Abstract EN:

Winter oilseed rape is a very nitrogen-fertilizer consuming crop and is characterized by low nitrogen use efficiency (NUE). A high proportion of absorbed nitrogen remains immobilized in senescent leaves and is returned to the soil failing to contribute to seed production. Improving organic nitrogen remobilization from source leaves in the species is of primary interest to preserve yield performance in relation to sustainable production requirements at low level of nitrogen inputs and increased risk of exposure to water shortage the objective of this work was to investigate, in oilseed rape, the metabolic components likely to be involved in the reallocation process of carbon and nitrogen resources from vegetative tissues to growing organs. This was achieved by metabolite profiling of products from carbon and nitrogen primary metabolisms with the aim to assign the growing leaf tissue imprints according to their source or sink status and in relation to the levels of nitrogen nutrition and water supply under experimental conditions conducted in greenhouse and field. The results show that the composition and levels of metabolites (i. E. Carbohydrates, amino acids, organic acids) differ markedly between leaf ranks and reflect the state of leaf development from emergence to senescence. A relationship is established between the metabolic profile of the tissue and its ability to import or export organic nitrogen. Situations of limited nitrogen fertilization and water supply exert a significant impact on productivity and contribute to typical metabolic adjustments. The metabolic, physiological and phenological effects of water stress during vegetative growth are clearly associated.