高硼土壤增施硫肥对油菜硼吸收与分配的影响

Effects of Sulfur Fertilizer on Boron Uptake and Distribution of Rape in B-contaminated Soil

【目的】探索高硼环境下施用硫肥对油菜硼吸收和分配的影响,为合理施用硫肥缓解油菜硼毒害提供理论基础。【方法】以油菜华油杂9号为试验材料,在高硼灰潮土上(全硼含量13.44 mg·kg^(-1),有效硼5.03 mg·kg^(-1))进行盆栽试验。研究了6个硫水平(0、20、50、100、200、500 mg·kg^(-1))对油菜果荚、叶、茎、根部的硼含量及硼的分配、细胞壁的提取率、细胞壁硼含量和比例的影响。【结果】随着施硫量增加,油菜各部位的生物量呈先增加后降低的趋势,其中施硫50 mg·kg^(-1)时,油菜鲜重生物量最高,可达364.5 g/株。施用不同量硫肥后,油菜硼含量及分配均为果荚>叶>茎>根,表明果荚为硼的主要累积器官。增施硫肥,油菜果荚的硼含量呈下降趋势,施硫量由0增至100 mg·kg^(-1),油菜果荚硼含量和分配显著降低,降幅分别为14.8%和15.0%。油菜果荚细胞壁提取率增加43.0%,其细胞壁硼含量和比例无显著变化,继续增施硫肥至200 mg·kg^(-1),油菜果荚硼含量、硼分配比和细胞壁硼均下降至显著水平,且细胞壁硼分配比显著上升。与果荚不同,增施硫肥后油菜叶、茎和根的硼含量则呈缓慢上升的趋势。施硫量由0增至100 mg·kg^(-1),油菜叶、茎和根硼含量分别增加15.0%、32.9%和34.9%,其分配比例分别增加13.4%、29.6%和18.6%,同时油菜叶片、茎和根部细胞壁硼含量显著增加12.3%、22.9%和14.9%,表明增施硫肥增加了油菜叶、茎和根的硼含量。【结论】硫肥可通过增加油菜生物量,限制硼从根、茎、叶到果荚的转运,以及增加油菜果荚细胞壁硼含量来缓解高硼对油菜果荚的毒害,最佳施硫量为50—100 mg·kg^(-1)。

【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.