黑麦草（Lolium perenne）根际细菌多样性对Ni污染沉积物修复效果的响应

应用黑麦草（Lolium perenne）对某滨海城市南排污河的重金属污染沉积物——底泥进行植物修复，并结合变性梯度凝胶电泳（DGGE）分析了黑麦草根际土壤的重金属Ni含量和细菌多样性的关系。结果表明，黑麦草对Ni的修复效果较好，种植黑麦草后根际土壤Ni浓度降低了11.8%。根际土壤中Ni有效态含量与根际土壤pH值的变化呈较好的正相关关系，相关系数为0.968 8。对根际土壤细菌多样性进行分析，重金属Ni含量变化能够影响土壤细菌的多样性，根际土壤细菌多样性随黑麦草的生长而不断演变，且与根际土壤中Ni浓度变化有密切联系。对DGGE电泳后回收的部分片段进行测序并建立了进化树，结果表明，测序片段与非培养方法得到的菌种的同源性较高，且其均在土壤或河道底泥的相关研究中被发现。不同时期细菌群体组成和Shannon指数随着修复时间而变化，并与细菌总数有正相关关系。

Response of Bacteria Diversity of Ryegrass （Lolium perenne ） Rhizosphere to Phytoremediation Effect of Ni Polluted Sediment

Ryegrass（ Lolium perenne ） was applied to phytoremediation of heavy metal-contaminated sediments from a sewage river in a coastal city of China. Based on the PCR-DGGE （polymerase chain reaction-denatured gradient gel electrophoresis）, relationship between heavy metal Ni and bacteria diversity in rhizosphere sediments of ryegrass were analyzed. Results showed that ryegrass had good phytoreme- diation effect on heavy metal Ni, and the Ni2＋ concentration in rhizosphere sediments of ryegrass decreased by 11.8% after ryegrass planted. There was a good correlation between concentration of available Ni and pH in rhizosphere sediments, and the correlation coefficient was 0.968 8. The diversity of bacteria in rhizosphere sediments of ryegrass was analyzed and the result indicated that the Ni concentration could affect the diversity of bacteria. The diversity of bacteria in rhizosphere sediments Of ryegrass was evolved with the growth of ryegrass. Evolu- tionary tree was built by specific fragments obtained from electrophoresis, and results showed that sequenced bands had high homology with uncultured bacteria harvested from soil or river sediment samples. Bacterial community composition and shannon index in different growth stages of ryegrass changed over time, and Shannon index had a positive correlation with the total number of bacteria.