Gibberellin- and cytokinin-like activities in marine algae from central Mediterranean.

The distribution of gibberellin- and cytokinin-like activities in twenty-one species of mediterranean algae belonging to Phaeophyta and Rhodophyta has been investigated. Fractions containing each of these activities have been obtained by partitioning aqueous-methanolic extracts of algae against ethyl acetate and butanol successively at different pH values. The stimulation or inhibition of amaranthin synthesis in Amaranthus sp. seedlings have been used a biological tests to assay the cytokinin- or gibberellin-like activities respectively. One or both these two hormonal activities have been detected in all species examined. While cytokinin-like activity has been found with the same frequency in the two phyla, the gibberellin-like activity was less frequent in Phaeophyta.