In vitro propagation of Xao tam phan (Paramignya trimera (Oliv.) Guill.)

Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", has been used in Vietnamese folk for the treatment of numerous cancers. Due to word of mouth about the anticancer properties of this plant, its stems and roots have been overexploited leading to the serious decline of this species in Phu Yen, Khanh Hoa and Ninh Thuan provinces. The aim of the study was to establish an in vitro propagation protocol for the conservation of P. trimera. In this research shoot clusters (5–8 shoots/cluster) were regenerated from axillary bud explants of 1–3 year-old trees after 3 months of cultures on the WPM (woody plant medium) supplemented with STS 3 and BA 5–7 mg/L. STS (silver thiosulfate) was used to prevent the leaf abscission. These shoot clusters grew slowly and reached 1–3 cm in heights after 4 months of the cultures. These shoot clusters did not form any roots after 2 months of culture on the rooting media with IBA and/or NAA 1–5 mg/L. However, there was 51 % of the treated shoot clusters acclimatized and produced new stem and leaves after 2 months growing in greenhouse. WPM supplemented with STS 3, BA 5 and IBA 5 mg/L showed the best response for callus induction in leaf explants after 3 months of cultures. Among the callus types, the milky white compact calli were induced at the cut surface of leaf explants after 3 months of the cultures and became the compact and nodulated calli within 4 weeks later.