Abstract
The influence of a 12-h pretreatment with either NO3-, NH4+, glutamine, or glutamate (300 [mu]M) on the apparent induction of NO3- uptake was investigated. Net fluxes of NO3- into roots of intact, 7-d-old barley (Hordeum vulgare L. cv Prato) seedlings in solution culture were estimated from ion activity gradients measured with NO3--selective microelectrodes in the unstirred layer of solution immediately external to the root surface. Control plants, pretreated with nitrogen-free nutrient solution, exhibited a sigmoidal increase in net NO3- uptake, reaching a maximum rate between 8 and 9 h after first exposure to NO3-. Plants pretreated with NH4+ or Glu exhibited a delay of several hours in the initiation of the induction process after they had been exposed to NO3-. In Gln-pretreated plants, however, responses ranged from no delay of the induction process to delays comparable to those observed following NH4+ or Glu pretreatments. Only treatment with NO3-resulted in the induction of NO3- uptake, whereas pretreatments with NH4+, Gln, or Glu tended to delay induction of NO3- uptake upon subsequent exposure to NO3-.
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Selected References
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- Aslam M., Travis R. L., Huffaker R. C. Comparative kinetics and reciprocal inhibition of nitrate and nitrite uptake in roots of uninduced and induced barley (Hordeum vulgare L.) seedlings. Plant Physiol. 1992;99:1124–1133. doi: 10.1104/pp.99.3.1124. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bloom A. J., Caldwell R. M., Finazzo J., Warner R. L., Weissbart J. Oxygen and carbon dioxide fluxes from barley shoots depend on nitrate assimilation. Plant Physiol. 1989 Sep;91(1):352–356. doi: 10.1104/pp.91.1.352. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bloom A. J., Sukrapanna S. S. Effects of Exposure to Ammonium and Transplant Shock upon the Induction of Nitrate Absorption. Plant Physiol. 1990 Sep;94(1):85–90. doi: 10.1104/pp.94.1.85. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bloom A. J., Sukrapanna S. S., Warner R. L. Root respiration associated with ammonium and nitrate absorption and assimilation by barley. Plant Physiol. 1992 Aug;99(4):1294–1301. doi: 10.1104/pp.99.4.1294. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Breteler H., Siegerist M. Effect of ammonium on nitrate utilization by roots of dwarf bean. Plant Physiol. 1984 Aug;75(4):1099–1103. doi: 10.1104/pp.75.4.1099. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Henriksen G. H., Bloom A. J., Spanswick R. M. Measurement of net fluxes of ammonium and nitrate at the surface of barley roots using ion-selective microelectrodes. Plant Physiol. 1990 May;93(1):271–280. doi: 10.1104/pp.93.1.271. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Henriksen G. H., Raman D. R., Walker L. P., Spanswick R. M. Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes : II. Patterns of Uptake Along the Root Axis and Evaluation of the Microelectrode Flux Estimation Technique. Plant Physiol. 1992 Jun;99(2):734–747. doi: 10.1104/pp.99.2.734. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siddiqi M. Y., Glass A. D., Ruth T. J., Fernando M. Studies of the Regulation of Nitrate Influx by Barley Seedlings Using NO(3). Plant Physiol. 1989 Jul;90(3):806–813. doi: 10.1104/pp.90.3.806. [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]
- Tomino Y., Sakai H., Woodroffe A. J., Clarkson A. R. Studies on glomerular immune solubilization by complement in patients with IgA nephropathy. Acta Pathol Jpn. 1987 Nov;37(11):1763–1767. doi: 10.1111/j.1440-1827.1987.tb02869.x. [DOI] [PubMed] [Google Scholar]
- Warner R. L., Huffaker R. C. Nitrate transport is independent of NADH and NAD(P)H nitrate reductases in barley seedlings. Plant Physiol. 1989;91:947–953. doi: 10.1104/pp.91.3.947. [DOI] [PMC free article] [PubMed] [Google Scholar]
