phytochromen.
/ˈfʌɪtəkrəʊm/, U.S. /ˈfaɪdəˌkroʊm/ 1. Xanthophyll; chlorophyll. rare and disused.
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the world > plants > part of plant > cell or aggregate tissue > [noun] > pigment
chlorophyll1819
chromule1835
anthoxanthin1836
viridine1837
chlorophyllite1838
anthocyanin1853
phytochlore1866
chromophyll1882
aspergillin1891
phytochrome1893
the world > life > biology > substance > pigment > [noun] > plant pigments > yellow
quercitrin1833
anthoxanthin1836
xanthein1857
xanthin1857
phycoxanthin1873
phytochrome1893
zeaxanthin1929
violaxanthin1931
xanthophyll1931
the world > matter > colour > named colours > green or greenness > green colouring matter > [noun] > of natural bodies
chlorophyll1819
chlorophyllite1838
xylochlo(e)ric acid1862
phytochlore1866
phycochrome1867
marennin1885
phytochrome1893
the world > matter > colour > named colours > yellow or yellowness > colouring matter > [noun] > of natural bodies
polychroite1815
quercitrin1833
anthoxanthin1836
xanthophyll1838
xanthein1857
xanthin1857
phylloxanthin1858
safranine1868
phycoxanthin1873
ooxanthine1875
phytochrome1893
the world > life > biology > substance > pigment > [noun] > plant pigments > green > chlorophyll
chlorophyll1819
chlorophyllite1838
leaf-green1839
phytochlore1866
phycochrome1867
phytochrome1893
1893 New Sydenham Soc. Lexicon Phytochrome, a name for chlorophyll.
1902 Webster's Internat. Dict. Eng. Lang. Suppl. Phytochrome, yellow pigment of plants.
2. Biology. Any of a class of blue-green biliproteins (originally thought to be a single compound) present in plant cells, which occur in two forms interconvertible by the absorption of light, and which regulate photoperiodism and other aspects of plant development influenced by changing light conditions.
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1960 Bot. Gaz. 121 242/2 Pr and Pfr designate the red- and far-red-absorbing forms, respectively, of phytochrome, the photoperiodic pigment.
1960 Science 28 Oct. 1223/1 This control of flowering..implies a time-measuring system that distinguishes between light and darkness through mediation of a pigment... The pigment, now called phytochrome,..exists in two forms interconvertible by light.., with 660 and 730 mμ the absorption maxima of the two forms.
1977 J. L. Harper Population Biol. Plants v. 144 The phytochrome system which controls the light sensitivity of germination in many species involves an interconversion of two forms of phytochrome.
1998 Science 20 Nov. 1488/1 Phytochrome B is the primary high-intensity red light photoreceptor for circadian control, and phytochrome A acts under low-intensity red light.
2003 Daily Tel. (Nexis) 30 Apr. 20 The crucial events in a plant's sex life take place (like our own) mainly at night. They involve special proteins called phytochromes, which help decide when to burst into bloom. Phytochromes are sensitive to light, red light most of all.
This entry has been updated (OED Third Edition, March 2006; most recently modified version published online March 2022).
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n.1893