The Origin and Development of Embryoids in Oil Palm ( Elaeis guineensis Jacq) Embryo Culture

Abstract

Mature zygotic embryos of Elaeis guineensis Jacq var tenera were excised and cultured on Eeuwens (1976, 1978) medium containing 2 mg/l 2, 4-D. Callus was initiated from these embryos within 8 weeks. Embryoids were induced from the primary callus cultured on Murashige and Skoog (1962, MS) medium supplemented with 0.5 mg/l 2, 4-D. For embryoid differentiation and plantlet regeneration, two successive media were employed. The first medium was MS-CAP devoid of 2, 4-D but containing 0.05% activated charcoal . The second medium was MS-CAP containing 0.1 mg/l 2, 4-D and 2.5 mg/l BA. The embryoids were harvested at various time, fixed, sectioned, stained and examined microscopically. The histological origin of embryoids was from single cells in the subepidermis along the surface of callus clumps. Embryoids proceeded in a standard development pattern to the globular-, heart- and finally to the cotyledon stage. Secondary embryoids occurred on the cotyledon of primary embryoids and originated from single, densely staining cells of the epidermis.