Optimization of in vitro conditions for induction of somatic embryos and regeneration of plantlets in Euphorbia hirta L.

Plantlet regeneration methods through somatic embryogenesis were standardized from stem explants of Euphorbia hirta in this report. The explants were surface sterilized with 0.1% (w/v) mercuric chloride solution. The sterilized explants were inoculated on MS (Murashige and Skoog) medium to induce somatic embryos. The explants with somatic embryos were transferred to the embryo germination and shoots elongation medium. The explants responded maximum on MS medium augmented with 0.4 mg/L 6benzyleaminopurine (BAP) and kinetin (Kin) combined with 0.5 mg/L á-naphthalene acetic acid (NAA). About 93% response was observed when indole-3 acetic acid (IAA) was used at the place of NAA in the medium with BAP and Kin. Sucrose at 3% concentration was reported optimum for the induction of somatic embryos. Somatic embryos were differentiated into plantlets within 4 weeks on half strength MS medium supplemented with 0.5 mg/L BAP and 0.1 mg/L Kin. Maximum 83.9±0.51plantlets (average length of 5.3±1.60 cm) per culture vessel were yielded on this medium combination after 4–5 subcultures. The induction of somatic embryos from the epidermal and subepidermal cells of the explants was confirmed by the microscopic observations of the transverse sections of explants with the embryoids. The methods were developed and the conditions were optimized for the induction of somatic embryos from the nodal explants of E. hirta in this study.