Initial requirements for embryogenic calluses initiation in thin cell layers explants from immature female oil palm inflorescences

This study highlights procedures for embryogenic calluses induction from immature female inflorescences of oil palm using thin-cell-layers explants (TCL). In three experiments, the ability of calluses induction were examined and identified through different types of basal media, position of the TCL explants in the rachillae and concentrations of 2,4-D and types of antioxidants added into the medium. Samples of embryogenic calluses obtained were isolated and transversal and longitudinal cross sections were obtained and stained for observations in light microscopy. The results achieved suggest that immature female inflorescences of oil palm can be reverted from the floral state to the embryogenic vegetative state and are excellent alternative sources of explants for the induction of somatic embryogenesis. In general, 225 to 450 μM of 2,4-D are required to induce embryogenic callus in explants composed of immature oil palm inflorescences and the composition formed by salts and vitamins of MS medium provides superior results than Y3 medium. The activated charcoal at concentration of 3.0 g l -1 is the most indicated antioxidant for preventing the oxidation of floral oil palm explants and its presence can be considered essential for the formation of embryogenic callus. Key words: Elaeis guineensis, somatic embryogenesis, micropropagation, floral explants, morphogenesis, agroenergy.