Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou 510520, China.
Chongqing Jinyun Forest Ecological Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
Ecotoxicol Environ Saf. 2021 Jun 1;215:112152. doi: 10.1016/j.ecoenv.2021.112152. Epub 2021 Mar 27.
The relationship between soil respiration (SR) and microbial community structure (MCS) is relevant to changes in forest soil ecosystem stability and chemical cycling under acid rain. Simulated acid rain treatments of pH 4.5 (control), 4.0, 3.25 and 2.5 were applied to two forest stands in the Three Gorges Reservoir Area of Jinyun Mountain, Chongqing. We used phospholipid fatty acid (PLFA) analysis to observe the MCS in the 0-10 cm soil layer and measured SR in situ from January 2016 to December 2017. Additionally, we determined the effects of soil properties on the MCS and SR. Acid rain simulation significantly increased the fungal PLFA abundance and decreased the bacterial PLFA abundance in the mixed coniferous and broad-leaved forest (CF). However, in the evergreen broad-leaved forest (BF), the abundance of bacterial and fungal PLFAs did not differ significantly among treatments. Redundancy analysis (RDA) showed that significant changes in the MSC were mainly due to the C/N ratio, hydrolysable N content, content, fine root biomass and sucrase activity. Acid rain simulation in the CF and BF significantly inhibited SR, but the SR sensitivity to simulated acid rain differed among forests. In 2017, the annual mean SR in the CF under the pH 4.0, 3.25 and 2.5 treatments decreased significantly by 6.1%, 19.2% and 28.9%, but in the BF, SR decreased significantly by 25.6% only under pH 2.5. The structural equation model showed that the relationship between the MCS and the variation in SR was closer and more direct than that with soil nutrients. The microbial community structure was an important factor driving the response of soil respiration to acid rain.
土壤呼吸（SR）与微生物群落结构（MCS）之间的关系与森林土壤生态系统在酸雨下的稳定性和化学循环变化有关。采用 pH 值为 4.5（对照）、4.0、3.25 和 2.5 的模拟酸雨处理，对重庆缙云山两个林分进行了处理。我们使用磷脂脂肪酸（PLFA）分析观察了 0-10 cm 土层中的 MCS，并于 2016 年 1 月至 2017 年 12 月进行了原位 SR 测量。此外，我们还确定了土壤性质对 MCS 和 SR 的影响。酸雨模拟显著增加了针阔混交林（CF）中的真菌 PLFA 丰度，降低了细菌 PLFA 丰度。然而，在常绿阔叶林（BF）中，处理之间细菌和真菌 PLFA 的丰度没有显著差异。冗余分析（RDA）表明，MSC 的显著变化主要是由于 C/N 比、可水解 N 含量、含量、细根生物量和蔗糖酶活性。CF 和 BF 中的酸雨模拟显著抑制了 SR，但森林之间对模拟酸雨的 SR 敏感性不同。2017 年，CF 在 pH 值为 4.0、3.25 和 2.5 处理下的年平均 SR 分别显著降低了 6.1%、19.2%和 28.9%，而在 BF 中，仅在 pH 值为 2.5 时 SR 显著降低了 25.6%。结构方程模型表明，MCS 与 SR 变化之间的关系比与土壤养分之间的关系更紧密、更直接。微生物群落结构是驱动土壤呼吸对酸雨响应的重要因素。
