The Diffusion of Carbon Dioxide and Water Vapour through Stomata

An account is given of the diffusion of carbon dioxide and of water vapour through the stomata of leaves in the presence of air. It shows that the argument given in K. J. Parkinson and H. L. Penman's paper (1970): ‘A Possible Source of Error in the Estimation of Stomatal Resistance’ is substantially incorrect. However, the correction factors to the sugar beet data presented in their paper are valid owing to a fortuitous set of circumstances including the similarity in magnitude of two mutual diffusion coefficients. The concept of stomatal resistance is criticized.