RAPID AND SIMPLE ASSAY OF THE VIABILITY OF CRUSTOSE CORALLINE ALGAE

Viability of crustose coralline algae was measured using three oxidati on-reduction indicators: 2,3,5-triphenyl tetrazolium chloride (TTC), 3 -(4,5-dimethyl-tiazolyl-2)-2,5-diphenyl tetrazolium chloride (MTT) and alamar blue. The two tetrazolium salts, TTC and MTT, were reduced to form colored formazan in living corallines, but were not reduced in de ad corallines. These formazans were extracted and quantified spectroph otometrically. Bluish violet MTT-formazan could be distinguished easil y from red phycoerythrin and was useful for judging the viability of c rustose corallines. Alamar blue indicated the viability visually and s pectrophotometrically by changing the color of the culture medium. The alamar blue assay did not cause any damage to the growth of crustose corallines, indicating that it is suitable for estimating the viabilit y of an individual plant over time. These results suggested that MTT a nd alamar blue can be used for rapid and simple assay in ecological an d physiological investigations for crustose corallines.