关键词: 硼, 硫肥, 油菜, 硼分配, 细胞壁

Abstract:

【Objective】This study explored the effects of sulfur (S) fertilizer application on B uptake and distribution in rapeseed under high boron (B) environment, and provided a theoretical basis for rational application of S fertilizer to alleviate B toxicity in rapeseed (Brassica napus L.). 【Method】Rape plants (cv. Huayouza 9) were grown in pots filled with calcareous alluvial soil contaminated with B (total B content: 13.44 mg·kg ^-1; available B: 5.07 mg·kg ^-1) and the effects of S fertilizer level (0, 20, 50, 100, 200, and 500 mg·kg ^-1) on B concentration, distribution, cell wall extraction rate, cell wall B concentration and its proportion of total B in different parts of the rape were determined at the podding stage. 【Result】 With the increase of S application, the biomass increased at first and then decreased in different parts of rape. When the S was applied at 50 mg·kg ^-1, the fresh biomass of rape was the largest, reached 364.5 g/plant under different S application, and the B concentration and distribution in different parts of rape followed the order of pods>leaves>stems>roots, which indicated that the pods were the main accumulation site of B. As the S fertilizer level increased from 0 to 100 mg·kg ^-1, the pod B concentration and distribution ratios decreased by 14.8% and 15.0%, respectively. The extraction rate of cell wall of rapeseed pods increased by 43.0%, and there was no significant change in the B concentration and proportion in the cell wall. When S fertilizer was continuously applied to 200 mg·kg ^-1, the B concentration, distribution ratios and cell wall B concentration of rapeseed pods decreased significantly, and cell wall B proportion increased significantly compared with that of non-sulfur fertilizer. The opposite trends were found in the B concentrations and cumulative distribution ratios in the leaves, stems and roots. As the S fertilizer level increased from 0 to 100 mg·kg ^-1, the B concentration significantly increased by 15.0%, 32.9% and 34.9% in rape leaves, stems, and roots, respectively. The B distribution ratios significantly increased by 13.4%, 29.6% and 18.6%, and B concentration in the cell wall significantly increased by 12.3%, 22.9% and 14.9% in rape leaves, stems, and roots, respectively. It showed that the addition of S fertilizer increased the B concentration of the leaves, stems and roots of rapeseed. 【Conclusion】S fertilizer application effectively alleviated B toxicity by increasing biomass, limiting B translocation from roots, stems and leaves to pods, and by increasing the extraction rate of cell wall in rape plants grown on B-contaminated soil. The optimum amount of S fertilizer application was 50-100 mg·kg ^-1.

Key words: boron contamination, sulfur fertilizer, rape, boron distribution, cell wall