Photosynthetic mechanism of maize yield under fluctuating light environments in the field.

The photosynthetic mechanism of crop yields in fluctuating light environments in the field remains controversial. To further elucidate this mechanism, we conducted field and simulation experiments using maize (Zea mays) plants. Increased planting density enhanced the light fluctuation frequency and reduced the duration of daily high light, as well as the light-saturated photosynthetic rate, biomass, and yield per plant. Further analysis confirmed a highly significant positive correlation between biomass and yield per plant and the duration of photosynthesis related to daily high light. The simulation experiment indicated that leaf area and photosynthetic rate of maize leaves decreased gradually and considerably when shortening the daily duration of high light, while the quantum yield of regulatory energy dissipation decreased slightly. Under an identical duration of high light exposure, increasing the fluctuation frequency decreased leaf area and the light-saturated photosynthetic rate slightly and increased the quantum yield of regulatory energy dissipation distinctly. Proteomic data also demonstrated that photosynthesis was mainly affected by the duration of high light, not the light fluctuation frequency. Consequently, the current study proposes that an appropriate duration of daily high light under fluctuating light environments is the key factor for greatly improving photosynthesis while the regulatory energy dissipation changes slightly in maize plans. This is a promising mechanism through which to enhance the photosynthetic productivity and yield of maize under complex light environments in the field.