Screening of some South African seaweeds for cytokinin-like activity

Abstract

Seven Chlorophyla, two Phaeophyta and eleven Rhodophyta from the KwaZulu-Natal coast (Soulh Africa) were collected on three occasions during 1994 and screened for cytokinin-like activity. Ethanotic extracts were initially purified by cation exchange and paper chromatography. Cytokinin-like activity was detected using the soybean callus bioassay. All species yielded positive results indicating that cytokinin-like activity is widespread in algae. The cytokinin levels in most of the seaweeds were lower than in slems of herbaceous pla nts. Only two of the seaweeds, Valonia macro physa Kutz. and Spyridia hypnoides (Bory) Papenf., consislently yielded cytokinin levels similar 10 those in the dicotyledonous plants used for comparison. Fractionation and tentative identification by HPLC suggested that iso-penlenylad enine-like cytokinins are most abundant in seaweeds. Seawater also gave cytokinin-like activity.