Response of four medical plants of Euphorbia species in callus initiation in vitro

Abstract

Callus cultures were initiated for four Euphorbia species. Nodule explants cultured on Murashige and Skoog (MS) medium, supplemented with different concentrations 0,0.5,1,1.5,2 mg/l of the auxin 2,4-Dichlorophenoxy acetic acid 2,4-D. Half of the cultures were incubated for16 hrs/day photoperiod, while the other half was incubated under complete darkness. The incubation temperature was 25±1ºC. Observations on number of nodule explants initiated callus were recorded at 2,4,6,8 weeks of culture. For callus maintenance, 50mg of callus produced were re-cultured on MS medium supplemented with different concentrations of 2,4-D 0,0.4,0.8,1.2,1.6 mg/l. Callus fresh and dry weights were recorded after 4 weeks. Results showed that nodule explants of Epeplus and Ehirta incubated under light conditions achieved the highest response to callus initiation 75-100% compared with the other species under experimental conditions. E.Helioscopia incubated under light conditions achieved the lowest response for callus initiation 25-75%. Results also showed significant differences between Euphorbia species in fresh and dry callus weights, E. Ehirta produced the highest fresh and dry weight of callus reaching 1.410 and 0.046 mg respectively. The amount of fresh and dry weight of callus produced under dark conditions was significantly higher than that produced under light conditions.