Regeneration of somatic embryos of oil palm (Elaeis guineensis) using temporary immersion bioreactors

Abstract

Oil Palm is not only an economically important plant species, but it is also the second largest source of edible oil in the world. Since the oil palm has a single growing apex which prevents its vegetative multiplication by conventional methods, micropropagation via somatic embryogenesis is one of the only forms of clonal propagation of the plants. Owing to greater efficiency in protocols for large-scale propagation of oil palm plants by somatic embryogenesis, several studies have evaluated the substitution of semi-solid media with liquid consistency media in different phases of the process. Current assay comprises a viable methodology to improve the regeneration of oil palm plants from somatic embryos, employing liquid medium in temporary immersion systems. Clusters of somatic embryos in the torpedo stage were cultivated in semi-solid (SS) medium, RITA® (Recipient for Automated Temporary Immersion) bioreactors, and Twin Flask—TIS (Temporary Immersion System) bioreactors and the regenerated plants were acclimatized in a greenhouse. The best results for the number of plants regenerated were assessed after approximately 90 days when the embryos were cultivated in bioreactors, regardless of the model used, averaging 15 plants per fresh weight of inoculated somatic embryos. When the bioreactors were compared, the TIS model produced the greatest accumulation of biomass. Further, 36% of the plants were taller than 2.5cm when regenerated in TIS, whereas approximately 15% of the plants were taller than 2.5cm when SS and RITA systems were used. With regard to acclimatization in a greenhouse, survival rates confirmed approximately 82% of the regenerant plants, which were not inhibited in their initial development process.