phytochrome

[ fahy-tuh-krohm ]
/ ˈfaɪ təˌkroʊm /

noun Botany.

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.

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Origin of phytochrome

First recorded in 1890–95; phyto- + -chrome
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for phytochrome

phytochrome
/ (ˈfaɪtəʊˌkrəʊm) /

noun

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

Scientific definitions for phytochrome

phytochrome
[ fītə-krōm′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.