EFFECT OF ORGANIC COMPOUNDS ON PHOTOSYNTHETIC OXYGENATION .1. CHLOROPHYLL DESTRUCTION AND SUPPRESSION OF PHOTOSYNTHETIC OXYGEN PRODUCTION

This paper describes the inhibition of chlorophyll synthesis and the destruction of chlorophyll in Chlorella pyrenoldosa due to the presence of selected organic compounds. Emphasis in Part I is directed toward an explanation of laboratory techniques and an evaluation of changes in photosynthetic oxygen production due to the addition of selected compounds. In Part II, which will follow the influence of certain organic compounds on the design of waste stabilization ponds will be considered. Changes in extractable chlorophyll concentrations are presented in terms of exposure time and concentration of chemical additives. Selected algal cultures were grown for a test period of 72 hr in test tubes under constant temperature conditions, with continuous illumination, and under controlled nutrient supplies. Under such conditions the chlorophyll content decreases markedly in relation to the concentration of the organic additive. For the compounds evaluated, the chlorophyll reduction seems to be a function of the substituted groups and their relative positions. Also, a direct manometric technique is described for measurement of photosynthetic gas exchange. Results show that oxygen production is suppressed by chlorinated and nitrated phenols. © 1968.