Metabolism of reduced and inorganic sulphur in pea cotyledons and distribution into developing seedlings

Authors

  • Cornelia Herschbach,

    1. Fraunhofer Institut für Atmosphärische Umweltforschung (FhG-IFU), Kreuzeckbahnstr. 19, D-82467 Garmisch-Partenkirchen, Germany. Present address: Institut für Forstbotanik und Baumphysiologie, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee Gebäude 053/054, D-79085 Freiburg, Germany
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  • Birgit Pilch,

    1. Institut für Pflanzenphysiologie, Karl-Franzens-Universität Graz, Schubertstraße 51, A-8010 Graz, Austria
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  • Michael Tausz,

    Corresponding author
    1. Institut für Pflanzenphysiologie, Karl-Franzens-Universität Graz, Schubertstraße 51, A-8010 Graz, Austria
      Author for correspondence: Michael Tausz Tel: +43 316380 8794 Fax: +43 316380 9880 Email: michael.tausz@uni-graz.at
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  • Heinz Rennenberg,

    1. Fraunhofer Institut für Atmosphärische Umweltforschung (FhG-IFU), Kreuzeckbahnstr. 19, D-82467 Garmisch-Partenkirchen, Germany. Present address: Institut für Forstbotanik und Baumphysiologie, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee Gebäude 053/054, D-79085 Freiburg, Germany
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  • Dieter Grill

    1. Institut für Pflanzenphysiologie, Karl-Franzens-Universität Graz, Schubertstraße 51, A-8010 Graz, Austria
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Author for correspondence: Michael Tausz Tel: +43 316380 8794 Fax: +43 316380 9880 Email: michael.tausz@uni-graz.at

Summary

  •  Sulphur export and redistribution from the cotyledons of pea (Pisum sativum) seedlings was investigated to determine the role of cotyledons as a sulphur source during root–shoot axis development.
  •  Thiols and sulphate were analysed using standard biochemical techniques, and 35S fed to cotyledons by injection.
  •  After 35S-cysteine injection, c. 50% of the labelled S in the cotyledon was metabolized to 35S-sulphate. This reaction was partly inhibited by aminooxyacetic acid, an inhibitor of cysteine-desulfhydrase. After 35S-sulphate application, c. 1% of the radiolabel was found in cysteine and glutathione in the cotyledon. After 2 h, c. 20% of the 35S was transported into the root–shoot axis independently of whether 35S-sulphate or 35S-cysteine was injected into the cotyledon. After 4 h, 40% of 35S was found outside the cotyledon.
  •  Cotyledons of pea seedlings are capable of sulphate assimilation and cysteine degradation. Both sulphate and reduced sulphur were allocated from the cotyledons to the developing tissues of the pea seedlings.

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