Abstract
An increase in the activity of peroxidases under the influence of kinetin has been demonstrated in the protonema of the moss Ceratodon purpureus. It was connected above all with initiation and acceleration of the differentiation process of gametophore buds which showed a high activity of these enzymes. The increase in peroxidase activity was also noted in the degenerating intercalary cells which produced the buds. The colour reaction characteristic for peroxidases was best noticeable in the minute spherical granules (peroxysomes), nucleoli and cell walls.