[Illumination Burst of CO2 and Carbon Dioxide Inner Reserves in Zea Mays]

When a leaf of maize (Zea mays) is illuminated following a long enough period of darkness (t≃10 min) under pure nitrogen, the oxygen evolution occurs only after a lag time from one to several minutes. During this delay, a burst of CO2 occurs the maximum of which corresponds to the start of oxygen evolution. The source of carbon dioxide is thought to be a stable internal CO2 reserve which has been previously formed in the leaf and is assumed to be malic acid. For as yet unknown reasons the carbon dioxide issued from the reserve by action of light at the beginning of illumination is not fixed and escapes into the atmosphere; this process could require the phytochrome system.