Studies on the hormonal relationships of algae in pure culture : III. Tryptamine is an intermediate in the conversion of tryptophan to indole-3-acetic acid by the blue-green alga Chlorogloea fritschii.

In an earlier communication of this series (Ahmad and Winter, 1968b), we described the effect of potential precursors of Indole-3-Acetic acid (IAA) on the growth of several freshwater blue-green algae. It was reported that the growth of Chlorogloea fritschii was significantly pro moted by the addition of tryptophan into the basal medium at a hormonal concentration. We suggested that this alga may be capable of converting tryptophan to IAA. It is the purpose of this communica tion to present evidence for the conversion of tryptophan to IAA via tryptamine by the blue-green alga Chlorogloea fritschii.