REGENERATION OF TREMA-ORIENTALIS (BLUME) LINN - EFFECT OF GROWTH-REGULATORS, CULTURE CONDITIONS, AND AGE AND SOURCE OF EXPLANTS

Optimal conditions for high frequency shoot bud regeneration from leaf callus of Trema orientalis (Blume) Linn. were studied. The regenerati on rate was controlled by the growth regulators, the age and the sourc e of the explants, and the illumination conditions. Irrespective of il lumination conditions, shoot bud regeneration was achieved only in med ia containing benzyladenine (BA) + alpha-naphthaleneacetic acid (NAA) combinations, with the best results being obtained in the presence of 2.5 mg/l BA and 0.25-0.5 mg/l NAA. The morphogenic response was less f requent in the calluses derived from leaf explants of the mature trees compared to those of the in vitro-grown seedlings. The rate of shoot bud regeneration was more pronounced in the cultures maintained for 4 weeks in the light (16-h photoperiod) than the cultures incubated in t he dark. Regenerated shoots were rooted on the medium containing 1/2 s trength basal Murashige and Skoog (MS) salts supplemented with 0.01 mg /l NAA or indole-3-butyric acid (IBA). The rooted plantlets were estab lished in the greenhouse.