Pigments are organic substances essential for plants for their physiological functions, these are responsible for photosynthesis, the absorption of visible light and the protection of the plant. The best known are chlorophylls since they are the protagonists in photosynthetic processes. In the following Post I will show a series of photographs taken during the experiment of the extraction of the different pigments of the plant of "Phaseolus vulgaris" under different conditions, one planted in shade and another planted in sun, besides presenting a brief biochemical explanation of the studied phenomena of separation according to the chemical structure of the pigments.

Pigments in Sun and Shade Conditions

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Fig 1.Extraction of photosynthetic plant pigments in sun and shade.

In fig 1. you can see two test tubes with a green substance, that substance is a mixture of extracted pigments, you can see that there are two shades of green, being one more dark than the other, this is due to the concentration of pigments that the shade plant has in relation to the sun plant. It is logical to think that the plant in sun will photosynthesize so the concentration of chlorophyll will be higher however in shady conditions the plant needs to generate more pigments in order to capture more efficiently the minimum amount of light possible for their physiological processes.

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Fig 2. Test tubes with pigment extract
In Figure 2 it can be better appreciated the difference in shade in terms of the plant in shade conditions and light conditions

Extracted Pigments

Plants have various pigments called "accessory pigments" and other essentials such as chlorophylls (chlorophyll a and chlorophyll b), among the accessories we have beta carotenes and xanthophylls.

These pigments were extracted by cutting 10 discs from the leaves of the plants with a hole, macerating the sample with a mortar adding calcium carbonate to regulate the pH caused by the rupture in the vacuoles and adding a solvent of slightly apolar nature such as 100% acetone, then the mash was filtered and added in test tubes wrapped in aluminum foil and cold stored to avoid enzymatic action.
The differentiation of these pigments lies in their structures since some may be more polar than others. These can be studied by thin layer chromatography where the plate is a fairly polar compound (silica gel) and the solvent set is apolar in nature (benzine, isopropanol). Finally, 50 drops of both pigment samples (sun and shade) were planted and left in the chromatography chamber for 2 hours. </ div>
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Fig 3. Pigment chromatogram extracted from the plant in sun and shade.

When looking at figure 3 the first thing to observe is the intensity of colors of one sample versus the other, this is due to the above explained (the concentration of pigments in shade plants) however you can see different colors, ie it exists in it shows something more than chlorophyll. The reason for the appearance of each pigment in order from top to bottom will be explained.

Betacarotene

Figure 3 shows how the first yellow spot, are accessory pigments with the protection function of the plant to radiation, are of apolar nature so they run a greater distance because they have less affinity for the stationary phase (plate silica gel) which is polar and runs freely with the solvent front which is the mobile phase which is apolar.
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reference: http: //www.sbsportlive.com/suplementacion-con-beta-caroteno-en-el-triatlon/
the next gray spot is not pigments associated with the plant if it is not the degradation of some by the action of acids in the vacuole at the time of cutting the leaves, it is the pheophytin that is part of the degradation of chlorophyll.

Chlorophyll a

Represented as a bluish green stain, it differs from chlorophyll b because it does not have the aldehyde group, which makes it less polar and can interact better with the mobile phase.

Chlorophyll b

It is presented in figure 3 as a green color and this is more polar because it has an aldehyde group.

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ref: http://www.efn.uncor.edu/departamentos/biologia/intrbiol/fotosint.htm

Finally, in the chromatogram, xanthophylls are observed, which are accessory carotenoid pigments that are represented with a yellow color and are polar in structure. When visualizing the following image they consist of two OH groups that provide a great polarity to the molecule due to the formation of hydrogen bonds and intermolecular forces.

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