RAPID PROPAGATION THROUGH SHOOT-TIP CULTURE OF TRICHOPUS-ZEYLANICUS GAERTN, A RARE ETHNOMEDICINAL PLANT

Rapid micropropagation of Trichopus zeylanicus Gaertn. subsp. travanco ricus Burkil ex Narayanan, a rare ethnomedicinal herb endemic to the W estern Ghats of southern India, was achieved by culturing shoot tips ( 0.3-0.5 cm) of 2-month-old axenic seedlings on Woody Plant Medium. Amo ng the cytokinins tested, only BAP induced callus-free multiple shoot bud formation, with a maximum of 8.5+/-0.4 buds per explant being obta ined with 2.0 mg.l(-1) BAP after 8 weeks of culture. Shoot tips contai ning proliferated buds were divided and subcultured on medium containi ng 0.2 mg.l(-1) BAP to produce 12.0+/-1.0 shoots per explant in 6 week s. Excision of buds after culture initiation, with subculture of the d ebudded basal tissue in 2 successive passages yielded 20.0+/-1.0 and 1 3.5+/-0.5 buds per explant respectively. Each bud cultured in turn for 4 weeks on WPM with 1.0 mg.l(-1) BAP formed 3.8+/-0.4 secondary buds which were repeatedly recultured to increase bud production. Altogethe r this method enabled an estimated harvest of 7848 buds from a single shoot tip in 28 months. Shoots (3-5 cm) developed from bud cultures we re rooted in half-strength WPM medium with 0.5 mg.l(-1) each of NAA an d IBA, and 90-100% of the rooted plants were established in the field after hardening. Micropropagated plants were grown to maturity free of defects in growth, morphological, flowering and seed set characterist ics.