Plants have several types of pigments that allow them to absorb light for photosynthesis. Each pigment absorbs different wavelengths, so that the best wavelengths for plants depend on the type of pigment it has the most of.
Chlorophyll a, which is present in all photosynthetic organisms, absorbs blue light with wavelengths of 430 nanometers (nm) and red light of 662 nm. It reflects green light, so that the plants that contain it appear green. Compared to other pigments, chlorophyll a exists most abundantly in plants.
Chlorophyll b, which is similar in structure to chlorophyll a, exists in green algae and plants. It absorbs light of 453 nm and 642 nm. Chlorophyll a helps plants absorb a more extensive range of light wavelengths.
All organisms that conduct photosynthesis have carotenoids. They absorb green light between 460 nm and 550 nm best. Plants that contain mostly cartenoids appear red, orange or yellow.
- Juergen Bosse/Photodisc/Getty Images