四环素残留对黄豆芽营养品质及根际微生物的影响

Effect of tetracycline residue on rhizosphere microbes and nutrients of soybean sprouts

摘要:

【目的】探究土壤中四环素残留对土培黄豆芽的生长发育、根际微生物及营养品质的影响，为正确评估抗生素残留对蔬菜种植业的影响及制定土壤-蔬菜系统中抗生素污染防控策略提供理论基础。【方法】模拟土壤中不同四环素残留水平(0、25、50 mg/kg)，采用高效液相色谱(high performance liquid chromatography, HPLC)方法测定黄豆芽中的四环素残留量、理化方法测定黄豆芽的营养品质、高通量技术测定根际微生物群落。【结果】黄豆芽中四环素累积量随土壤中四环素残留量的增加而增加，累积量分布表现为根>下胚轴>子叶；四环素残留显著抑制黄豆芽的根和下胚轴的发育及其生物量、维生素C含量和抗氧化性，但增加了纤维素含量。在这些指标中维生素C含量的变化最显著，在黄豆芽生长第5天，25 mg/kg和50 mg/kg四环素残留组中，黄豆芽中维生素C含量较对照组分别降低41.35%和49.80%；此外，四环素残留显著影响黄豆芽根际微生物群落结构，尤其是与氮循环相关的属。其中，明显增加了不动杆菌属(Acinetobacter)和栖热菌属(Thermus)的相对丰度，减少了假黄色单胞菌属(Pseudoxanthomonas)和氢嗜菌属(Hydrogenophaga)的相对丰度。【结论】土壤中的四环素残留显著影响黄豆芽的生长发育、根际微生物群落结构以及维生素C等重要营养品质指标。

Abstract:

[Objective] To explore the effect of soil tetracycline on the growth and development, rhizosphere microbes, and nutrients of soybean sprouts, and to lay a theoretical basis for evaluating the influence of antibiotic residue on vegetable cultivation and preventing and controlling antibiotic contamination in soil-vegetable system. [Methods] We simulated different levels of tetracycline (0, 25, 50 mg/kg) in soil and determined the tetracycline in soybean sprouts by high performance liquid chromatography (HPLC). The nutrients in soybean sprouts were measured with physicochemical methods and rhizosphere microbes were elucidated by high-throughput sequencing.[Results] Tetracycline accumulation in soybean sprouts rose with the increase in the level of tetracycline in soil, and the distribution followed the order of root>hypocotyl>cotyledon. Tetracycline residue in soil significantly inhibited the development and biomass of root and hypocotyl, vitamin C synthesis, and antioxidant activity of soybean sprouts, particularly the vitamin C synthesis. To be specific, on the fifth day of growth, vitamin C content in soybean sprouts cultivated in soil with 25 mg/kg and 50 mg/kg tetracycline was 41.35% and 49.80% lower than that of the control, respectively. Moreover, tetracycline residue significantly affected the microbial community structure in rhizosphere of soybean sprouts, especially the nitrogen cycling-related genera. Specifically, the relative abundance of Acinetobacter and Thermus significantly increased and that of Pseudoxanthomonas and Hydrogenophaga reduced. [Conclusion] Tetracycline residue in soil suppressed the growth of soybean sprouts, rhizosphere microbial community structure, and important nutrients such as vitamin C.