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研究了黄瓜根部土壤主要微生物类群随连作茬次的反应,并着重用变性梯度凝胶电泳(DGGE)监测黄瓜根际未培养优势菌群的动态变化。结果表明:随着连作茬次增加,土壤可培养微生物数量减少,其中细菌数量降低更为明显,对连作表现出较高的敏感性,放线菌对黄瓜连作反应稍滞后,至第三茬时开始呈现降低趋势。黄瓜连作致使少数真菌种群富集,同时多种真菌类群数量减少,种群变化呈现单一化趋势,多样性水平降低。DGGE分析结果表明黄瓜连作引起根际Bacillus sp.、Pseudom onas sp.和另一未培养细菌种群数量减少,而同时引起Sphingom onas sp.类群数量增加。实验结果暗示,黄瓜连作破坏根部微生物种群生态平衡,使其多样性水平降低。
The main soil microbial populations in cucumber plants were studied for their response to continuous cropping. The dynamic changes of uncultured dominant colonies in cucumber rhizosphere were monitored by denaturing gradient gel electrophoresis (DGGE). The results showed that with the increase of continuous cropping, the number of soil culturable microorganisms decreased, the number of bacteria decreased more obviously, and the sensitivity to continuous cropping was higher. Actinomyces reacted slowly to the cucumber until the third crop Began to show a downward trend. Continuous cropping of cucumber resulted in the enrichment of a few fungi, while the number of multiple fungi decreased, the population showed a trend of simplification and the diversity decreased. The results of DGGE analysis showed that the number of Bacillus sp., Pseudomonas sp. And the other uncultured bacteria decreased in the rhizosphere while the number of Sphingom onas sp. The experimental results suggest that cucumber continuous destruction of root microbial population ecological balance, so that the level of diversity decreased.