Abstract: Protoplasts were isolated from spongy calli in a well growing state. Protoplasts were induced to undergo sustained divisions and to form colonies in the liquid C81V medium supplemented with 2,4-D and kinetin. When protoplast derived colonies were transferred onto agarsolidified medium, the spongy, white calli developed. After being subcultured on N6 medium plus 6BA and IBA, the light-yellow, granular embryogenic calli emerged on the protoplast regenerated callus surface. A large number of plantlets were obtained on MS medium with NAA and IBA via somatic embryogenesis Cytological observation on the donor calli used for protoplast isolation and plantlets regenerated from protoplasts were carried out. Remarkable variation of nucleus morphology and chromosome numbers were observed in donor calli. However, the cytological abnormalities in plantlets regenerated from protoplasts were comparatively less seen. The reason are discussed.

Key words: Levisticum officinale Koch, Protoplast culture, Sometic embryogenesis, Plantlet regeneration, karyological variation