Nitrogen deficiency impacts on leaf cell and tissue structure with consequences for senescence associated processes in Brassica napus

François Mariette,Maja Musse,Alain Bouchereau,Laurent Leport,Mireille Cambert,Clément Sorin

doi:10.1186/s40529-016-0125-y

Abstract

Improvement of nutrient use efficiency is a major goal for several crop plants, especially Brassica napus. Indeed, the low nitrogen use efficiency (NUE) in this crop results in negative economic and ecological consequences. The low NUE of oilseed rape is mainly due to low remobilization of nitrogen from vegetative parts to growing organs. Remobilization of leaf nitrogen takes place during senescence, a process known to strongly modify cell and tissue structure. This study focused on the impact of moderate N depletion, expected to induce 30 % reduction of seed yield, on these structural modifications. Two genotypes (Aviso and Express) were studied, with different tolerance of nitrogen depletion, evaluated through seed yield and dry mass production. Structural modifications of leaf cells and tissues were investigated through NMR relaxometry and light microscopy. Lower tolerance of N depletion was associated with higher impact on senescence associated structural modification pattern. The link between leaf structure modifications and nutrient remobilization is discussed. It is proposed that leaf structure monitoring during senescence through NMR device could be developed to select genotypes with high NUE.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-016-0125-y) contains supplementary material, which is available to authorized users.

Highlights

Brassica napus is a worldwide crop with numerous uses in food, feed and non-food products
Nitrogen depletion induced a decrease in chlorophyll content (Fig. 1A, B) in all leaves of the Aviso plants, while this trend was less marked for express leaves
The other physiological parameters measured, i.e, water content, dry matter and indicators of photosynthesis performance were not significantly impacted by N depletion, indicating that the study was focused on an early phase of nitrogen deficiency

Summary

Introduction

Brassica napus is a worldwide crop with numerous uses in food, feed and non-food products (biofuel, lubricants, etc.). Nitrogen (N) fertilization is one of the highest costs of oilseed rape production (Singh 2005). Conventional crop management practices requires the use of relatively high amounts of N fertilizers (from 150 to 300 kg of N ha−1) to ensure an optimum yield (Rathke et al 2006). Whatever the rate of N fertilization, the oilseed rape N harvest index is low compared to cereals (Dreccer et al 2000) and, despite. Greater NRE has been considered a major target in the current context of Nitrogen input reduction, in order to maintain oilseed rape yield (Berry et al 2010; Kessel and Becker 1999; Miro 2010)

Methods

Results

Conclusion