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

Since leaves require light to perform photosynthesis, the colour of a leaf kept in the dark changes from a darker to a lighter shade of green. Sometimes, it also turns yellow. The production of the chlorophyll pigment essential for photosynthesis is directly proportional to the amount of light available. In the absence of light, the production of chlorophyll-a molecules stops and they get broken slowly. 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.

Chlorophyll is unable to absorb energy in the absence of light and thus loses its stability. This leads to yellowing of leaves. The yellowing of leaves also shows that xanthophylls is more stable.

Since leaves require light to perform photosynthesis, the colour of a leaf kept in the dark changes from a darker to a lighter shade of green. Sometimes, it also turns yellow. The production of the chlorophyll pigment essential for photosynthesis is directly proportional to the amount of light available. In the absence of light, the production of ‘chlorophyll – a‘ molecules stops and they get broken slowly. This changes the colour of the leaf gradually to light green. During this process, the xanthophyll and cartenoid 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.