ISSN:
1573-5036
Keywords:
amides
;
free ammonium
;
MSX
;
net ammonium uptake inhibition
;
total free amino acids
;
Triticum aestivum L.
;
wheat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract When N deficient 10-day-old wheat plants were supplied with 1.5 mol m−3 NH4 +, net NH4 + uptake rapidly decreased during the first 6h, while root free-NH4 + and free amino acids concentration increased. However, after 24 h the NH4 + uptake rate increased again, as the internal NH4 + concentration decreased. When plants were pretreated during 40 h with different external NH4 + concentrations, net uptake measured on 1.0 mol m−3 NH4 + decreased with the increasing ion concentration during the pretreatment. This decrement coincided with both root free-NH4 + and total free amino acids levels. When N-starved and NH4 + fed plants were treated during 0, 3 or 6 h with 1.0 mol m−3 NH4 + in the presence of 1.0 mol m−3 MSX2, net uptake (measured without MSX) decreased with the length of the inhibitor treatment. In both groups, MSX significantly increased root free-NH4 + concentration, while the level of total free amino acids was only increased in N-starved plants. When N-starved plants were externally supplied with 1.0 mol m−3 of different amino acids or amides, net NH4 + uptake was only strongly inhibited in the presence of glutamine or asparagine. It is concluded that rapid changes in the concentration of certain amino acids during NH4 + nutrition might regulate the ion absorption, though at high endogenous levels of free NH4 + net uptake could be suppressed independently of the root concentration of free amino acids.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00016286
