林下三七种植对土壤微生物群落的影响

Cultivation of Panax notoginseng in forestland alters the soilmicrobial community

【背景】目前,林下三七种植对林地土壤的理化性质及其土著微生物群落结构和功能产生影响的研究比较匮乏。开展林下三七种植对土壤微生物群落影响的研究将对林下三七种植产业发展具有重要的科学指导意义。【目的】分析林下不同生长期的三七种植地在雨季、旱季的土壤微生物群落变化特征,阐明林下土壤微生物群落对于三七种植过程的响应规律及其关键影响因子。【方法】选择未种植三七的人工自然林地土壤为对照,以不同生长期的三七种植林地土壤为研究对象,运用高通量测序技术和生物化学分析方法,对林下三七种植过程中林地土壤微生物群落的动态变化进行研究,并在此基础上采用冗余分析法分析土壤微生物群落变化的驱动因子。【结果】自然对照林地和三七种植林地土壤中优势细菌种群以变形菌门(Proteobacteria)为主,优势真菌种群以担子菌门(Basidiomycota)为主,并且有益微生物门和属的相对丰度都呈现增加趋势。自然对照林地中土壤真菌和细菌特有属的个数最少,而两年生三七种植林地土壤真菌和细菌特有属的个数最多,三年生三七种植林地土壤Chao1和ACE指数最高;主坐标分析(principal coordinate analysis,PCoA)结果显示,三七种植林地土壤微生物组成的分布区范围随着种植年份的增加出现偏移,且分布圈范围呈逐年缩小趋势;相较于雨季,旱季土壤微生物组成的分布范围整体表现为更紧密的特征。冗余分析(redundancy analysis,RDA)表明,土壤中全磷和酸性磷酸酶是影响三七种植林地土壤微生物群落变化的主要驱动因素。【结论】林下三七种植过程显著改变了种植地土壤微生物的组成,随着种植年份增加微生物组成分布的范围表现出了逐步偏移和收缩的趋势,雨旱季交替加速了三七种植林地土壤微生物群落组成与结构的分化过程。全磷和酸性磷酸酶是影响土壤微生物群落的主要环境因子。

[Background]The knownledge is limited about the effects of Panax notoginseng cultivation in forestland on the physicochemical properties of the soil and the structure and function of the soil microbial community.Studying such effects will be of great significance in guiding the cultivation of P.notoginseng in forestland.[Objective]To analyze the soil microbial communities in the forestland cultivated with P.notoginseng for different years during the rainy and dry seasons,and to elucidate the response patterns of soil microbial communities to the P.notoginseng cultivation process as well as the key influencing factors.[Methods]The natural forestland soil without P.notoginseng cultivation was taken as the control.High-throughput sequencing and biochemical tests were carried out to reveal the dynamics of soil microbial communities in the soil of the forestland with P.notoginseng cultivation.Based on the results,the redundancy analysis was then performed to clarify the drivers of the microbial community changes.[Results]The dominant bacteria and fungi in the soil of the forestland with and without P.notoginseng cultivation were Proteobacteria and Basidiomycota,respectively.The abundance of beneficial microbial phyla and genera showed an increasing trend.The number of unique genera of fungi and bacteria in soil was the lowest in the control,while it was the highest in the forestland with two-year P.notoginseng cultivation.The Chao1 and ACE indexes were the highest in the forestland with three-year P.notoginseng cultivation.The results of the principal coordinate analysis showed that the microbial distribution area in the forestland with P.notoginseng cultivation shifted and shrank with the increase in cultivation years.The soil microbial community composition was more similar among different groups in the dry season than in the rainy season.The redundancy analysis showed that total phosphorus and acid phosphatase were the main soil factors driving the changes of soil microbial communities in the forestland with P.notoginseng cultivation.[Conclusion]P.notoginseng cultivation in the forestland significantly changed the microbial community composition in the soil,and the microbial distribution presented a gradual shift and contraction with the increase in cultivation years.The alternation of rainy and dry seasons accelerated the composition and structure differentiation of the soil microbial communities in the forestland with P.notoginseng cultivation.Total phosphorus and acid phosphatase were the main environmental factors affecting the soil microbial communities.