This study investigates the temporal and spacial dissipation dynamics of a dioxin-like polychlorinated biphenyl (PCB 77) in the rhizosphere of alfalfa. A three-chamber rhizobox was designed to compare the PCB 77 dissipation efficiency in the rhizosphere, near-rhizosphere, and far-rhizosphere zones. Culture-independent techniques, including quantitative PCR (qPCR), Biolog-ECO plate, and denatured gradient gel electrophoresis (DGGE) were employed to investigate the variation of bacterial quantity, metabolic diversity and community structure in the alfalfa-rhizobium symbiosis rhizosphere at different rhizoremediation stages. PCB dissipation rates in different rhizosphere zones were in the order: rhizosphere (90.9%) > near-rhizosphere (80.5%) > far-rhizosphere (31.7%). The number of the bacterial 16S rRNA gene copies in the rhizosphere zone in the polluted treatment reached the highest value of all the treatments. Microbial metabolic diversity, as indicated by average well color development (AWCD) in both rhizosphere and near-rhizosphere zones, had recovered from the PCB 77 pollution. The soil bacterial community diversity improved greatly in the rhizosphere of alfalfa, with some new species appeared in the rhizosphere and near-rhizosphere zones. In conclusion, the dissipation of PCB 77, the quantity of total soil bacteria, soil microbial metabolic diversity, and soil microbial community structure were significantly improved in rhizosphere and near-rhizosphere zones of alfalfa.

中文翻译：

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苜蓿对二恶英样PCB污染土壤的根际修复：时空尺度的动态表征

本研究调查了苜蓿根际二恶英样多氯联苯（PCB 77）的时空消散动态。设计了一个三腔的根状盒，以比较PCB 77在根际，近根际和远根区域的耗散效率。采用非培养独立技术，包括定量PCR（qPCR），Biolog-ECO板和变性梯度凝胶电泳（DGGE），研究了不同根际修复作用下苜蓿-根瘤菌共生根际细菌数量，代谢多样性和群落结构的变化。阶段。在不同的根际区域中，PCB的耗散率依次为：根际（90.9％）>接近根际（80.5％）>远离根际（31.7％）。在被污染的处理中，根际区细菌的16S rRNA基因拷贝数达到了所有处理中的最高值。根际和近根际区域的平均井颜色发展（AWCD）表明，微生物代谢多样性已从PCB 77污染中恢复。苜蓿的根际土壤细菌群落多样性得到了很大的改善，在根际和近根际区域出现了一些新物种。综上所述，苜蓿根际和近根际区的PCB 77消散，土壤细菌总数，土壤微生物代谢多样性和土壤微生物群落结构得到了显着改善。如根际和近根际区域的平均井颜色发展（AWCD）所示，已从PCB 77污染中恢复过来。苜蓿的根际土壤细菌群落多样性得到了很大的改善，在根际和近根际区域出现了一些新物种。综上所述，苜蓿根际和近根际区的PCB 77消散，土壤细菌总数，土壤微生物代谢多样性和土壤微生物群落结构得到了显着改善。如根际和近根际区域的平均井颜色发展（AWCD）所示，已从PCB 77污染中恢复过来。苜蓿的根际土壤细菌群落多样性得到了很大的改善，在根际和近根际区域出现了一些新物种。综上所述，苜蓿根际和近根际区的PCB 77消散，土壤细菌总数，土壤微生物代谢多样性和土壤微生物群落结构得到了显着改善。