短期施肥对桉树人工林土壤真菌群落结构及功能类群的影响

为探索桉树人工林土壤真菌群落对短期施肥的响应特征,本研究利用Illumina高通量测序技术和FUNGuild平台,分析短期施肥和不施肥(control, CK)处理下土壤真菌的群落结构、功能类群及其影响因子。结果表明:桉树土壤真菌群落主要由担子菌门和子囊菌门主导,分别占48.61%—46.74%和39.31%—38.08%,短期施肥对真菌门水平的影响不显著。在目水平上,施肥处理中牛肝菌目(23.73%)和散囊菌目(19.95%)的相对丰度显著高于CK处理,分别为CK的7.65和1.72倍,而古根菌目、爪甲团囊菌目、银耳菌目等优势菌目的相对丰度则低于CK处理。短期施肥后土壤真菌α多样性和丰富度指数有所降低,主坐标分析表明,施肥组与CK组真菌群落结构差异显著。桉树土壤真菌的营养类型以腐生型为主,施肥处理中共生型真菌相对丰度显著增加,是CK的4.19倍,且增加以外生菌根马勃菌为主,而大多数其他营养类型真菌的相对丰度则显著减少。冗余分析表明,土壤有效养分含量、微生物碳、土壤有机碳、pH值和土壤含水量等土壤因子是影响群落的主要因子。短期施肥显著改变桉树人工林土壤真菌群落结构和功能类群,增加共生真菌比例,改善土壤质量。

Effects of short-term fertilization on soil fungal community structure and functional group in Eucalyptus artificial forest

In order to investigate the response characteristics of the soil fungal community to short-term fertilization in Eucalyptus artificial forest, Illumina high-throughput sequencing and FUNGuild platforms were performed in this study. The soil fungal community composition, functional groups and their impact factors were analyzed under the short-term fertilization and non-fertilization (control, CK) treatments. As the result shown, Basidiomycota and Ascomycota were identified as the dominant fungi at the class level, accounting for 48.61%-46.74% and 39.31%-38.08%, respectively. The soil fungal community at the class level was not significantly changed by short-term fertilization. On the order level, the relative abundance of (23.73%) and Eurotiales (19.95%) was significantly increased by 7.65 and 1.72 times under the fertilization treatment, respectively, when compared with CK treatment. However, the ratios of Archaeorhizomycetales, Onygenales, Tremellales, and other dominant orders were obviously decreased in soil under the fertilization treatment. The alpha diversity and abundance index of soil fungi were slightly decreased under the fertilization treatment. Meanwhile, the principal coordinate analysis indicated that the fungal community composition was significant difference between the fertilization and CK treatments. Spatrotroph group was identified as the most dominate trophic group in the soil of Eucalyptus artificial forest. The ratio of symbiotroph group was significantly increased by 4.19 times under the fertilization treatment when compared with CK treatment. In addition, the ectomycorrhizal fungus Pisolithus was mainly increased in the symbiotroph group, whereas the relative abundance of other trophic group fungi was obviously decreased. Moreover, the redundancy analysis showed that the soil fungal community was mainly influenced by the soil factors including the contents of soil available nutrition, soil organic carbon, microbial biomass carbon, pH value, and soil moisture. Our results indicated that the short-term fertilization treatment altered the soil fungal community structure and functional group in Eucalyptus artificial forest, and also increased the proportion of symbiotic fungi and improved the soil quality.