ABSTRACT

A hydroponic experiment was conducted to explore the effects of nitrogen on cotton root morphology and related hormone contents and to analyse the correlation between the indexes. The effects of different nitrogen concentrations (N0, N1, N2, and N3 with 0, 2, 4, and 8 mmol l⁻¹, respectively) on main and lateral roots were evaluated. A moderate nitrogen concentration (N2, 4 mmol l⁻¹) promotes root growth. Lateral roots responded quickly to changes in nitrogen concentrations. Compared with N0 treatment, N2 treatment resulted in significantly greater main root volume after 12 days as well as increased lateral root length, root projected area, root surface area, and root volume after 8 days. Nitrogen significantly decreased abscisic acid (ABA), salicylic acid (SA), and isopentenyladenine (iP) content, which were the lowest in N2 treatment (33.92% lower than N0). The ABA and SA content were negatively correlated with root morphology. This shows that a moderate nitrogen concentration (4 mmol l⁻¹) significantly decreased ABA and SA content in the main and lateral roots and promoted root growth in cotton plants. These results will contribute to root growth theory regarding efficient nitrogen utilization by cotton plants and will provide a theoretical basis to ensure nitrogen resources are utilized efficiently.

摘要

通过水培试验，探讨氮肥对棉花根系形态及相关激素含量的影响，并分析各指标间的相关性。评估了不同氮浓度（分别为 0、2、4 和 8 mmol l ^{-1 的}N0、N1、N2 和 N3 ）对主根和侧根的影响。中等浓度的氮（N2，4 mmol l ^-1) 促进根系生长。侧根对氮浓度的变化反应迅速。与 N0 处理相比，N2 处理导致 12 天后主根体积显着增加，8 天后侧根长度、根投影面积、根表面积和根体积增加。氮显着降低脱落酸（ABA）、水杨酸（SA）和异戊烯基腺嘌呤（iP）的含量，这些含量在N2处理中最低（比N0低33.92%）。ABA和SA含量与根形态呈负相关。这表明中等浓度的氮（4 mmol l ^-1) 显着降低主根和侧根中 ABA 和 SA 的含量，促进棉花植株根系生长。这些结果将有助于棉花植物氮素有效利用的根系生长理论，并为确保氮素资源的有效利用提供理论依据。