Autumn colors

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The sad time has come to say goodbye to the red summer. Gradually, the entire tree-shrub brotherhood is dressed in gold and crimson. What a beautiful, unsurpassed play of various shades of yellow-red colors. And in the crystal clear blue sky, the cranes are already screaming. Farewell Summer! Nature puts on an elegant dress for a farewell banquet. It is not for nothing that the poet called this time "the charm of the eyes."

According to the calendar, as you know, autumn comes on the first of September. Astronomers consider the beginning of autumn the day of the autumnal equinox - September 22, meteorologists - the date of a steady transition of the average daily air temperature through 10 degrees to lower temperatures. The transition of the average daily temperature through 5 degrees is a sign of the end of the growing season. Autumn is usually divided into two periods. The first lasts from the first frost until the end of November, and the second - from the end of November to the beginning of winter. The first frosts are the beginning of autumn. But after them, as a rule, warm and dry weather begins, the so-called "Indian summer" begins. In these days of golden autumn, summer seems to be returning again, and a number of plants bloom again. But this joyful, colorful period of autumn is very short.

Phenologists believe that autumn comes with the onset of a noticeable yellowing of the leaves on trees and bushes. In different years, the leaves turn yellow at different times. The first to turn yellow are the leaves on the birches, later on the linden, then the bird cherry, the branches, crowns, viburnum bushes are covered with purple. Yellowing of the leaves and November are the most characteristic features of autumn. Why do leaves turn yellow in autumn? This question is often heard from different people. In summer, the leaves are green from the presence of a large amount of green pigment - chlorophyll. But, in addition to chlorophyll, the leaf also contains yellow-orange pigments - carotene and xanthophylls. In summer, the pigments are masked by chlorophyll, so the leaf looks green. In autumn, chlorophyll is destroyed, and yellow-orange pigments give the leaves golden and orange tones. But, in addition to yellow, on many trees and plants, the leaves acquire even more diverse shades: from red-purple to purple flowers. This is explained by the presence in the cells of the leaves of a special colored substance - anthocyanin. With cooling, the content of anthocyanin increases, because low temperatures and bright light contribute to its formation.

No less characteristic of autumn is the fall of leaves from trees and. This phenomenon cannot be explained only by the onset of cold weather, as some believe. If you transplant a tree into a room or greenhouse where the temperature does not drop, it will still shed its leaves. This is because by autumn a special cork layer forms at the base of the leaf petioles. This layer separates the leaf from the plant. A light breath is enough, and the leaf falls off. By November, many substances that the plant does not need accumulate in the leaves, and with the fall of the leaves, these substances are removed from the plant. November, as well as the change in the color of the leaves, is associated with a change in the vital activity of plant organisms in connection with the preparation for adverse winter conditions. This vital adaptation has been developed over thousands of years under the influence of the climatic features of the temperate zone. After all, with leaves, the trees could not survive in the harsh conditions of winter. During the warm period, trees, for example, evaporate about seven thousand kilograms of water through their leaves ... If a birch had remained for the winter with leaves, it would have died from a lack of water, since it is impossible to take it from the soil in such quantities in winter ... Another thing is coniferous trees, they do not shed their clothes for the winter, which, due to the special structure of their needle-shaped needle leaves, evaporate very little water, and therefore they are not afraid of winter water hunger.

Gradually, the leaves fall off the trees and bushes, but the herbaceous plants still retain their green color. True, among them there are already quite a few with yellowed stems and leaves, and many plants are even blooming. Some plants bloom a second time only occasionally, and for some, repeated flowering in the fall has become almost commonplace. Plants such as adonis, fragrant violet, marigold, cuckoo flower, forest anemones and a number of others often bloom a second time. Particularly conducive to re-blooming are the peculiar weather conditions of autumn, when after a cold snap a prolonged warming occurs.

Some plants, in particular weeds, can bloom, as they say, from snow to snow, that is, from early spring to late autumn. Among them are starfish or wood lice, talaban (yarutka) and others. In autumn, later forms of some plant species can also be found with flowers. These are eyebright, tenacious, field violet, gravel, etc. These species bloom in early summer, seem to disappear later, and bloom again by autumn. Such seasonal forms of individual plant species are still very little studied.

Part of the autumn-flowering species are plants that bloom in the second half of summer and continue their flowering in the fall. Chicory, cinquefoil, crow's feet, some, carnations, tansy, sverbizhnitsa and others fade late. In damp places, the succession still blooms.

And there are some types of plants that bloom only in autumn. Among them, first of all, it should be noted - the most interesting plant in its biology. Only in autumn, the yellow flowers of Sternbergia of the autumn Amaryllis family also open. This rare plant is found in our Odessa region and in the Crimea. Autumn snowdrops, some types of saffron, etc. bloom in autumn. Finally, they bloom too. Early winter is coming, and the first loose white snow will cover the ground.