Role of Pigments in Detection of Light

Role of Pigments in Detection of Light

In order to optimise the gain of light energy for photosynthesis, green plants have evolved a series of photoreceptors, which aid growth and development in relation to the presence, amount, direction, duration and quality of incident light radiation. The best characterized of these photoreceptors is the red/far-red light-absorbing phytochrome family. This pigment phytochrome is made up of two protein molecules each joined to a light absorbing protein. Collectively, the phytochromes regulate all aspects of plant development from seed germination to seedling establishment.

Phytochrome exists in two forms. The first form is particularly sensitive to red light and hence is referred to as PR and the second form is sensitive to a colour, which is outside of the norm visible spectrum. This is sensitive to far-red and therefore is referred to as PFR. These two types are said to be interchangeable, this is because if PR absorbs red light it conv...