南亚热带森林丛枝菌根真菌与土壤结构的关系

The relationship between arbuscular mycorrhizal fungi and soil structure in southern subtropical forest

研究了南亚热带不同演替阶段森林土壤理化性质、团聚体组成、微生物群落结构以及球囊霉素相关蛋白(GRSP)含量,探讨丛枝菌根真菌(AMF)与土壤结构的关系。结果表明:1)南亚热带森林土壤养分、大团聚体(粒径>2000μm)含量、平均重量直径(MWD)、AMF生物量以及GRSP含量均随演替而增加。2)不同演替阶段森林土壤团聚体组成的差异主要发生在10—20cm土层,该土层总GRSP含量、易提取GRSP占比、AMF生物量、土壤有机碳(SOC)含量与其MWD具有显著正相关性。3)相关性分析表明,在南亚热带森林,AMF生物量与其总GRSP含量、易提取GRSP占比、土壤微生物量、SOC含量具有显著正相关性;总GRSP含量、易提取GRSP占比、AMF生物量、土壤微生物量、SOC含量与其大团聚体含量、MWD具有显著正相关性,而与其中、小型团聚体含量具有显著负相关性。以上研究结果表明,AMF能够通过分泌GRSP、改变土壤微生物群落、促进土壤碳固持等措施影响南亚热带森林土壤结构稳定性。

The aim of this study is to understand the relationship between arbuscular mycorrhizal fungi(AMF)and soil structure in southern subtropical forests.Soil properties,soil aggregate compositions,microbial community structure and glomalin-related soil protein(GRSP)concentrations were measured.The results are as follows.(1)Soil nutrients,macro aggregate(particle size>2000μm)concentration,mean weight diameter(MWD),AMF biomass and GRSP concentration increased with the forest succession.(2)The variations of soil aggregate composition in southern subtropical forests mainly occurred in 10-20 cm soil layer.Correlation analysis presented that MWD had a significantly positive correlation with the total GRSP(T-GRSP)concentration,the ratio of easy extractable GRSP to T-GRSP(EE-GRSP/T-GRSP),the AMF biomass and the soil organic carbon(SOC)content in 10-20 cm soil layer.(3)Correlation analysis indicated that AMF biomass had a significantly positive correlation with the T-GRSP concentration,EE-GRSP/T-GRSP,soil microbial biomass and SOC content.The T-GRSP concentration,EE-GRSP/T-GRSP,AMF biomass,soil microbial biomass and SOC content had a significantly positive correlation with macro aggregate concentration and MWD,but had a significantly negative correlation with micro aggregate concentration in southern subtropical forests.Our results suggested that AMF could influence the stability of soil structure by secreting GRSP,changing soil microbial community and promoting SOC sequestration in southern subtropical forests.