EFFECTS OF STARVATION ON THE METABOLISM OF CHLORELLA

Abstract

Photosynthetic and respiratory activity and certain cellular characteristics of C. pyrenoidosa were studied as a function of time of starvation (0-5 days) in darkness. The rate of photosynthesis under light and CO2 saturation decreased only about 20% during 5 days of starvation. The most marked effect of starvation was the decrease in the rate of endogenous respiration. An initial high rate persisted up to a time corresponding to the disappearance of starch and was followed by a low rate which approached a constant value. It was inferred that only the final rate represents a truly endogenous respiration. Over a 2-day period of starvation the R.Q.''s closely approached values characteristic of carbohydrate metabolism. No evidence for an appreciable lipid metabolism could be found.