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'Ioxynil' in keywords Facet   Publication Year 1979  [X]
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1Author    S. Reimer, K. Link, A. TrebstRequires cookie*
 Title    Comparison of the Inhibition of Photosynthetic Reactions in Chloroplasts by Dibromothymoquinone, Bromonitrothymol and Ioxynil  
 Abstract    The inhibition of photosynthetic electron flow in broken chloroplasts by dibromothymoquinone and dibromothymohydroquinone (DBMIBH2) is reversed by dithiothreitol (DTT) as well as by serum albumin. The reversal of DBMIBH2 inhibition by DTT shows a time lag, that of DBMIB only, when chloroplasts and DBMIB had been preilluminated. This is to show that chloroplasts reduce DBMIB and that probably DBMIBH2 is the actual inhibitor species. Bromonitrothymol, ioxynil and related inhibitory phenolic compounds have a different relation­ ship of inhibitory potency to chemical structure than DCMU and the analogous triazinone herbicide metribuzin but nevertheless inhibit photosynthetic electron flow at the same functional site. This is supported by the finding that labelled metribuzin is displaced from the thylakoid membrane by bromonitrothymol and ioxynil indicating identical binding sites. On the other hand inhibition by the phenolic inhibitors bromonitrothymol and ioxynil but not that of DCMU and metribuzin has a time lag of about 4 min. 
  Reference    Z. Naturforsch. 34c, 419 (1979); received October 31 1978 
  Published    1979 
  Keywords    Photosynthesis, Inhibition, Herbicides, Dibromo-thymoquinone, Bromonitrothymol, Ioxynil 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0419.pdf 
 Identifier    ZNC-1979-34c-0419 
 Volume    34 
2Author    A. TrebstRequires cookie*
 Title    Inhibition of Photosynthetic Electron Flow by Phenol and Diphenylether Herbicides in Control and Trypsin-Treated Chloroplasts  
 Abstract    Alkyl substituted 2-halogen-4-nitro-phenols (like brom onitrothymol) are potent inhibitors of photosynthetic electron flow in chloroplasts. There inhibition site is identical to that of DCMU, though the phenols do not contain th eir essential chemical elem ent responsible for inhibition nor do they follow their correlation of chemical structure and biochemical function. Binding of labelled m etribuzin on the chloroplast m em brane and its replacem ent by the phenol inhibitors support the notion of identical binding sites, however. In trypsin treated chloroplasts, the prim ary acceptor of photosystem II becomes accessible to ferricyanide, whose photoreduction is therefore DCMU insensitive. A fter trypsin treatm ent also the sensitivity of ferricyanide reduction to phenol inhibitors is lost as is the binding of labelled m etri­ buzin. The dinitrophenylethers of brom onitrothym ol and of ioxynil and other diphenylethers are potent inhibitors of photosynthetic electron flow. T heir site of inhibition is after the function of plasto-quinone, i. e. they are DBMIB analogues. 
  Reference    Z. Naturforsch. 34c, 986 (1979); received May 26 1979 
  Published    1979 
  Keywords    Photosynthesis, Herbicides, Trypsin Treatm ent, Brom onitrothymol, Ioxynil, Diphenylether 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0986.pdf 
 Identifier    ZNC-1979-34c-0986 
 Volume    34