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Effect of Nitrate on Uptake of Pertechnetate by Tomato Plants
Author(s) -
Krijger G. C.,
Kollöffel C.,
Wolterbeek H. T.
Publication year - 2000
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2000.00472425002900030023x
Subject(s) - chemistry , lycopersicon , nitrate , pertechnetate , horticulture , efflux , botany , nuclear chemistry , biochemistry , technetium , biology , organic chemistry
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 [ 99m Tc]TcO − 4 , [ 35 S] SO 2− 4 and H 2 [ 32 P]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 m M 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 ( K i = 3.3 m M ), although about 30% of the TcO − 4 influx is suggested to be insensitive to NO − 3 . In contrast, H 2 PO − 4 (30 m M ) did not inhibit TcO − 4 influx, whereas SO 2− 4 (30 m M ) 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.