ABA enhances plant regeneration of somatic embryos derived from cell suspension cultures of plantain cv. Spambia (Musa sp.)

Creamy friable calli were induced from meristems (scalps) of proliferating shoots of plantain (Musa sp.) cv. Spambia (genome AAB) incubated on a semi-solid modified Murashige and Skoog (MS) medium supplemented with 4.5 mu M 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mu M zeatin. About 25% of shoot-tip explants formed scalps, and about 98% of scalps developed embryogenic calli. Small dense aggregates of cells, were obtained when these calli were transferred to liquid MS medium supplemented with 4.5 mu M 2,4-D and 1.0 mu M zeatin. Upon transfer to semi-solid MS medium of the same composition as described above, aggregates of cells formed somatic embryos. In the presence of 2.5 mu M abscisic acid (ABA), maturation of somatic embryos was 2.6-fold higher than that of control (lacking ABA), and regardless of the type of cytokinin used in the medium. Upon transfer to MS medium supplemented with 1.25 mu M 6-benzyladenine (BA), 80% of germinated embryos developed into plantlets.