a plant pigment that is associated with the absorption of light in the photoperiodic response and that may regulate various types of growth and development.
Origin of phytochrome
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botany a blue-green pigment existing in two interchangeable forms, present in most plants, that mediates many light-dependent processes, including photoperiodism and the greening of leaves
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Any of a group of cytoplasmic pigments found in green plants and some green algae that absorb red light and regulate dormancy, seed germination, and flowering. Phytochromes consist of a bile pigment attached to a protein, and occur in an active and inactive form, each of which can be converted into the other depending on the wavelength of red light that is absorbed.
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