In vitro propagation of Alangium salviifolium (L. f.) Wangerin: an important tropical medicinal tree

Alangium salviifolium (L.f.) Wangerin, sage-leaved alangium, is a medicinally important tree species of the Alangiaceae. It is a source of numerous bioactive therapeutic compounds, but its conventional propagation through seeds is beset with poor germination and seedling survival. Here, we report an efficient and reproducible protocol for its micropropagation using nodal segments and shoot apices collected from two-month-old plants. Murashige and Skoog (MS) medium and Woody Plant Medium (WPM) supplemented with various concentrations of plant growth regulators, either alone or in combination were evaluated. Bud break (≈ 71%) occurred from nodal explants after 3 weeks on WPM containing 1.11 µM N6 -benzyladenine (BA) plus 2.64 µM α-Napthoxy acetic acid (NAA), producing a single shoot of about 1.82 cm long by 4–6 weeks. WPM containing 1.42 µM IAA and 1.11 µM BA was optimum for shoot proliferation from nodal explants and shoot apices, yielding an average of 2.80 shoots per nodal explant after three successive subcultures. Elongated shoots were separated from the clumps and multiplied. Once they were 2.5–3.5 cm tall they were transferred to WPM medium with 2.46 µM indole-3-butyric acid (IBA), where 53–60% of shoots developed 1–3 cm long roots within 10–15 days. A reverse photoperiod (16 h dark/8 h light) was crucial for root induction. Well rooted shoots were transferred to pots, acclimatized in greenhouse and 60% of plants were transferred to soil after hardening. This is the first report of micropropagation in A. salviifolium and this protocol could serve for large scale propagation of this medicinal tree species. The effects of auxins and cytokinins on shoot multiplication and rooting of the medicinal tree Alangium salviifolium (L.f.) Wangerin were studied. A reverse photoperiod enhanced rooting. Plants survived field transfer.