INDUCTION OF SOMATIC EMBRYOGENESIS IN CYNARA-CARDUNCULUS L (COMPOSITAE)

This report describes procedures for the production of somatic embryos from cotyledons and first leaves of in-vitro grown seedlings of Cynar a cardunculus L. (Compositae). Embryogenic calli were obtained after 4 -5 weeks of culture on solid B-5 medium containing selected combinatio ns and concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and ki netin (KIN) or 6-benzylaminopurine (BAP). In the presence of 2,4-D at 1 mg litre-1 and KIN at 0.1 mg litre-1, initial stages of somatic embr yo development were formed on the surface of the embryogenic calli. Co tyledon explants presented a higher percentage of embryogenic inductio n than leaf explants. The transfer of these cultures to B5 liquid medi um containing 2,4-D (0.1, 0.5, 1 mg litre-1) and zeatin (ZEA) at 1 mg litre-1 allowed induction of more embryos and their further developmen t. 2,4-D at the optimum concentration of 0.1 mg litre-1 was necessary for embryo development. Some embryos presented abnormalities that were not prevented by the addition of abscisic acid (ABA) to the culture m edium. Mature embryos when transferred to the same liquid medium lacki ng growth regulators showed root apex growth and greening of cotyledon s. However, the germination of the embryos was still only occasional a nd plantlets obtained showed arrest of growth before development of le aves.