For humans, light reacts with the short, medium, and long photoreceptors in the eyes, allowing us to see colors. For plants, light reacts with chlorophyll and plant pigments to promote growth. For example, the chlorophyll absorption curve is mainly responsible for photosynthesis to promote plant growth. Plant pigments are sensors of plants that respond to the environment and adjust their shape.
The metrics of human vision cannot be applied to plant lighting because the lighting indicators of plants are essentially based on photons. For example, photon flux (PF) measures the number of photons emitted from a light source in μmol/s, while photon flux density (PFD) measures the number of photons reaching plants. Unless artificial LED lights are also used as conventional lighting sources, color attributes such as color rendering index (CRI) and correlated color temperature (CCT) are no longer relevant for plant lighting.
