Phosphorus (P) deficiency is a common challenge in crop production because of its poor mobility through the soil. The root system plays a significant role in P absorption from the soil and is the initial indicator of low P levels. However, the phenotypic dynamics and longevity of cotton roots under P stress remain unknown. In this study, RhizoPot, an improvised in situ root observation device, was used to monitor the dynamics of root phenotypes of cotton seedlings under P-deficient (PD) and P-replete (PR) conditions. Low P stress reduced P absorption and accumulation in the roots, leading to low dry weight accumulation. Cotton seedlings responded to low P stress by increasing the number of lateral roots, specific root length, branch density, root length density, and length of root hairs. Additionally, the life span of root hairs was prolonged. Low P stress also reduced the average diameter of roots, promoted root extension, expanded the root coverage area, and increased the range of P acquisition. Principal component analysis revealed that the net root growth rate, root length density, root dry weight, P absorption efficiency, average root hair length, and taproot daily growth significantly influenced the cotton root architecture. Collectively, these results show that low P stress reduces the net growth rate of cotton seedling roots and restricts plant growth. Plants respond to P deficiency by extending the life span of root hairs and increasing specific root length and lateral root branch density. This change in root system architecture improves the adaptability of plants to low P conditions. The findings of this study may guide the selection of cotton varieties with efficient P utilization.

中文翻译：

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通过 RhizoPot 揭示磷胁迫下棉花幼苗的原位根表型。

磷 (P) 缺乏是作物生产中的常见挑战，因为它在土壤中的流动性较差。根系在从土壤中吸收磷方面起着重要作用，并且是低磷水平的初始指标。然而，棉花根在磷胁迫下的表型动态和寿命仍然未知。在这项研究中，RhizoPot 是一种简易的原位根观察装置，用于监测缺磷 (PD) 和富磷 (PR) 条件下棉花幼苗根表型的动态。低磷胁迫减少了根部对磷的吸收和积累，导致干重积累低。棉花幼苗通过增加侧根数、比根长、分枝密度、根长密度和根毛长度来响应低磷胁迫。此外，延长了根毛的寿命。低磷胁迫还降低了根的平均直径，促进了根的伸展，扩大了根覆盖面积，增加了磷的获取范围。主成分分析表明，净根生长速率、根长密度、根干重、磷吸收效率、平均根毛长度和主根日生长显着影响棉花根系结构。总的来说，这些结果表明低磷胁迫降低了棉花幼苗根部的净生长速率并限制了植物生长。植物通过延长根毛的寿命和增加比根长度和侧根分支密度来应对缺磷。根系结构的这种变化提高了植物对低磷条件的适应性。