Somatic embryogenesis and plantlet regeneration from immature anthers of Opuntia ficus-indica

Abstract

SummaryAn in vitro protocol has been developed for callus induction, somatic embryogenesis, and plant regeneration in the Barbary fig (Opuntia ficus-indica) cultivars ‘Gialla’ and ‘Moore’. Immature anthers cultivated in the dark on induction medium which consisted of Chée and Pool medium containing 2.0 mg l–1 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.5 mg l–1 thidiazuron (TDZ), produced primary nodular and greenish calli within 6 – 8 weeks. Periodic transfer of nodular calli on induction medium in the dark induced the formation of compact embryogenic masses after 4 – 5 months of cultivation, with induction rates of 58.97 ± 1.10% and 61.15 ± 1.16% for ‘Moore’ and ‘Gialla’, respectively. Various distinct stages were observed during the development of somatic embryos on induction medium, including pro-embryogenic, globular, heart-, torpedo-, and cotyledonary-shaped somatic embryos, as well as secondary somatic embryos. Further development of somatic embryos was accomplished using half-strength Murashige and Skoog medium containing 1% (w/v) activated charcoal under a 16-h photoperiod. Bipolarity of the somatic embryos was confirmed by environmental scanning electron microscopy. Regenerated plantlets with well-developed cladodes and roots were transferred to a greenhouse and acclimatised successfully.