Elaeis guineensis (African oil palm) and E. oleifera (American oil palm) are bred to attain high
oil yields, disease resistances, and decelerated shoot elongation. We
cultivated immature zygotic embryos from backcrossed and F1 interspecific progenies on media containing 110, 150, or 200 mg·l-1 2,4-diclorophenoxyacetic acid (2,4-D) to obtain embryogenic cultures. These
were set to multiply on medium containing 8 mg·l-1 2,4-D or lower concentrations of auxins and finally we induced plantlets
regeneration, from each zygotic embryo, independently, in order to have the clones
organized according to their respective origins. Reductions in auxins induced
cultures to revert from highly embryogenic into competent for embryogenesis
and finally to organogenic degenerated callus lines. Histology and the
expression of SOMATIC EMBRYOGENESIS RECEPTOR KINASE, DEHYDRIN, DEFENSIN, TRANSPOSASE, and LIPID TRANSFER PROTEIN were analyzed on four callus lines representative
of morphological aspects consistently
observed. The highest number of embryogenic
cultures was obtained on 150 mg·l-1 2,4-D. Maturation and multiplication of
somatic embryos through secondary embryogenesis occurred simultaneously on 8 mg·l-1 2,4-D. LIPID TRANSFER PROTEIN expression
was detected in one of the embryogenic cultures and correlated with protoderm onset. Three six-week cycles on induction medium
yielded 1.5 shoots above 6 cm per poly-embryogenic complex, which performed
better than embryoids individualized
mechanically. Rooting was observed for 77% and 82% of shoots from these
two types of explants, respectively. Rooted plantlets ready for acclimatization
were obtained nine months after shoot induc