引用本文:姚小东,王兴祥,丁昌峰,韩正敏,李孝刚.连作和轮作模式下花生土壤微生物群落不同微域分布特征[J].土壤学报,2019,56(4):975-985.
YAO Xiaodong,WANG Xingxiang,DING Changfeng,HAN Zhengmin,LI Xiaogang.Microzone Distribution Characteristics of Soil Microbial Community with Peanut Cropping System, Monocropping or Rotation[J].Acta Pedologica Sinica,2019,56(4):975-985
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连作和轮作模式下花生土壤微生物群落不同微域分布特征
姚小东1, 王兴祥2, 丁昌峰2, 韩正敏1, 李孝刚1
1.南方现代林业协同创新中心,南京林业大学生物与环境学院;2.中国科学院土壤环境与污染修复重点实验室(南京土壤研究所)
摘要:
根际微生物区系失衡是作物连作障碍发生的重要原因,而不同的种植管理模式下作物极可能选择特定的根际微生物群落减缓或加重连作障碍。采用经典可培养技术和分子分类方法,分析连作和轮作体系下花生根表、根际及非根际土壤微生物群落变化规律及其与连作障碍之间的关系。结果表明:与轮作相比,连作栽培模式下花生荚果产量降低45.8%、根瘤数减少57.5%、植株生物量下降24.1%;相应的青枯病和根腐病病情指数分别增加至2.93倍和2.43倍。轮作和连作两种管理方式下,土壤细菌和真菌数量均呈明显空间分异规律,从“根表—根际—非根际”显著下降,尤其根表微生物数量是根际微域的2.83倍~329倍。进一步分析则发现,轮作和连作条件下花生根表微生物的数量差异最大,细菌约为1.06倍~3.28倍、真菌约为1.14倍~14.44倍,这种差异明显高于轮作和连作花生在根际和非根际微域上的差异,表明根表微生物群落受花生根系生理代谢活动影响最大,与连作障碍关系最为密切。针对可培养微生物菌群的分子鉴定则表明,轮作花生根表有益微生物主要包括假单胞菌(Pseudomonas sp.)、白地霉(Geotrichum candidum),其比例明显高于连作,而连作花生根表的病原菌比例则明显高于轮作,包括踝节菌( Talaromyces sp.)、黑曲霉(Aspergillus niger)、粉红粘帚菌(Clonostachys rosea )和沙雷氏菌(Serratia sp.)等。这些结果表明连作种植模式有利于病原真菌在根表定殖,抑制了有益细菌的生长,可能是花生连作障碍下土传病害大幅上升的重要原因。
关键词:  花生  连作  根表  土壤可培养微生物  土传病害
DOI:10.11766/trxb201807020131
分类号:
基金项目:国家自然科学基金项目(41671306)和国家重点研发计划项目(2017YFD0200604)
Microzone Distribution Characteristics of Soil Microbial Community with Peanut Cropping System, Monocropping or Rotation
YAO Xiaodong1, WANG Xingxiang2, DING Changfeng2, HAN Zhengmin1, LI Xiaogang1
1.Co-Innovation Center for the Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University;2.Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences
Abstract:
【Objective】 Imbalance of soil microflora in rhizosphere is an important cause impeding continuous cropping of crops. And crops under different cropping systems may have certain specific rhizospheric soil microbial communities that would mitigate or aggravate the impediment to continuous cropping. 【Method】 By employing the classic culturable method and molecular classification method, this study investigated variations of the soil microbial communities in the rhizoplane, rhizosphere and bulk soils of peanut under continuous cropping and rotation systems and their relationships with impediment to continuous cropping.【Result】 Compared with the peanut under rotation, the crop under continuous cropping was 45.8% lower in pod yield, 57.5% lower in number of root nodules, and 24.1% lower in plant biomass, but 2.9 times and 2.4 times higher in incidence of bacterial wilt and root rot, respectively. In the peanut fields under either rotation or continuous cropping fields, distribution of bacterial and fungal populations varied significantly, displaying a decreasing trend from rhizoplane, rhizosphere to bulk soils. Particularly, the number of microbes in the rhizoplane was 2.83 to 329 times higher than that in the rhizosphere. Further investigations found that population of soil microbes in the rhizoplane differed sharply between the peanuts under rotation and continuous cropping. The former was 1.06 to 3.28 times higher in bacterial population and 1.14 to 14.44 times higher in fungal population than the latter. The difference was more significant than that in the rhizosphere and bulk, which indicates that the soil microbial community in the rhizoplane was affected the most significantly by physiological and metabolic activities of peanut root and the most closely related with impediment to continuous cropping. Molecular identification of culturable microbial groups shows that the proportion of beneficial microbes, including Pseudomonas sp., Geotrichum candidum, in the rhizoplane of peanut under rotation was higher than that under continuous cropping, while the proportion of pathogenic microbes ( Talaromyces sp., Aspergillus niger, Clonostachys rosea , Serratia sp.) was in a reverse trend. 【Conclusion】 All the findings in this study suggest that continuous cropping favors pathogenic fungi colonizing in rhizoplane, thus inhibiting growth of the beneficial bacteria, which could be the major cause of sharp increase in soil-borne diseases under continuous cropping.
Key words:  Peanut  Continuous cropping  Rhizoplane  Soil culturable microbes  Soil-borne disease