Abscisic acid and desiccation tolerance in oil palm (Elaeis guineensis Jacq.) somatic embryos

Abstract

The effect of exogenous abscisic acid (ABA) on the desiccation tolerance, soluble sugar contents and germination rates of oil palm somatic embryos was studied. ABA was added during the development or germination of the somatic embryos. The treatments had no effect on embryo dry weights or water and sucrose contents. In contrast, monosaccharide levels decreased in ABA-treated embryos and raffinose was detected in embryos treated for 6 weeks with increasing concentrations of ABA (from 5 to 25 μM). ABA significantly improved embryo tolerance to rapid desiccation. Embryos treated with 25 μM ABA exhibited survival rates higher than that of the control. The 2-week ABA treatment induced a delay in shoot emission during embryo germination on hormone-free media. In contrast, embryos treated with 50 μM ABA displayed no germination. The presence of ABA in germination media induced inhibition of embryo shoot emission. These results suggest that ABA plays a role in the maturation and the acquisition of desiccation tolerance of oil palm somatic embryos.