School of Geography, Nanjing Normal University, Nanjing 210023, China.
College of Tropical Crops, Hainan University, Haikou 570228, China.
Sci Total Environ. 2023 Jul 15;882:163641. doi: 10.1016/j.scitotenv.2023.163641. Epub 2023 Apr 18.
The effects of exotic plants on soil nitrogen (N) transformations may influence species invasion success. However, the complex interplay between invasive plant N uptake and N transformation in soils remains unclear. In the present study, a series of N-labeled pot experiments were carried out with Solidago canadensis L. (S. canadensis), an invasive plant, and the Ntrace tool was used to clarify the preferred inorganic N form and its effects on soil N transformation. According to the results, nitrate-N (NO-N) uptake rates by S. canadensis were 2.38 and 2.28 mg N kg d in acidic and alkaline soil, respectively, which were significantly higher than the ammonium-N (NH-N) uptake rates (1.76 and 1.56 mg N kg d, respectively), indicating that S. canadensis was a NO-N-preferring plant, irrespective of pH condition. Gross N mineralization rate was 0.41 mg N kg d in alkaline soil in the presence of S. canadensis L., which was significantly lower than that in the control (no plant, CK, 2.44 mg N kg d). Gross autotrophic nitrification rate also decreased from 5.95 mg N kg d in the CK to 0.04 mg N kg d in the presence of S. canadensis in alkaline soil. However, microbial N immobilization rate increased significantly from 1.09 to 2.16 mg N kg d, and from 0.02 to 2.73 mg N kg d after S. canadensis planting, in acidic and alkaline soil, respectively. Heterotrophic nitrification rate was stimulated in the presence of S. canadensis to provide NO-N to support the N requirements of plants and microbes. The results suggested that S. canadensis can influence the mineralization-immobilization turnover (MIT) to optimize its N requirements while limiting N supply for other plants in the system. The results of the present study enhance our understanding of the competitiveness and mechanisms of invasion of alien plants.
外来植物对土壤氮（N）转化的影响可能会影响物种入侵的成功。然而，入侵植物对土壤中氮的吸收和氮转化之间的复杂相互作用仍不清楚。在本研究中，我们进行了一系列用加拿大一枝黄花（S. canadensis）进行的 N 标记盆栽实验，使用 Ntrace 工具来阐明其对土壤氮转化的偏好无机氮形态及其影响。结果表明，在酸性和碱性土壤中，S. canadensis 的硝酸盐-N（NO-N）吸收速率分别为 2.38 和 2.28 mg N kg d，明显高于铵态-N（NH-N）吸收速率（1.76 和 1.56 mg N kg d），这表明 S. canadensis 是一种偏好硝酸盐-N 的植物，与 pH 条件无关。在碱性土壤中，添加 S. canadensis 后，总氮矿化率为 0.41 mg N kg d，明显低于对照（无植物，CK，2.44 mg N kg d）。碱性土壤中，自养硝化速率也从 CK 的 5.95 mg N kg d 下降到添加 S. canadensis 后的 0.04 mg N kg d。然而，微生物氮固定率在酸性和碱性土壤中分别从添加 S. canadensis 前后的 1.09 和 0.02 mg N kg d 显著增加到 2.16 和 2.73 mg N kg d。添加 S. canadensis 后，异养硝化速率受到刺激，为植物和微生物提供 NO-N 以满足其氮需求。结果表明，S. canadensis 可以影响矿化-固定转化（MIT），以优化其氮需求，同时限制系统中其他植物的氮供应。本研究的结果增强了我们对入侵植物竞争力和入侵机制的理解。
