The bleaching induced by the phenylpyridazinone herbicide Metflurazon in Chlorella is a metabolic and reversible process

摘要: Abstract The treatment of synchronized cells the green alga Chlorella fusca under photoautotrophic conditions with metflurazon (SAN H 6706; 4-chloro-5-dimethylamino-2-(α,α,α-trifluoro-m-tolyl-3(2H)-pyridazinone)) induces a bleaching process and results in white-appearing cells. This was followed by quantitative analysis cell growth division, photosynthetic oxygen evolution, respiratory consumption, pigment pattern at 0, 6, 12, 18, 24, 48, 72 hr after incubation different concentrations metflurazon. Increasing gradually affected measured as increase diameter. Cell division inhibited completely 1, 10, 100 μM Photosynthetic evolution consumption were not 1 during first 6 hr; this time increased inhibition observed. Both parameters immediately herbicide addition. A detailed content revealed that: (a) is simple photochemical like photobleaching boiled cells, but directed active metabolism itself. (b) characterized two phases: an accumulation pigments their degradation. phase extends to (c) During phase, chlorophyll accumulated 380 106% treated metflurazon, respectively, compared initial content. breakdown chlorophyll, however, degradation 5 times faster than treatment. difference resulted appearance white low concentration. (d) treatment, biosynthesis chlorophylls, xanthophylls, carotenes 56, 74, 78%, when nontreated control. When related amounts, are 380, 230, 153%, respectively. However, synthesis violaxanthin specifically inhibited, α-carotene. α-carotene again, most rapidly disappearing pigments. Continuous culturing regeneration 96, 240, 384 for metflurazone, evidently dependent on functioning itself regulated disassembly apparatus, which reversible lethal.