Imbalance between boron and phosphorus supply influences boron deficiency symptoms in Brassica napus L

The occurrence of boron (B) deficiency in Brassicaceae crops has increased in recent years. Inappropriate application of B with other nutrients often exacerbates symptoms of B deficiency. The aim of this study was to explore the interactive effects of B and phosphorus (P) on the B deficiency symptoms of rapeseed (Brassica napus L.). Two rapeseed cultivars ('W10' and 'ZS11') were treated with two B application rates (low and high B) and three P application rates (low, medium, and high P), and the growth parameters (root morphology, B absorption and distribution, and the P/B ratio) were examined in pot and hydroponic experiments.

Under low B conditions, plants showed severely reduced root and shoot growth but it was greatly improved when supplemented with medium P supply. Further analysis revealed that high P combined with low B decreased the B concentration of newly initiated leaves and seeds, and increased the P/B ratio in plants compared with the medium P and low B combination, resulting in the aggravation of B deficiency of rapeseed. In comparison with the B-inefficient cultivar 'W10', the B-efficient cultivar 'ZS11' had superior growth and seed yield under low B conditions. Furthermore, 'W10' and 'ZS11' displayed significant differences in the response of the interaction between B and P to plant P/B ratio and root morphological parameters, which may reflect distinct genotype characteristics.

The findings emphasize the importance of interactions between B and P in the growth and yield formation of rapeseed in B-deficient soils, as imbalanced B and P supply can exacerbate B deficiency symptoms in rapeseed. © 2025 Society of Chemical Industry.