【摘要】 长期集约化种植带来的连作障碍问题已成为限制设施蔬菜行业可持续发展的重要瓶颈,阐明设施蔬菜长期连作条件下的土壤障碍因子(类型)是发展形成高效连作障碍克服技术的前提。以豫北地区设施黄瓜连作生产系统为研究对象,通过采集具有不同黄瓜连作年限的土壤样品(1,5,10,15,20 a),应用Real-time PCR和高通量测序的手段,探讨了温室黄瓜连作对土壤真菌数量和群落结构的影响。结果表明,温室黄瓜连作显著改变了土壤真菌数量,随着连作年限延长真菌数量呈先增加后降低的趋势,且在连作10 a土壤中达到峰值。土壤真细比变化趋势与真菌数量一致。高通量测序分析进一步表明,黄瓜连作显著影响了真菌群落的β多样性而非α多样性。随着连作年限延长,真菌群落中独有的OTU数量逐渐减少。子囊菌门(Ascomycota)是门水平下连作土壤真菌群落的优势成员,但其平均相对丰度对黄瓜连作响应不敏感。在目水平,小囊菌目(Microascales)、盘菌目(Pezizales)、未分类子囊菌(Norank_p_Ascomycota)和粪壳菌目(Sordariales)是真菌群落优势成员;在属水平,假埃希氏菌属(Pseudallescheria)、Lasiobolidium、赭霉属(Ochroconis)和毛壳菌属(Chaetomium)是真菌群落优势成员。这些优势真菌目和属的平均相对丰度受温室黄瓜连作影响显著,且多数与土壤理化因子存在显著的线性相关关系。冗余分析证明,土壤硝态氮、速效钾和有机质含量是驱动温室黄瓜连作土壤真菌群落结构变化的主要因子。总的来看,温室黄瓜长期连作显著影响了土壤真菌数量和群落结构。更多还原

【Abstract】 Continuous cropping obstacles caused by long-term intensive cultivation has become an important bottleneck restricting the sustainable development of greenhouse vegetable industry. Increasing the knowledge available regarding the soil mechanisms behind continuous cropping obstacles is beneficial to develop the effective approaches to overcome this difficult problem present in intensive greenhouse vegetable production. Here,based on a continuous greenhouse cucumber cropping system located at North Henan Province of China,we evaluated the changes in soil fungal abundance and community structure with increasing cucumber cultivation history(the duration from 1 to 20 years with the interval of 5 years per treatment)through Real-time PCR and high-throughput sequencing. Continuous cropping of greenhouse cucumber significantly altered soil fungal abundance. In brief,fungal abundance initially increased and then decreased as increasing greenhouse cultivation history,and the peak occurred at the tenth year after continuous cropping of greenhouse cucumber. The tendency of the ratio of soil fungal to bacterial abundance with increasing greenhouse cultivation history was in line with soil fungal abundance. High-throughput sequencing revealed that the β diversity rather than α diversity of soil fungal community was obviously altered by continuous cropping of greenhouse cucumber. Increasing greenhouse cucumber cultivation history lowered the numbers of unique OTU in fungal community. At phylum level,Ascomycota dominated soil fungal community,and its average relative abundance was insensitive to continuous cropping of greenhouse cucumber. At order level,Microascales,Pezizales,Norank_p_Ascomycota and Sordariales together dominated fungal community. At genus level,Pseudallescheria,Lasiobolidium,Ochroconis and Chaetomium were the predominant members in fungal community. Continuous cropping of greenhouse cucumber significantly changed average relative abundances of these dominant community members. Meanwhile,most of these dominant community members significantly correlated to soil physicochemical variables. RDA analysis indicated that soil nitrate and available potassium and organic mater contents were the most important contributors to the alteration of soil fungal community structure. In conclusion,the results demonstrated soil fungal abundance and community structure as affected by continuous cropping of greenhouse cucumber.更多还原