Plant regeneration of mesophyll protoplasts from axenic potato (Solanum tuberosum L.) shoot.

Mesophyll protoplasts from commercial potatoes were cultured in shallow liquid media. The regenerated cells divided and formed calli. Regenerant plants of two potato lines (Ke Xin 4; 68-62) were obtained from the regenerated calli after transfer to solid medium. The division frequency of the regenerated cells was influenced by culture protoplast density. Growth of the protoplast-derived colonies was sensitive to sucrose concentration in the liquid medium. The protoplast culture medium obviously affected differentiation frequency for the protoplast-derived calli (P-calli). The P-callus differentiation frequency was raised by supplementing the medium with 3% mannitol, which also shortened the P-callus differentiation.