Somatic embryogenesis from chestnut cotyledon tissue cultured in vitro

Globular, heart-shaped and torpedo-shaped embryoids have differentiated from explants of ungerminated chestnut cotyledon cultured in vitro on a solid mineral medium. Somatic embryogenesis took place in most of the cultures containing 2,4-dichlorophenoxyacetic acid (2,4-D), either alone or combined with kinetin, 6-benzylaminopurine or zeatin. When 1 mg 1-1 2,4-D was combined with 0.1 mg 1-1 cytokinin, the embryoids remained in the globular state, whereas when 0.1 mg 1-1 2,4-D was combined with 1 mg 1-1 cytokinin, anomalous structures were formed. The medium with Murashige and Skoog's macronutrients was more effective in inducing embryoids than that containing Heller's macronutrients. In sections of the tissue, bipolar structures are interpreted as being globular to cotyledonary stages of embryoid development. The transfer of embryogenic callus to an auxin-free medium after 4 weeks culture on 2,4-D medium failed to bring about the embryoids' development into plantlets