Question

The red absorbing form of phytochrome gets converted to the far-red absorbing form after getting irradiated at

• A. 660 nm
• B. 730 nm
• C. 530 nm
• D. 660 nm to 730 nm

Answer 1

The correct option is A 660 nm

Phytochrome exists in two interconvertible forms. The red (660nm) absorbing form Pr and far red (740 nm) absorbing form Pfr. 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. Many flowering plants use it to regulate the time of flowering based on the length of day and night (photoperiodism) and to set circadian rhythms.

So, the correct answer is '660 nm'