Autoradiographic analysis of the effect of cytokinin on protein and RNA syntheses in the Ceratodon purpureus protonema

Abstract

In the protonema of Ceratodon purpureus (Hedw.) Brid., apical parts of the protonemal filaments (apical cells, initials of protonemal side branches and of gametophore buds) proved to be preferential sites of [14C]-leucine incorporation into proteins. In some filaments, a similar preference for [3H]-uridine incorporation into RNA was observed, whereas in others there was a rather uniform distribution of label over all cells. A short (0.5-2 h) treatment with cytokinin (N6-2-isopentenyladenine) enhanced [14C]-leucine incorporation, without changing the relative distribution of label. No such enhancement, as well as no change in label distribution could be observed in [3H]-uridine incorporation. No direct relationship seems to exist between the early promotion of protein synthesis by cytokinin in the protonema and cytokinin induction of gametophore buds.