Kennedy Nabla, Brodie Eoin, Connolly John, Clipson Nicholas
Microbial Ecology Group, Department of Industrial Microbiology, University College Dublin, Belfield, Dublin 4, Ireland.
Environ Microbiol. 2004 Oct;6(10):1070-80. doi: 10.1111/j.1462-2920.2004.00638.x.
A microcosm-based approach was used to study impacts of plant and chemical factors on the bacterial community structure of an upland acidic grassland soil. Seven perennial plant species typical of both natural, unimproved (Nardus stricta, Agrostis capillaris, Festuca ovina and F. rubra) and fertilized, improved (Holcus lanatus, Lolium perenne and Trifolium repens) grasslands were either left unamended or treated with lime, nitrogen, or lime plus nitrogen in a 75-day glasshouse experiment. Lime and nitrogen amendment were shown to have a greater effect on microbial activity, biomass and bacterial ribotype number than plant species. Liming increased soil pH, microbial activity and biomass, while decreasing ribotype number. Nitrogen addition decreased soil pH, microbial activity and ribotype number. Addition of lime plus nitrogen had intermediate effects, which appeared to be driven more by lime than nitrogen. Terminal restriction fragment length polymorphism (TRFLP) analysis revealed that lime and nitrogen addition altered soil bacterial community structure, while plant species had little effect. These results were further confirmed by multivariate redundancy analysis, and suggest that soil lime and nitrogen status are more important controllers of bacterial community structure than plant rhizosphere effects.
采用基于微观世界的方法研究植物和化学因素对旱地酸性草原土壤细菌群落结构的影响。在一项为期75天的温室试验中，选取了7种多年生植物，这些植物分别代表天然未改良草原（硬羊茅、细叶羊茅、匍匐紫羊茅和红羊茅）和施肥改良草原（绒毛草、多年生黑麦草和白三叶草），对其要么不进行改良，要么用石灰、氮或石灰加氮进行处理。结果表明，与植物种类相比，石灰和氮改良对微生物活性、生物量和细菌核糖体型数量的影响更大。施用石灰提高了土壤pH值、微生物活性和生物量，同时减少了核糖体型数量。添加氮降低了土壤pH值、微生物活性和核糖体型数量。添加石灰加氮产生了中间效应，这似乎更多地是由石灰而非氮驱动的。末端限制性片段长度多态性（TRFLP）分析表明，添加石灰和氮改变了土壤细菌群落结构，而植物种类的影响很小。多变量冗余分析进一步证实了这些结果，并表明土壤石灰和氮状况比植物根际效应更能控制细菌群落结构。
