ENGLISH LITERATURE (CBSE/UGC NET)

Detailed explanation-1: -In autumn when it starts to get cold, some plants stop making chlorophyll. Instead, those plants break down chlorophyll into smaller molecules. As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall.

Detailed explanation-2: -The chlorophyll breaks down and the green fades away, letting the yellow/orange carotenoids blaze forth, giving autumn its splash, dash and panache. At the same time, other chemical changes occur, giving rise to more pigments which vary from yellow to red to blue.

Detailed explanation-3: -As the tree becomes dormant, a compound called abscisic acid triggers a seal to develop at the base of the leaves, before they fall off. This reduces water reaching the leaf and traps the chemicals remaining in the leaves. They gradually break down, changing the colour of each leaf before it drops to the ground.

Detailed explanation-4: -Autumn’s shorter days and colder temperatures are less conducive for growth, and photosynthesis is reduced. Chlorophyll continues to deteriorate during this time, and at this point not as much is replaced.

Detailed explanation-5: -Plants’ production of new chlorophyll is regulated by light. In response to shorter days in the fall, plants produce less chlorophyll. But existing chlorophyll molecules break down at a steady rate. Therefore, in the fall, the amount of chlorophyll in plants decreases and the green color fades.