Carotene, xanthophyll and chlorophyll are photosynthetic pigments present in almost all the plants. Their absorption spectrum is between 400-700nm. Blue-green receptor of plant absorb red and far-red light which ranges between 700-750nm. This receptor helps in seed germination, flowering, leaf elongation etc. Phytochrome receptor are of two types Pr and Pfr which absorbs red and far-red light respectively. They are responsible for flowering due to photoperiodism.