Zur Mutagenit�t von Urethanen

By making a tongue-slit in the shaft of the inflorescence ofArabidopsis thaliana 7 different urethanes (1/200 mol+1/200 mol KCl) were forced into the buds through the transpiration stream. After this treatment with 6 of these substances the frequency of the monohybrid segregating mutations was significantly raised 5- to 10times over the control as determined by seedling tests. The mutation frequency was positively correlated with the size of the urethan molecule and seemed to be little affected by its chemical substitution. The mutants were of the same type than those obtained after irradiation with X-rays. These results are in agreement with the conception that the mutagenic effect of the urethanes is indirect and probably due to general disturbances of different metabolic processes in the cell.