Nitrogen dynamics in field grown oilseed rape. Effect of nitrogen fertilization and genotype
Despite a high nitrate uptake capacity, the nitrogen use efficiency (NUE) of oilseed rape is weak due to a relatively low N remobilization from vegetative (mostly leaves) to growing parts of the plant Thus, this crop requires high rate of N fertilization and leaves fall with high N content. In order to reduce the rate of N fertilization and to improve the environmental impact of oilseed rape without decreasing yield, it is crucial to better understand the dynamics of N through the plant. This study presents the effect of contrasted N fertilizations and genotypes on the N dynamics of oilseed rape grown under field conditions.The experiment was conducted in a field-grown winter oilseed rape under three levels of N dose (0, 100 and 200 kg N ha-1)and three genotypes (cv. Capitol, Pollen and Saturnin). Plants were sampled frequently from stem extension (GS 2,4) to maturity (GS 9,9) by using a 15N labelling technique in order to distinguish in each tissue N coming from uptake or remobilization.N fertilization increased biomass and N accumulation whatever the genotype. The partitioning of N taken up was affected by N fertilization and genotype, whereas N uptake decreased during flowering irrespective of N fertilization and genotype. Whatever the N treatment and the genotype, more than 60％ of pods N came from N rernobilization ofvegetative tissues, green leaves being the main source of remobilized N. The timing and the part of N remobilized from the different vegetative organs depended on the N supply and cultivar. The efficiency ofN remobilization in leaves increased with the rate of N fertilization and along an axial gradient from the basal to the uppermost leaves.Better synchronising leaf N remobilization and grain filling could improve the NUE of oilseed rape.
Julie Gombert Frédérik Le Dily Philippe Etienne Philippe Lainé Alain Ourry
UMR 1NRA-UCBN 950 Ecophysiologie Végétale, Agronomie et Nutritions N, C, S.Université de Caen, F-14032 Caen cedex
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
1058-1161
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）