Why does chlorophyll absorb red and blue light the most?
Red and blue light is believed to have a higher quantum yield of CO2 assimilation. The blue and red parts of the spectrum are effective to satisfy the energy requirement of plants. Hence plants absorb these two colors more than any other color.
Absorption spectra of the chlorophyll a and b pigments in the visible light range, measured in a solvent. Both types barely absorb green light. Chlorophyll a absorbs violet and orange light the most. Chlorophyll b absorbs mostly blue and yellow light.
Plant pigment molecules absorb only light in the wavelength range of 700 nm to 400 nm; this range is referred to as photosynthetically-active radiation. Violet and blue have the shortest wavelengths and the most energy, whereas red has the longest wavelengths and carries the least amount of energy.
In conclusion, plant leaves are green because green light is less efficiently absorbed by chlorophylls a and b than red or blue light, and therefore green light has a higher probability to become diffusely reflected from cell walls than red or blue light. Chlorophylls do not reflect light.
Chlorophyll a is the most abundant pigment in plants. Chlorophyll a absorbs light mostly 430nm (blue) and 662nm (red) wavelength light. It reflects green light so it appears green to us.
In plants, chlorophyll a and chlorophyll b are the main photosynthetic pigments. Chlorophyll molecules absorb blue and red wavelengths, as shown by the peaks in the absorption spectra above.
Answer and Explanation: The wavelength of light which is most likely to be absorbed by chlorophyll a is b) blue. The absorption of both blue light and red light can take place in the presence of chlorophyll a.
BLUE LIGHT AND PLANT GROWTH
In addition, blue light regulates the opening of stomata, which are the tiny openings on leaves that control both water loss and the uptake of carbon dioxide. Generally, only a low intensity of blue is needed in a light spectrum for fully functional photosynthesis.
It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.
Chlorophyll absorbs light in the red region. Because red light has the highest absorption by chlorophyll, it is the most effective wavelength for photosynthesis.
Why do plants like blue and red light?
Red light is necessary for seed germination, root growing. 600-700 nm wavelength range red light is used to support the development of a plant and improving the taste of fruit. Blue light provides chlorophyll production (the most active pigment for photosynthesis) in plants.
The two types of chlorophyll found in plants, chlorophyll a and chlorophyll b, absorb light very well in the blue-violet and red regions of the visible spectrum, but not in the green region, as shown in the graph. Leaves reflect green light, which is why plants look green.

Blue light is highly absorbed by both chlorophyll a and b, as well as an intact leaf system. This high absorption rate corresponds to the photosynthetic action spectrum from isolated chloroplasts and intact leaves.
Red and blue light support the highest rates of photosynthesis because: chlorophyll absorbs these wavelengths more than other wavelengths.