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添加生物质炭对滨海盐碱土固氮菌丰度及群落结构的影响

宋延静1,2,张晓黎1,龚骏1**   

  1. (1中国科学院烟台海岸带研究所, 山东烟台 264003; 2中国科学院大学, 北京 100049)
  • 出版日期:2014-08-10 发布日期:2014-08-10

Effects of biochar amendment on the abundance and community structure of nitrogen-fixing microbes in a coastal alkaline soil.

SONG Yan-jing1,2, ZHANG Xiao-li1, GONG Jun1**     

  1. (1Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, Shandong, China; 2University of Chinese Academy of Sciences, Beijing 100049, China)
  • Online:2014-08-10 Published:2014-08-10

摘要:

利用荧光定量PCR和变性梯度凝胶电泳(DGGE)等技术研究了实验室条件下滨海盐碱土施加不同比例(0、5%、10%、20%,w/w)生物质炭后84 d内土壤固氮菌nifH基因丰度与群落结构的动态变化。结果表明:nifH基因拷贝数在不同取样时期的差异极为显著(P=0.003),但不同添加量对其丰度影响不大(P>0.05);添加生物质炭14 d后固氮菌丰度明显增加,20%组处理42 d后nifH基因丰度显著高于对照组(P<0.05),10%组处理56 d后对固氮菌的促长作用最为显著(P<0.05);对照和低比例(5%)处理组中的固氮菌群落结构较为相似,而中高比例(10%和20%)处理组则较为相似;生物质炭的添加量显著影响固氮菌的群落结构(ANOSIM,P=0.001),而处理时间对其无显著影响;施加生物质炭后,滨海盐碱土的固氮菌类群会发生改变,Ideonella和Skermanella等属的相对丰度会增加,但土壤重要的固氮菌类群如固氮螺菌属(Azospirillum)基本不受影响。
 

关键词: 固结试验, 有机质, 抗剪强度, 黏粒, 压缩-回弹, 三轴试验

Abstract: Biochar amendment may affect abundance and diversity of soil microbial community. However, the effects of biochar amendment on nitrogen-fixing bacterial community in coastal alkaline soils remain unclear. Using realtime quantitative PCR and DGGE profiling, this study investigated the variations of abundance and diversity of nifH genes in a coastal alkaline soil amended with different doses (0, 5%, 10%, 20%, w/w) of biochar during an 84-day incubation. This microcosm experiment showed that the incubation time significantly influenced nifH gene abundance (P<0.05), but no differences were observed among treatments (P>0.05). Following 14-day incubation, the copy number of nifH genes was significantly stimulated. On the 42nd day, the nifH abundance in the 20% biochar treatment was significantly higher than that in the control. For the 10% biochar treatment, however, higher abundance of nifH was observed on the 56th day, compared with the control. NMDS and CLUSTER analyses showed that the samples could be separated into two major groups, the lowdose group (0 and 5% biochar treatments) and the high-dose group (10% and 20% biochar treatments). ANOSIM indicated that the dose of biochar application significantly affected the community structure of nitrogen-fixing microbes in the coastal soil (P=0.001). DGGE analysis and sequencing of the major bands indicated that the relative abundance of Ideonella and Skermanella increased following biochar amendment, whereas the population of Azospirillum, an important nitrogen-fixer, remained relatively stable.

Key words: clay, organic matter, soil compression-rebound, shear strength, triaxial test, oedometer test