title: Combined agronomic and physiological aspects of nitrogen management in wheat highlight a central role for glutamine synthetase.
abstract: In wheat the period of grain filling is characterized by a transition for all vegetative organs from sink to source status. To study this transition, the progression of physiological markers and enzyme activities representative of nitrogen metabolism was monitored from the vegetative stage to maturity in different leaf stages and stem sections of two wheat (Triticum aestivum) cultivars grown at high and low levels of N fertilization. In the two cultivars examined, we found a general decrease of the metabolic and enzyme markers occurred during leaf ageing, and that this decrease was enhanced when plants were N-limited. Both correlation studies and principal components analysis (PCA) showed that there was a strong relationship among total N, chlorophyll, soluble protein, ammonium, amino acids and glutamine synthetase (GS) activity. The use of a marker such as GS activity to predict the N status of wheat, as a function of both plant development and N availability, is discussed with the aim of selecting wheat genotypes with better N-use efficiency.
authors.affiliation: Laboratoire d' Androgenèse et Biotechnologie Végétale, Université de Picardie Jules Verne, 33 Rue saint-Leu, F-80039 Amiens Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kichey
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Heumez
authors.forename: Delphine
authors.initials: D
authors.lastname: Pocholle
authors.forename: Karine
authors.initials: K
authors.lastname: Pageau
authors.forename: Hélène
authors.initials: H
authors.lastname: Vanacker
authors.forename: Frédéric
authors.initials: F
authors.lastname: Dubois
authors.forename: Jacques
authors.initials: J
authors.lastname: Le Gouis
authors.forename: Bertrand
authors.initials: B
authors.lastname: Hirel
mesh_terms: D035264:Flowers / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D018547:Plant Stems / Q000254:growth & development / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D014908:Triticum / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen