Abstract
Several studies have indicated that chlorate (ClO3-) and nitrate (NO3-) may share a common transport system in higher plants. Here, we compared the interactions between ClO3- and NO3-uptake by roots of intact tomato (Lycopersicon esculentum cv T5) plants. Exposure to ClO3- for more than 2 h inhibited both net ClO3- and K+ uptake, presumably because of ClO3- toxicity; consequently, subsequent measurements were conducted after short exposures to ClO3-. The apparent affinity and apparent maximum rate of absorption for net ClO3- and NO3- uptake were very similar. Interactions between ClO3- and NO3- transport were complex; 50 [mu]M NO3- acted as a mixed inhibitor of net ClO3- uptake, but 50 [mu]M ClO3- had no significant effect on net NO3- uptake, and 500 [mu]M ClO3- had no significant effect on 15NO3- influx. If the two ions share a single common high-affinity transport system, it is much more selective for NO3- than would be suggested by the similarity of net NO3- and ClO3- uptake kinetics. Our results indicate that, although NO3- may interfere with root ClO3- uptake, ClO3- is not a useful analog for the root high-affinity NO3- transport system.
Full Text
The Full Text of this article is available as a PDF (755.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cove D. J. Chlorate toxicity in Aspergillus nidulans. Studies of mutants altered in nitrate assimilation. Mol Gen Genet. 1976 Jul 23;146(2):147–159. doi: 10.1007/BF00268083. [DOI] [PubMed] [Google Scholar]
- Deane-Drummond C. E., Glass A. D. Nitrate Uptake into Barley (Hordeum vulgare) Plants : A New Approach Using ClO(3) as an Analog for NO(3). Plant Physiol. 1982 Jul;70(1):50–54. doi: 10.1104/pp.70.1.50. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hole D. J., Emran A. M., Fares Y., Drew M. C. Induction of nitrate transport in maize roots, and kinetics of influx, measured with nitrogen-13. Plant Physiol. 1990 Jun;93(2):642–647. doi: 10.1104/pp.93.2.642. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kosola K. R., Bloom A. J. Methylammonium as a Transport Analog for Ammonium in Tomato (Lycopersicon esculentum L.). Plant Physiol. 1994 May;105(1):435–442. doi: 10.1104/pp.105.1.435. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Murphy T. M., Imbrie C. W. Induction and Characterization of Chlorate-resistant Strains of Rosa damascena Cultured Cells. Plant Physiol. 1981 May;67(5):910–916. doi: 10.1104/pp.67.5.910. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siddiqi M. Y., Glass A. D., Ruth T. J., Rufty T. W. Studies of the Uptake of Nitrate in Barley: I. Kinetics of NO(3) Influx. Plant Physiol. 1990 Aug;93(4):1426–1432. doi: 10.1104/pp.93.4.1426. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siddiqi M. Y., King B. J., Glass A. D. Effects of nitrite, chlorate, and chlorite on nitrate uptake and nitrate reductase activity. Plant Physiol. 1992 Oct;100(2):644–650. doi: 10.1104/pp.100.2.644. [DOI] [PMC free article] [PubMed] [Google Scholar]