太白贝母根际微生物分布与生物碱含量的相关性

Correlation between rhizospheric microorganisms distribution and alkaloid content of Fritillaria taipaiensis

以重庆市巫溪县不同生长年限栽培与野生太白贝母鳞茎及其根际土壤为研究对象,采用常规方法测定根系的菌根侵染率和侵染强度、鳞茎中贝母辛和总生物碱的含量以及相应生长地根际土壤可培养微生物数量、微生物生物量碳含量,探讨了根际土壤微生物数量与太白贝母品质的关系。结果表明:AM真菌均可侵染不同采样点太白贝母根系并形成典型的丛枝-泡囊型菌根,侵染率78.74%~98.68%,侵染强度13.29%~37.06%。太白贝母根际土壤微生物资源丰富,根际土壤可培养微生物数量的分布规律是:细菌数量>放线菌数量>真菌数量。随着生长年限的增加,根际细菌、放线菌、解无机磷细菌、解有机磷细菌数量及微生物总数量整体上表现为先增加后减少的趋势,而解钾细菌整体上呈现递减趋势,真菌整体上呈现递增趋势,土壤微生物区系由高肥力的'细菌型'向低肥力的'真菌型'过渡。贝母辛和总生物碱质量分数整体上呈现出随着生长年限先增加后减小的趋势,与其根际土壤可培养微生物细菌、放线菌的变化趋势一致,即生长年限对太白贝母地的土壤质量及药材品质均有不同程度的影响。由此可见,随着太白贝母生长年限的增加,根际土壤的微生物群落多样性降低,进而引发太白贝母连作障碍,导致太白贝母药用品质下降。

In order to reveal the relationship between the amount of soil microorganisms and the quality of Fritillaria taipaiensis,both cultivated and wild F.taipaiensis were collected from Chongqing,Wuxi at different stages of their growth as objects of the research.The mycorrhizal infection rate and colonization intensity,peimisine and total alkaloid content in bulbs,the amount of microorganisms and biomass carbon content in rhizospheric soil were all determined using common methods.The results showed that the typical arbuscular-vesicle roots were formed after the AM fungi infected the F.taipaiensis roots which were collected from different origins.The mycorrhizal infection rates were ranged from 78.74%to 98.68%and the colonization intensities were ranged from 13.29%to 37.06%.The rhizospheric microorganisms of F.taipaiensis showed abundant resources.The distribution rule of them in the rhizospheric soil was as follows:the amount of bacteria>the amount of actinomycetes>the amount of fungi.The rhizospheric bacteria,decomposition inorganic phosphorus bacteria,decomposition organic phosphorus bacteria,actinomycetes amount and the total number of microbes increased first and then decreased with the increase of years,while decomposition potassium bacteria showed decreasing trend and fungi showed gradual increasing trend.The soil microbial flora content in the soil changed from'bacterial type'with a high fertility to'fungal type'with a low fertility.The mass fraction of peimisine and total alkaloid content increased first and then decreased with the increase of over the years,the same trend of culturable rhizosphere soil bacteria and actinomycetes indicated that the growth years affected the quality of soil and medicinal materials on different levels.Therefore,the diversity of microbial communities in rhizosphere soil reduced with the increase of years leading to the continuous cropping obstacles and the destruction of medicinal quality of F.taipaiensis.