Relationship of abscisic acid to somatic embryogenesis in Dactylis glomerata

Abstract The influence of abscisic acid (ABA) on somatic embryogenesis in orchardgrass ( Dactylis glomerata L.) was studied in one embryogenic (Embryogen-P) and one nonembryogenic (I-39) genotype. Leaf segments from the basal portions of the two innermost leaves were cultured for various lengths of time on SH medium containing 0.01–20.0 μM ABA. Somatic embryogenesis was increased in Embryogen-P by a 3-day exposure to 0.01–10.0 μM ABA; 20 μM was inhibitory. I-39 did not respond to any ABA treatment. Quantification by enzyme-linked immunosorbent assay (ELISA) indicated that exogenous ABA levels in leaf tissues were nearly the same in the two genotypes at the initiation of culture but decreased much more rapidly during the first 7 days in the nonembryogenic than in the embryogenic genotype. They were the same after 14 days of culture. These results suggest that somatic embryogenesis in the embryogenic genotype may be increased by manipulation of concentration and duration of ABA application. Attempts to induce somatic embryogenesis in the nonembryogenic genotype with ABA treatments were not successful.