Somatic embryogenesis in macaw palm ( Acrocomia aculeata) from zygotic embryos

Abstract

Macaw palm ( Acrocomia aculeata) is an oleaginous palm tree that is highly productive and adapted to semiarid ecosystems, which oil can be used to produce biodiesel. Such characteristics make macaw palm a potential crop to be used by farmers from semi-arid regions, but its propagation is still problematic. This paper reports the first description of somatic embryogenesis for macaw palm from zygotic embryos. The explants were cultured on Y 3 medium and different combinations of plant growth regulators. After 60 days of culture, embryogenic callus were induced with 9 μM of 4-amino-3,5,6-trichloropicolonic acid (picloram) or 2,4-dichlorophenoxyacetic acid (2,4-D), combined or not with 1 μM N-phenyl N′1,2,3 thidiazol-5-yl urea (TDZ). Naphthoxy acetic acid (NOA) and 4-chlorophenoxyacetic acid (CPA) did not generate embryogenic callus. Somatic embryos were only obtained when embryogenic callus were induced with 9 μM picloram and then subcultured for 120 days on the same medium with 3.0 g l −1 activated charcoal. Anatomical sections showed that somatic embryos had a typical protoderm, procambial strands and an apical meristem. When transferred to Y 3 medium +3.0 g l −1 activated charcoal, without growth regulators, half of the somatic embryos germinated, but only a few completed the germination.