CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, PR China; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China.
Nicholas School of the Environment & Pratt School of Engineering, Duke University, Durham, NC 27708, USA; Department of Forest Sciences, University of Helsinki, FI-00014, Finland.
Sci Total Environ. 2024 Nov 10;950:175175. doi: 10.1016/j.scitotenv.2024.175175. Epub 2024 Aug 5.
In many ecosystems, a large fraction of gross primary production is invested in mycorrhiza. Ectomycorrhizal (ECM) mycelium is involved in regulating soil carbon and nutrient cycling. However, little is known about how mycelial biomass, production and turnover differ depending on ECM fungal community composition and associated tree species. We quantified fine root biomass and length using soil cores, and mycelial traits (biomass, production, and turnover) using mesh-bags and ergosterol analysis, and identified ECM exploration types by Illumina MiSeq sequencing of four ECM-dominated tree species (Picea asperata, Larix gmelinii, Quercus aquifolioides and Betula albosinensis) in subalpine forest. The ECM fungal community composition separated between needle-leaved and broadleaved species, and between evergreen and deciduous species. The ratio of mycelial to fine root biomass was similar across the species regardless of genus-scale community composition and the relative abundance of exploration types. Compared to the other species, Q. aquifolioides displayed higher fine root biomass and mycelial biomass and production, dominated by contact-short exploration type. Mycelial turnover rate tended to be lowest in P. asperata, dominated by medium-long exploration type. Much higher production of mycelium and only slightly higher turnover rate in Q. aquifolioides suggests that its steady-state mycelial biomass would be higher than of the other species. Moreover, compared to the two deciduous species, with similar production but somewhat lower turnover rate, the standing crop of mycelium in P. asperata may stabilize at a higher value. Our findings, that exploration type may affect production and turnover, highlight the importance of characterizing ECM fungal communities by exploration types when estimating the contribution of mycelium biomass to forest carbon sink and storage.
在许多生态系统中，很大一部分总初级生产量都投入到了菌根中。外生菌根（ECM）菌根真菌参与调节土壤碳和养分循环。然而，人们对外生菌根真菌群落组成和相关树种如何影响菌根生物量、生产力和周转率知之甚少。我们使用土壤芯来量化细根生物量和长度，使用网袋和麦角固醇分析来量化菌根特征（生物量、生产力和周转率），并通过 Illumina MiSeq 测序来确定四种 ECM 占主导地位的树种（云杉、落叶松、麻栎和白桦）的 ECM 探索类型，这些树种位于亚高山森林中。 ECM 真菌群落组成在针叶树种和阔叶树种之间，以及常绿树种和落叶树种之间存在差异。无论属级群落组成和探索类型的相对丰度如何，菌根与细根生物量的比值在各物种间都相似。与其他物种相比，麻栎的细根生物量和菌根生物量和生产力较高，以接触短探索类型为主。菌根周转率在云杉中倾向于最低，以中长探索类型为主。麻栎的菌根生产力较高，而周转率略高，表明其稳定态菌根生物量将高于其他物种。此外，与两种落叶树种相比，虽然生产能力相似，但周转率略低，云杉的菌根生物量在稳定状态下可能会稳定在更高的值。我们的研究结果表明，探索类型可能会影响菌根的生产力和周转率，当估计菌根生物量对森林碳汇和储存的贡献时，通过探索类型来描述 ECM 真菌群落的特征显得尤为重要。
