Initiation and proliferation of carrot callus using a combination of antibiotics.

Calli were initiated from carrot (Daucus carota L. subsp. sativus Hoffm.) root expiants and grown on media supplemented with a combination of carbenicillin at 0.3 mg/ml and vancomycin at 0.1 mg/ml in the absence of plant hormones or hormone analogs. The growth rate was about half of that obtained with a combination of α-naphthaleneacetic acid and N(6)-benzyladenine at 1 mg/l each. Carbenicillin in the combination with vancomycin could be replaced by penicillin G; other penicillins tested in this combination, however, caused only limited growth. The calli produced can be grown on media supplemented with α-naphthaleneacetic acid and N(6)-benzyladenine, but not on media without the antibiotics and the plant growth substances. Calli obtained using the plant growth substances can also be subcultured on media supplemented with only the antibiotics.