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What is the absorption spectrum of photosynthesis?

The absorption spectrum of photosynthesis is related to the absorption of light energy that plants use to convert into their own food and subsequently reproduce. More specifically, it is known as a radiant energy, whose intensity – emitted at each wavelength – is considered an average of the amount of energy that passes through a selective absorption substance.

These substances or pigments that absorb energy are mainly chlorophyll (A and B) and carotenoids. Also, as a related element, we find the spectrum of action, which shows us in a specific way, how effective have been the wavelengths of light that plants have absorbed and used to perform their photosynthesis process.

From this, we can understand that photosynthesis is the process by which the absorption of light (made by pigments) by plants is achieved, in which the pigments found in their leaves, are responsible for absorbing it, storing it and converting it into sugar to feed.

Now, what can this knowledge bring us?

Well, knowing in depth how the process of photosynthesis is achieved and how the light or energy of the sun is absorbed by plants and subsequently converted into food, allows to establish an artificial lighting system for plants that are grown indoors and that is totally suitable for them; even if they are not in a totally natural environment.

Incidentally, we know that artificial lights are those that fulfill the function of sunlight inside greenhouses and through which plants manage to perform the process of photosynthesis correctly; also reaching greater size or flowering (as preferred).

The best thing about that aspect is that having the plants under a controlled environment, much more optimal harvest results will be achieved according to the needs of each grower. For these reasons, we want to explain in greater depth everything related to the functioning of the absorption spectrum of photosynthesis.

How does the absorption spectrum of photosynthesis work?

The absorption spectrum of photosynthesis is the process that is defined as a part of electromagnetic or luminous radiation, which occurs in portions of radiation that were absorbed and are shown in the form of black stripes or bands.

The streaks of the different absorption spectra come from transits that absorb energy from the different external electrons of the atoms, which contain much higher energy levels.

It is composed of two pigments known as chlorophyll and carotenoids, which are also the main channels responsible for the process to be carried out.


What are pigments? How do they absorb light through photosynthesis?

As with animals, plants also require energy to do their work. In their case, they need sunlight (or light energy) to achieve the process known as photosynthesis; and this absorption is possible thanks to the action of plant pigments.

The latter (pigments), we know them as those substances that absorb light; the color of each pigment is given by the wavelength that is absorbed and therefore reflected.

For example, black pigments are those that absorb all the wavelengths that reach them, unlike white pigments that reflect practically all the energy they can receive. That is, some absorb and conduct energy and others absorb it, but also reflect it.

Chlorophyll A (absorbs blue-violet light)

Chlorophyll is a molecule that contains a magnesium atom in the center, which is held by a ring formed by porphyrins and is known as the green pigment that is common in all photosynthetic cells of plants. This pigment is responsible for absorbing all wavelengths that are visible spectrum.

Carotenoid (absorbs blue-green-violet light and reflects yellow, red and orange)

Chlorophyll B, also known as "carotenoids", are the pigments that are responsible for absorbing the wavelength of the green pigment, that is, only the one that can practically receive. It is important to mention that, both chlorophylls also absorb in the final region of the spectrum, that is, orange - red colors.


What is the process of photosynthesis?

Photosynthesis is the process by which plant organisms – and also some bacteria – are able to create organic matter from inorganic matter and light. Plants contain green pigments that are known as chlorophyll and are responsible for absorbing the energy that light transmits to them; all that energy is stored in the form of sugar, and that's where the process of photosynthesis begins. Its stages are as follows:

  1. Absorption: at this stage the plants are responsible for absorbing the water and all the minerals they have in their environment, this usually happens through their roots.
  2. Circulation: in the stage of circulation, the nutrients that were absorbed circulate through the vegetable until finally reaching the leaves, which is where the process of photosynthesis begins to take place.
  3. Photosynthesis: it is the stage where the photosynthesis process begins to be carried out, through this, the procedure of transforming water, carbon dioxide and light into pure energy for plants is carried out. It is a fairly complex stage, where two phases are differentiated, the luminous one (in which the plants transform the luminous energy into sugars) and the dark phase (when the plant no longer requires more light).
  4. Feeding and growth: the last stage of the process is where the plant uses all the compounds that were previously produced to feed and in this way, produce new structures, and finally achieve the growth process.  

In short, the light spectrum shows all the light that is normally absorbed in a sheet, while the action spectrum is responsible for showing all the light that is actually used in the process of photosynthesis and that is more efficient.

What is light energy?

Light energy (also known as light energy) is that energy that is transported and composed by the waves of light.

But what exactly is light?

Light is a type of electromagnetically shaped radiation that is composed of particles known as photons. The light that is visible between the infrared and ultraviolet areas of the spectrum are those that have a fairly particular range in terms of frequency, wavelengths and energy as such.

Light can be detected by our sense of sight, and we can find it in light bulbs, the sun, and laser beams. Each of these emits light that can be visible at any time by our eyes.


The light energy is then that which is produced by the light waves and transported by means of it. That is, it is the energy of visible light; it is an energy that is considered radiant because it manages to move through electromagnetic radiation.

Another definition it can have is that it is the energy that is within the electromagnetic spectrum, between the infrared and ultraviolet part that is visible to the human eye, that is, visible light.

The sun also emits a large amount of electromagnetic radiation that is known as sunlight, and in addition also the human eye can observe without any problem.

What is the light spectrum? What is the visible light spectrum?

The visible light spectrum is known as the region of the electromagnetic spectrum that the human eye is able to perceive and finally observe in the different colors that we already know.

In the case of white light, the visible spectrum contains all the colors that human beings can observe; the most common example is the rainbow, which occurs thanks to the refraction of light generated by water in the atmosphere and is responsible for altering its speed until it decomposes into the different colors observed by the human eye.

Advantages and disadvantages of light energy

This type of energy consists of two aspects, like any process, it contains the positive and negative aspects. Among the advantages of light energy you have to:

  • Using light energy is totally free because it comes from the sun.
  • It is an almost inexhaustible energy – because it only disappears at night.
  • It is not polluting for the environment.
  • The facilities where they use this type of energy are easy to maintain.

On the other hand, as for the disadvantages of light energy, there are those described below:

  • Light energy is not storable compared to other types of energy.
  • Prolonged exposure to sunlight can cause serious skin damage.
  • Ultraviolet light causes collateral damage if they are constantly exposed to it without any protection.


The importance of the absorption spectrum in the photosynthesis process

Finally, it is favorable to take into account the importance of knowing the correct functioning of the light energy that manages each of the plants, this especially in the crops that are carried out indoors.

The use of good lighting must be taken into account to help them comply with the process and grow favorably and in good condition. It is also important to have a space that is suitable for them, where they have enough lights that are also the ones that contribute to the results of each of the crops.

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