Question

Why do leaves change colour during the autumn fall

Answer 1

Answer:

Explanation:

Leaf colour comes from pigments. These are natural substances produced by leaf cells to help them obtain food. The three pigments that colour leaves are chlorophyll (green), carotenes (yellow) and anthocyanins (reds and pinks).

As summer turns into autumn, the shorter days and cooler nights trigger three major changes in the leaf which have consequences for its colour.

The days become shorter and production of green chlorophyll slows down and eventually stops. Existing chlorophyll in the leaf breaks down and the green colour fades.

Yellow and orange carotenes that you can’t normally see in spring and summer leaves (because they are masked by the green of the chlorophyll) become visible, making the leaf look yellow or orange.

A layer of corky cells forms across the base of the leaf stalk, in preparation for leaf shedding. This restricts the movement of sugars back to the main part of the tree. Sugars become trapped and concentrated in the leaf and are eventually converted to anthocyanins giving the leaf a red, purple or pink colour.

 

Answer 2

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⟹Why do leaves change colour during the autumn fall?

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• Apart from chlorophyll, which gives green colour to leaves other Pigments such as and Xanthophylls (Yellow), Carotin (Orange) and Anthocyanin (Bright red) are also present in leaves although their invisible.