Question

Why the colour of a leaf kept in the dark frequently is yellow or pale green? Which pigment do you think is more stable?

Answer 1

Leaf has a green colour pigment known as chlorophyll. The production of the chlorophyll pigment is essential for photosynthesis is directly proportional to the amount of light available. In the absence of light, the production of chlorophyll a molecule stops and they degenerate. This changes the colour of the leaf gradually to light green. During this process, the xanthophyll and carotenoid pigments become predominant, causing the leaf to become yellow. These pigments are more stable as light is not essential for their production. They are always present in plants.