The Effect of Subjecting Peas to Air Enriched with Carbon Dioxide: I. THE PATH OF GASEOUS DIFFUSION, THE CONTENT OF CO2AND THE BUFFERING OF THE TISSUE

The intake of oxygen by an isolated pea was shown to be entirely through the micropyle; the loss of CO2 was about two-thirds via the micropyle and the rest through the cuticle. The internal atmosphere of a pea in air contains about 11 per cent CO2 v/v. Peas transferred from air to CO2 in air mixtures required nearly 24 h for their internal CO2 content to come to equilibrium. The increase in internal CO2 content was found to be balanced by a decrease in the content of malic acid and the pH of the tissue changed little. On return to air the changes were reversed. Slices of cotyledons in water apparently maintained their pH by loss of cations rather than change in malate content.