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'Carotenoids' in keywords Facet   section ZfN Section C:Volume 035  [X]
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1980 (2)
1Author    Marc Symons, Anthony CroftsRequires cookie*
 Title    Flash-Induced Electrochromic Band Shifts, is It a Simple Mechanism?  
 Abstract    The flash-induced carotenoid bandshifts have been studied for various strains of both Rho-dopseudomonas sphaeroides and capsulata. A technique for calculating shifts o f isobestic points down to 0.05 nm is described. To this end, special attention has been paid to the appropriate cor­ rection for reaction center absorbance changes occuring concommitantly with the carotenoid bandshifts. Plots of the wavelength o f the isobestic point versus the corresponding absorption changes at the maximum o f the difference spectrum have been made, suggesting the existence o f different pools of carotenoids. The various pools of carotenoids seem to have different sizes, in­ ducing non-linearities in the plots. In some cases spectral differences of the pools have to be assumed. A possible interpretation o f the results would be that each electrogenic span of the electron transport chain is to be associated with its own pool of carotenoids, all the pools behaving in somewhat independant way. We discuss possible difficulties in making those measurements. 
  Reference    Z. Naturforsch. 35c, 139—144 (1980); received August 16 1979 
  Published    1980 
  Keywords    Electrochromism, Carotenoids, Electron Transport, Membrane Potential, Photosynthesis 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0139.pdf 
 Identifier    ZNC-1980-35c-0139 
 Volume    35 
2Author    K. H. Grumbach, M. DrollingerRequires cookie*
 Title    The Effect of Phytochrome and Proteinsynthesis-Inhibitors on the Formation of Chlorophylls and Carotenoids in Radish Seedlings Treated with Photosystem II and Bleaching Herbicides  
 Abstract    Etioplasts of radish seedlings treated with photosystem II (DCM U, bentazon) and chlorotic herbicides (amitrole, SAN 6706) were tested on their ability to perform the phytochrome mediated chlorophyll and carotenoid biosynthesis. The cytoplasmic influence on the chloroplastic action o f herbicides was also investigated by inhibition of protein synthesis either in the chloro­ plast with chloramphenicol or in the cytoplasm with actidion. In all herbicide treated radish seedlings a phytochrome mediated chlorophyll and carotenoid biosynthesis was obtained as found in control plants. In plants treated with DCM U the bio­ synthesis o f carotenoids is enhanced compared to the control plants, while SAN 6706 significantly suppresses the carotenoid formation. It is concluded, that photosystem II and chlorotic herbicides do not interfere with the primary action o f phytochrome but rather do develope their effects on the terpenoid metabolism through phytochrome. Chloramphenicol applied at the time o f sowing very strongly suppresses the formation of chlorophylls and carotenoids in control plants. The sensitivity towards actidion is, however, very much lower. If chloramphenicol and actidion treated plants were also supplied with herbicides, the pigment pattern is completely different In SAN 6706-treated plants chloramphenicol acts synergistic, resulting in an even lower chlorophyll and carotenoid content than in plants supplied only with chloramphenicol. On the other hand SAN 6706 in combination with actidion enhances the formation of pigments, leading to a much higher chlorophyll and carotenoid content as in plants treated only with actidion. A stimulatory effect on the formation o f chlorophylls and carotenoids was also found for DCMU-treated plants in combination with actidion. The observation, that in plants treated with SAN 6706 together with actidion, which inhibits protein synthesis in the cytoplasm, the herbicidal response in the chloroplast is completely abolished, gives evidence that the photooxidative action of SAN 6706 in the chloroplast is developed by the cytoplasm. 
  Reference    Z. Naturforsch. 35c, 445 (1980); received February 8 1980 
  Published    1980 
  Keywords    Photosystem II Herbicides, Chlorotic Herbicides, Chlorophylls, Carotenoids, Phytochrome, Inhibitors 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0445.pdf 
 Identifier    ZNC-1980-35c-0445 
 Volume    35