Purpose

The effects of trees on soil nematode communities are related to nutrient cycles in forest ecosystems. We conducted greenhouse pot experiments to determine the effects of a single tree species for each of coniferous and broad-leaved tree on soil nematodes.

Methods

Soils were collected from a coniferous plantation and broad-leaved forests. Seedlings of a coniferous tree (Cryptomeria japonica) and a broad-leaved tree (Quercus serrata) were planted in soils derived from each species. After 11 months, seedling biomass, soil properties, and ectomycorrhizal fungal colonization of Q. serrata were measured. Soil nematodes were morphologically identified to the genus/family level and differentiated by community and trophic composition.

Results

C. japonica root biomass was significantly higher than that of Q. serrata regardless of the soil and nematode community structures were significantly different between the species. The fungal: bacterial ratio and density of fungivorous nematodes were significantly higher in broad-leaved soils. Herbivorous nematodes increased significantly in C. japonica seedlings grown in broad-leaved soils. Structural equation modeling indicated that soil origin and tree species directly regulated nematode trophic compositions.

Conclusion

Our findings suggest that tree species modify soil micro-food webs by affecting microbial abundance and nematode trophic composition. Specifically, C. japonica, with a larger root biomass, increased the number of herbivorous nematodes, whereas Q. serrata, with ectomycorrhizal fungal symbiosis, increased the number of fungivorous nematodes. Thus, tree species are tightly involved in shaping nematode communities in forest ecosystems through root traits and mycorrhizal types.

中文翻译：

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树种特性和土壤来源对针阔叶林土壤线虫群落和营养成分的影响

目的

树木对土壤线虫群落的影响与森林生态系统的养分循环有关。我们进行了温室盆栽实验，以确定每种针叶树和阔叶树的单一树种对土壤线虫的影响。

方法

土壤是从针叶林和阔叶林收集的。将针叶树（日本柳杉）和阔叶树（锯齿栎）的幼苗种植在来自每个物种的土壤中。11 个月后，测量了锯缘栎的幼苗生物量、土壤特性和外生菌根真菌定植情况。土壤线虫在形态上被鉴定为属/科水平，并通过群落和营养成分进行区分。

结果

无论土壤如何，粳稻根系生物量均显着高于锯叶栎，且种间线虫群落结构存在显着差异。阔叶土壤中真菌：细菌比例和食真菌线虫密度显着较高。在阔叶土壤中生长的粳稻幼苗中，草食性线虫显着增加。结构方程模型表明，土壤来源和树种直接调节线虫的营养成分。

结论

我们的研究结果表明，树种通过影响微生物丰度和线虫营养成分来改变土壤微食物网。具体而言，C. japonica具有较大的根生物量，增加了食草线虫的数量，而Q. serrata具有外生菌根真菌共生，增加了食真菌线虫的数量。因此，树种通过根性状和菌根类型密切参与森林生态系统中线虫群落的形成。