| | 1 | Author
| Istvan Jablonkai | Requires cookie* | | | Title
| Basis for Differential Chemical Selectivity of MG-191 Safener against Acetochlor and EPTC Injury to Maize  | | | | Abstract
| The influence of MG-191 safener on the uptake, translocation and metabolism of [l4C]acetochlor and [14C]EPTC was studied. The amounts o f absorbed radioactivity by maize seedlings at 3, 6, 24, and 72 h after applications of [l4C]labeled herbicides and [l4C]MG-191 were different. Plants treated with [l4C]acetochlor took up 30-to 50-fold more radiolabel with in 72 h than [14C]EPTC-or [14C]MG-191-treated plants. Addition of MG-191 caused only mi nor changes in the rate of herbicide absorption. EPTC and MG-191 and/or their metabolites moved quickly acropetally and partitioned equally between root and shoot tissues up to 72 h. The amount of acetochlor and/or its labeled metabolites translocated to shoot tissues was less than 10%. MG-191 practically had no influence on herbicide translocation rates. With all chemicals the amounts of water-soluble and unextractable fractions increased while the ratio of hexane-extractable metabolites decreased with time. TLC analyses of both water-and hex ane-soluble metabolites confirmed the fast metabolism o f acetochlor. The acetochlor metabo lism took place via GSH conjugation and more polar, non-conjugated metabolites compared to parent molecule were detected in hexane-soluble fraction. MG-191 enhanced acetochlor metabolism by decreasing the portion of non-metabolized acetochlor. EPTC metabolism re sulted in water-soluble metabolites having similar chromatographic properties to those of ace tochlor. However, there was no safener effect on non-metabolized EPTC content of plants. It appears that MG-191 protects maize against EPTC by enhancing the early rate of conjugation with GSH after initial oxidative metabolism. | | | |
Reference
| Z. Naturforsch. 46c, 836—845 (1991); received March 26 1991 | | | |
Published
| 1991 | | | |
Keywords
| Chemical Selectivity, Safener, MG-191, Acetochlor, EPTC, Uptake, Translocation, Metabo lism | | | |
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| default:Reihe_C/46/ZNC-1991-46c-0836.pdf | | | | Identifier
| ZNC-1991-46c-0836 | | | | Volume
| 46 | |
| 2 | Author
| Gyula Oros, Tam Ás, K. Öm Íves | Requires cookie* | | | Title
| Effects of Phenylamide Pesticides on the GSH-Conjugation System of Phytophthora spp. Fungi | | | | Abstract
| Phytophthora cactorum, Ph. cambivora, Ph. cinnamomi, Ph. citricola, Ph. cryptogea, Ph. drechsleri, Ph. infestans, Ph. megasperma, Ph. parasitica, and Ph. syringae contain GSH-conju-gation systems as indicated by the presence o f active GST enzyme in addition to GSH. Basal levels of both GSH and GST in the thalli of Phytophthora strains studied did not correlate with either fungal sensitivity to phenylamides (acetochlor, butachlor, metolachlor, dimethachlor, propachlor, ofurace, CGA-29212, metalaxyl, RE-26745, benalaxyl, furalaxyl, LAB-149202) or their acquired resistance to metalaxyl. Thalli o f Phytophthora strains from axenic cultures ex posed to sublethal concentrations of the above pesticides contained significantly higher levels of both GSH and GST than the untreated controls. This response was independent of the sen sitivity and tolerance o f the strains to phenylamides. When the responses of Phytophthora strains to phenylamide chemicals were compared by means of principal com ponent analysis, four independent com ponents were detected account ing for 88% of the total variation. Biological properties (basal and induced levels of GST and GSH, growth intensity, degree of acquired resistance to metalaxyl, sensitivity to propiconazole and to cis-and /ra«s-tridem orph) of the strains contributed differently to this variation. It was concluded that, in contrast to plants, sensitivity or tolerance o f Phytophthora species to phenylamide pesticides is not regulated by the efficiency of the GSH-conjugation system. In addition, our data clearly indicate that the acetanilide pesticides have multiple sites of action in the Phytophthora genus. | | | |
Reference
| Z. Naturforsch. 46c, 866—874 (1991); received | | | |
Published
| 1991 | | | |
Keywords
| M arch 26, 1991 Phytophthora, G lutathione, G lutathione S-Transferase, Acetochlor, Metalaxyl, Fungicide Mode of Action, Acetanilide (Chloroacetamide) Pesticides | | | |
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| default:Reihe_C/46/ZNC-1991-46c-0866.pdf | | | | Identifier
| ZNC-1991-46c-0866 | | | | Volume
| 46 | |
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