Aims Phosphorus (P) export with harvested grains is a key step of the P cycle in agroecosystems. In wheat, the accumulation of P in grains originates from both exogenous and endogenous P sources. We investigated the effects of different post-anthesis P supply on P partitioning and P remobilization in two durum wheat cultivars with contrasting biomass allocation. Methods Wheat plants were grown on a complete nutrient solution with sufficient P until anthesis. Thereafter, half of the plants were deprived of P and the other half was maintained on the complete nutrient solution. P uptake, allocation, remobilization, and traits related to yield and grain P were determined. Results Modifications of post-anthesis P supply had no effect on grain yield. Grain P concentrations at maturity for deprived P supply ranged from 2.2 to 3.4 mg P g DW − 1 . Without P, net P fluxes to grains essentially came from leaves (35%), roots (28%) and stems (17% ). With P, net P fluxes came mainly from post-antheis P uptake. Conclusions Our results suggest that when the P nutrition of durum wheat is limited after anthesis, endogenous P remobilization can sustain grain growth with minor yield penalties if the plants are well supplied during vegetative growth.

中文翻译：

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灌浆期不同磷供给对两个具有对比生物量分配的硬粒小麦品种的磷吸收和分配的影响

目标 与收获的谷物一起输出磷 (P) 是农业生态系统中磷循环的关键步骤。在小麦中，谷物中磷的积累来源于外源和内源。我们研究了不同的开花后磷供应对两个具有对比生物量分配的硬粒小麦品种中磷分配和磷再动员的影响。方法 小麦植株在含充足磷的完全营养液中生长直至开花。此后，一半的植物被剥夺了磷，另一半则保持在完整的营养液中。测定了磷的吸收、分配、再动员以及与产量和籽粒磷相关的性状。结果花后磷供应的修改对谷物产量没有影响。缺乏磷供应的成熟谷物磷浓度范围为 2.2 至 3.4 mg P g DW − 1 。没有磷，谷物的净磷通量主要来自叶 (35%)、根 (28%) 和茎 (17%)。对于 P，净 P 通量主要来自花后 P 吸收。结论我们的结果表明，当硬粒小麦开花后磷营养有限时，如果植物在营养生长期间供应充足，内源性磷再动员可以维持谷物生长，但产量损失较小。