Evidence for C4 photosynthesis in barley pericarp tissue

The products of photosynthetic carbon dioxide fixation were determined in isolated pericarps of immature barley grains. Of the carbon dioxide fixed after 1 min photosynthesis 84% was in the C4 acid malic acid. The remaining label was in hexose phosphates and sucrose. By 2 min sucrose was the major labelled product and at 6 min accounted for 94% of the total carbon dioxide fixed.