| | 1 | Author
| R. Blaich, O. Bachmann, Iris Baumberger | Requires cookie* | | | Title
| Studies of Photosynthesis Inhibition by Phytoluminography  | | | | Abstract
| Inhibition of photosynthesis by simazine or diuron, as well as disturbance brought about by darkness, fungal infections, heat, high concentrations or lack o f C 0 2, lead to a luminescence of chloroplasts after irradiation with photosynthetically active light. This effect is the basis of phytoluminography, a new method which may replace in many cases the tedious procedures used at present to determine the photosynthetic capacity o f living plant tissue. Both qualitative analyses of luminescence images produced by an image intensifier as well as quantitative measurements using a photomultiplier are possible. Autoradiographic studies have shown that luminescence images of herbicide-damaged leaves are identical with autoradiographs of the same leaf obtained after labelling with radioactive C 0 2. In contrast to autoradiography, phytoluminography does not damage the tested parts of plants nor is there danger o f contamination. There is no need for expensive chemicals and skilled technicans, and immediate results are obtained. Quantitative measurements o f phytoluminescence after the application o f simazine and diuron (DCMU) to Elodea canadensis in submersed culture showed that approximately 1 M of inhibitor per 20 m of chlorophyll (a + b) is needed to obtain maximal luminescence, which indicated total inhibition of photosynthesis. Both luminescence and inhibition are reversible if the inhibitor is removed by dialysis. | | | |
Reference
| Z. Naturforsch. 37c, 452 (1982); received January 18 1982 | | | |
Published
| 1982 | | | |
Keywords
| Chlorophyll Luminescence, Photosynthesis Inhibition, Simazine, Phytoluminography | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0452.pdf | | | | Identifier
| ZNC-1982-37c-0452 | | | | Volume
| 37 | |
| 2 | Author
| W. Bilger, U. Heber, U. Schreiber | Requires cookie* | | | Title
| Kinetic Relationship between Energy-Dependent Fluorescence Quenching, Light Scattering, Chlorophyll Luminescence and Proton Pumping in Intact Leaves | | | | Abstract
| A measuring system was designed for simultaneous recording of modulated chlorophyll fluorescence and light scattering changes. The kinetic relationship was investigated between light-induced changes in non-photochemical fluorescence quenching, as determined by the saturation pulse method, and in light scattering, as measured via the apparent absorbance change at 543 nm. Very similar, but not identical kinetics were observed, reflecting a close non-linear relationship between these two indicators of thylakoid membrane energization. Fluorescence was found more sensitive at low levels of energization, while scattering continued indicating further increases in energization when quenching already was saturated. A general relationship between quenching and scattering is demonstrated which holds irrespective of whether energization is varied during induction or via changes in light intensity or C02 concentration. In the light-off responses, only part of fluorescence quenching was found to relax with the same kinetics as scattering. It is suggested that at high levels of energization slowly reversible membrane changes may be induced which have the potential of non-photochemical quenching at a low level of energization, and which are not accompanied by scattering changes. Neither quenching nor scattering changes displayed kinetics sufficiently fast to be taken as a direct expression of internal thylakoid acidifica-tion in intact leaves. This conclusion is drawn from comparative measurements of proton-uptake, as reflected by C02-solubilization upon light-induced stroma alkalization, and of chlorophyll luminescence. Both, the initial C02-gulp and the pH-dependent luminescence rise were found to clearly precede the development of energy-dependent quenching. | | | |
Reference
| Z. Naturforsch. 43c, 877—887 (1988); received July 18 1988 | | | |
Published
| 1988 | | | |
Keywords
| Chlorophyll Fluorescence, Light Scattering, Chlorophyll Luminescence, Thylakoid Membrane, Proton Pumping | | | |
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| default:Reihe_C/43/ZNC-1988-43c-0877.pdf | | | | Identifier
| ZNC-1988-43c-0877 | | | | Volume
| 43 | |
| 3 | Author
| W. Bilger, U. Schreiber | Requires cookie* | | | Title
| Modulation of Millisecond Chlorophyll Luminescence by Non-Photochemical Fluorescence Quenching | | | | Abstract
| By combining a high frequency modulation system for measurement of fluorescence with a phosphoroscope type apparatus for measurement of luminescence, recordings of fluorescence and luminescence induction kinetics under identical conditions were obtained. Both measuring sys tems tolerated the application of saturating pulses of white light for rapid, transient elimination of photochemical quenching at photosystem II reaction centers, thus allowing determination of the non-photochemical quenching component. The saturation pulse induction curves of luminescence are well correlated with the corresponding curves of fluorescence, suggesting that luminescence yield is lowered by the same type of non-photochemical quenching (mostly "energy dependent quenching") as fluorescence. Hence, in order to evaluate luminescence signals in terms of the rate of charge recombination at photosystem II reaction centers, knowledge of fluorescence quenching is required. | | | |
Reference
| Z. Naturforsch. 44c, 966 (1989); received June 28 1989 | | | |
Published
| 1989 | | | |
Keywords
| Chlorophyll Luminescence, Chlorophyll Fluorescence, Energy Dependent Quenching, Photo system II, Photosynthesis Induction | | | |
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| default:Reihe_C/44/ZNC-1989-44c-0966.pdf | | | | Identifier
| ZNC-1989-44c-0966 | | | | Volume
| 44 | |
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