[Objective] The effects of agricultural streptomycin, difenoconazole and zineb on endophytic bacterial communities in cucumber were studied. [Method] T-RFLP was used to analyze the influences of endophytic bacteria communities on cucumber roots, stems and leaves by treating three kinds of fungicides. [Result] The endophytic bacteria communities in cucumber roots and stems were abundant, but scarce on the leaves. The endophytic bacteria communities in cucumber leaves were considerably decreased after treatments, and the index in cucumber roots was increased. During the treatments, the changes of communities in cucumber, which were treated from one to five days, reached the maximum, and the endophytic bacteria became stable after fourteen days. The results of T-RFLP analysis showed that the microorganisms had stable and dominant T-RFs, including 222, 283 or 326 bp, in cucumber roots, stems and leaves. Bacteroidetes, firmicutes, α-and β-proteobacteria were the dominant species in cucumber roots stems and leaves. In cucumber leaves, some T-RFs fragments disappeared (e.g.,151, 193, 203, 243, 305 and 326 bp) after disposal by three kinds of fungicides. It showed that the bacteria in Proteobacteria and Firmicutes was more sensitive to fungicides. [Conclusion] Compared with the three kinds of fungicides, agricultural streptomycin played the most important roles, while zineb played the least important role.The effects of fungicides on plant leaves were the most direct.%[目的]明确农用链霉素、苯醚甲环唑和代森锌对黄瓜内生细菌群落多样性的影响.[方法]采用末端限制性片段长度多态性(T-RFLP)技术分析3种杀菌剂对黄瓜根、茎、叶的内生细菌群落多样性的影响.[结果]黄瓜根、茎中的内生细菌种群比较丰富,而叶片中则较少.3种杀菌剂处理后,黄瓜茎、叶的内生细菌多样性指数减少,根部则有所升高,处理后1～5d内生细菌的种群变化达到最大,14d后趋于稳定.T-RFLP分析得出黄瓜根、茎、叶中优势的T-RFs片段有222、283、326 bp,可知拟杆菌门,厚壁菌门,α-和β-变形细菌是优势种群.在叶片中,经杀菌剂处理后有6个T-RFs片段消失(如151、193、203、243、305 bp和326 bp),可知变形菌门和厚壁菌门中的一些细菌对杀菌剂比较敏感.[结论]农用链霉素对内生细菌的多样性影响最大,苯醚甲环唑次之,代森锌的影响最小.杀菌剂对黄瓜叶片的内生细菌群落作用最为直接.
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