Micropropagation of mature Terminalia catappa (Indian Almond), a medicinally important forest tree

Abstract

We report an efficient in vitro propagation method for Terminalia catappa using nodal segments of a 15-year-old mature tree. The nodal segments were cultured on MS medium supplemented with 6-benzyladenine (BA; 0.5–3.0 mg l⁻¹) or Kinetin (Kn; 0.5–3.0 mg l⁻¹) for bud breaking and multiple shoot induction. About 85% of the explant responded (2.8 ± 0.41 shoots per node with 2.7 ± 0.14 cm length) within 15 days of inoculation in Murashige and Skoog medium fortified with 2.0 mg l⁻¹ of BA. Further shoot multiplication was achieved by repeated transfer of mother explants and subculturing of in vitro-produced shoots on medium supplemented with various concentrations of BA (0.25–1.5 mg l⁻¹) or Kn (0.25–1.5 mg l⁻¹) or on their combinations. Optimal number of shoots and shoot length were recorded on MS medium supplemented with 0.25 mg l⁻¹ of BA and 0.25 mg l⁻¹ of Kn. The multiplied shoots were used for ex vitro rooting after treatment for 4 min with indole-3-butyric acid (IBA; 50–500 mg l⁻¹) or α-naphthalene acetic acid (NAA; 50–500 mg l⁻¹). About 80% of the shoots treated with 200 mg l⁻¹ of IBA produced ex vitro roots with an average of 2.8 roots per shoot. Nearly 75% of these plantlets could be acclimatized within 5 weeks and successfully established in the field. This is the first report on micropropagation of T. catappa, which can be applied for further genetic transformation assays and pharmaceutical purposes.