Effects of spermidine, proline and carbohydrate sources on somatic embryogenesis from main root transverse thin cell layers of Vietnamese ginseng (<i>Panax vietnamensis</i> Ha et. Grushv.)

Abstract

The in vitro main roots transverse thin cell layers of Vietnamese ginseng (Panax vietnamensis Ha et. Grushv.) were cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg.l^-1 2,4- dichlorophenoxyacetic acid (2,4-D), 0.2 mg.l^-1 kinetin and 0.5 mg.l^-1 naphthaleneacetic acid (NAA), 30 g.l^-1 sucrose and 8.5 g.l^-1 agar to establish embryogenic culture. The effects of exogenous spermidine and proline on enhancement of somatic embryogenesis was investigated. The results show that spermidine (0.1 mM) and proline (300 mg.l^-1) resulted in a high frequency of somatic embryogenesis (93.3% and 86.7%, respectively). To further optimize a culture medium for induction of embryo formation of P. vietnamensis, three carbohydrate sources (sucrose, glucose and fructose) at 10 to 60 g.l^-1 were tested. Among them, glucose and fructose were not suitable for somatic embryogenesis in this species while sucrose at 50 g.l^-1 produced the highest embryogenic frequency (86.7%) number of embryos per responding explant (167). This study confirmed the importance of spermidine, proline and osmotic potential provided by sucrose in enhancement of somatic embryogenesis.

Key words: Panax vietnamensis, somatic embryos, spermidine, proline, carbohydrate.