Abstract Oilseed rape (Brassica napus L.) is an important crop in China. Although its yields are restricted by phosphorus (P) supply, the response of its root system to P supply has not been explored systematically. This study aimed to investigate the contribution of root morphological and biochemical traits to P acquisition from soils with deficient P (30 kg P2O5 ha−1) and sufficient P (90 kg P2O5 ha−1) supplies in the field at the leaf development, stem elongation, flowering, pod development and ripening stages. The total root length and root surface area in the surface soil (0−10 cm soil layer) were both reduced significantly by decreasing P supply. However, a larger root/shoot ratio and root length ratio were observed in plants with the deficient P supply at the flowering stage. Roots of plants with a deficient P supply also secreted more acid phosphatase and organic acid into the rhizosphere from stem elongation to pod development than plants with a sufficient P supply. Seed yield (SY), shoot dry weight (SDW) and total P content (TPC) were strongly correlated with root morphological traits at the leaf development and flowering stages, especially with the coarse root length (CRL) and root surface area in the surface soil. However, there were no correlations between SDW or TPC and root biochemical traits (rhizosphere pH, acid phosphatase activity and organic acid content). It is hypothesized that greater CRL in the surface soil (0−10 cm soil layer) at the leaf development and flowering stages, served as a scaffold for fine roots, enhancing soil exploration and P acquisition, and, thereby, increasing seed yield.

中文翻译：

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不同形态生化根性状对甘蓝型油菜磷吸收及种子产量的影响

摘要 油菜（Brassica napus L.）是我国重要的农作物。尽管其产量受到磷（P）供应的限制，但尚未系统地探索其根系对磷供应的响应。本研究旨在调查根部形态和生化性状对从叶片发育、茎秆中缺磷（30 kg P2O5 ha-1）和充足磷（90 kg P2O5 ha-1）供应的土壤中获取磷的贡献。伸长、开花、豆荚发育和成熟阶段。表层土壤（0-10 cm 土层）中的总根长和根表面积均因磷供应减少而显着降低。然而，在开花期磷供应不足的植物中观察到较大的根/芽比和根长比。与磷供应不足的植物相比，磷供应不足的植物的根部还会向根际分泌更多的酸性磷酸酶和有机酸，从茎伸长到豆荚发育。种子产量（SY）、地上部干重（SDW）和全磷含量（TPC）与叶片发育和开花阶段的根系形态性状密切相关，特别是与表面粗根长度（CRL）和根表面积相关土壤。然而，SDW 或 TPC 与根生化性状（根际 pH、酸性磷酸酶活性和有机酸含量）之间没有相关性。据推测，在叶片发育和开花阶段，表层土壤（0-10 cm 土层）中较大的 CRL 可作为细根的支架，增强土壤勘探和磷的获取，从而提高种子产量。