Dynamics of nitrogen uptake and mobilization in field-grown winter oilseed rape (Brassica napus) From stem extension to harvest. II. An ¹⁵N-labelling-based simulation model of N partitioning between vegetative and reproductive tissues

• Published in: Annals of botany Vol. 95; no. 7; pp. 1187 - 1198
• Main Authors: Malagoli, P, Laine, P, Rossato, L, Ourry, A
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.06.2005; Oxford Publishing Limited (England)
• Subjects: 15N labelling; Biological Transport, Active; Brassica napus; Brassica napus - metabolism; Brassica napus L; Computer Simulation; Crop harvesting; Crops; cycling N pool; developmental stages; Dynamic modeling; equations; field conditions; field experimentation; flowers; Leaves; mathematical models; mobilization; Modeling; modelling; Models, Biological; N dynamics; N uptake; Nitrogen; Nitrogen - metabolism; Nitrogen Isotopes; nutrient transport; nutrient uptake; Oilseeds; Original; plant reproduction; Plant roots; Plant Stems; Plants; pods; quantitative analysis; radiolabeling; rapeseed; roots; simulation models; Simulations; stems; Time Factors; vegetative growth
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mci131

BACKGROUND AND AIMS: Oilseed rape (Brassica napus) has often been used as a catch crop to deal with the issue of N leaching, but for this to be effective, prediction of the crop's N uptake capability and N partitioning is required. The aim of this work was to build a compartmental model of N dynamics in oilseed rape, based on the kinetic description of N uptake, partitioning and mobilization in each organ. MODEL: In this study, logistic and exponential equations were fitted to the N relations of each compartment, especially the leaf at each node. Data previously obtained from an ¹⁵N-labelling field experiment was used to quantify the partitioning of total N content, the allocation of N taken up and subsequent changes in the sink/source status for endogenous N in each tissue throughout the growth cycle. KEY RESULTS AND CONCLUSIONS: This modelling approach provides a unique tool for the quantitative estimation of cycling of endogenous N in relation to changes in N uptake at the whole-plant level. Furthermore, as oilseed rape is known to release large amounts of N to the soil during spring through leaf loss, this model was used to identify potential methods for improving the N harvest index of the crop. Simulations showed that N content or yield could be improved by 15 % by optimizing N transfer from vegetative to reproductive tissues and by reducing the residual %N (DW) in abscised leaves.