Kloos K, Hüsgen U M, Bothe H
Botanisches Institut, Universität zu Köln, Germany.
Z Naturforsch C J Biosci. 1998 Jan-Feb;53(1-2):69-81. doi: 10.1515/znc-1998-1-214.
Bacteria isolated from different layers of four soils of the Cologne area were analyzed for denitrifying, nitrifying and N2-fixing isolates by colony hybridization using gene probes. In the soils tested, the percentage of denitrifying bacteria among the total population isolated was 3-8% (in one case exceptionally 15%) and thus small. Denitrifying bacteria were particularly enriched in the upper layer (depth approximately 5 cm) and were present only in low amounts at 25 cm depth in two gleysol soils. Nitrate apparently did not determine the distribution of denitrifying bacteria in these soils. The potential denitrification activity of different soil layers coincided with the distribution pattern of isolates assessed by DNA-probing. The total number of bacteria and of denitrifying isolates was considerably higher in or at the roots of plants than in the bulk, root-free soil adjacent to the plants. The percentage of the isolated aerobic N2-fixing bacteria varied between 0-3%, and these bacteria could be isolated mainly from the upper 5 cm layer. A small portion of the isolates hybridized with the probe coding for part of one subunit of ammonia monooxygenase from Nitrosomonas europaea. The investigation showed that DNA-probing can provide useful information about the relative distribution of denitrifying and N2-fixing bacteria in different soils and their layers.
通过使用基因探针进行菌落杂交，对从科隆地区四种土壤的不同土层中分离出的细菌进行了反硝化、硝化和固氮菌株分析。在所测试的土壤中，分离出的细菌总数中反硝化细菌的比例为3%-8%（在一个案例中异常地达到了15%），因此比例较小。反硝化细菌在上层（深度约5厘米）特别富集，在两种潜育土中，25厘米深度处的反硝化细菌数量仅处于低水平。硝酸盐显然并未决定这些土壤中反硝化细菌的分布。不同土壤层的潜在反硝化活性与通过DNA探测评估的菌株分布模式一致。植物根系内或根系处的细菌总数和反硝化菌株总数显著高于植物附近无根系的大块土壤。分离出的好氧固氮细菌的比例在0%-3%之间，这些细菌主要可从上层5厘米土层中分离得到。一小部分分离菌株与编码欧洲亚硝化单胞菌氨单加氧酶一个亚基部分的探针杂交。该研究表明，DNA探测可为不同土壤及其土层中反硝化细菌和固氮细菌的相对分布提供有用信息。
