Most plants on planet Earth are green. These are endless fields, meadows, huge forests. Very often one can hear a question from babies: “Mom, why are the plants green?” Let's try to answer this question from the point of view of chemistry, physics and a simple layman.
Why are plant leaves green? Just about complicated
Foliage and grass on our planet are yellow, red, but mostly green. This is because plants stain tiny pigments. They are in the cells of each blade of grass and leaf. Some of them give the plant a red color, others - yellow, and others - green. The most common pigment is chlorophyll, a substance that gives plants a green color.
What is chlorophyll and photosynthesis?
Foliage and grass are stained with a pigment called chlorophyll (this is a green substance that is involved in the process of photosynthesis). As a result of this, nutrients are formed and oxygen is produced.
Thanks to the light of the sun, a complex biochemical process takes place, as a result of which inorganic substances and water obtained by the plant from the soil are converted into organic ones (fats, carbohydrates, proteins, starch, sugar). The main significance of photosynthesis is that the plant absorbs carbon dioxide and produces oxygen, which is important for the life of all organisms on Earth.
Physics and chemistry of green light
Let's try to understand more deeply why the plants are green.
Physicists explain the coloring of all objects by how much light is absorbed / reflected by them. The things around us have a color that reflects them. For example, if the subject is white, it means that it reflects all the colors of the spectrum. If black, then all shades are absorbed by this subject. White sunlight consists of seven colors that all living organisms, plants and inanimate objects receive. Grass and foliage of all tones reflect only green (it is not needed for the photosynthesis process) and that is why all plants have such a shade. And the chlorophyll pigment produces energy for growth and nutrition from the red and blue spectrum.
Scientists can explain why most plants reflect green light rather than absorb it. Each of the colors in the spectrum has a specific energy and number of photons (tiny particles of light). It is this energy that is important for photosynthesis. The largest number of photons is contained in red, while blue has the most useful energy. Green photons are neither energy nor useful, and therefore nature does not use it.
From the point of view of chemistry, everything is explained differently. Scientists believe that the color of objects depends on the concentration of certain metals. For example, the blood is red due to the fact that the hemoglobin in it contains iron. Almost all of the vegetation is green because there is magnesium in chlorophyll. The most interesting thing is that this theory does not have strong evidence. Scientists tried to replace magnesium with zinc, but despite this, the plants remained the same green.
Why does fall foliage turn yellow?
Why then does the grass turn yellow in autumn, does the foliage dry and fall off? This is due to a lack of sunlight. With the beginning of autumn, the days become shorter, cooler and darker. Plants are sensitive to the reduction of daylight hours. Chlorophyll lacks a sunny color, and it begins to collapse, the green color is lost, turning into a brown, red, yellow, crimson.
Why aren't all plants green?
Why in nature, in addition to green, are plants of other colors found? Because in addition to chlorophyll, plants can contain many other pigments. For instance:
- Anthocyanin is a pigment that absorbs rays of green light, and reflects all the rest. Leaves containing the substance may have any color except green.
- Carotene is a pigment that reflects a yellow and red palette. Leaves and herbs in which the amount of carotene is much greater than chlorophyll are red or yellow.
- Xanthosine is a substance that absorbs the entire palette of colors except yellow. Accordingly, the foliage containing xanthosine is yellow in color.
Now both the adult and the child will understand why the plants are green. Everyone will understand the importance of the process of photosynthesis, how plants get nutrients and grow, and why in the fall they turn yellow and wilt. Explore the world, it is very interesting!