THE PHOTOCHEMICAL REACTION IN PHOTOSYNTHESIS.

Measurements of photosynthesis were made in continuous and flashing light of high intensity, using cells varying in chlorophyll content. The amount of chlorophyll present per molecule of carbon dioxide reduced per single flash of light was found to be about 2480 molecules. The length of time required for one unit in the photosynthetic mechanism to complete the cycle of photochemical and Blackman reactions was found to be about 0.02 sec. at 25 degrees C. The equation R = AIN was shown to give a good description of the rate of the photochemical reaction, when A is a velocity constant, I the intensity of light, and N the number of units in the photosynthetic mechanism.