Proteinaceous Pigment Controlling Light Activities

The correct answer is option 'A' which is phytochrome. Phytochrome is a proteinaceous pigment that controls activities related to light. Let's understand phytochrome in detail.

Phytochrome

Phytochrome is a proteinaceous pigment present in plants that detects and responds to light. It controls various activities in plants such as seed germination, stem elongation, flowering, and fruit ripening.

Structure

Phytochrome is composed of two parts - a chromophore and a protein. The chromophore is a light-absorbing pigment that is responsible for detecting light, while the protein is responsible for transmitting the signal to the plant's cells.

Function

Phytochrome plays a crucial role in plant growth and development. It helps plants to detect the presence and quality of light, which in turn affects various physiological processes. For example, when a seed is exposed to red light, phytochrome present in the seed coat is activated, which triggers the germination process.

Similarly, phytochrome also controls the process of photoperiodism, which is the response of plants to the duration of light and darkness. For example, some plants require long nights to flower, while others require short nights. This is because phytochrome controls the production of hormones that regulate these processes.

Conclusion

In summary, phytochrome is a proteinaceous pigment that plays a critical role in plant growth and development. It detects and responds to light, which in turn affects various physiological processes.

Phytochrome is a photoreceptor, a pigment that plants use to detect light. It is sensitive to light in the red and far red region of the visible spectrum.
Phototropins can be found throughout the leaves of a plant. Along with cryptochromes and phytochromes they allow plants to respond and alter their growth in response to the light environment. Phototropins may also be important for the opening of stomata and the movement of chloroplasts.