GROWTH OF PLANT CELL CULTURES. I. ISOLATION OF CULTURES, SELECTION OF MEDIA, AND EFFECTS OF FREQUENCY OF TRANSFER

Callus structures were isolated from a number of edible plants and maintained on simple defined media for extended periods. Growth rates are slow in comparison to other microbial systems, and increase tends to be linear. Static cultures on solid media double in 5-10 days, yield up to 0.26 mg dry weight per ml per day, and attain a maximum weight of about 12 mg dry weight per ml. Suspension cultures double in 2-5 days, yield up to 1.1 mg dry weight per ml per day, and attain a maximum weight of about 23 mg dry weight per ml. These growth rates are of the same order of magnitude as those for higher plants growing conventionally. Considerable improvements in these growth rates will be required before use of plant cell cultures as food can be realized economically.