Physiologically active form of phytochrome is

Question

Physiologically active form of phytochrome is (A) P 730 / P Fr  (B) P 660 / Pr (C) P700 (D) P 680

Tardigrade Admin · Accepted Answer

Phytochrome is a photoreceptive pigment which is a bright blue or bluish green pigment. Phytochrome occurs in

2

forms ie,

P_{R}

and

P_{FR}

(ie, red light and for red light absorming forms) in which

P_{FR}

is the active form.

P_{R}

absorbs red light of

660 nm

and

P_{FR}

absorbs far red light of

730 nm

.
Phytochrome affects many processes like stem elongation, leaf expansion, stomatal development, flowering and seed germination.

Q. Physiologically active form of phytochrome is