C₄ monocots and C₄ dicots exhibit rapid photosynthetic induction response in contrast to C₃ plants.

Considering the prevalence of ever-changing conditions in the natural world, investigation of photosynthetic responses in C₄ plants under fluctuating light is needed. Here, we studied the effect of dynamic illumination on photosynthesis in totally 10 C₃, C₃-C₄ intermediate, C₄-like and C₄ dicots and monocots at CO₂ concentrations of 400 and 800 μmol mol¹. C₄ and C₄-like plants had faster photosynthetic induction and light-induced stomatal dynamics than C₃ plants at 400 μmol mol¹, but not at 800 μmol mol¹ CO₂, at which the CO₂ supply rarely limits photosynthesis. C₄ and C₄-like plants had a higher water use efficiency than C₃ plants at both CO₂ concentrations. There were positive correlations between photosynthetic induction and light-induced stomatal response, together with CO₂ compensation point, which was a parameter of the CO₂-concentrating mechanism of C₄ photosynthesis. These results clearly show that C₄ photosynthesis in both monocots and dicots adapts to fluctuating light conditions more efficiently than C₃ photosynthesis. The rapid photosynthetic induction response in C₄ plants can be attributed to the rapid stomatal dynamics, the CO₂-concentrating mechanism or both.