College of Environmental Science and Engineering, Beijing Forestry University, Beijing, China.
PLoS One. 2019 May 2;14(5):e0216244. doi: 10.1371/journal.pone.0216244. eCollection 2019.
Alpine wetlands are important ecosystems, but an increased availability of soil nutrients may affect their soil nitrous oxide (N2O) fluxes and key enzyme activities. We undertook a 3-year experiment of observing nitrogen (N) and/or phosphorus (P) addition to alpine wetland soils of the Tibetan Plateau, China, with measurements made of soil extracellular enzyme activities and soil N2O fluxes. Our study showed that soil N2O flux was significantly increased by 72% and 102% following N and N+P additions, respectively. N addition significantly increased acid phosphatase (AP) and β-1, 4-N-acetyl-glucosaminidase (NAG) activities by 32% and 26%, respectively. P addition alone exerted a neutral effect on soil AP activities, while increasing NAG activities. We inferred that microbes produce enzymes based on 'resource allocation theory', but that a series of constitutive enzymes or the treatment duration interfere with this response. Our findings suggest that N addition increases N- and P-cycling enzyme activities and soil N2O flux, whereas P addition exerts a neutral effect on P-cycling enzyme activities and N2O flux after 3 years of nutrient applications to an alpine wetland.
高山湿地是重要的生态系统，但土壤养分的增加可能会影响其土壤一氧化二氮（N2O）通量和关键酶活性。我们在中国青藏高原的高山湿地土壤上进行了为期 3 年的氮（N）和/或磷（P）添加实验，测量了土壤细胞外酶活性和土壤 N2O 通量。研究表明，N 和 N+P 添加后，土壤 N2O 通量分别显著增加了 72%和 102%。N 添加分别使酸性磷酸酶（AP）和β-1,4-N-乙酰氨基葡萄糖苷酶（NAG）活性显著增加了 32%和 26%。单独添加 P 对土壤 AP 活性没有影响，但增加了 NAG 活性。我们推断，微生物根据“资源分配理论”产生酶，但一系列组成性酶或处理时间会干扰这种反应。我们的研究结果表明，N 添加增加了 N 和 P 循环酶活性和土壤 N2O 通量，而 P 添加在向高山湿地施加养分 3 年后对 P 循环酶活性和 N2O 通量没有影响。
