在亚高山森林中，土壤节肢动物通过调节微生物碳限制和生态酶化学计量来促进凋落物酶活性。
Soil arthropods promote litter enzyme activity by regulating microbial carbon limitation and ecoenzymatic stoichiometry in a subalpine forest.
作者信息
Liu Jingru, You Chengming, Xu Zhenfeng, Liu Yang, Zhang Li, Li Han, Wang Lixia, Liu Sining, He Shuqin, Luo Ziteng, Tan Bo
机构信息
Institute of Ecology & Forestry, Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China; Key Laboratory of Forest Resources Conservation and Ecological Security in Upper Reaches of Yangtze River, Chengdu 611130, China.
Institute of Ecology & Forestry, Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China; Key Laboratory of Forest Resources Conservation and Ecological Security in Upper Reaches of Yangtze River, Chengdu 611130, China.
出版信息
Sci Total Environ. 2023 Jun 10;876:162789. doi: 10.1016/j.scitotenv.2023.162789. Epub 2023 Mar 11.
Soil arthropods are crucial decomposers of litter at both global and local scales, yet their functional roles in mediating microbial activity during litter decomposition remain poorly understood. Here, we conducted a two-year field experiment using litterbags to assess the effects of soil arthropods on the extracellular enzyme activities (EEAs) in two litter substrates (Abies faxoniana and Betula albosinensis) in a subalpine forest. A biocide (naphthalene) was used to permit (nonnaphthalene) or exclude (naphthalene application) the presence of soil arthropods in litterbags during decomposition. Our results showed that biocide application was effective in reducing the abundance of soil arthropods in litterbags, with the density and species richness of soil arthropods decreasing by 64.18-75.45 % and 39.19-63.30 %, respectively. Litter with soil arthropods had a greater activity of C-degrading (β-glucosidase, cellobiohydrolase, polyphenol oxidase, peroxidase), N-degrading (N-acetyl-β-D-glucosaminidase, leucine arylamidase) and P-degrading (phosphatase) enzymes than litter from which soil arthropods were excluded. The contributions of soil arthropods to C-, N- and P-degrading EEAs in the fir litter were 38.09 %, 15.62 % and 61.69 %, and those for the birch litter were 27.97 %, 29.18 % and 30.40 %, respectively. Furthermore, the stoichiometric analyses of enzyme activity indicated that there was potential C and P colimitation in both the soil arthropod inclusion and exclusion litterbags, and the presence of soil arthropods decreased C limitation in the two litter species. Our structural equation models suggested that soil arthropods indirectly promoted C-, N- and P-degrading EEAs by regulating the litter C content and litter stoichiometry (e.g., N/P, LN/N and C/P) during litter decomposition. These results demonstrate that soil arthropods play an important functional role in modulating EEAs during litter decomposition.
土壤节肢动物在全球和局部尺度上都是凋落物的关键分解者，然而它们在凋落物分解过程中介导微生物活动的功能作用仍知之甚少。在此，我们进行了一项为期两年的田间实验，使用凋落物袋评估土壤节肢动物对亚高山森林中两种凋落物基质（岷江冷杉和红桦）细胞外酶活性（EEAs）的影响。在分解过程中，使用一种杀菌剂（萘）来允许（未使用萘）或排除（使用萘）凋落物袋中土壤节肢动物的存在。我们的结果表明，施用杀菌剂有效地降低了凋落物袋中土壤节肢动物的丰度，土壤节肢动物的密度和物种丰富度分别下降了64.18 - 75.45%和39.19 - 63.30%。有土壤节肢动物的凋落物比排除了土壤节肢动物的凋落物具有更高的碳降解（β - 葡萄糖苷酶、纤维二糖水解酶、多酚氧化酶、过氧化物酶）、氮降解（N - 乙酰 - β - D - 氨基葡萄糖苷酶、亮氨酸芳基酰胺酶）和磷降解（磷酸酶）酶活性。土壤节肢动物对冷杉凋落物中碳、氮和磷降解EEAs的贡献分别为38.09%、15.62%和61.69%，对桦木凋落物的贡献分别为27.97%、29.18%和30.40%。此外，酶活性的化学计量分析表明，在有和没有土壤节肢动物的凋落物袋中都存在潜在的碳和磷共同限制，并且土壤节肢动物的存在降低了两种凋落物种中的碳限制。我们的结构方程模型表明，土壤节肢动物通过在凋落物分解过程中调节凋落物碳含量和凋落物化学计量（如N/P、LN/N和C/P）间接促进了碳、氮和磷降解EEAs。这些结果表明，土壤节肢动物在凋落物分解过程中调节EEAs方面发挥着重要的功能作用。
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