Effects of Nitrate and Ammonium Nitrogen on the Accumulation and Distribution of Imidacloprid in Maize Seedlings

【Objective】The study is carried out to explore the accumulation and distribution law of imidacloprid in maize under different nitrogen supply conditions, which will provide a theory foundation for improving imidacloprid utilization rate and rational application of nitrogen fertilizer and imidacloprid.【Method】The seedlings of maize was exposed to imidacloprid in hydroponic solution with different nitrogen treatments (4 mmol/L NO3-, 10 mmol/L NO3-, 4 mmol/L NH4+, 10 mmol/L NH4+). The content of imidacloprid in maize was determined by HPLC.【Result】Leaf was the main part for imidacloprid accumulation in maize, followed by root and stem, and all nitrogen treatments showed similar accumulation law. The imidacloprid accumulation was closely related with nitrogen forms in maize under different imidacloprid concentrations. Under the treatments of 3 imidacloprid concentrations, the content of imidacloprid in the roots, stems and leaves of maize cultured with NO3- as the nitrogen source was significantly higher than that of maize cultured with NH4+. For example, when the imidacloprid concentration was 2.5 mg/L, the contents of imidacloprid in roots of NO3- treatment were 3.09 and 5.15 times those of NH4+ treatment, respectively, 1.90 and 3.04 times those in stems, and 1.70 and 3.22 times those in leaves, respectively. When the imidacloprid concentration was 5.0 mg/L, the TFleaf/stem of imidacloprid in maize seedlings was the highest, and that of NO3- and NH4+ treatments was 7.54, 5.07, 4.19 and 4.13 respectively, indicating that NO3- was more beneficial to imidacloprid transportation from stems to leaves. Compared with NO3- treatments, the TFleaf/stem of imidacloprid in maize seedlings of NH4+ treatments was significantly lower, indicating that NO3- was more beneficial to imidacloprid transportation to leaves under 5.0 mg/L imidacloprid treatment.【Conclusion】The accumulation of imidacloprid in maize seedlings was correlated with addition dose of imidacloprid, the higher the concentration of imidacloprid in culture solution, and higher imidacloprid accumulation in maize. The accumulation of imidacloprid in maize seedlings was influenced by the nitrogen form, and NO3- is more beneficial to the accumulation of imidacloprid in maize.