key concept 36.4 Photoreceptors Initiate Developmental Responses to Light

As we pointed out in Key Concept 36.1, plants respond to many different environmental cues, and light is possibly the most important of these cues. Much has been learned about the receptors that plants use to sense light, and we will focus on those receptors here.

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  • Plants have several blue-light receptor pigments.

  • Phytochrome, a photoreceptor pigment, controls plant responses to red and far-red light, and exists in two forms, Pr and Pfr.