Nuclear division in isolated protoplasts from cells of higher plants grown in vitro.

Protoplasts were isolated from cell suspensions of Haplopappus gracilis. The cell walls were degraded by the cellulase preparation "Onozuka P 1500" at a concentration of 5%. Sorbitol was found to work well as osmotic stabilizer in concentrations of 0.4-0.6 M. The protoplasts were cultured in growth medium after isolation; 3-5% went through nuclear division once and less than 1% also for a second time. No nuclear fusion was observed.