The Fluorescence of Chloroplasts and Chlorella in Relation to Their Photochemical Activity

摘要

1. The fluorescence of chloroplasts was found to increase as the temperature was lowered. The activation energy was -2.3 kcal.n2. The effect of incubation of chloroplasts at temperatures up to 30° C. was found to be highly variable. Most preparations shoved a decline in fluorescence but some showed no such decline. Ethyl carbamate was found to accelerate the decay of fluorescence of incubated chloroplasts. Other carbamates were without effect.n3. The pH of the suspending media had a marked effect on the fluo¬rescence of chloroplasts. The fluorescence was found to go through a maximum at pH 5.5 and minima at pH 5 and pH 8.n4. The relative fluorescence yield of chloroplasts was measured as a function of incident light intensity. The fluorescence was found to approach an upper limit as the light intensity was increased and a lower limit greater than zero as the light intensity was decreased.