Light use efficiency

The potential yield is the product of (photosynthetic) light energy uptake of a crop and its light use efficiency (LUE).  Light use efficiency of a plant canopy is determined by the photosynthetic rates of the individual leaves and the canopy structure, which controls light distribution over the canopy and is characterized by the light extinction coefficient. The photosynthetic rate of a leaf depends on its photosynthetic capacity and the availability of CO2 in the mesophyll. The rate of CO2 transport into the mesophyll depends on stomatal conductance and atmospheric CO2 concentration, which can be controlled by the grower. The photosynthetic capacity is mainly determined by the capacity of the biochemical apparatus, Vcmax, and capacity of the electron transport chain, Jmax.

Plants exchange gases like carbon dioxide, oxygen and water vapor through their stomata with the environment: . Depending on the CO2 concentration in the atmosphere, which can be controlled in the greenhouse by enrichment from gas tanks or heaters. The stomatal conductance is controlled by light, the CO2 content and the water vapor pressure of the atmosphere, and plant water status

Figure: Determinants of light interception efficiency and light use efficiency
Figure: Determinants of light interception efficiency and light use efficiency