File:Autumn Leaf Colors in Europe.webm

English: Free video about autumn leafs. This free video was created for you by http://epsos.de and can be used for free under the creative commons license with the attribution of epSos.de as the original author of this autumn leafs video.

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During the months of autumn, many trees deciduous experiencing autumn leaf color before they fall. This change of color, which exists in many trees, is often called fall colors. A leaf is green because of the presence of a group of pigments called chlorophyll. When chlorophyll is abundant in the cells, as is the case during the period of plant growth, the green chlorophyll molecules dominates and masks the color of any pigment which may be present in the sheet. Thus, in summer the leaves are usually green.

Chlorophyll occupies the vital function of absorbing sunlight and use energy resulting from this absorption in the development of the "food" of the plant - the simple sugars produced from water and dioxide carbon. These sugars are the basis of plant metabolism and are essential for its growth and development. Like any molecule, chlorophyll a lifetime, and is therefore continually destroyed. However, during the period of growth, the loss of chlorophyll is compensated by the plant and the level of chlorophyll there is still high and the leaves remain green. At the end of the summer, the ribs that provide the transport of fluids to the inside and outside of the sheet are progressively clogged with a cork at the leaf base, where the petiole is precisely break. With the development of this layer of cork, the influx of water and minerals is reduced more rapidly. It was during this period that the level of chlorophyll begins to decrease.

The red and purple colors and their combinations which adorn the fall foliage, are from another family of pigments called anthocyanins. Unlike carotenoids, these pigments are generally not present in the sheet during the growth period. These molecules appear at the end of the summer. Indeed, while the sap continues to flow into the leaf, the sap, loaded with sugar, it is blocked by the cork and causes a forced accumulation of sugar in the leaf tissue.

Their yellow and orange tinged leaves tree species hardwood such as ash, the maple, the tulip tree, the poplar, the aspen, the birch, the birch, the sycamore, the sassafras, and alder. Carotenoids are commonly found in the living world, and are particularly responsible for the characteristic color of the carrot, the corn, the canary, the daffodils and that of egg yolk and banana.

Leaves are characterized by a relative to the sheet thickness of large leafs. The chemical processes in the jettisoning of plant parts treated the products abscission, see senescence in plants. Between leaf and tree a layer, the so-called cork corked. This allows the sheet no longer be supplied and drops. For collecting leaves as tools to rake and leaf blowers are used.

There are so the views of the remaining yellowish red carotenoids free. The logistics of the material displacement is in the leaf often easily recognizable: Peripheral areas lose their green first, along the leaf veins, it lasts longer. Autumn colors are a phenomenon that, in many blade-changing trees and bushes occurs. The color of the leaves of many trees and shrubs shifts in the autumn months for several weeks slowly from their normal green color to a range of colors, ranging from yellow, orange to red and brown. At the end of this period the leaves fall.

Leaf fall in autumn is preceded by changes in the tissues or in the leaf base. In the always already present separation layer (abscission), which is made ​​with weakly thickened walls of short cells, is produced by a low-frequency cell divisions brick-shaped cells. The phenomenon is in English known as fall colors and autumn colors. In the late summer in some areas of the United States, particularly New England, and in Canada supplies the so-called leaf peeping tourism in the period between the beginning of the fall season and the time when the autumn leaves finally fall down a major contribution to the local economy.

Although a color change occurs in the leaves of deciduous trees, the foliage color change is observed more in various regions of the world such as North America, East Asia (including China, Korea and Japan), Europe, Patagonia, eastern Australia and the South Island of New Zealand. Japan, Canada and New England are popular destinations to see the autumn foliage.

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