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Is the remobilization of S and N reserves for seed filling of winter oilseed rape modulated by sulphate restrictions occurring at different growth stages?

Author:
Dubousset, L., Etienne, P., Avice, J.C.
Source:
Journal of experimental botany 2010 v.61 no.15 pp. 4313-4324
ISSN:
0022-0957
Subject:
Brassica napus var. napus, bolting, buds, developmental stages, filling period, leaves, pods, rapeseed, roots, seed development, seed quality, seeds, source-sink relationships, stems, sulfates, sulfur, surveys, yield components
Abstract:
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 LS₃₂, LS₅₃, and LS₇₀. Long-term ³⁴SO[Formula: see text] and ¹⁵NO[Formula: see text] labelling was used to explore S and N partitioning at the whole-plant level. In LS₅₃, the sulphur remobilization efficiency (SRE) to seeds increased, but not enough to maintain seed quality. In LS₃₂, 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 LS₇₀ treatment, which did not affect yield components.
Agid:
445521