| 释义 |
paraquat|ˈpærəkwɒt, -kwæt|
[f. para-1 2 b + quaternary a. and n.
So called from the fact that the bond between the two pyridyl groups is in the para position with respect to their quaternary nitrogen atoms.]
Any salt, esp. the dichloride or dimethylsulphate (both crystalline and water-soluble), of the 1,1′-dimethyl-4,4′-bipyridylium ion, ({b1}C5H4N+·CH3)2, a quick-acting contact herbicide that is rendered inactive by the soil.
1961Weed Abstr. X. 572 Paraquat di(methyl sulphate), previously PP.910, a new herbicide. Publ. Plant Protection Ltd., 1961 pp. 6. Paraquat (1,1′-dimethyl-4,4′-bipyridylium) is the name given to the free radicle. Two salts are currently under test, the di(methyl sulphate) (PP.910) and the dichloride (PP.148)... Paraquat salts are very rapidly absorbed into the aerial parts of plants. 1962New Scientist 6 Sept. 490/1 The active ingredient—paraquat—is a member of a family of herbicidal chemicals (quaternary salts of bipyridyls). 1962Listener 15 Nov. 836/1 A new family of weed-killing substances based on ‘paraquat’ may herald a new agricultural revolution. Paraquat is almost a total weed-killer but is especially useful in killing grasses. 1965Economist 5 June 1193/2 The ‘Paraquat’ herbicides, used in ploughless cultivation. 1968Times 17 Dec. 10/5 The weedkiller paraquat..is highly poisonous but is swiftly broken down to harmless components by bacteria in the soil. 1972Country Life 20 Jan. 169 The advent of paraquat was one of the most important developments in British farming in the 1960's. 1974Daily Tel. 2 Feb. 1/1 The weedkiller paraquat has been officially declared a poison... Only registered pharmacists or firms will be able to sell paraquat, and only people engaged in agriculture or horticulture will be able to buy it. 1974Times 2 Feb. 4/2 At least twenty deaths in Britain in the past 10 years are known to have been caused by paraquat. In almost all cases death followed the decanting of agricultural paraquat solutions into soft drink bottles. Granular preparations containing less than 5 per cent of paraquat salts are not affected by the new controls. 1977Jrnl. R. Soc. Arts CXXV. 567/2 Paraquat acts..by killing the green top growth of all plants and is inactivated by soil. |