| | 1 | Author
| C. Buschm, K.H G Ru | Requires cookie* | | | Title
| Herbicides which Inhibit Electron Transport or Produce Chlorosis and Their Effect on Chloroplast Development in Radish Seedlings II. Pigment Excitation, Chlorophyll Fluorescence and Pigment-Protein Complexes  | | | | Abstract
| DCM U, bentazon, amitrole and SA N 6706 affected the form ation o f the pigm ent-protein com plexes and caused drastic alterations in the absorption o f light and in the transfer o f the absorbed energy in the antennae systems. Bentazon and D C M U , photosystem II inhibitors, did not change the pigment absorption and fluorescence excitation spectra. After application o f both herbicides the long wavelength fluorescence em ission band at 740 nm was reduced sim ilar as in young d e veloping leaves. Although D C M U and bentazon inhibit the photosynthetic electron transport at the same site, bentazon mainly suppressed the form ation o f the photosystem I com plexes C P Ia and CPI while DC M U mainly reduced the photosystem II com plex CPa. Bentazon specifically en hanced the formation o f LHCP3. This may be im portant for the increased grana stacking in plas-tids from bentazon treated plants. The bleaching herbicides amitrole and SA N 6706 inhibited the form ation o f carotenoids lead ing to an accumulation o f lycopene, phytofluene and phytoene, w hile the accum ulation o f chloro phylls was suppressed. This bleaching effect was m ost pronounced during growth under higher intensities o f light. In weak light (100 lux) am itrole reduced the long wavelength fluorescence maximum but the fluorescence excitation was not affected. W ith am itrole at 2000 lux and SAN 6706 at 100 lux the long wavelength em ission band was further decreased and the fluores cence excitation spectra point to a less efficient energy transfer to chlorophyll a. The fluorescence spectra changed due to herbicide treatment resem bled those o f not yet fully developed leaves. In contrast to the photosystem II herbicides the bleaching herbicides am itrole and SA N 6706 had a similar effect on the formation o f pigm ent-protein com plexes. After growth at 2000 lux both herbicides suppressed the formation o f the photosystem I com plex C P Ia and the photosystem II complex CPa. At 100 lux only the formation o f C P Ia was affected. Except for D C M U all herbicides assayed primarily changed the form ation o f photosystem I. | | | |
Reference
| Z. Naturforsch. 37c, 632 (1982); received April 2 1982 | | | |
Published
| 1982 | | | |
Keywords
| Bleaching Herbicides, Carotenoids, Chlorophylls, C hlorophyll Fluorescence, Photosystem II Herbicides, Pigm ent-Protein-Complexes | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0632.pdf | | | | Identifier
| ZNC-1982-37c-0632 | | | | Volume
| 37 | |
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