An updated model for nitrate uptake modelling in plants. II. Assessment of active root involvement in nitrate uptake based on integrated root system age: measured versus modelled outputs
Résumé
An updated version of a mechanistic structural-functional model was developed to predict nitrogen (N) uptake throughout the growth cycle by a crop of winter oilseed rape, Brassica napus, grown under field conditions. The functional component of the model derives from a revisited conceptual framework that combines the thermodynamic Flow-Force interpretation of nitrate uptake isotherms and environmental and in planta effects on nitrate influx. Estimation of the root biomass (structural component) is based upon a combination of root mapping along the soil depth profile in the field and a relationship between the specific root length and external nitrate concentration. The root biomass contributing actively to N uptake was determined by introduction of an integrated root system age that allows assignment of a root absorption capacity at a specific age of the root. Simulations were well matched to measured data of N taken up under field conditions for three levels of N fertilization. The model outputs indicated that the two topsoil layers (0-30 and 30-60 cm) contained 75-88 % of the total root length and biomass, and accounted for 90-95 % of N taken up at harvest. This conceptual framework provides a model of nitrate uptake that is able to respond to external nitrate fluctuations at both functional and structural levels.
Mots clés
Nitrate
N uptake regulation
Flow-Force interpretation
nitrogen uptake
efficiency
root development
root longevity
functional-structural
plant model
N uptake modelling
Brassica napus
winter oilseed rape
temporal growth-patterns
brassica-napus l
nutrient-uptake
no3-uptake
electrokinetic
interpretation
arabidopsis-thaliana
biological systems
diurnal
regulation
Domaines
Biologie végétale
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2014_Malagoli_Ann_Bot_{777B8E29-8925-4DAB-A2D6-60B572768FCB}.pdf (1.12 Mo)
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