Why do leaves change color in the fall?

Do You Know? The next season in northern hemisphere, after winter. If your answer is Autumn; then you are right.

Autumn is a season in which we can see the trees naked. 

If I say you to close your eyes and think about the Autumn. Then what will be your imagination's first picture.

My imagination's picture will be ' a naked tree in the garden and the leaves fallen on the ground. And a sweeper is sweeping the leaves and I am watching him sweeping. 

That's my imagination. Tell your imagination in the comment section. 

Now, let's moves towards our topic, that's reason of falling of leaves. Let's start and take you to the your aim of reading this post. 

First of all, we have to know about the chemicals which are responsible for colour changes in leaves.

What Changes colour of Leaves?

Plants consists of many chemicals. But now we have to only concentrate on the colour chemicals. 

There are three major chemicals which effects plant's leaves colour. Which are: 

Chlorophyll

Carotenoids (carotene and xanthophyll are it's two major chemicals).

Anthocyanins

Let's know about their functions in short description.

First is Chlorophyll, which is responsible for green colour in leaves. It's major function is to absorb sunlight and make it useful in food processing process of plant, Photosynthesis.

Second one are Carotenoids, which consists of two major chemicals. They are Carotene and xanthophyll. Carotene is responsible for orange (carrots), while xanthophyll is for yellow (squash). 

Third one is Anthocyanins, which created many tourists attraction places in eastern Northern America. Yes, it's maple leaf, which have a attractive reddish colour.

Now, let's learn about it's reason.

Why colour Change in Leaves?

During the growing season, when there are the most hours of daylight, chlorophyll is at peak performance, converting the energy of sunlight into sugar molecules that can release the energy later or be used to build other molecules needed by the tree. 

But when sunlight diminishes in winters (it shrinks steadily from June 21 through to December 21), so the behaviour of plants get changed.

 The energy that a leaf absorbs from the sun is less than the energy it uses to perform the chemical work required to maintain its machinery. To prevent wasting resources, the tree begins to shut down its leaves.

As the leaves shut down, chlorophyll molecules are shipped back into the tree. (Nitrogen is a limited resource, too, so the tree also stores it for use the next spring.)

As the chlorophyll is withdrawn, other compounds in the leaf are left behind. Most of those compounds are carotenoids, and two of the most important are carotene and xanthophyll. 

Due to the chlorophyll depletion, the carotene and xanthophyll are exposed,  that's why the color of the leaf changes.

This chlorophyll's draw back and xanthophyll and corotenes' explosion causes colour in leaves.

I have told you about two types of colour changing chemicals. But there is on more chemical which gives leaf an amazing colour like maple leaf, red.

That's chemical is  known as Anthocyanins. Let's learn about it in deep.

Why Maple Leaf is Red?

It is Red due to the presence of Anthocyanins chemicals. 

Anthocyanins aren’t present in leaves. But when the leaves’ adjustment to winter begins, the tree manufactures them. 

That is the mystery of the anthocyanins, and it has generated some interesting ideas in scientists minds. 

Let's read about that ideas.

One is that the anthocyanin pigments protect against sunlight. The change in color is happening at a time of year when sunlight is in decline. 

It is very important for tree because one unusually bright day in fall could cause significant damage to a tree, but thanks to the anthocyanins in its leaves, the tree can absorb high levels of sunlight.

Some people have proposed the idea that leaves turn red to protect themselves against aphids that might lay eggs on them. It confirmed that trees with red leaves were more successful at warning aphids to stay away.

Red as Warning theory had been proved wrong the final outcome is that:

It turns out that aphids(a small bug) have no red receptors in their eyes. But maybe they are still able to discriminate between colors. 

And maybe it doesn’t matter: as it turns out, it might not be the red color itself that’s warning insects away. Rather, the red covers up the yellow shades of the leaf (those exposed by the removal of the green chlorophyll). 

Those yellows are very attractive to a broad range of insects, including aphids. So the red hue isn’t a stop sign after all. But because amber means “Go” to an aphid, disguising it with red has the same effect.

Conclusion

Color change and shedding of Leaves is a technique of Trees to save water. 

It is just a Adaptation of Trees.

Find Extra, To Become Extraordinary.