phytochrome

Phytochrome is a plant pigment that detects light, especially red and far-red wavelengths. It acts as a light sensor, helping plants gauge the quality, quantity, and duration of light exposure. This information influences key processes like seed germination, stem growth, flowering, and leaf development. Phytochrome exists in two interconvertible forms: Pr (inactive, absorbs red light) and Pfr (active, absorbs far-red light). When exposed to red light, Pr converts to Pfr, triggering growth responses. Conversely, far-red light converts Pfr back to Pr, halting these processes. This system allows plants to adapt their growth to changing light conditions for optimal development.