Modeling nitrogen uptake in oilseed rape cv Capitol during a growth cycle using influx kinetics of root nitrate transport systems and field experimental data.
The use of kinetic equations of NO3- transport systems in oilseed rape (Brassica napus), determined by 15NO3- labeling under controlled conditions, combined with experimental field data from the INRA-Châlons rape database were used to model NO3- uptake during the plant growth cycle. The quantitative effects of different factors such as day/night cycle, ontogenetic stages, root temperature, photosynthetically active radiation, and soil nitrate availability on different components of the constitutive high-affinity transport systems, constitutive low-affinity transport systems, inducible low-affinity transport systems, and inducible high-affinity transport systems of nitrate were then determined to improve the model's predictions. Simulated uptake correlated well with measured values of nitrogen (N) uptake under field conditions for all N fertilization rates tested. Model outputs showed that the high-affinity transport system accounted for about 89% of total NO3- uptake (18% and 71% for constitutive high-affinity transport systems and inducible high-affinity transport systems, respectively) when no fertilizer was applied. The low-affinity transport system accounted for a minor proportion of total N uptake, and its activity was restricted to the early phase of the growth cycle. However, N fertilization in spring increased the duration of its contribution to total N uptake. Overall, data show that this mechanistic and environmentally regulated approach is a powerful means to simulate total N uptake in the field with the advantage of taking both physiologically regulated processes at the overall plant level and specific nitrate transport system characteristics into account.
Malagoli
Philippe
P
Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Université de Caen Basse-Normandie, 950 de Physiologie et Biochimie Végétales, IRBA, Université de Caen, 14032 Caen, France.
Lainé
Philippe
P
Le Deunff
Erwan
E
Rossato
Laurence
L
Ney
Bertrand
B
Ourry
Alain
A
D001693:Biological Transport, Active; D029688:Brassica napus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D004777:Environment; D007700:Kinetics; D008954:Models, Biological; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D017440:Photoperiod; D018517:Plant Roots / Q000378:metabolism
D009566:Nitrates; D009584:Nitrogen