title: Oxygen and carbon dioxide exchanges in crassulacean-acid-metabolism-plants.
abstract: The 24 h O2 uptake and release together with the CO2 balance have been measured in two CAM plants, one a non-succulent Sempervivum grandifolium, the other a succulent Prenia sladeniana. The O2 uptake was estimated by the use of (18)O2. It was found that the mean hourly O2 uptake in the light was 7 times that in the dark for Sempervivum and 5 times that for Prenia, after correction for the lightdark temperature difference. It was estimated that oxygen uptake in the light was 2.4 times greater than oxygen release (=net photosynthesis) in Sempervivum and 1.4 times greater in Prenia. In both plants there was a positive carbon balance over the 24 h period under the experimental conditions. It was estimated that malate formed during the night could, if completely oxidized to CO2 and water, account for 74% of the light phase O2 uptake in Sempervivum. In Prenia the O2 uptake was more than sufficient to account for a full oxidation of malate.
authors: Département de Biologie, Service de Radioagronomie, CEN Caderache, B. P. No. 1, F-13115, Saint-Paul-les-Durance, France.
authors: M
authors: M
authors: André
authors: D A
authors: DA
authors: Thomas
authors: D J
authors: DJ
authors: von Willert
authors: A
authors: A
authors: Gerbaud