Stomatal resistance in different gases.
Modern porometers measure the rate at which water vapour diffuses out of leaves. The stomatal resistance can be deduced directly from this measurement. However, the resistance will vary with the ambient gas in the porometer, and N2O has been used in a porometer. Calculations and experimental measurements of stomatal resistance in leaves of wheat cv. Kleiber in N2O and in He were compared to that in air. The stomatal resistance measured in N2O can be converted to that in air by dividing by 1.3.