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This article in JEQ

  1. Vol. 29 No. 3, p. 866-870
    Received: Jan 25, 1999

    * Corresponding author(s): h.t.wolterbeek@iri.tudelft.nl
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Effect of Nitrate on Uptake of Pertechnetate by Tomato Plants

  1. G. C. Krijger,
  2. C. Kollöffel and
  3. H. T. Wolterbeek *
  1. Delft Univ. of Technology, Dep. of Radiochemistry, Interfaculty Reactor Institute, Mekelweg 15, 2629 JB Delft, The Netherlands.
    Univ. of Utrecht, Faculty of Biology, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands.



Nitrate has been shown to affect the acquisition of the nuclear waste product technetium (Tc) by plants. The mechanism responsible for this phenomenon is unknown. The uptake of [99mTc]TcO4, [35S] SO2−4 and H2[32P]PO4 was studied in tomato plants (Lycopersicon esculentum Mill., cv. Tiny Tim) with different growth rates due to culture at 0.5, 4.0, or 30 mM NO3. In experiments lasting 24 h, net TcO4 uptake decreased at higher NO3 supplies. The inhibitory effect of NO3 on TcO4 uptake also was shown in TcO4 influx experiments (Ki = 3.3 mM), although about 30% of the TcO4 influx is suggested to be insensitive to NO3. In contrast, H2PO4 (30 mM) did not inhibit TcO4 influx, whereas SO2−4 (30 mM) tended to increase TcO4 influx, probably due to the ionic strength of the uptake solution. Significant effects of the NO3 supply on Tc efflux were not found. Overall, this leads to the conclusion that TcO4 and NO3 share at least one transporter.

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