【摘要】 【目的】针对药用植物怀牛膝耐连作甚至表现连作促进的特殊现象,分析不同连作年限怀牛膝根际土壤关键微生物群落结构变化,探讨不同连作年限怀牛膝根际微生物组的演变过程,为破解大多数药用植物连作障碍提供理论借鉴。【方法】本研究以连作1年、10年、15年怀牛膝根际土壤与撂荒田对照土壤为试验材料,采用变性梯度凝胶电泳(DGGE)技术分析芽孢杆菌属和镰刀菌属群落结构差异。【结果】在怀牛膝根际土壤中,芽孢杆菌属种类丰富,其中优势菌群为枯草芽孢杆菌(Bacillus stubtilis)和蜡样芽孢杆菌(Bacillus cereus);且与1年土壤相比,连作10年和15年的土壤中会明显增加枯草芽孢杆菌和耐盐芽孢杆菌的相对含量。镰刀菌属的条带数目相对较少,种类多样性少,在群落结构上CK和15Y比较相似,1年和10年相似,优势菌群为腐皮镰刀菌(Fusarium solani)和尖孢镰刀菌(Fusarium oxysporum)。qPCR定量分析显示,怀牛膝连作下会增加其有益细菌的含量,而有害菌镰刀菌属基本维持在一个水平。【结论】多年连作怀牛膝能够增加根际有益微生物群落的多样性与种群丰度,抑制病原微生物群落的多样性与种群丰度,通过选择性促抑影响根际微生物组成而自我塑造健康的根际微生态环境。更多还原

【Abstract】 【Objective】 Changes on the key microbial communities in the continuously cropped rhizosphere soil(CCRS) of Achyranthes bidentata Blume were studied to analyze the allelopathic effect for operational improvement on cultivation of the medicinal plants. 【Method】 The community structures of Bacillus spp. and Fusarium spp. in the rhizosphere soil of A.bidentata under 1, 10, and 15 years of consecutive monoculture were determined using denaturing gradient gel electrophoresis(DGGE). Soil sample from a virgin land was used as control(CK). 【Result】 Abundant Bacillus spp. dominated by B.stubtilis and B. cereus were isolated from the CCRS specimens. The CCRS under 10-year(10 Y) and 15-year(15 Y) of continuous cropping had a greater relative content of B. subtilis and B. halodurans than their 1-year(1 Y) counterpart. With respect to Fusarium spp., the number of bands and species were relatively few, the community structure tended to be similar between CK and 15 Y as well as between 1 Y and 10 Y, and F. solani and F. oxysporum being the dominant species. The qPCR results also indicated that continuous monoculture of A. bidentata increased the abundance of the beneficial bacteria but kept that of the harmful Fusarium spp. largely unchanged. 【 Conclusion】 Continuous cropping A. bidentata enhanced the diversity and abundance of the beneficial Bacillus spp. without encouraging the expansion of the pathogenic Fusarium community in the rhizosphere. It appeared that the rhizosphere allelopathy under the cultivation practice had created a healthy ecosystem that promoted the growth of A. bidentata.更多还原