Effects of Light and Darkness on Gaseous Exchange of Bean Leaves

Abstract

rate of respiration of chlorophyllose tissue in the light. The results of these experiments have varied with the experimental technique employed and the process, CO2 evolution or 02 consumption, being measured. Early work by Brown and associates (2,19) indicated that respiratory rates of Chlorella and several vascular plants were identical in light and darkness. Decker (5) has questioned the interpretation of these results, and in his own work with tobacco (Nicotiana lacngsdorfii and N. sanderae) has reported CO2 production in the light to be greater than in the dark (4). Subsequently Brown and Weis (3) and Weis and Brown (23) derived equations for correcting respiratory rates of algae measured in the gaseous phase of Warburg vessels to make them correspond to rates which prevail in the liquid phase. These equations are based primarily on the relative diffusion barrier to 02 and CO2 presented by the gas-liquid interface. Use of these equations resulted in substantially lower values for respiration rates. Values for CO2 evolu