Do Plants Absorb Light? 13 Interesting Facts You Should Know


This article would focus on the idea associated with “Do plants absorb light?” in order to present around 13 different interesting facts. 

Plants are known as “autotrophs” and hence can synthesise their own food. In order to produce the food, it has to engage in the process called photosynthesis where light forms an important part.

What light do plants absorb? 

The best wavelengths of visible light suitable for photosynthesis has been between blue range (425–450 nm) and red range (600–700 nm). This range is identified as “photosynthetically-active radiation”.

In plants there are organelles called chloroplasts which engage in absorbing the energy of only certain wavelengths of light which further processes a molecular chain reaction identified as the light-dependent reactions of photosynthesis. 

 Violet and blue lights tend to have the shortest wavelengths but carry the most energy. The red light has the longest wavelengths and carries a minimum amount of energy.

do plants absorb light
Light absorption by plants from Wikimedia

When do plants absorb light?

Green plants have the inbuilt ability in making their own food through the process called photosynthesis. A green pigment identified as chlorophyll is used which has the ability to absorb light at different wavelengths. 

The pigment chlorophyll engages in absorbing light, mostly sunlight. The energy which is absorbed from the wavelengths of light is further transferred into two different types of energy-storing molecules. 

Further, the stored energy is utilised by the plants using carbon dioxide in the process of photosynthesis to produce glucose and sugar. 

Do all plants absorb light?

Mostly all the plants have chloroplast and all the plants have the pigment chlorophyll which ensures absorbing light by all the plants. The colour of the pigment can vary, based on which the wavelength of the light is absorbed to further facilitate the process of photosynthesis. 

Do plants reflect light?

All wavelengths of light are not absorbed by plants. Only the wavelength between the blue range (425–450 nm) and red range (600–700 nm) , which is the visible light range for photosynthesis, is absorbed by the plants and the rest are reflected. 

What light do plants reflect? 

Plants mostly reflect the green light which provides the leaves of the plants with the colour green. 

Do plants absorb green light?

Plants do not engage in absorbing green light, rather it is reflected back. Only the wavelength between the blue range (425–450 nm) and red range (600–700 nm) is absorbed by the plants to support photosynthesis. 

Do chloroplasts absorb light?

Chloroplasts in the plants contain chlorophyll as pigments that engage in absorbing light between the red and the blue wavelengths in the region of visible light spectrum.  

Does chloroplast absorb light energy?

Chloroplasts engage in capturing light energy in order to use the energy in making glucose, the food for plants, through the process of photosynthesis. 

The process is initiated with effective absorption of lights by using the specialised organic molecules identified as pigments, known as chlorophyll, which are present inside the chloroplasts.  

Why can’t chloroplasts absorb green light?

Plants tend to engage in reflecting green light because green is less efficiently absorbed by the pigment chlorophyll. The pigments engage in more easily absorbing the red and blue lights. 

Thus, the green light is not absorbed, instead it is diffusely reflected back from the cell walls of the plants. 

What light chloroplast absorbs the most?

The primary pigment that is present in the chloroplast, termed as chlorophyll which is used in the photosynthesis process, absorbs the red and the blue lights the most. This range between the red and blue lights is identified as “photosynthetically-active radiation”.

Why do plants absorb red light?

The red lights have been identified to be the shortest wavelength but have the highest levels of energy. The chlorophyll within the chloroplasts takes all the energy that is being carried through these light rays. 

The energy being taken by the chloroplasts would engage in making the glucose for the plants which is further used to generate energy for synthesising various plant functions.   

Why is white light best for photosynthesis?

For photosynthesis, white light is the most preferred light because it provides a spectrum of coloured lights. In chloroplasts, there are various coloured pigments and each colour can absorb the light that would be best suited. 

In using any single colour, red can be the second best colour right for processing photosynthesis.

What part of chloroplast absorbs light?

The part of chloroplast that engages in absorbing the light is chlorophyll. Chlorophyll is identified as the green photosynthetic pigment present in the grana of the chloroplast which is effective in absorbing light energy.  

What is light absorption in photosynthesis?

Light energy from the lights being absorbed are used in initiating the photosynthesis process after the lights are being absorbed by the pigments. The range of energy levels being absorbed by the organic pigments are quite narrow. 

The wavelength range for the organic pigment chlorophyll is blue range (425–450 nm) and red range (600–700 nm). 

The energy levels that are lower than the ones represented by the red light do not have the sufficient energy to raise the orbital electron to an excited state. The energy levels that are higher than the ones represented by the blue light will tear apart the molecules through the process of bleaching.

Sayantani Misra

Hi, I am Sayantani Mishra, a science enthusiast trying to cope with the pace of scientific developments with a master’s degree in Biotechnology. Let's connect through LinkedIn-https://www.linkedin.com/mwlite/in/sayantani-misra-a54a83200

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