Modelling of nitrogen uptake based on a cross-combination of Flow-force interpretation of nitrate uptake isotherm and environmental and in planta regulation of nitrate influx rate - Archive ouverte HAL Accéder directement au contenu
Poster De Conférence Année : 2015

Modelling of nitrogen uptake based on a cross-combination of Flow-force interpretation of nitrate uptake isotherm and environmental and in planta regulation of nitrate influx rate

Résumé

A mechanistic structural–functional model was developed to predict nitrogen uptake throughout the growth cycle by a crop of winter oilseed rape (Brassicanapus) grown under field conditions. The functional component of the model (nitrate uptake activity) 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. The Flow-Force theory was proposed in the seventies to describe ion isotherms based upon biophysical “flows and forces” relationships of non-equilibrium thermodynamics. This perspective appears more realistic for describing root N uptake at kinetic and molecular levels than the carrier viewpoint of Enzyme-Substrate interpretation. Indeed, the Enzyme-substrate interpretation has not withstood recent molecular analyses about nitrate transporters. At least four families of nitrate transporters operating at both high and/or low external nitrate concentrations and located in series and/or parallel in the different cellular layers of the mature root are involved in nitrate uptake. Likewise, the demonstration was made that Vmax and Km parameters deduced from influx isotherms are only “apparent” parameters representative of the overall behaviour of the root sample studied for the absorption process. Estimation of structural component of the model (root biomass) 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 concentrations. 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. This conceptual framework provides a model of nitrate uptake that is able to respond in a more realistic manner to external nitrate fluctuations and to changes of climatic and in planta factors throughout the plant growth cycle at both functional and structural levels.

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Dates et versions

hal-02740018 , version 1 (02-06-2020)

Identifiants

  • HAL Id : hal-02740018 , version 1
  • PRODINRA : 358150

Citer

Erwan Le Deunff, Philippe P. Malagoli. Modelling of nitrogen uptake based on a cross-combination of Flow-force interpretation of nitrate uptake isotherm and environmental and in planta regulation of nitrate influx rate. 3. International Symposium on Plant, Signaling & Behavior, Jun 2015, Paris, France. Univ. Paris Diderot Publischers, pp.134, 2015, 3. International Symposium on Plant, Signaling & Behavior. ⟨hal-02740018⟩
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