In vitro multiplication of Calophyllum apetalum (Clusiaceae), an endemic medicinal tree of the Western Ghats

Young shoots collected from mature trees of Calophyllum apetalum during the flush season (November-February) were red (1-2 weeks), pinkish-red (3-5 weeks), pale green (6-8 weeks) and dark green (9-10 weeks) coloured after different periods of growth. All the shoot tip and single node explants of the youngest 1-2-week-old shoots cultured in Murashige and Skoog's (1962) agar medium were lost due to excessive browning and necrosis; nodes of the 6-8-week-old shoots subjected to transfers twice a week in fresh medium containing 8.8 muM BAP responded the most (68% of explants) with the formation of 3.2 shoots per explant in 7 weeks. The shoot tip was a relatively poor source of regeneration (2.3 shoots per explant; 39% of explants). Subculturing of explants from in vitro derived shoots for 5 weeks in medium containing 4.4 muM BAP resulted in the formation of an increased number and percentage of shoots in the nodes (5.3 per explant; 74% of explants). The shoot cultures were transferred to 1/2 MS basal medium for 4 weeks to induce the elongation of shoots (similar to3.0 cm). Rooting of the microshoots (> 2.0 cm) was achieved when cultured in quarter strength MS medium supplemented with 9.8 muM IBA for 4 weeks followed by transfer to 1/4 MS basal medium for 4 weeks. The rooted plantlets transferred to clay pots filled with soil, sand and farmyard manure (1:1:1), maintained in a mist chamber at a relative humidity of 80-90%, acclimatised at a 56% rate after 6 weeks. Out of 345 plants restored to their native habitat in the forest at three locations of the institute campus, 293 plants survived and showed uniform growth free of morphological defects.