THE EFFECT OF LIGHT QUALITY ON THE PRODUCTS OF PHOTOSYNTHESIS IN GREEN AND BLUE-GREEN ALGAE, AND IN PHOTOSYNTHETIC BACTERIA

Abstract

The effect of light quality on the products of photosynthesis has been studied in two species of green algae, Chlorella pyrenoidosa and Scenedesmus acuminatus, the blue-green alga Microcystis aeruginosa, and the photosynthetic bacterium Chromatium sp.The test organism was placed in C14-bicarbonate and illuminated at saturation intensities of red, red plus supplementary blue, blue alone, or white light. After 30 minutes, the distribution of C14among the products of photosynthesis was determined using the techniques of paper chromatography and autoradiography.At a high concentration of cells of Chlorella pyrenoidosa, blue light caused an increase in C14in aspartic, glutamic, fumaric, and malic acids and a decrease in sucrose and phosphate esters, although the rate of photosynthesis remained the same. At a low concentration of cells, similar changes were found, and these were accompanied by an increase in the rate of photosynthesis.Similar changes in the distribution of C14due to blue light were found also in Scenedesmus. In Microcystis, a substantial increase in C14due to blue light was found only in glutamic acid. The rate of photosynthesis remained the same in both organisms.The results indicate that the nature of the effect of blue light is the same in all of these organisms and in Chlorella vulgaris which was studied previously.Pretreatment in darkness is a prerequisite for a pronounced effect of blue light on the products as well as the rate of photosynthesis.No effect of light quality was found in Chromatium.