Is the remobilization of S and N reserves for seed filling of winter oilseed rape modulated by sulphate restrictions occurring at different growth stages?
How the remobilization of S and N reserves can meet the needs of seeds of oilseed rape subject to limitation of S fertilization remains largely unclear. Thus, this survey aims to determine the incidence of sulphate restriction [low S (LS)] applied at bolting [growth stage (GS) 32], visible bud (GS 53), and start of pod filling (GS 70) on source-sink relationships for S and N, and on the dynamics of endogenous/exogenous S and N contributing to seed yield and quality. Sulphate restrictions applied at GS 32, GS 53, and GS 70 were annotated LS(32), LS(53), and LS(70). Long-term (34)SO(4)(2-) and (15)NO(3)(-) labelling was used to explore S and N partitioning at the whole-plant level. In LS(53), the sulphur remobilization efficiency (SRE) to seeds increased, but not enough to maintain seed quality. In LS(32), an early S remobilization from leaves provided S for root, stem, and pod growth, but the subsequent demand for seed development was not met adequately and the N utilization efficiency (NUtE) was reduced when compared with high S (HS). The highest SRE (65 ± 1.2% of the remobilized S) associated with an efficient foliar S mobilization (with minimal residual S concentrations of 0.1-0.2% dry matter) was observed under LS(70) treatment, which did not affect yield components.
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INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & nutritions NCS, Esplanade de la Paix, F-14032, Caen, France.
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D001692:Biological Transport; D018533:Biomass; D029741:Brassica rapa / Q000254:growth & development* / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D010938:Plant Oils / Q000378:metabolism*; D000074262:Rapeseed Oil; D012621:Seasons; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*; D013460:Sulfur Isotopes
D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D000074262:Rapeseed Oil; D013431:Sulfates; D013460:Sulfur Isotopes; D009584:Nitrogen