Researchers Show the cause of Productivity Loss in the Fluctuating Light of Maize Crop Canopies

A team from the University of Illinois has measured the dynamic leakiness of CO₂ from C4 plants. Previous studies had measured the leakiness under steady-state conditions, but this group took the measurements to prove that leakiness can and should be measured as a dynamic parameter.

"Last year, we predicted that during photosynthetic induction, C4 cycle activation is faster than the Calvin-Benson cycle, which would cause more CO₂ leaking, but we didn't have any evidence," said Yu Wang, a postdoctoral researcher at Illinois, who led this work for a research project called Realizing Increased Photosynthetic Efficiency (RIPE). "Now our results prove it's real. We have the first measurements of the leakiness under dynamic conditions."

While the group's previous prediction, published in the Plant Journal last year, was a proven concept, these first-of-their-kind measurements show that their modeling of the C4 and C3 photosynthetic cycles are accurate. Their recent work, studying sorghum and maize, was published in New Phytologist.

"Our research shows that during photosynthetic induction, the activation of C4 cycle is faster than the Calvin-Benson cycle," said Wang. "This is why leakiness is higher for the first several minutes after the light comes on."