JXB Advance Access published online on January 30, 2004
Journal of Experimental Botany, doi:10.1093/jxb/erh066
© 2004 by Oxford University Press
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 The Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, UK
* To whom correspondence should be addressed. E-mail: b.thornton{at}macaulay.ac.uk.
Plants of Lolium perenne L. were grown in sterile solution culture supplied with 2 mol m-3 nitrogen as either nitrate or ammonium. Glutamine at 5 mol m-3 was added to the nutrient solution of half the plants for 24 h. Root nitrate influx (at external nitrate concentrations 0-2000 mmol m-3) and amino acid concentrations were determined. In a second experiment the concentration of the added glutamine was varied from 0-5 mol m-3 and nitrate influx determined at 250 and 2000 mmol m-3. The maximum rate of influx attributed to the high affinity transport system (HATS) was reduced by 66% by the presence of glutamine achieved through an 84% reduction in its constitutive component and a 59% reduction in its inducible component. Influx attributed to LATS was unaffected by the addition of glutamine. The inhibition of total nitrate influx by glutamine was positively related to the contribution of HATS to the total influx. In both nitrate- and ammonium-grown plants, the concentration of glutamine required to inhibit nitrate influx significantly was lower when influx was determined at 250 mmol m-3 compared with 2000 mmol m-3 nitrate. The addition of glutamine increased its concentrations in root tissue. However, the results cannot be attributed to changes in glutamine alone as its addition also resulted in increased concentrations of other amino acids. Implications for plants growing under field conditions are discussed.
© 2004 Society for Experimental Biology
RESEARCH PAPER
Inhibition of nitrate influx by glutamine in Lolium perenne depends upon the contribution of the HATS to the total influx
Abstract 
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. J. Miller, X. Fan, Q. Shen, and S. J. Smith Amino acids and nitrate as signals for the regulation of nitrogen acquisition J. Exp. Bot., January 1, 2008; 59(1): 111 - 119. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Thornton, S. M. Osborne, E. Paterson, and P. Cash A proteomic and targeted metabolomic approach to investigate change in Lolium perenne roots when challenged with glycine J. Exp. Bot., May 1, 2007; 58(7): 1581 - 1590. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Fan, R. Gordon-Weeks, Q. Shen, and A. J. Miller Glutamine transport and feedback regulation of nitrate reductase activity in barley roots leads to changes in cytosolic nitrate pools J. Exp. Bot., March 1, 2006; 57(6): 1333 - 1340. [Abstract] [Full Text] [PDF]
|
|