Why fall yellow leaves?

Adults, plunging into everyday problems, cease to pay attention to the world around, while children are daily surprised by its characteristics. And how does it work? And why? What for? And so it is necessary? That only does not interest these little pincers! And if you wear the proud title of a mom or dad, sooner or later you will necessarily hear the question: "Why do the leaves turn yellow in the fall?" Like the question itself is not very complicated, it is one of the signs of autumn , but it will necessarily entail a series of Additional, which must be answered in detail and understandable. Well, let's try to do it!

And why do the leaves turn yellow?

In spring and summer in each leaflet pigment chlorophyll lives, which has a green color. It is a large amount of chlorophyll that makes the leaves on the trees green. This pigment is needed by the tree not just for beauty, but for delicious food, because chlorophyll can use daylight to transform carbon dioxide and water into nutrients. So, thanks to its spring-summer green color, the tree grows and develops. But there comes a season when nature prepares for winter, when its vital activity is suspended, when leaves turn yellow - this happens in autumn. The leaves are getting less water, chlorophyll is gradually destroyed, and the plants lose their green color. It is interesting that chlorophyll is more actively destroyed by the sun, so the period when the leaves begin to turn yellow in the fall does not always occur at the same time. In the dry, clear autumn, the leaves change color faster, and in the rainy autumn they remain green for a long time.

And why are those yellow, and those red ones?

The attentive kid will necessarily ask why some leaves in the trees turn yellow, others turn red, and still others turn brown. The answer is quite simple. The fact is that in addition to chlorophyll, the leaves of plants contain other pigments, but because of the predominant green they are simply not visible. As the green chlorophyll recedes, other colors become visible:

• yellow leaves get their color as a result of the "work" of the plant pigment xanthophyll;
• orange leaves put on their autumn outfit, when the pigment carotene becomes visible, which, by the way, is familiar to everyone by the bright orange color of carrots;
• red leaves acquire this unexpected color due to pigments Anthocyanins;
• brown leaves - this is not the coloring of pigments, but the color of the cell walls of the leaf, it appears when other visible dye pigments are absent.

And why do the leaves fall?

If we talk about the very process of falling leaves, then the mechanism is quite clear - in the autumn, when the leaves turn yellow, a thin separating layer of cells appears on the base of the leaf, the so-called cork layer. Gradually, this partition breaks the connection between the tree and the leaf. It remains to wait for the wind to blow and the sheet is on the ground. On the branch in the place of detachment leaves a small scar that overgrows a protective cork layer, which means that for the tree it is a completely painless period. If you ask yourself why the leaves turn yellow and fall off, in a global sense, it can be understood that this is a protective mechanism, which nature invented for the survival of trees in the cold season. Most of the nutrition is obtained from all the plants with water, which comes from the soil, but in winter the water freezes. That is, if the leaves were left on the trees, they would need to eat, but the frozen water could not bring the necessary nutrition, so the leaves would draw substances from the roots, trunk and branches. Most likely, having lost vitality, the woody organism would die. So falling leaves is an opportunity to withstand the winter, and in the spring to dissolve the kidneys again.