Effect of Nitrate on Uptake of Pertechnetate by Tomato Plants
- G. C. Krijger,
- C. Kollöffel and
- H. T. Wolterbeek *
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]TcO−4, [35S] SO2−4 and H2[32P]PO−4 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 NO−3. In experiments lasting 24 h, net TcO−4 uptake decreased at higher NO−3 supplies. The inhibitory effect of NO−3 on TcO−4 uptake also was shown in TcO−4 influx experiments (Ki = 3.3 mM), although about 30% of the TcO−4 influx is suggested to be insensitive to NO−3. In contrast, H2PO−4 (30 mM) did not inhibit TcO−4 influx, whereas SO2−4 (30 mM) tended to increase TcO−4 influx, probably due to the ionic strength of the uptake solution. Significant effects of the NO−3 supply on Tc efflux were not found. Overall, this leads to the conclusion that TcO−4 and NO−3 share at least one transporter.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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