Effects of Plant Growth Regulators on Propagation of Gynostemma pentaphyllum Thunb. in Lowland Tropics
Introduction: Gynostemma pentaphyllum is a herbaceous plant with high medicinal value, commonly known as "valuable grass". It grows wild and is widely cultivated in the northern mountainous regions of Vietnam. Aim: G. pentaphyllum is recognised for its high gypenoside saponin content. This study investigated its growth under lowland tropical conditions and evaluated the saponin content of the propagated plant material. Methods: In vitro propagation was conducted using tissue culture techniques to produce uniform and disease-free parent plant material. Results: Four basal media, MS, 1/2MS, WPM and 1/2WPM, were used to culture the initial samples. MS medium was suitable for in vitro culture. MS propagation medium supplemented with 0.1 mg/L BA produced the most favourable results for the number of shoots (1.40), number of nodes (6.60) and number of leaves (34.97). The 1/2MS medium supplemented with 0.1 mg/L NAA was suitable for the development of long and healthy roots. The saponin content was 13.13 µg/mg in in vitro plantlets and 14.38 µg/mg in garden-grown plants under tropical conditions. Conclusion: The findings may support the conservation and pilot-scale propagation of tropical G. pentaphyllum clones.