Abstract:
Objective This paper is the result of soil geochemistry. Boron (B) is an essential micronutrient for plants, playing critical roles in cell wall synthesis, membrane stability, and reproductive organ development. However, in calcareous soils, high pH and elevated calcium carbonate levels significantly reduce boron bioavailability, adversely affecting wheat growth, yield, and quality. This study systematically investigates the translocation mechanisms and absorption regulation of boron in the calcareous soil−wheat system, aiming to provide a theoretical basis for precise boron fertilization and stable wheat production.
Methods A pot experiment was conducted outdoors using wheat cultivar "Shixin 828" under six boron concentration gradients (0–4.0 mg/kg). Soil and plant samples were collected in the jointing and maturity stages to measure soil available boron, total boron, and boron content in various wheat organs. Enrichment and translocation coefficients were calculated to analyze boron distribution and migration patterns, and the relationship between soil available boron and wheat boron uptake was examined.
Results The available boron content (0.48 mg/kg) in calcareous soil was below the deficiency threshold (0.50 mg/kg), with bioavailability significantly constrained by high pH. In the jointing stage, boron primarily accumulated in leaves (37.0 mg/kg), while in maturity, it was redistributed to stems (15.1 mg/kg) and grains (9.3 mg/kg), demonstrating growth−stage dependence and organ specificity. Soil available boron showed a strong positive correlation with boron content in wheat organs (e.g., jointing−stage leaves, r=0.846; maturity−stage grains, r=0.871), whereas total boron had minimal influence.
Conclusions Calcareous soils restrict boron availability, while exogenous boron application significantly enhances wheat boron uptake and translocation. Boron accumulation follows a "leaf−preferential in jointing, coordinated transport to stem and grain in maturity" pattern, with soil available boron being the key regulatory factor. This study provides a scientific basis for precise boron management in wheat cultivation on calcareous soils, offering substantial practical value.
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