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| Effects of oxygenation on the nitrogen uptake of Myriophyllum aquaticum and sediment microenvironment |
| Received:February 25, 2022 |
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| KeyWord:nitrogen uptake;pH value of sediment;organic matter;ammonium nitrogen;nitrate nitrogen;oxygenation treatment |
| Author Name | Affiliation | E-mail | | LI Hanchang | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | ZHANG Wenping | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | zhangwenping_hunau@hunau.edu.cn | | WEN Qingbai | Ouyanghai Irrigation District Water Conservancy and Hydropower Engineering Administration of Hunan Province, Leiyang 421800, China | | | TAN Xin | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | LI Zonghao | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | ZHONG Cheng | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | LI Yan | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | YI Dali | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | | | YANG Liangjiu | College of Hydraulic & Civil Engineering, Hunan Agricultural University, Changsha 410128, China | |
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| Abstract: |
| To investigate the effects of oxygenation on nitrogen uptake by Myriophyllum aquaticum and sediment microenvironment, a pot experiment was conducted using Myriophyllum aquaticum as tested material. The control group was treated without oxygenation, and four oxygenation levels of O1（4 min）、O2（6 min）、O3（8 min）、O4（10 min） were designed. The variation characteristics of nitrogen uptake by plants and the content of ammonium nitrogen and nitrate nitrogen in sediments under different culture periods were systematically studied. The mechanism of oxygenation regulating sediment microenvironment and improving the degradation ability of nitrogen pollutants in water by Myriophyllum aquaticum was revealed. Results showed that, with oxygenation or not, the nitrogen uptake of roots and shoots and the nitrogen accumulation of plants all increased gradually with the extension of culture time, and the nitrogen uptake of shoots was higher than that of roots. Oxygenation significantly promoted the absorption of nitrogen by Myriophyllum aquaticum. Oxygenation for 8 min in the early growth stage（t1 and t2 periods）and for 6 min in the middle and late growth stage（t3, t4, and t5 periods）corresponded to the maximum nitrogen accumulation of Myriophyllum aquaticum. The maximum nitrogen accumulation of plants in the t5 sampling periods was 171.08 mg·plant-1 with 6 min of oxygenation. Oxygenation resulted in the decrease of the sediment pH in the early growth stages and an increase in the organic matter content of the sediment in the late growth stages. Oxygenation decreased the nitrate nitrogen content in the t 2 period and the ammonium nitrogen content in the t4 and t5 periods but increased the nitrate nitrogen content of the sediment in the t5 period, thus promoting the absorption and accumulation of nitrogen by Myriophyllum aquaticum. Oxygenation affected the pH value and organic matter of sediment by increasing dissolved oxygen content in water. Thereby, the form transformation of sediment nitrogen was regulated and released to the water body, effectively improving the degradation ability of Myriophyllum aquaticum to the nitrogen pollutants in polluted water bodies. |
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