Cell-Suspension Culture of Maize ( Zea mays L.)

A shake flask culture was established from maize (hybrid C 103 X W 155) callus initiated at nodal and internodal stem segments and maintained in the medium containing the inorganic constituents of Murashige and Skoog (1962), 20 g/l sucrose, 0.4 mg/l thiamine, 1 g/l casein hydrolysate and 1 mg/l 2,4-D. Small aggregates that lacked inner organization were predominant in the suspension. Cells were of a parenchyma-type, mostly round-shaped, and their sizes were distributed in log-normal pattern (the mean diameter 40-50 µ). The exponential growth in the batch-grown culture lasted to 4th-5th day, the transition to the stationary phase took place during the 5th-6th day, and after the 9th day a considerable degradation was observed in the culture. Doubling periods for the cell number, and dry matter and protein during the exponential growth were about 28 h at 26 °C, and the total increase was at least 15-fold during the 7-day subculture cycle. Respiration rate on the fresh weight, protein and cell basis was constant from the 1st to the 6th day and then declined 2-fold, however, it was completely restored during the first 12 h after cell transfer to the fresh medium.