Increased mechanical impedance induced by soil drying or compaction causes reduction in plant growth and crop yield. However, how mechanical impedance interacts with nutrient stress has been largely unknown. Here, we investigated the effect of mechanical impedance on the growth of wheat seedlings under contrasting phosphorus (P) supply in a sand culture system which allows the mechanical impedance to be independent of water and nutrient availability. Two wheat genotypes containing the Rht-B1a (tall) or Rht-B1c (gibberellin-insensitive dwarf) alleles in the Cadenza background were used and their shoot and root traits were determined. Mechanical impedance caused a significant reduction in plant growth under sufficient P supply, including reduced shoot and root biomass, leaf area and total root length. By contrast, under low P supply, mechanical impedance did not affect biomass, tiller number, leaf length, and nodal root number in both wheat genotypes, indicating that the magnitude of the growth restriction imposed by mechanical impedance was dependent on P supply. The interaction effect between mechanical impedance and P level was significant on most plant traits except for axial and lateral root length, suggesting an evident physical and nutritional interaction. Our findings provide valuable insights into the integrated effects of plants in response to both soil physical and nutritional stresses. Understanding the response patterns is critical for optimizing soil tillage and nutrient management in the field.

由土壤干燥或压实引起的机械阻抗增加会导致植物生长和农作物减产。然而，机械阻抗如何与养分胁迫相互作用尚不清楚。在这里，我们研究了在沙培养系统中磷（P）的对比下，机械阻抗对小麦幼苗生长的影响，这使得机械阻抗与水和养分的有效性无关。两种含有Rht-B1a（高）或Rht-B1c的小麦基因型使用Cadenza背景中的（赤霉素不敏感的矮人）等位基因，并确定其芽和根性状。在足够的磷供应下，机械阻抗导致植物生长显着下降，包括减少的枝条和根生物量，叶面积和总根长。相比之下，在低磷供应下，机械阻抗不影响两种基因型小麦的生物量，分till数，叶长和节根数，表明由机械阻抗施加的生长限制的大小取决于磷的供应。除轴向和侧根长度外，机械阻抗和磷水平之间的相互作用对大多数植物性状均具有显着影响，表明明显的物理和营养相互作用。我们的发现为植物应对土壤物理和营养胁迫的综合效应提供了宝贵的见解。了解响应模式对于优化田间土壤耕作和养分管理至关重要。