The Influence of CO2 on the Metabolism of Rhizome Tissue in Iris pseudacorus

In vitro experiments showed that concentrations of CO2 above 6 per cent inhibited succinate oxidation; 30–10 per cent of succinate oxidation may be blocked in the presence of 12 per cent CO2. Storage of rhizome cores in CO2 increased the levels of all the main acids except malic. The amino acids, aspartate, glutamate and alanine, also increased in amounts under these conditions. Cores fix CO2 probably via the reaction phosphoenolpyruvate to oxaloacetate. Raised CO2 levels increased the rate of diminution of carbohydrate, but carbon itself was conserved due to a reduction in CO2 output.