研究了免耕秸秆覆盖（CntWntS）、耕作秸秆覆盖（CntWtS）、免耕秸秆不覆盖（CntWnt）和耕作秸秆不覆盖（CntWt）四种保护性耕作措施对黄淮海平原典型潮土中纤维素降解菌多样性的影响。采用PCR-RFLP技术分别对纤维素降解菌cbhⅠ基因进行多样性分析。结果表明，CntWntS与CntWnt相比，纤维素降解菌的数量增加了148%，而CntWtS与CntWt相比，纤维素降解菌的数量也增加了130%。纤维素降解菌cbhⅠ基因分型在四个处理小区比较丰富，共有44个OTUs，其中CntWntS、CntWtS、CntWnt、CntWt 处理中分别有35、34、30、30个OTUs。多样性指数分析显示，Shannon-Wiener指数的数值范围为3.09～3.36。系统发育分析表明，文库中的纤维素降解菌分别属于Basidiomycot（担子菌门）和Ascomycota （子囊菌门），同时发现土壤中存在大量的未培养纤维素降解菌。因此，免耕和秸秆覆盖等保护性耕作能够明显提高土壤中纤维素降解菌数量和cbhⅠ基因多样性。
Conservation tillage, a new kind of cultivation technique or agricultural practice includes no-till, reduced tillage and straw mulching. The aim of conservation tillage is to protect the environment, improve soil quality and save farming cost. Straw degradation plays a very important role in implementation of conservation tillage. Therefore, it is of great significance to study diversity of cellulose degrading bacteria in the soils different in conservation tillage practice. Currently, scholars at home and abroad have been doing a lot to study cellulose degrading bacteria, focusing mainly on screening and isolating of cellulose degrading bacteria and cloning of cellulose degrading gene. But little has been reported on diversity of cellulose degrading genecbhⅠ. It is, therefore, necessary to do something in depth on diversity of cellulose degrading gene cbhⅠ in soils under different conservation tillage practices. Hence, effects of four conservation tillage practices, i.e. CntWtS (tillage with mulching), CntWntS (no-tillage with mulching), CntWt (tillage without mulching) and CntWnt (no-tillage without mulching) were explored on diversity of cellulose-degrading bacteria in typical fluvo-aquic soil in the Huang-Huai-Hai Plain. Cellulose degradation bacteria in soils of different treatments were counted using the traditional plate colony counting method, and diversity of cellulose-degrading gene cbhⅠ was analyzed using the PCR-RFLP techinique (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism). Results show that Treatment CntWntS was 148% higher than Treatment CntWnt in population of cellulose-degrading bacteria, and Treatment CntWtS was 130% higher than Treatment CntWt, too. And the four treatments were all quite rich in cbhⅠ genotyping, amounting to 44 OTUs in total. Treatnent CntWntS was found to have 35 OTUs, Treatment CntWtS 34 OTUs, Treatment CntWnt 30 OTUs and Treatment CntWt 30 OTUs, indicating that straw mulching could increase the number of cellulose-degrading bacteria that can decompose the straw, releasing nutrients into the soil. Analysis of diversity index shows that Shannon-Wiener index varied in the range between 3.09 and 3.36, and that straw mulching and no-tillage improved the diversity of cellulose degradation bacteria. Phylogenetic analysis shows that the cellulose-degrading bacteria in the libraries mainly belong mainly to Basidiomycota and Ascomycota. And Basidiomycota is the dominant phylum. Tillage and no-tillage have some influence on Basidiomycota, but almost none on Ascomycota. Meanwhile, a large number of uncultured cellulose-degrading bacteria were found living in the soils. Therefore, it can be concluded that conservation tillage, like no-tillage and straw mulching, can significantly increase the number of cellulose-degrading bacteria and enrich its cbhⅠ gene diversity.
陈 坤,李传海,朱安宁,彭文涛,钱明媚,曹 慧.长期保护性耕作对纤维素降解基因cbhⅠ多样性的影响[J].土壤学报,2015,52(2):406-414. DOI:10.11766/trxb201406050268 Chen Kun, Li Chuanhai, Zhu Anning, Peng Wentao, Qian Mingmei, Cao Hui. Effects of long-term conservation tillage on diversity of cellulose degradating gene cbhⅠ in Fluvo-aquic soil[J]. Acta Pedologica Sinica,2015,52(2):406-414.复制