Photosynthesis and air movement
Plants interact with their microclimate, simultaneously responding to and influencing it. A key element in this interaction is the leaf boundary layer: a stagnant air layer enveloping the leaf, creating a resistance to heat and gas exchange. Its thickness, altered mainly by airflow and leaf morphology, determines the leaf-to-air interaction. Field crops experience wind speeds of 0–8 m/s at the canopy top, with wind gusts up to 20 m/s, but wind speeds drop significantly within the canopy, creating localized low-airflow conditions. Conversely, indoor-grown crops always encounter low wind speeds (0–1 m/s) and these, especially with larger leaves, restrict heat and gas exchange, impacting photosynthesis and transpiration. Although the effect of the leaf boundary layer on plant exchange processes has been defined, its magnitude remains poorly characterized and is frequently underestimated.
Model predictions and literature data demonstrate that low boundary layer results in a complex interplay with a large impact on leaf microclimate and limitation of photosynthesis of up to 23%, which depends on stomatal sensitivity to the microclimate, photosynthetic capacity, and the temperature response.
