ADVANCES IN SOMATIC EMBRYOGENESIS AND PLANT-PRODUCTION OF BLACK LOCUST (ROBINIA-PSEUDOACACIA L)

Black locust (Robinia pseudoacacia L.) immature seeds of different dev elopmental stages were tested for the ability to initiate embryogenic cultures. Best results (average of 12% embryogenic cultures) were obta ined when seeds collected 2-3 weeks post-anthesis were cultured for 3 weeks on modified Finer and Nagasawa medium containing 2,4-D (45-90 mu M) and BA (2.2 muM) and then transferred to the same medium without gr owth regulators. Embryo conversion was obtained from naked or encapsul ated somatic embryos derived from a long-term embryogenic line. Withou t cold treatment, 71% of naked embryos and 41% of the encapsulated emb ryos converted into plants. Fifteen days of cold treatment increased c onversion rates up to 95% for naked embryos and 80% for encapsulated e mbryos. Recovered plantlets were acclimatized and grown in the greenho use.