Abstract
Effects Oif adenosdne-3',5'-cyclic monophosphate (cAMP), N6,O2-dibuityryl adenosine-3',5'-cyclic monophosphate (DBcAMP), caffeine and theophylline on the bud-inducing activity of cytokinin in the protonema of two moss species, Ceratodon purpureus and Funaria hygrometrica were examined. The sub-stances have been found ineffective as gametophore bud inducers. Some synergism between cytokinin and cAMP or DBcAMP was observed with relation to the buds' growth, but this effect is nonspecific since it can be obtained with 5'-AMP or 5'-GMiP as well, The results seem to exclude the possibility of an involvement of cAMP as a second messenger in the mechanism of cytokinin action on morphogenetic processes in moss protonemata.