Between light and shade, from young to old: unraveling the dynamics of leaf photosynthesis in the crop canopy

Plants within crop canopies experience constantly changing light conditions-from full sunlight at the top to shade in the lower layers. In addition, leaves age over time. In this PhD research, I studied how these factors influence leaf photosynthesis, including both steady-state and dynamic responses. The results show that leaves at the top of the canopy respond faster to light fluctuations than those in lower layers. I further examined three key factors: light intensity, the red-to-far-red ratio, and leaf age. Among these, leaf age had the strongest effect on the speed of photosynthetic responses, whereas light intensity and the red-to-far-red ratio had smaller effects. These findings improve our understanding of how leaves use fluctuating light under real conditions and may inform the design of more effective greenhouse lighting strategies to enhance crop productivity.