A Direct Confirmation of the Standard Method of Estimating Intercellular Partial Pressure of CO2

摘要

The partial pressure of CO2 inside leaves of several species was measured directly. Small gas exchange chambers were clamped above and below the same section of an amphistomatous leaf. A flowing gas stream through one chamber allowed normal CO2 and water vapor exchange. The other chamber was in a closed circuit consisting of the chamber, an infrared gas analyzer, and a peristaltic pump. The CO2 in the closed system rapidly reached a steady pressure which it is believed was identical to the CO2 pressure inside the leaf, because there was no flux of CO2 across the epidermis. This measured partial pressure was in close agreement with that estimated from a consideration of the fluxes of CO2 and vapor at the other surface.