镉污染对稻田土壤真菌群落结构及多样性的影响

Effects of cadmium pollution on fungal community structure and diversity in paddy field

  • 摘要: 【目的】探究镉胁迫对稻田土壤真菌群落结构及其多样性的影响,为阐释镉胁迫对稻田土壤微生物多样性的影响机制提供科学依据。【方法】以湖南某镉矿周边3个镉污染程度(高、中和低)的稻田土壤为研究对象,采集土壤样品,测定土壤养分含量,利用Illumina MiSeq高通量测序技术探究土壤真菌群落结构,对比分析不同镉污染组土壤真菌群落多样性和群落结构差异。【结果】稻田土壤的真菌α多样性随着镉污染水平升高逐渐降低,高镉组(总镉含量>3.0 mg/kg) α多样性显著低于中镉组(总镉含量0.3~3.0 mg/kg)和低镉组(总镉含量<3.0 mg/kg)(P<0.05,下同),但中镉组和低镉组之间的差异较小。高镉组与中、低镉组土壤样品间真菌群落具有显著差异。在门水平上,子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和被孢霉门(Mortierellomycota)在所有样品组中均属优势菌门,相对丰度在51.09%~81.93%。韧伞属(Hypholoma)、篮状菌属(Talaromyces)、Meliniomyces属在高镉组的相对丰度显著高于中镉组和低镉组,可能是潜在的耐镉菌。有机质、pH、碱性氮、有效磷、有效钾、总磷、总镉及有效镉均与土壤真菌群落结构呈极显著正相关(P<0.01)。【结论】高浓度镉污染可降低稻田土壤真菌群落α多样性并改变土壤真菌群落结构。pH、碱性氮、有效磷、有效钾、总磷、有机质、总镉及有效镉均与土壤真菌群落结构显著相关,是影响土壤真菌群落结构的主要驱动因子。

     

    Abstract: 【Objective】To investigate the effects of cadmium stress on soil fungal community structure and diversity in paddy fields, so as to provide scientific basis for explaining the effect of mechanism of cadmium stress on paddy soil microbial diversity.【Method】Soil samples with 3 levels of cadmium pollution(high, medium and low) collected from paddy fields with around a cadmium mine in Hunan province were taken as research object, and soil nutrient contents were measured. Soil fungal community structure was explored through Illumina MiSeq high-throughput sequencing technology to analyze the difference of soil fungal community diversity and structure.【Result】The results showed that the fungal α diversity of rice soils decreased with the increase of Cd pollution level. The α diversity in high Cd group(total cadmium content>3.0 mg/kg) was significantly lower than that in medium Cd(total cadmium content:0.3-3.0 mg/kg) and low Cd (total cadmium content <3.0 mg/kg) groups(P<0.05, the same below), but there was a slight difference between medium and low Cd groups(P>0.05). There were significant differences in fungal communities among high Cd group, medium Cd group and low Cd group. At the phylum level, Ascomycota, Basidiomycota and Mortierellomycota were dominant phyla in all sample groups, with relative abundance ranging from 51.09% to 81.93%. Relative abundance of Hypholoma, Talaromyces and Meliniomyces in the high Cd group was significantly higher than that in the medium and low Cd groups, and they may be cadmium-resistant microbes. Organic matter, pH, alkaline N, available P, available K, total P, total Cd and available Cd were extremely significantly positively correlated with soil fungal community structure(P<0.01).【Conclusion】High concentrations of cadmium pollution can reduce α diversity of soil fungal community and change soil fungal community in paddy field. pH, alkaline N, available P, available K, total P, organic matter, total Cd and available Cd are significantly correlated with soil fungal community structure, which is the main factor affecting soil fungal community structure.

     

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