At Night, When Little Red Light is Available to the Plants

Question

At night, when little red light is available to the plants in an area, what occurs?
A) Pr stimulates flowering.
B) Pr is converted to Pfr.
C) Pfr is converted to Pr.
D) Pr and Pfr are both destroyed.
E) Pr and Pfr are both formed from inactive phytochrome.

Accepted Answer

At night, in the absence of red light, the active form of phytochrome (Pfr) is slowly converted back to the inactive form (Pr).