RELATIONS BETWEEN PIGMENT CONTENT AND PHOTOSYNTHETIC CHARACTERISTICS IN A BLUE-GREEN ALGA

Abstract

The blue-green alga Anacystis nidulans was cultured under steady state conditions at 25 and 39[degree] C and under several different light intensities to give 5 different types of cells. Cells were submitted to pigment analysis based upon acetone extracts and aqueous extracts obtained by sonic disintegration. The different cell types show a 3-fold range of chlorophyll content and a 4-fold range of phycocyanin content with only minor changes in the chlorophyll/phycocyanin ratio. Cells of highest pigment content were estimated to contain 2.8% chlorophyll a and 24% phycocyanin, the latter on a total chromoproteid basis. Light intensity curves of photosynthesis were obtained for each of the cell types at 25 and 39[degree] C. The slopes of the light-limited regions of the curves are approximately linear functions of chlorophyll and phycocyanin contents. Maximum light-saturated rates of photosynthesis at 25 and 39[degree] C show no simple relation to pigment content.