REGENERATING PLANTS FROM IN-VITRO CULTURE OF BLACK LOCUST COTYLEDON AND LEAF EXPLANTS

A protocol to achieve efficient plant regeneration from juvenile black locust (Robinia pseudoacacia L.) explants is described. Direct advent itious shoots were induced from cotyledon explants on woody plant medi um containing 22.2 muM BA and 0.4 muM 2,4-D. Shoots developed and new shoots were induced when the explants were transferred to medium witho ut growth regulators. The effect of dark incubation on shoot regenerat ion from cotyledons indicated that 15 days of darkness resulted in a h igh regeneration frequency (91.7%). Adventitious shoot formation also was induced from sections of in vitro-derived leaves cultured in darkn ess on Murashige and Skoog medium supplemented with 4.4 muM BA and 24. 6 muM IBA. A shoot regeneration frequency of 89% was obtained when exp lants were subcultured on a medium containing 4.4 muM BA and 0.5 muM I AA. Shoots were rooted on Schenk and Hildebrandt medium with or withou t IBA. Plantlets were acclimatized and grown in the greenhouse. Chemic al names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 2,4-dichlorophe noxyacetic acid (2,4-D); indole-3-acetic acid (IAA); indole-3-butyric acid (IBA).