Question

Which property of the pigment is responsible for its ability to
initiate the process of photosynthesis? Why is the rate of
photosynthesis higher in the red and blue regions of the
spectrum of light?

Answer 1

Explanation:

Pigments present in plants help in absorbing light at a specific wavelength. This indicates that different plant pigments can absorb different lights of the spectrum. The absorbed light energy excites the electron in the reaction center, which initiates the process of photosynthesis.

Absorption of light by :

● The rate of photosynthesis is higher in the red and blue regions of the spectrum of light because these regions have maximum energy which is sufficient to excite electrons from the reaction centers $P680$ and $P700$ of $PSII$ and $PS$ I respectively.

● Also, the absorption spectrum shows peaks in the regions of blue and red between $400$ nm and $700$ nm, i.e., chlorophyll a (main pigment associated with photosynthesis) absorbs maximum radiation in the blue and red regions.

● Due to this the action spectrum of photosynthesis is higher in the red and blue regions of the spectrum of light.