A STUDY OF THE PIGMENTS PRODUCED IN DARKNESS BY CERTAIN GREEN ALGAE

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Abstract
Chlorella vulgaris and Protococcus sp. were grown on large agar flats in darkness and in light. Pigments were extracted by a modification of the Mudd low-temp. ball-mill technique. A cell suspension was rapidly frozen at [long dash]80[degree] in a metal ball-mill, desiccated under low pressure, ground at [long dash]80[degree], and extracted with 90% acetone at room temp. Spectral absorption curves of the total and non-saponifiable pigments in ether soln. were detd. with a photoelectric spectrophotometer. No significant qualitative differences were found between the pigments produced in darkness or in light. The production of chlorophyll b in darkness by Protococcus was confirmed by the prepn. of sucrose chromatograms. The induction period of photosynthesis shown by Chlorella cultured in liquid media in darkness and in light was studied by the Warburg technique. The induction after several hrs. dark rest shown by cells grown in light is not appreciably different from that shown by cells grown in continued darkness. The pigments formed in darkness by this strain of C. vulgaris are con- sidered adequate for photosynthesis. From a comparison with other data in the literature on the induction period, it is suggested that there is a dissimilarity between the induction in O2 evolution and the induction in CO2 uptake.