Effect of sucrose concentrations on somatic embryogenesis in carnation (Dianthus caryophyllus L.)

The effect of sucrose concentration on callus induction followed by differentiation of embryogenic callus derived from petal explants of four carnation cultivars (Nelson, Sagres, Spirit and Impulse) was investigated. Embryogenic calli were produced on Murashige and Skoog [Murashige, T., Skoog, F.A., 1962. Revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant 154, 73–479] basal medium (MS) culture medium containing six concentrations of sucrose (3, 6, 9, 12, 15 and 18%, w/v) all supplemented with 9 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.8 μM 6-benzyladenine (BA). Maximum frequency of embryogenic callus was obtained from the media containing 9 and 12% sucrose. Somatic embryos were induced on a hormone-free MS media containing the seven concentrations of sucrose. Development of somatic embryos was enhanced by increasing sucrose concentration from 1.5 to 12%, while it was reduced in higher concentrations of 15 and 18%. However, normal embryos were not developed in the media containing 1.5 and 3% sucrose. Ninety-five percent of somatic embryos were regenerated to form the entire plantlets when they transferred onto the half-strength hormone-free MS culture medium containing 3% sucrose. Plantlets were also continued to grow normally under greenhouse condition.