Somatic embryogenesis in sawara cypress (Chamaecyparis pisifera Sieb. et Zucc.) for stable and efficient plant regeneration,propagation and protoplast culture

Somatic embryogenesis inChamaecyparis pisifera was initiated from immature seeds collected from the end of June to early July. We obtained initiation frequencies ranging from 12.5 to 33.3% using whole seed explants in liquid media. Embryogenic cultures were maintained and proliferated for more than a year in solid and liquid media. High maturation frequencies of ‘high quality’ embryos were obtained on maturation media containing abscisic acid (ABA), activated charcoal (AC), and polyethylene glycol (PEG) as osmotic agent. More than one thousand cotyledonary embryos on average per 100 mg initial fresh weight of embryogenic cells were attained on medium containing 100μM ABA, 2 gL⁻¹ AC, and 150 gL⁻¹ PEG. About 97% germination frequencies and 92% plant conversion rates were achieved without any pretreatment. Growing of plants regenerated from somatic embryos has been monitored in the field. Furthermore, a procedure for culture of protoplasts isolated from embryonal masses was also described. This work was supported in part by the Japan Science and Technology Corporation and in part by a Grant for Research for the Future Program from the Japan Society for Promotion of Science.