Question

Photosynthesis is maximum in

• A. green light
• B. blue followed by red light
• C. red followed by blue light
• D. blue light

Answer 1

Answer: (D)

Light is an essential factor for photosynthesis. There is a linear relationship between incident light and $C{O}_2$ fixation at low light intensities. At higher light intensities, gradually the rate does not show further increase as other factors become limiting. Light between $400-700nm$ wavelength constitute the photosynthetically active radiation (PAR). Maximum absorption of light by chlorophyll a occurs in red and blue regions of the absorption spectrum. So that, the rate of photosynthesis is maximum in red and blue light of the visible spectrum. Minimum photosynthesis takes place in the green light. Minimum absorption of chlorophyll a occurs in the green region because plants themselves are green due to the pigment Chlorophyll.