Abstract Background Euphorbia milii is a flowering ornamental plant that plays an important role in folk medicine. It has a variety of therapeutic effects due to its high content of many active compounds. This research presents a simple protocol for micropropagation of Euphorbia milii and studies the effect of certain additives on shoot multiplication. Root induction and the adaptation stage in vitro were studied. Results Nodal stem segments from regenerated shoots were cultured on MS medium containing different levels of benzyladenine (BA) (0, 0.5, 1, 1.5 mg L − 1 ). Regenerated microshoots were cultured on different rooting media including full-strength Murashige and Skoog (MS), ½ MS, ¼ MS and free-MS medium. Organic additives (malt extract, yeast extract and peptone) and phytohormones (salicylic acid, abscisic acid and gibberellic acid) at different concentrations were added to MS medium fortified with 1 mg L − 1 BA. The results showed that 1 mg L − 1 BA was the optimal treatment for shoot multiplication. Full-strength MS medium produced the highest number of roots. In the case of organic additives ‘effect on shoot multiplication, malt extract (400 mg L − 1 ) was produced the highest number of shoots per explant and shoot length followed by yeast extract at 3 g L − 1 concentration. In the case of phytohormones’ effect, abscisic acid (0.5 mg L − 1 ) gave both the highest number of shoots per explant and shoot length, followed by salicylic acid at 2 mg L − 1 . The plantlets were successfully acclimatized by transferring them into a potting mixture of peat moss: sand in equal proportion with 100% survival was observed. Conclusions Stem nodal explants were the optimal source for proliferation and rapid in vitro propagation of Euphorbia milii on a large scale. Different additives had a significant effect on plant growth; especially, malt extract and abscisic acid which are the preferable agents for shoot multiplication. Plants derived from the treatment of 1.0 mg L − 1 BA + 400 mg L − 1 ME showed good growth and flowering performance in nursery pots. These in vitro cultures resulted from the previously studied treatments will be extracted to examine their content of valuable secondary metabolites and antimicrobial potentials for further study.
Girgis et al. (Tue,) studied this question.