Nitrogen storage and remobilization in Brassica napus L. during the growth cycle

Rossato, L., Noquet, C., Malagoli, P. and Ourry, A. (2004). Nitrogen storage and remobilization in Brassica napus L. during the growth cycle. In: T. Fischer, 4th International Crop Science Congress (4ICSC), Brisbane, Australia, (). 26 September - 1 October 2004.


Author Rossato, L.
Noquet, C.
Malagoli, P.
Ourry, A.
Title of paper Nitrogen storage and remobilization in Brassica napus L. during the growth cycle
Formatted title
Nitrogen storage and remobilization in Brassica napus L. during the growth cycle
Conference name 4th International Crop Science Congress (4ICSC)
Conference location Brisbane, Australia
Conference dates 26 September - 1 October 2004
Place of Publication Gosford NSW
Publisher The Regional Institute Ltd
Publication Year 2004
Sub-type Fully published paper
ISBN 1920842217
Editor T. Fischer
Total pages not found
Language eng
Abstract/Summary Oilseed rape (Brassica napus L.) is commonly grown for oil or bio-fuel production, while the seed residues can be used for animal feed. It can also be grown as a catch crop because of its efficiency in extracting mineral N from the soil profile. However, the N harvest index is usually low, due in part to a low ability to remobilize N from leaves and to the fall of N-rich leaves which allows a significant amount of N to return to the environment. In order to understand how N filling of pods occurs, experiments were undertaken to quantify N flows within the plant by 15N labelling. N uptake capacity decreased at flowering to a non significant level during pod filling. However, large amounts of endogenous N were transferred from the leaves to the stems and to taproots which acted as a buffering storage compartment later used to supply the reproductive tissues. About 15% of the total N cycling through the plant was lost through leaf fall and 48%, nearly all of which had been remobilized from vegetative tissues, was finally recovered in the mature pods. A 23 k Da polypeptide, accumulated in the taproots during flowering and later fully hydrolyzed to sustain grain filling, has been characterized as a vegetative storage protein (VSP). A mechanistic N uptake model based on the functioning of NO3- transport system has also been proposed. The overall results are discussed in relation to plant strategies which optimize N cycling to reproductive sinks by means of buffering vegetative tissues such as stems and taproots.
Subjects 0703 Crop and Pasture Production
Keyword Brassica napus
N fluxes
VSP
source/sink relationships
high and low affinity nitrate transport systems
mechanistic model of N uptake
Q-Index Code E1

 
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Created: Thu, 28 Jan 2010, 15:17:12 EST by Thelma Whitbourne on behalf of Sustainable Minerals Institute