中文摘要：

采用基因指纹图谱ARDRA分析和RFLP分析，对免耕水稻土壤中的细菌多样性及其在0—5、5-10、10-15cm土层的空间分布进行了研究。结果表明：在不同层的水稻土壤环境中，细菌种类非常丰富，但由于其多样性受土壤水分或土壤层次等多种因子的影响，在不同层土壤环境中其多样性存在差异。表层土壤环境中细菌种类最丰富，多样性最高，且基因型中无明显的优势类群。10-15cm土层的细菌种类相比之下最少，且基因型中有相对的优势类群。不同层的土壤环境间细菌群落的相似性较低，表层土壤的细菌克隆文库与5-10cm的文库的Jaccard指数是20．65％，与10—15cm的文库的Jaccard指数仅为8．31％。5—10cm的文库与10—15cm的文库的Jaccard指数为38．75％。表明细菌群落结构以及土壤空间隔离的复杂性。

英文摘要：

Diversity and its spatial distribution of bacteria in 0 - 5 cm, 5 - 10 cm and 10 - 15 cm depths of non-tillage paddy fields were studied based on the molecular method of ARDRA（amplified ribosomal DNA restriction analysis）. Results indicted that in different soil layers of the paddy field, bacteria were very high in species diversity, which, however, varied from layer to layer due to differences in soil moisture, soil depth, soil temperature, daylight and some other factors. Bacteria in the surface layer were the highest in species diversity, but without a dominant genotype. They were relatively low in species diversity in the 10 - 15 cm soil layer, but they did have some dominant genotype. Bacteria communities in different soil layers showed little similarity. The Jaccard index was 20.65 % between the bacterial clones libraries of the 0 - 5 cm and 5 - 10 cm soil layers; only 8.31% between those of the 0 - 5 cm and 10 - 15 cm soil layers and 38.75% between those of the 5 - 10 cm and 10 - 15 cm soil layers, indicating complexity of the structures of soil bacteria communities and spatial segregation in the soil.