Guri, A., Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50 250, Israel
Zelcer, A., Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50 250, Israel
Izhar, S., Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50 250, Israel

Significantly higher than normal mitotic index (MI) values were induced in Petunia cell suspensions following treatments with colchicine, aphidicolin, drastic medium replacement, or a sequential application of aphidicolin and colchicine. This last treatment yielded the highest MI values: cells incubated with 30 μg/ml aphidicolin for 18 h, then cultured in drug-free medium for 8 h and finally exposed to 0.1% colchicine for 8 additional hours exhibited MI of 62.8% and 65.7% respectively, for the two cell lines in study. © 1984 Springer-Verlag.