Plant Regeneration by Somatic Embryogenesis From Parts of Cultured Mature Embryos of Pennisetum americanum (L.)K. Schum.

Whole and excised parts of mature embryos and seedlings of Pennisetum americanum (L.)K. Schum. were cultured in Murashige and Skoog's medium (MS)supplemented with 2,4-dichlorophenoxyacetic acid and coconut milk. A soft friable callus, which later developed only roots, was formed when whole embryos or isolated mesocotyl and radicle were cultured. A compact embryogenic callus was induced only from the shoot apex and the two youngest leaf primordia excised from mature embryos or 4-5 day old seedlings. The complete removal of mesocotyl tissue from the base of the shoot apex at the time of culture was critical for the formation of compact callus, and for inhibiting the development of the friable callus. The embryoids developed by a sequence of internal segmenting divisions from single embryogenic cells, and showed a well organized embryonic axis with a closed vascular system, a coleoptile, a coleorhiza, and a scutellum. Upon transfer to media which promoted shoot and root growth, normal plantlets were formed and transferred successfully to soil.