Influence of Air Flow Rates on Photosynthesis and Respiration of Poplar Leaves under Various Environmental Conditions

Abstract

The effect of air flow rate on the rate of CO₂ exchange of leaves either in the light or in the dark was studied under the various environmental conditions. The efficiency of air flow rate on photosynthesis was not so affected by temperature in the air surrounding the leaf but was greatly enhanced by increasing light intensity. The rate of CO₂ evolution in the light was stimulated by the higher rate of air flow by disturbing the reabsorption of the evolved CO₂ at the boundary layer of the leaf surface, while the rate of CO₂ evolution in the dark was not influenced by the rate of air flow because of the lack of the reabsorption. The CO₂ compensation point was also independent of the rate of air flow. Since the supply of CO₂ for photosynthesis at the compensating point of CO₂ was derived from the intracellular evolution of CO₂ by respiration, the CO₂ compensation point was not influenced by the rate of air flow.
The role of air flow rate for photosynthesis was proposed to be the supply of CO₂. The estimation of the supply of CO₂ for the leaf was done by multiplying CO₂ concentration by the triple root of air flow rate.