Comparison of somatic embryogenesis efficiency from in vitro explant sources of Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.)

This study on the efficiency of embryogenesis from various explant sources of Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.) was conducted to select the appropriate materials and optimise embryogenesis in vitro. In this study, in vitroexplants from leaf fragments, petioles, roots, and embryos (globular, heart-shaped, and cotyledon) were cultured on MS medium supplemented individually or in combination with 2,4-D (2,4-dichlorophenoxyacetic acid: 0.2, 0.5, and 0.7 mg/l) and TDZ (Thidiazuron: 0.1, 0.3, and 0.5 mg/l). The results showed that all explants had embryogenesis after 6 weeks of culture (100%). The average number of embryos per leaf fragment (51.00 embryos) on the optimal medium was significantly higher than that of petioles (29.67 embryos) and root samples (18.00 embryos). Interestingly, the globular embryo explant was noted as the most suitable material source for embryogenesis (68.33 embryos/sample). The culture medium with the combination of 2,4-D and TDZ increased the ability to create secondary embryos in globular embryos, the highest result was achieved at the concentration of 0.7 mg/l 2,4-D combined with 0.1 mg/l TDZ in the medium containing 0.5 mg/l NAA - 1-Naphthaleneacetic acid (73.33 embryos/sample).