Efficient and repetitive production of leaf-derived somatic embryos of Oncidium

Abstract

Oncidium cultivars gave different embryogenic responses of leaf explants when affected by auxins (2,4-D, IAA, IBA and NAA), cytokinins (2iP, BA, kinetin, TDZ and zeatin), sucrose, NaH2PO4, casein hydrolysate, peptone, and glutamine. The best embryogenic responses of cv. Sweet Sugar were at 20 g dm-3 sucrose, 85 mg dm-3 NaH2PO 4 and 3 mg dm-3 kinetin, respectively. The development of somatic embryos on leaf explants of cv. Sweet Sugar was delayed for about 10 - 20 d in comparison with cv. Gower Ramsey. On growth regulator-free medium, about 40 % of leaf derived embryos of cv. Gower Ramsey were fused together in their basal parts and so called multiple-state embryos. However, under the same condition, the embryos of cv. Sweet Sugar were all in multiple-state form.