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.
(© 2024 The Author(s). Physiologia Plantarum published by John Wiley & Sons Ltd on behalf of Scandinavian Plant Physiology Society.)