Green light is considered the least efficient wavelength in the visible spectrum for photosynthesis, but it is still useful in photosynthesis and regulates plant architecture.
Posted on February 6, 2014 by Heidi Wollaeger, Michigan State University Extension, and Erik Runkle, Michigan State University Extension, Department of Horticulture
Sometimes one may hear that plants don’t use green light for photosynthesis, they reflect it. However, this is only partly true. While most plants reflect more green than any other in the visible spectrum, a relatively small percentage of green light is transmitted through or reflected by the leaves. The majority of green light is useful in photosynthesis. The relative quantum efficiency curve (Photo 1) shows how efficiently plants use wavelengths between 300 and 800 nm. Green light is the least efficiently used color of light in the visible spectrum.
Photo 1. Relative quantum efficiency curve. (Adapted by Erik Runkle from McCree, 1972. Agric. Meteorology 9:191-216.)