| | 1 | Author
| Jürgen Feierabend | Requires cookie* | | | Title
| Comparison of the Action of Bleaching Herbicides  | | | | Abstract
| Among chlorosis-inducing herbicides that interfere with carotenoid synthesis two groups o f different potency can be discriminated (group 1; aminotriazole amd haloxidine; group 2 with more extensive photodestructions: pyridazinone herbicides and difunon). After application o f herbicides o f group 2 colored carotenoids were com pletely absent and preexisting chlorophyll was degraded by photochem ical reactions requiring high light intensity and 0 2, that occurred also at 0 °C . In treatments with group 1 herbicides direct photodegradation o f chlorophyll was not sufficient to generate the chlorosis. Light-induced interference with constituents o f the chloroplast protein synthesis apparatus being more sensitive to ph otooxidative dam age than chlorophyll, appeared to indirectly m ediate the chlorosis. In the absence o f chloroplast protein synthesis further chlorophyll accum ulation is prevented. Photodegradation o f chlorophyll in the presence o f group 2 herbicides involved the participation o f 0 2~ radicals and was accom panied by lipid peroxidation. In all herbicide treatments the catalase activity o f the leaves was very low. Only in the presence o f group 2 herbicides chloroplast enzym es o f cytoplasm ic origin (e.g. NADP-glyceraldehyde-3-phosphate dehydrogenase) were also inactivated. Rapid inactivation o f catalase as well as o f N A D P-glyceraldehyde-3-phosphate dehydrogenase was induced by exposure o f dim-light-grown herbicide-treated leaves to bright light, also at 0 ° C . In treatments with herbicides o f group 2 also other peroxisom al enzymes (e.g. glycolate oxidate, hydroxy-pyruvate reductase) were affected. The elim ination o f these peroxisom al enzym es also appeared to depend on photooxidative processes o f the chloroplast. | | | |
Reference
| Z. Naturforsch. 39c, 450 (1984); received N ovem ber 4 1983 | | | |
Published
| 1984 | | | |
Keywords
| Bleaching Herbicides, Carotenoids, Catalase, Chlorosis, Leaf Peroxisom es, Photooxidation | | | |
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| default:Reihe_C/39/ZNC-1984-39c-0450.pdf | | | | Identifier
| ZNC-1984-39c-0450 | | | | Volume
| 39 | |
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