Abstract:

A reproducible protocol for somatic embryogenesis was established for the ornamental ginger Hedychium coronarium. Immature filaments were cultured on Murashige and Skoog（MS）medium supplemented with 4 mg · L^-1 2,4-D，4 mg · L^-1 NAA，1 mg · L^-1 6-BA. After culture for 180 days，three types of callus were obtained，type Ⅰcallus were light yellow and friable with tightly packed cell contained dense cytoplasm that appeared to be embryogenic；type Ⅱ callus were white with long，highly vacuolated cells that appeared to be non-embryogenic；type Ⅲ callus were yellow with large，less packed cells contained dense cytoplasm that appeared to between embryogenic and non-embryogenic. Medium containing 1 mg · L^-1 2,4-D，0.25 mg · L^-1 NAA，0.25 mg · L^-1 6-BA was suitable for embryogneic callus proliferation. Embryogenic calli were cultured on somatic embryo induction medium containing MS basal salts，vitamin B₅，100 mg · L^-1 glutamine，230 mg · L^-1 proline，100 mg · L^-1 malt extract，0.25 mg · L^-1 NAA，0.5 mg · L^-1 TDZ，45 g · L^-1 sucrose and 7 g · L^-1 agar for 20 days，then transferred on MS medium free hormone for 30 days. About 50–60 somatic embryos were induced from per gram callus. Germination percentage of 85% were observed in germination medium，which consisted of MS basal salts，0.2 mg · L^-1 NAA and 0.5 mg · L^-1 6-BA. Regenerated plantlets with normal shoot and root were developed after 30 d on half strength MS medium with 1 g · L^-1 active charcoal. Well rooted plantlets were successfully acclimatized with a survival rate of 90% and grew vigorously. The chromosome number of 100 regenerated plants showed a wide range of variation，89 of them were diploid（2n = 2x = 34），3 were triploid（2n = 3x = 51），6 were tetraploid（2n = 4x = 68）and 2 were hexaploid（2n = 6x = 102）.

Key words: Hedychium coronarium, embryogenic callus, plant regeneration