不同年限三七根系丛枝菌根真菌多样性及其与土壤理化性质的相关分析

Correlation analysis between diversity of arbuscular mycorrhizal fungi in roots and soil physicochemical properties of Panax notoginseng(Burk.)F. H. Chen at different ages

  • 摘要: 【目的】明确不同年限三七根系丛枝菌根真菌(AMF)多样性、群落结构差异及其与根际土壤理化性质的关系,为AMF在缓解三七连作障碍中的应用提供参考依据。【方法】以1年生、2年生和3年生三七根系及根际土壤为试验材料,采用显微形态法观察并测定根系AMF侵染率,通过Illumina高通量测序技术分析不同年限三七根系AMF多样性和群落结构差异,探讨三七根系AMF多样性和相对丰度与根际土壤理化性质的相关性。【结果】三七根系AMF侵染率在83%~95%,且随着种植年限延长,根际土壤的碱解氮、全氮和全磷含量逐渐减少,有效磷和速效钾含量先降低后升高,土壤酸化加强。通过高通量测序技术在三七根系中共检测到55个OTUs,排除不可归类,分属于球囊霉菌纲(Glomeromycetes)的4目6科7属19种,其中球囊霉属(Glomus)占比最高(达45.30%)。多样性分析结果发现,对比其他2个年限,3年生三七根系OTUs最少,且多样性和丰富度最低。偏最小二乘法判别分析(PLS-DA)结果表明,不同年限三七根系AMF群落结构差异明显,其中球囊霉属是1年生和3年生三七根系的优势属(占比分别为32.31%和53.68%),类球囊霉属(Paraglomus)为2年生三七的优势属(占比50.39%)。相关分析结果发现,三七根系AMF的ACE和Chao指数与根际土壤全磷含量呈显著正相关(P<0.05,下同),与有效磷和速效钾含量呈显著或极显著(P<0.01)负相关。【结论】不同年限三七根系AMF的丰富度和群落结构存在明显差异,随种植年限增加,三七根系AMF丰富度和OTUs逐渐降低,但球囊霉属相对丰度逐渐上升。在三七根际土壤中,有效磷和速效钾含量是影响其根系AMF群落结构的主要因素。

     

    Abstract: 【Objective】To clarify the relationship between arbuscular mycorrhizal fungi (AMF)diversity,community structure and physicochemical properties of rhizosphere soil of Panax notoginseng(Burk.) F. H. Chen in different years, and provide reference for the application of AMF in alleviating the obstacles of continuous cropping of P. notoginseng.【Method】In this study,the root system and rhizosphere soil of P. notoginseng aged one,two and three year-old were used as experimental materials. The AMF infection rate of root system was observed by using the microscopic morphology observation method. The differences of AMF diversity and community structure of the P. notoginseng root system were analyzed using Illumina high-throughput sequencing. Pearson correlation coefficient method was used to reveal the correlation between relative abundance of P. notoginseng roots AMF diversity and physicochemical properties of rhizosphere soil.【Result】The results showed that the AMF infection rates of P. notoginseng root ranged from 83% to 95%. With the extension of planting years,the contents of alkali-hydrolyzed nitrogen,total nitrogen and total phosphorus in rhizosphere soil gradually decreased,the contents of available phosphorus and available potassium first decreased and then increased, and the soil acidification was strengthened. A total of 55 OTUs were detected in the root system of P. notoginseng by highthroughput sequencing. Excluding the unclassified groups,these OTUs belonged to 19 species,4 orders,6 families,7 genera of Glomeromycetes,and Glomus accounted for the highest proportion(45.30%). The results of the diversity analysis showed that the three-year-old P. notoginseng had the least number of root OTUs and the lowest diversity and richness compared to the one-year-old and two-year-old P. notoginseng. Partial least squares discriminant analysis(PLS-DA) showed that the AMF community structure of P. notoginseng root system was different in different years samples,and Glomus was the dominant genus of one-year-old and three-year-old root system(proportions were 32.31% and 53.68%), while Paraglomus was the dominant genus of two-year-old root system(proportion 50.39%). The results of correlation analysis showed that the ACE and Chao indexes of AMF of P. notoginseng root was significantly positively correlated with total phosphorus in rhizosphere soil (P<0.05),and significantly or extremely significantly(P<0.01)negatively correlated with available phosphorus and available potassium.【Conclusion】There are obvious differences in the abundance and community structure of AMF in the root system of P. notoginseng in different years. With the increase of planting years, the abundance and OTUs of AMF in the root system of P. notoginseng gradually decrease,but the relative abundance of Glomus gradually increases. In the rhizosphere soil of P. notoginseng,the contents of effective phosphorus and quickacting potassium are the main factors affecting the community structure of AMF in its root system.

     

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