Abstract

Embryogenic callus induction starting from three explants coming from mature seeds (mature zygotic embryos, hypocotils and cotyledons) was studied. The results indicated that the medium 13 (B5 + ANA 0.5mg·l-1 + BAP 1.0mg·l-1) produced the largest percentages of callus formation in all the expiants. Micromorphology revealed the presence of embryogenic cells in all expiants, while globular states in initial phases were found in hypocotils and cotyledons. Later, in the differentiation phase, a maximum of 25 globular states by callus were obtained in a B5 medium with maltose (2% p/v) added, when using mature zygotic embryos. The histological study showed internal differentiation of globular states, characterized by a concentric formation of vascular bundles, parenchymatous cells towards the periphery and, finally, a protodermis formed by isodiametrical cells. © 2007 Asociación Interciencia.