Question

What is the relationship between chlorophyll and the colour of plants?

Answer 1

Chlorophyll is a greek word which means green leaf. There are five types of chlorophyll in nature, namely a, b, c, d, and e. Chlorophyll a and b are the two major types of chlorophylls found in plants. They serve as the major photosynthetic pigment.

Complete answer:
The colour of plants, mostly the foliages, are seen in various shades of green due to the chlorophyll. Chlorophyll is the green photopigment that absorbs some light wavelengths and reflects the others. More specifically, chlorophyll-a absorbs the red and violet region of the visible spectrum of light, and chlorophyll-b absorbs mostly blue and orange light, and the light wavelengths which are reflected are the colours that we see. Thus, chlorophyll-a appears to be bright or blue-green, chlorophyll-b appears to be yellow-green in the chromatogram or to our naked eyes.
Plants also contain xanthophylls, a yellow-coloured pigment and carotenoids, yellow to yellow-orange coloured pigments, which further helps in light absorption. But their quantity is comparatively less than chlorophyll. Chlorophyll present in the chloroplast reflects several types of wavelengths of lights in the spectrum, but the most predominant one among them is the green colour. That's why we observe green plants around us. There are other shades of plant parts or foliages too. In the case of autumn leaves, the chlorophyll breaks down to form yellow to orange colours due to changes in temperature and duration of daylight. Other chemical reactions may change the colours of foliage additionally.

Note:
Carotenoids such as carotenes and xanthophyll, Betalains including betacyanin and betaxanthins, Flavonoids such as anthocyanin, flavanonols, anthocyanidins, flavans, isoflavonoids, and flavanones which give other shades of colours to plants, not only to leaves but also to the fruits and flowers. The brown colour of leaves or dead leaves is not the result of any pigment but rather cell walls that are devoid of pigments.