phytoalexinn.
/ˌfʌɪtəʊəˈlɛksɪn/, U.S. /ˌfaɪdoʊəˈlɛks(ə)n/ Biology.
A substance that is produced by plant tissues in response to contact with a parasite and specifically inhibits the growth of that parasite.The term was originally defined with regard to fungal parasites only, but in 1956 Müller extended the meaning to cover all parasites.
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the world > plants > part of plant > plant substances > [noun] > injurious to parasites
phytoalexin1949
1949 Nature 26 Mar. 498/2 The necrosis of the affected tissues must be accompanied by the formation or activation of a principle (‘phytoalexin’) which exercises a retarding influence on the penetrating parasite.
1956 K. O. Müller in Phytopathologische Zeitschr. 27 254 ‘Phytoalexines’ [sic] are defined as antibiotics which are the result of an interaction of two different metabolic systems, the host and the parasite, and which inhibit the growth of microorganisms pathogenic to plants.
1964 in J. B. Harborne Biochem. Phenolic Compounds xiii. 534 Susceptibility [to fungal attack] may be due to the inability of the infecting fungus to stimulate the formation of the phytoalexin or to its capacity to tolerate the phytoalexin produced.
1993 New Scientist 2 Oct. 15/2 The compounds produced by the rape to fight the fungus invasion, called phytoalexins, inhibit the production of sirodesmin PL.
This entry has been updated (OED Third Edition, March 2006; most recently modified version published online March 2022).
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n.1949