新型介孔二氧化硅纳米颗粒的构建及负载丙硫菌唑在大豆植株中的吸收、分布和代谢规律研究

丙硫菌唑用量逐年递增，提高农药利用率是降低农药残留、保障环境安全的基础。利用纳米材料作为载体负载农药，控制农药缓慢释放，使其长时间连续有效的作用于靶标中，是提高利用率的有效途径。本项目在前期已获得介孔二氧化硅纳米颗粒（MSNs）基础上，拟通过巯基化和引入亲水性基团构建新型介孔二氧化硅纳米颗粒，增加水分散性便于植物吸收；再利用前期青年基金项目中合成的功能性荧光探针标记得到新型农药载体。开展MSNs负载丙硫菌唑、荧光探针标记MSNs及丙硫菌唑在大豆植株上的暴露实验，结合高效液相色谱质谱联用和激光扫描共聚焦技术，替代传统的放射性同位素标记及直接荧光标记法，探究丙硫菌唑在大豆根、茎和叶中的残留水平，建立研究丙硫菌唑在大豆植株中吸收、可视化分布和代谢规律的新方法，明确不同施药方式和环境因子影响吸收、分布和代谢规律的机制。研究结果可望提高丙硫菌唑的利用率和降低使用风险，为农药减量化提供理论与技术指导。

As the dosage of prothioconazole is on a rise, the improvement of the utilizing rate is the basis for reducing the pesticide residues and ensuring environmental safety. It is an effective way to improve the utilizing rate of pesticides by using nanomaterials as the carriers to load pesticides and control the release rate of pesticides so that they can continuously and effectively work in the target environment for a long time. Based on the previous mesoporous silica nanoparticles (MSNs) obtained, this project focuses on the modification of MSNs through thiolation and hydrophilic groups to increase its dispersibility in water so that MSNs can easily be uptake by the plant. Then MSNs were loaded with prothioconazole and the thiol fluorescent probe obtained previously was used to label MSNs to prepare the novel MSNs. Exposure experiments of prothioconazole-loaded MSNs, prothioconazole and fluorescent probe-labeled MSNs on the soybean plants were performed by hydroponics and leaf dropwise addition, respectively. The residual levels of prothioconazole in soybean roots, stems and leaves were investigated by the combination with high performance liquid chromatography-mass spectrometry, fluorescence spectrophotometer and laser scanning confocal microscopy, instead of the traditional radiolabeling and direct fluorescence labeling technology. Thus the effects of different doses and durations on the absorption, distribution and metabolism of prothioconazole in soybean plants can be revealed. Therefore, a new method was developed to study the absorption, visualization distribution and metabolism of prothioconazole in soybean plants. These results may reveal the effects of different application methods and environmental factors on pesticide utilization rate, and provide useful theoretical and technical guidance for pesticide reduction.