C 4 monocots and C 4 dicots exhibit rapid photosynthetic induction response in contrast to C 3 plants.

Considering the prevalence of ever-changing conditions in the natural world, investigation of photosynthetic responses in C 4 plants under fluctuating light is needed. Here, we studied the effect of dynamic illumination on photosynthesis in totally 10 C 3 , C 3 -C 4 intermediate, C 4 -like and C 4 dicots and monocots at CO 2 concentrations of 400 and 800 μmol mol -1 . C 4 and C 4 -like plants had faster photosynthetic induction and light-induced stomatal dynamics than C 3 plants at 400 μmol mol -1 , but not at 800 μmol mol -1 CO 2 , at which the CO 2 supply rarely limits photosynthesis. C 4 and C 4 -like plants had a higher water use efficiency than C 3 plants at both CO 2 concentrations. There were positive correlations between photosynthetic induction and light-induced stomatal response, together with CO 2 compensation point, which was a parameter of the CO 2 -concentrating mechanism of C 4 photosynthesis. These results clearly show that C 4 photosynthesis in both monocots and dicots adapts to fluctuating light conditions more efficiently than C 3 photosynthesis. The rapid photosynthetic induction response in C 4 plants can be attributed to the rapid stomatal dynamics, the CO 2 -concentrating mechanism or both.