Efficient regeneration of carnation (Dianthus caryophyllus L.) via somatic embryogenesis

An efficient method of somatic embryogenesis and plant regeneration from callus cultures of four cultivars of carnation (Nelson, Sagres, Spirit, and Impulse) was established. Embryogenic calli were produced on MS culture medium containing 3% sucrose (w/v), 2.0 mg l(-1) 2,4-D and 0.2 mg l(-1) BA. Induction of embryogenic callus occurred only on petal explants, whereas the calli produced from leaf, sepal, receptacle and style explants were not embryogenic. Lower (0.5 and 1 mg l(-1)) and higher (6 mg l(-1)) concentrations of 2,4-D suppressed the formation of embryogenic callus. An interaction between sucrose and 2,4-D was found on the induction of embryogenic callus. Somatic embryos were formed when the embryogenic calli transferred on MS medium containing 3% sucrose alone or supplemented with different concentrations of mannitol (1.5, 3, 6, 9, 12 and 15%) without growth regulators. No somatic embryo was formed on the culture media containing mannitol without sucrose. Number of somatic embryos was significantly increased by adding mannitol to the culture media. Embryogenic calli were maintained for more than 1.5 years without apparent loss of regeneration capacity. 95% of somatic embryos were regenerated to form entire plantlets when they were transferred onto the half-strength MS culture medium containing 3% sucrose. Plantlets also continued to grow under greenhouse condition.