Most of the plants on planet Earth are green. These are endless fields, meadows, huge forests. Very often from kids you can hear the question: “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 complex
Foliage and grass on our planet are yellow, red, but mostly green. This is because plants color tiny pigments. They are in the cells of every blade of grass and leaf. Some of them give the plant a red color, others yellow, and still others green. The most common of the pigments is chlorophyll, the substance that gives plants their green color.
What is chlorophyll and photosynthesis?
Foliage and grass are colored by a pigment called chlorophyll (a green substance that is involved in the process of photosynthesis). As a result, nutrients are formed and oxygen is produced.
Thanks to the light of the sun, a complex biochemical process takes place, as a result of whichinorganic substances and water obtained by the plant from the soil are converted into organic substances (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 go deeper into why plants are green.
Physicists explain the colors of all objects by how much they absorb/reflect light. The things around us have a color that reflects them. For example, if an object is white, then it reflects all the colors of the spectrum. If black, then all shades are absorbed by this object. White sunlight consists of seven colors that all living organisms, plants and inanimate objects receive. Grass and foliage of all tones reflects only green (it is not needed for the process of photosynthesis) and this is why all plants have this shade. And the pigment chlorophyll extracts energy for growth and nutrition from the red and blue spectrum.
Scientists can explain why most plants reflect green light instead of absorbing it. Each of the colors of the spectrum has a specific energy and number of photons (tiny particles of light). This energy is essential for photosynthesis. The largest number of photons is contained in red, while blue has the most useful energy. Green photons are neither energetic nor useful, so nature does not use them.
From the point of view of chemistry, everything is explained differently. Scientists believethat the color of objects depends on the concentration of certain metals. For example, blood is red because the hemoglobin in it contains iron. Almost all vegetation is green because magnesium is present in chlorophyll. The most interesting thing is that this theory has no hard evidence. Scientists tried to replace magnesium with zinc, but despite this, the plants remained the same green.
Why do leaves turn yellow in autumn?
Why does the grass turn yellow in autumn, the foliage dries and falls off? This is due to lack of sunlight. As autumn begins, the days become shorter, cooler and darker. Plants are sensitive to the reduction of daylight hours. Chlorophyll lacks the color of the sun, and it begins to break down, the green color is lost, turning into brown, red, yellow, crimson.
Why aren't all plants green?
Why in nature, in addition to green, there are plants of other colors? Because besides chlorophyll, plants can contain many other pigments. For example:
- Anthocyanin is a pigment that absorbs green light and reflects the rest. Leaves containing the substance may be any color except green.
- Carotene is a pigment that reflects the yellow and red palette. Leaves and herbs, in which the amount of carotene is much higher than chlorophyll, are red or yellow.
- Xanthosine is a substance that absorbs the entire palette of colors, except for yellow. Accordingly, foliage containingxanthosine - yellow.
Now it will become clear to both adults and children why plants are green. Everyone will understand the importance of the process of photosynthesis, how plants obtain nutrients and grow, and why they turn yellow and wither in autumn. Explore the world, it's very interesting!
