Optimizing rooting and survival of oil palm (Elaeis guineensis) plantlets derived from somatic embryos

Abstract

In species of the Arecaceae, initial conversion of somatic embryos to non-rooted plantlets (those with only shoot development and no roots) is common. A consistent methodology for improving rooting and survival of oil palm plantlets derived from somatic embryos was developed. Two experiments were carried out. In the first, non-rooted shoots regenerated via somatic embryogenesis were inoculated in nutrient medium supplemented with 0, 53.7, or 107.4 μM indole-3-butyric acid (IBA) or 1-naphthaleneacetic acid (NAA). In the second, the optimum treatment as determined in the first experiment was evaluated in three culture systems: semi-solid medium (SS), stationary liquid (SL), and double-phase system (DP), with and without the addition of activated charcoal. Next, the plantlets were acclimatized in a greenhouse, where the influence of the presence or absence of roots, the number of roots, the length of the main root, and the height of the shoot on survival were assessed. Supplementation with 53.7 μM IBA and the DP system without activated charcoal provided the highest percentage of rooted plantlets (92.9%) and number of roots (6.3) and improved the length of the aerial parts (11.0 cm) and the survival of the plantlets during the acclimatization (82.1%). The best survival of plantlets was obtained when they were acclimatized with at least one root and with a height greater than 7.5 cm.