Aims

Root traits play an important role in regulating soil microbial communities by altering soil parameters. However, how the variation of root traits across tree species affects soil microbiome under different nutrient environments is unclear.

Methods

We chose six dominant ectomycorrhizal (ECM) tree species differing in root diameter in a temperate forest, and measured root growth, morphological and chemical traits, soil parameters and microbial communities under three nutrient addition treatments, including unfertilized control (CK), inorganic fertilizer (IF) and organic fertilizer (OF), using ingrowth bags.

Results

Compared with CK, IF and OF additions decreased soil bacterial α-diversity, and IF addition also decreased soil fungal α-diversity. The community co-occurrence network was more complex after OF addition than CK and IF treatments. The root morphological traits (root diameter and specific root length) were positively correlated with fungal community composition, whereas root chemical traits (total soluble sugar and phenol contents) influenced the composition and α-diversity of bacterial and fungal communities in the CK and IF treatments. The root growth traits (root length and biomass) affected the composition and α-diversity of bacterial and fungal communities in all treatments. Fine root traits and soil parameters interactively explained more variation in the bacterial than the fungal communities.

Conclusions

Our findings suggest that the variation of root traits across tree species, nutrient and carbon availability, and their interactions can drive soil bacterial and fungal diversity and composition.

中文翻译：

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根性状和土壤养分和碳的有效性驱动北部温带森林的土壤微生物多样性和组成

目标

根性状通过改变土壤参数在调节土壤微生物群落中发挥重要作用。然而，在不同营养环境下，不同树种根系特征的变化如何影响土壤微生物组尚不清楚。

方法

我们在温带森林中选择了 6 种根直径不同的优势外生菌根 (ECM) 树种，并在未施肥对照 (CK)、无机肥 ( IF) 和有机肥 (OF)，使用生长袋。

结果

与CK相比，IF和OF的添加降低了土壤细菌的α-多样性，IF的添加也降低了土壤真菌的α-多样性。OF 添加后的社区共现网络比 CK 和 IF 处理更复杂。根形态性状（根直径和比根长）与真菌群落组成呈正相关，而根化学性状（总可溶性糖和酚含量）影响CK和IF处理中细菌和真菌群落的组成和α多样性. 根系生长特性（根长和生物量）影响所有处理中细菌和真菌群落的组成和α多样性。细根性状和土壤参数交互解释了细菌比真菌群落更多的变异。

结论

我们的研究结果表明，树种、养分和碳的有效性及其相互作用的根性状变化可以驱动土壤细菌和真菌的多样性和组成。