EFFECT OF ABSCISIC-ACID AND CYTOKININS ON THE DEVELOPMENT OF SOMATIC EMBRYOS IN HEVEA-BRASILIENSIS

Addition of liquid medium, conditioned by an embryogenic suspension, to MH1 solid medium (3,4-dichlorophenoxyacetic acid 9 mu M, 6-benzyladenine 9 mu M) permitted the frequent induction of highly embryogenic calli from slices of internal integument of immature seeds of Hevea brasiliensis Mull. Arg. The proliferation of embryogenic cell clusters was achieved in MH1 liquid medium. Abscisic acid (ABA), cytokinins and adenine were tested for their ability to affect development of somatic embryos to plantlets. The transfer of embryogenic cell clusters on auxin-free solid medium with 10(-5)M ABA for 2 months stimulated embryo development. When torpedo-shaped embryos were transferred to medium with adenine or cytokinins they turned green in 1 month. Green embryos produced secondary embryos when they were collected and placed on medium without growth regulators.