Another advantage of a CCM in a land plant such as the Anthocerotae would be to reduce the oxygenase reaction in the enzyme Rubisco by elevating the CO2 Concentration around its active site, reducing competition from oxygen. The unique chloroplast architecture of the more “advanced” Anthocerotae posses thylakoids that cross the pyrenoid, termed channel thylakoids, Burr (1970), which have been speculated (through inference from work with algae) by Makay & Gibbs (1991) to be dominant in photosystem I and not Photosystem II (water splitting side of the light reaction, releasing oxygen), therefore reducing further oxygenation events.
