Plant Adaptaion Research, J. Blaustein Institute for Desert Research, Sede Boker, Ben Gurion University of the Negev, 84993, Israel.
Effect of NaCl salinity, nitrogen form, calcium and potassium concentration on nitrogen uptake and kinetics in Triticum aestivum L. cv. Gamtoos
Article first published online: 28 APR 2006
Volume 124, Issue 1, pages 171–177, May 1993
How to Cite
HAWKINS, H.-J. and LEWIS, O. A. M. (1993), Effect of NaCl salinity, nitrogen form, calcium and potassium concentration on nitrogen uptake and kinetics in Triticum aestivum L. cv. Gamtoos. New Phytologist, 124: 171–177. doi: 10.1111/j.1469-8137.1993.tb03807.x
- Issue published online: 28 APR 2006
- Article first published online: 28 APR 2006
- (Received 26 June 1992; accepted 22 January 1993)
- N nutrition;
- N kinetics;
- Triticum aestivum
In wheat plants it was found that salinity stress (50 mM NaCl) and an increase in the exogenous Ca2+ supply (to 5 mM) had a differential influence on N uptake capacity depending on the N source (NO3− or NH4+). In NO3−supplied wheat plants which had not been supplied with supplemental calcium, a salinity of 50 mM NaCl reduced the N uptake rate of the root by 30 %, reduced the Fmax of NO3− uptake by 38 % and the N concentration of the plants by 35 %. In NH4+supplied plants (which were not affected by a change in calcium concentration) a salinity of 50 mM resulted in a reduction in the N concentration by 16 % (only in the root), a reduction in the Fmax of NH4+uptake by 50 %, while the N uptake rate by the plant was reduced by 16 %. In salt-stressed NO3−supplied wheat, an exogenous Ca24 concentration of 5 mM resulted in a 65 % increase in Vmax of NO3− uptake, a 58% increase in NO3− uptake rate by the shoot per g root and a 61 and 5 % increase in shoot and root N concentration respectively. Increased exogenous concentrations of either Ca2+ or K+ had no effect on NH4+ uptake. Kinetic calculations indicate that the inhibitory activity of NaCl on both NO3− and NH4+ uptake was one of noncompetitive inhibition. When NO3−, but not NH4+, was the N source, Ca2+ at a concentration of 5 mM partially ameliorated the NaCl-mediated inhibition of NO3− uptake.