Why Do Leaves Change Color In the Fall

At the onset of autumn leaves change color, because of the chemical changes taking place in leaves, as their food ingredients are drained and deposited into the tree’s trunk, branches, and roots for winter storage, cause the leaves to cease synthesizing chlorophyll, the green pigment.

A green pigment, Chlorophyll is found in most algae, plants, and cyanobacteria. The term ‘Chlorophyll’ derives its name from the Greek chloros “green” and phyllon “leaf”. Chlorophyll absorbs light mostly in the red and blue but less in the green zones of the electromagnetic spectrum, therefore the green pigment of chlorophyll-containing tissues such as plant leaves.

In 1817, Joseph Bienaimé Caventou and Pierre Joseph Pelletier were able to first extract Chlorophyll. The role of Chlorophyll within the leaves — absorbing sunlight and using the sun’s energy — is not required any further, as the residual quantities of chlorophyll in the leaves finally degenerate.

Fall Leaves Why Do Leaves Change Color In the Fall

When the pigments of chlorophyll degenerates, secondary pigments, certain substances that absorb light, develop to replace it, and transform the leaves’ colors to their hues. For example, yellow and orange leaves have the carotene pigment, the same carotene impart carrots characteristic bright orange color.

Red, wine-red, and purple color of the leaves is due to anthrocyanins pigments that also impart their color to cabbage, roses, radishes, and geraniums. The major difference between anthrocyanins and carotene is that the anthrocyanins synthesizes in leaves during fall when the weather is cooled, particularly when the temperature ranges between 32o F to 45 o F.

Hereditary traits also contribute to the color scheme of the leaves. The color variation can also be influenced by weathering effects. For example, rich and thick foliage grows when there are weeks of cool and sunny weather in the Americas.

The shade of the foliage may fade out when fall is ushering into winter, as the nodes that attach leaves to the branches begin to lose their grip. Actually, cells at the ends of nodules fall apart, leaving the foliage attached by thin vascular connections that were used for water and food transportation in summer. At this juncture, a slight jerk (such as, an air thrust) can cause the leaves to drop due to built in inertia and potential energy.

Once the foliage is dropped on ground, the red and the yellow pigments can last for a few days; soon they degenerate / decay as did the chlorophyll. Finally, over the course of progressive decay, the thing that survives in the color is the brown tea hue! In the absence of water, the tea colored foliage fallen over ground gets dry and crisp while the trees stripped of foliage!

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