公路源重金属对青藏高原高寒草甸土壤线虫群落的影响

Effects of traffic-source heavy metals on soil nematode community in alpine meadow of the Tibet Plateau

为了解重金属对青藏高原高寒草甸土壤线虫群落的影响,在邦杰塘草原利用公路源重金属含量差异,采用高通量测序技术,分析重金属对高寒草甸土壤线虫群落多样性及群落组成的影响。结果表明:在重金属含量较低样本中,土壤线虫群落Shannon指数、Ace指数、Chao指数比重金属含量较高样本均要小,且整体上Shannon指数、Ace指数、Chao指数与重金属含量较高样本差异显著(P<0.05)。重金属含量升高改变了高寒草甸土壤线虫纲水平和目水平的群落结构,使近自然状况下的色矛纲(Chromadorea)、小杆目(Rhabdtida)优势土壤线虫群落转变为一类未分类线虫纲(unclassifiedpNematoda)、一类未分类线虫目(unclassifiedpNematoda)的优势土壤线虫群落。重金属Cu、Pb、Zn、Cd与线虫门(Nematoda)和刺嘴纲(Enoplea)正相关,但与色矛纲(Chromadorea)负相关,且对土壤线虫Chao指数的变异解释比例依次减小。研究表明土壤重金属含量对青藏高原高寒草甸土壤线虫群落多样性及组成产生很大影响,但仍需对高寒草甸区域进行系统的土壤线虫调查,并丰富土壤线虫生物信息数据库。

Soil nematode is a sensitive soil organism.In order to understand the effects of heavy metals on the alpine meadow soil nematode community in the Tibet Plateau,this study based on the differences in heavy metals content from highway sources in the Bangjietang grassland used the high-throughput sequencing technology to analyze the influence of heavy metals on the diversity and community structure of the alpine meadow soil nematode community.In August 2019,we collected soil samples at 0,5,15,30,50 and 75 m away from the highway in Bangjietang grassland.Cu,Pb,Zn,Cd were determined by flame atomic absorption spectrophotometry,and the community composition and structure of soil nematode were determined by high-throughput sequencing technology.The influence of heavy metals on soil nematode community was discussed by redundancy analysis.The results showed that the Shannon index,Ace index and Chao index of the soil nematode community in the samples with lower heavy metal content were smaller than the samples with higher heavy metal content(P<0.05).The increase of heavy metal content changed the community structure of soil nematode in alpine meadow,and the dominant soil nematode communities of Chromadorea and Rhabdtida under the natural conditions were transformed into the dominant soil nematoda communities of unclassifiedpNematoda and unclassifiedpNematoda.Cu,Pb,Zn and Cd were positively correlated with Nematoda and Enoplea,but negatively correlated with Chromadorea.The proportion of Cu,Pb,Zn,Cd to the variation explanation of Chao index decreased successively.The study shows that soil heavy metal content has a great influence on the diversity and structure of soil nematode community in alpine meadow of the Tibet Plateau,but it is still necessary to conduct a systematic investigation of soil nematode in alpine meadow and enrich the database of biological information of soil nematode.