Zeng Quan-Xin, Yuan Xiao-Chun, Zhou Jia-Cong, Wu Jun-Mei, Li Wen-Zhou, Lin Hui-Ying, Zhang Xiao-Qing, Chen Yueh-Min
School of Geographical Science, Fujian Normal University, Fuzhou 350007, China.
Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fujian Normal University, Fuzhou 350007, China.
Ying Yong Sheng Tai Xue Bao. 2022 Aug;33(8):2178-2186. doi: 10.13287/j.1001-9332.202208.018.
Soil phosphatases are important in the mineralization of organophosphates and in the phosphorus (P) cycle. The kinetic mechanisms of phosphatases in response to nitrogen (N) deposition remain unclear. We carried out a field experiment with four different concentrations of N: 0 g N·hm·a(control), 20 g N·hm·a(low N), 40 g N·hm·a(medium N), and 80 g N·hm·a(high N) in a subtropical Moso bamboo forest. Soil samples were then collected from 0 to 15 cm depth, after 3, 5 and 7 years of N addition. We analyzed soil chemical properties and microbial biomass. Acid phosphatase (ACP) was investigated on the basis of maximum reaction velocity (), Michaelis constant (), and catalytic efficiency (). Results showed that N addition significantly decreased soil dissolved organic carbon (DOC), available phosphorus, and organophosphate content, but significantly increased soil ammonium, nitrate-N content, and . There was a significant relationship between and the concentrations of available phosphorus, organophosphate, and soil DOC. In general, N addition substantially increased , but did not affect . The value in the high N treatment group was higher than that in the control group after five years of N addition. was significantly negatively associated with both available phosphorus and organophosphate. Medium and high N treatments had stronger effects on the kinetic parameters of ACP than low N treatment. Results of variation partition analysis showed that changes in soil chemical properties, rather than microbial biomass, dominated changes in (47%) and (33%). In summary, N addition significantly affected substrate availability in Moso bamboo forest soil and modulated soil P cycle by regulating ACP kinetic parameters (especially ). The study would improve the understanding of the mechanisms underlying soil microorganisms-regulated soil P cycle under N enrichment. These mechanisms would identify the important parameters for improving soil P cycling models under global change scenarios.
土壤磷酸酶在有机磷酸盐的矿化作用和磷（P）循环中起着重要作用。磷酸酶响应氮（N）沉降的动力学机制尚不清楚。我们在亚热带毛竹林中进行了一项田间试验，设置了四种不同浓度的氮：0 g N·hm⁻²·a（对照）、20 g N·hm⁻²·a（低氮）、40 g N·hm⁻²·a（中氮）和80 g N·hm⁻²·a（高氮）。在添加氮3、5和7年后，从0至15厘米深度采集土壤样本。我们分析了土壤化学性质和微生物生物量。基于最大反应速度（Vmax）、米氏常数（Km）和催化效率（Vmax/Km）对酸性磷酸酶（ACP）进行了研究。结果表明，添加氮显著降低了土壤溶解有机碳（DOC）、有效磷和有机磷含量，但显著增加了土壤铵、硝态氮含量以及Vmax/Km。Vmax与有效磷、有机磷和土壤DOC浓度之间存在显著关系。总体而言，添加氮显著增加了Vmax，但未影响Km。添加氮五年后，高氮处理组的Vmax/Km值高于对照组。Vmax/Km与有效磷和有机磷均显著负相关。中氮和高氮处理对ACP动力学参数的影响比低氮处理更强。变异分配分析结果表明，土壤化学性质的变化而非微生物生物量主导了Vmax（47%）和Vmax/Km（33%）的变化。总之，添加氮显著影响了毛竹林土壤中底物的有效性，并通过调节ACP动力学参数（尤其是Vmax/Km）来调节土壤P循环。该研究将增进对氮富集条件下土壤微生物调节土壤P循环潜在机制 的理解。这些机制将确定全球变化情景下改善土壤P循环模型的重要参数。
