In vitro propagation of Dipterocarpus alatus and Dipterocarpus intricatus

Seedlings were grown in vitro from embryos of Dipterocarpus alatus and D. intricatus. The problem of explant browning could be overcome by growing embryos initially on a filter paper bridge in liquid medium with activated charcoal. The best basal medium was Woody Plant Medium without the ammonium nitrate. Cytokinin appeared to stimulate seedling growth, 5×10^-5 M 2-isopentenyladenine and 10^-4 M 6-benzyladenine (BA) being the optimum concentrations for D. alatus and D. intricatus respectively. Cotyledonary nodes, excised from the seedlings, were induced to form axillary shoots and in the case of D. intricatus these could be multiplied rapidly. D. intricatus shoots elongated by reducing the BA level from 10^-5 M to 5×10^-7 M. Roots developed when shoots were dipped in 10^-3 M indolebutyric acid for two minutes and subsequently grown in liquid medium supported by a filter paper bridge.Abbreviations AC activated charcoal - BA 6-benzyladenine - 2iP 2-isopentenyladenine - IBA indolebutyric acid - MS Murashige & Skoog medium - PVP polyvinylpyrrolidone - PVPP polyvinylpolypyrrolidone - WPM Woody Plant Medium - 1/2 WPM Woody Plant Medium with half-strength macro salts - WPM (-NH₄NO₃) Woody Plant Medium without ammonium nitrate