苯并[a]芘累积污染土壤的微生物多样性响应机理

Benzo[a]pyrene, as a typical polycyclic aromatic hydrocarbon pollutants, has been accumulating gradually with low dose of superposition in soil, and will bring a serious impact on soil ecological security if the content of benzo[a]pyrene exceed the critical safety threshold. Soil benzo[a]pyrene pollution is a focus of current research, however, the effect mechanism on soil microorganism after the gradual accumulation of benzo[a]pyrene still lack systematic research. This project aims to select benzo[a]pyrene because of its far-ranging distribution and serious toxicity as a representation of polycyclic aromatic hydrocarbon pollutants, adopts the superposition method to simulate the accumulation process of benzo[a]pyrene in soil, combines the traditional manual incubation and modern molecular biology techniques to study the integrated toxicity effect of soil benzo[a]pyrene on soil microbial diversities under the condition of accumulative and one-off pollution. The microbial function, structure, species and heredity diversity will be studied by using of Biolog, PLFA, CFU, PCR-DGGE and high-throughput DNA sequencing techniques at four levels (including community, population, species and gene).And the identification of dominant microbial species and functional genes will be performed by using of sequencing technology, and the number and abundance of dominant microorganism will be detected by Real-time PCR technology to clarify the response mechanism of soil microbial diversity to benzo[a]pyrene pollution. The object of this paper is to elucidate soil microbial poisoning mechanism by analyzing the response of microbial diversity to benzo[a]pyrene accumulation and the relationship between benzo[a]pyrene and soil microbial diversity. The research results will provide a scientific method and theoretic bases for ecological toxicity diagnosis of soil polycyclic aromatic hydrocarbon pollutants.

苯并[a]芘正以低剂量叠加的方式在土壤中逐步积累，一旦超过其临界安全阈值，将会对土壤生态安全产生严重影响。有关苯并[a]芘在土壤中逐步积累后对微生物的影响机理还鲜有研究。本项目基于前期研究基础，采用逐步添加的方法模拟苯并[a]芘在土壤中的积累，研究苯并[a]芘累积污染对土壤微生物多样性的毒性效应。利用Biolog，PLFA,CFU，PCR-DGGE和高通量DNA测序技术，从群落、种群、物种和基因四个层次上研究苯并[a]芘累积污染对土壤微生物功能，结构，物种和遗传多样性的影响，对苯并[a]芘累积污染的优势和功能菌进行鉴定与测序，并采用Real-time PCR技术检测优势菌数量和丰度。通过分析微生物多样性对苯并[a]芘累积污染的响应特征及其与苯并[a]芘有效性间的关系，阐明微生物多样性对苯并[a]芘累积污染的响应机理，研究结果将为多环芳烃类污染物累积污染土壤的生态毒性诊断提供科学方法与依据。

苯并[a]芘正以低剂量叠加的方式在土壤中逐步积累，一旦超过其临界安全阈值，将会对土壤生态安全产生严重影响。有关苯并[a]芘在土壤中逐步积累后对微生物的影响机理还鲜有研究。本项目基于前期研究基础，采用逐步添加的方法模拟苯并[a]芘在土壤中的积累，研究苯并[a]芘累积污染对土壤微生物多样性的毒性效应。利用Biolog，PLFA,CFU，PCR-DGGE和高通量DNA测序技术，从群落、种群、物种和基因四个层次上研究苯并[a]芘累积污染对土壤微生物功能，结构，物种和遗传多样性的影响。结果表明，累积添加苯并[a]芘对土壤微生物物种多样性的影响明显小于一次性添加苯并[a]芘的处理；实验土壤（黄褐土）中的微生物区系对添加苯并[a]芘的毒害敏感程度依次是：放线菌>细菌>真菌；累积污染方式对土壤微生物的影响较一次污染缓和；累积污染条件下微生物表现出较高的微生物活度，较低的微生物群落物种丰富度，较低的常见物种丰富度和较低的物种均一性；B[a]P污染各处理检测出含量较高的Enterococcus（肠球菌）和Megamonas（巨单胞菌）种属，随着培养时间的延长，苯并[a]芘的添加刺激了Nocardioides（类诺卡氏菌属;诺卡氏菌）的生长，且高污染浓度处理的刺激作用更加明显；苯并[a]芘的添加刺激了Humicola（腐质霉属）、Penicillium（青霉属）和Trichoderma（木霉属）等真菌的生长，且高污染浓度处理的刺激作用更加明显。本实验设计符合苯并[a]芘在自然土壤中的叠加累积过程，具有重要的现实指导意义，研究结果将为多环芳烃类污染物累积污染土壤的生态毒性诊断提供科学方法与依据。