspension cultures of the licorice plant were established from the friable calluses obtained from the radicle, cotyledon and hypocotyl of the germinated seeds. The single cells, regardless of their origin showed little difference in cell size and morphology. After an apparent adjustment to the medium, the cells required 11-13 days of incubation to reach the maximum cell yield of 1.2 gm/100 ml medium, dry weight. During the growth period, the pH of the growth medium decreased from pH 5.6 to pH 4.7 in the first few days and then increased to about pH 6. A level of 10% coconut milk in PRL-4-CM medium was found to support good cell growth; the lower the coconut milk level, the longer the growth period required to reach the maximum cell yield. It was also found that 0.57% yeast extract could be used to replace the coconut milk in the PRL-4-CCM medium. The metabolites detected and examined in the licorice single cell suspension culture included a volatile apple aroma, a polysaccharide pectin-like material, steroids and triterpenoids. The analyses of the licorice cell volatile apple aroma found under anaerobic conditions indicated the presence of ethanol and some related esters. The monosaccharides found in the pectin-like polysaccharide hydrolysate were glucose, fructose, galactose, arabinose, xylose, galacturonic acid and glucuronic acid. The pectin-like material in the cell preparations reached a maximum yield of 1.1 mg/ml after one month of growth. Glycyrrhizinic acid, the common licorice constituent found in the root, could not be detected in the suspension cultures. However, several other related compounds which gave typical steroid and triterpenoid reactions were found. Sorbitol and fructose were found to be the two major sugars which accumulated in free form in the licorice cell medium.
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