Alterations in the antioxidative system of suspension-cultured soybean cells (Glycine max) induced by oxidative stress |
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Authors: | Oliver C Knörzer Jörg Burner Peter Boger |
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Institution: | O. C. Knörzer and P. Böger (corresponding author, fax +49–7531–883042), Lehrstuh! für Physiologie und Biochemie der Pflanzen, Univ. Konstanz, D-78434 Konstanz, Germanv: J. Burner, Waksman Inst., Rutgers Univ., Piscalaway, NJ 08855–0759, USA;. |
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Abstract: | The objectives of this study were the changes of antioxidative key enzyme activities under stress conditions induced by a peroxidizing herbicide using photoheterotrophi-cally grown, suspension-cultured soybean celts ( Glycine max L.). Within two days, 50 to 500 n M oxyfluorfen. a p-nitrodiphenyl ether herbicide, caused up to 100% inhibition of growth, while simultaneously, the chlorophyll was 25% to completely bleached. The major cellular antioxidants ascorbate and glutathione showed different responses. Under stress conditions with more than 250 n M oxyfluorfen, the cellular ascorbate- concentration was halved, whereas dehydroascorbate remained roughly constant. The glutathione content (approximately one-fifth of that of ascorbate in untreated control cells) increased nearly 3-fold in the presence of 250 n M oxyfluorfen. Under this condition, oxidized glutathione was 5 times above the control level. The specific activities of selected enzymes participating in cellular defence, namely ascor-bate peroxidase, glutathione reductase, rnonodehydroascorbate reductase. peroxidase and catalase increased by 40 to 70% with oxyfluorfen concentrations between 50 and 500 n M , while dehydroascorbate reductase showed a significant decrease. Glutathione transferase activity even increased 6-fold under oxyfluorfen stress. |
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Keywords: | Antioxidants antioxidative enzymes ascorbic acid diphenyl ether glutathione Glycine max Halliwell-Asada pathway herbicide homoglutathione oxidative stress oxyfluorfen plant cell culture soybean |
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