Protoplasts from Platycodon grandiflorum and Codonopsis lanceolata were isolated and cultured as a fundamental experiment for the production of their somatic hybrid. Source material used were in vitro cultured leaves and callus for P. grandiflorum. and fully expanded young leaves of the plants raised in the greenhouse and callus for C. lanceolata.
In shoot tip culture of P. grandiflorum, the MS medium supplemented with 1㎎/ℓ BA was most effective to induce multiple shoots. Callus was induced from stem segment culture of P. grandiflorum and C. lanceolata. Shoot differentiation was observed from C. lanceolata calli on the media containing NAA, indicating the need of supplementing NAA to media for differentiation.
Callus production was better on the media supplemented with 1㎎/ℓ each of 2.4-D and BA than on the media in which 2.4-D was substituted by NAA, but the protoplast yield was much better from the callus cultured on the latter media.
For protoplast isolation from P. grandiflorum and C. lanceolata, the enzyme mixture of CPW, 0.5% Macerozyme, 1% Cellulase R-10 and 0.7M mannitol, adjusted at pH 5.8∼6.8 was found to be suitable for leaf mesophyll, but higher concentrations of 2∼3% Cellulase R-10 were required for callus. Incubation for 3∼6 hours for P. grandiflorum and 6 hours for C. lanceolata appeared to be optimum.
The protoplasts of P. grandiflorum, when cultured, failed to regenerate, but sustained their original shape for 12 to 18 days. Meanwhile the protoplasts of C. lanceolata regenerated into cells and divided for 2 to 20 days after inoculation to form cell colonies.
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