STUDIES ON GAS EXCHANGE IN BRYOPHYLLUM DURING LIGHT PERIOD .I. ON PROBLEM OF CO2 EVOLUTION

1. Leaves of Bryophyllum daigremontianum without epidermis on the abaxial side evolved 14CO2 in light after they had fixed radioactive carbon dioxide in the dark. The efflux of 14CO2 in light exactly follows the net evolution of CO2 measured by infrared gas analyser. The source of carbon dioxide liberated in light was found to be malate formed in the dark period by dark fixation. 2. In light as well as in dark uptake and evolution of CO2 may occur simultaneously, indicating that there could be a compartmentation of CO2 metabolism in the leaf cells which allows CO2 production and consumption to occur independently of one another. © 1968 Springer-Verlag.