Leaf anatomy, post-illumination CO2 burst and NAD-malic enzyme activity of Panicum dichotomiflorum1

Light microscopic observation of leaf blades of Panicum dichotomiflorum showed that a mestome sheath was present and chloroplasts in bundle sheath cells were in the centrifugal position. However, a sharp pattern of post-illumination CO2 burst was observed in less than 30 sec after the extinction of light. Among three C4-acid decarboxylating enzymes, only the activity of NAD-malic enzyme was high. These results indicate that P. dichotomiflorum is a NAD-malic enzyme type species having centrifugal chloroplasts in bundle sheath cells and the sharp pattern of post-illumination CO2 burst is closely correlated with the C4-acid decarboxylation system through NAD-malic enzyme