| 释义 |
phytoalexin Bot.|ˌfaɪtəʊəˈlɛksɪn|
[a. G. phytoalexin (Müller & Börger 1941, in Arb. aus der biol. Reichsanstalt Land- und Forstwirtschaft XXIII. 223): see phyto- and alexin.]
Any 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 orig. defined with regard to fungal parasites only, but in 1956 Müller extended the meaning to cover all parasites.
1949Nature 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. 1956K. O. Müller in Phytopath. Zeitschr. XXVII. 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. 1964Cruickshank & Perrin 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. 1975Sci. Amer. Jan. 88/3 Plants do not produce antibodies but some of them do produce phytoalexins. 1977Observer 4 Sept. 4/2 Dr. David Smith..told a meeting of the British Association for the Advancement of Science last week that chemicals called phytoalexins—substances produced by plants when they are attacked by disease—merited a major investigation. |