Mutagenesis of cultured plant cells.

Experiments were designed to study the effectiveness of the chemical mutagens ethylmethane sulfonate and nitrosoguanidine on plant cells growing in liquid suspensions. Mutation frequency was defined as the number of colonies appearing on selective plates divided by the number of colonies growing on non-selective plates. The compounds tested usually increased mutation frequency by one order of magnitude over the spontaneously occurring rate, although the increase ranged from one to 140-fold. Cell killing was found to be directly correlated with mutation frequency.