Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China.
Miyaluo Research Station of Alpine Forest Ecosystem, Lixian County, Sichuan, China.
PeerJ. 2022 Sep 14;10:e14028. doi: 10.7717/peerj.14028. eCollection 2022.
Mycorrhizal fungi can form symbiotic associations with tree species, which not only play an important role in plant survival and growth, but also in soil carbon (C) and nitrogen (N) cycling. However, the understanding of differences in soil C and N cycling patterns among forests with different mycorrhizal types is still incomplete. In order to determine the similarities and differences of soil C and N cycling patterns in different mycorrhizal forest types, three primary forests dominated by ectomycorrhizal (EcM), arbuscular mycorrhizal (AM) and ericoid mycorrhizal (ErM) trees respectively were studied on the eastern Qinghai-Tibetan Plateau. Indicators associated with soil C and N cycling, including leaf litter quality, soil C and N contents, soil C and N fluxes, and soil microbial biomass C and N contents were measured in each mycorrhizal type forest. The results showed that leaf litter quality was significantly lower with high C:N ratio and lignin: N ratio in ErM forest than that in AM and EcM forests. Soil CO flux (508.25 ± 65.51 mg m h) in AM forest was significantly higher than that in EcM forest (387.18 ± 56.19 mg m h) and ErM forest (177.87 ± 58.40 mg m h). Furthermore, soil inorganic N content was higher in the AM forest than that in EcM and ErM forests. Soil net N mineralization rate (-0.02 ± 0.03 mg kg d) was lower in ErM forest than that in EcM and AM forests. We speculated that AM and EcM forests were relatively characterized by rapid soil C cycling comparing to ErM forest. The soil N cycling in EcM and ErM forests were lower, implying they were 'organic' N nutrition patterns, and the pattern in ErM forest was more obvious.
菌根真菌可以与树种形成共生关系，它们不仅在植物的生存和生长中起着重要作用，而且在土壤碳（C）和氮（N）循环中也起着重要作用。然而，对于不同菌根类型森林土壤碳和氮循环模式的差异，人们的理解仍不完整。为了确定不同菌根森林类型土壤碳和氮循环模式的异同，我们在青藏高原东部选择了三种以外生菌根（EcM）、丛枝菌根（AM）和杜鹃花菌根（ErM）为主导的原始森林进行研究。在每种菌根类型的森林中，我们测量了与土壤碳和氮循环相关的指标，包括叶凋落物质量、土壤 C 和 N 含量、土壤 C 和 N 通量以及土壤微生物生物量 C 和 N 含量。结果表明，与 AM 和 EcM 森林相比，ErM 森林的叶凋落物质量明显较低，具有较高的 C:N 比和木质素:N 比。AM 森林的土壤 CO 通量（508.25±65.51mg m h）明显高于 EcM 森林（387.18±56.19mg m h）和 ErM 森林（177.87±58.40mg m h）。此外，AM 森林的土壤无机 N 含量高于 EcM 和 ErM 森林。ErM 森林的土壤净氮矿化率（-0.02±0.03mg kg d）低于 EcM 和 AM 森林。我们推测，与 ErM 森林相比，AM 和 EcM 森林的土壤 C 循环相对较快。EcM 和 ErM 森林的土壤 N 循环较低，这意味着它们是“有机”N 营养模式，而 ErM 森林的模式更为明显。
