内蒙古产黄芪道地性与根际土壤微生物相关性研究

Genuine medicinal herbs , which are accepted by most of people, haved formed superior quality and efficacy in specific environment. To improve and enrich the theory of genuine medicinal herbs will provide important theoretical significance and application value for genuine medicinal herbs bases arrangement and quality improvement.Inner Mongolia has been recognized as one of the genuine origin of Astragalus since the Qing Dynasty.Now,the research of genuine medicinal herbs mainly focused on environmental and soil physical and chemical factors,sufficient knowledge and systematic research of the effect of rhizosphere soil microbial diversity forming the genuine medicinal herbs was lacked.Inner Mongolia has been recognized as one of the genuine origin of Astragalus since the Qing Dynasty. In this study, genuine origin of Wuchuan County in Inner Mongolia is chosen as the study site. The experiment was conducted both in field and pot, plate dilution method, cloning sequencing and DGGE were used to study the spatial and temporal dynamics of soil microbial diversity of Astragalus under different treatment:different species of Astragalus, continuous cropping (2 years,5 years and 8 years of continuous cropping) and rotation(naked oats;,5 year,10 years and 15 years of rotation ). The correlation of flavonoids and saponin content of Astragalus, the incidence of root rot and yield of Astragalus the rhizosphere soil microbial diversity were analyzed using principal component analysis. From the point of view that the changes of rhizosphere soil microbial characteristics and soil enzymes activities, the study aimed to reveal the scientific connotation of Astragalus genuineness formation and to provide a theoretical basis for the standardization of Astragalus planting.

道地药材是被大众传统公认的、在特定生境下形成的、疗效好且质量优的一类中药材，完善与丰富道地药材形成的理论，对中药材生产规划布局及提高药材产品质量有重要的理论意义和应用价值。目前道地药材的研究多围绕环境及土壤理化因子展开，关于根际土壤微生物多样性对药材道地性形成的影响还缺乏足够认识和系统研究。内蒙古自清朝以来便被公认为是黄芪的道地产地之一，本项目以内蒙古黄芪道地产区武川县为试验基地，以蒙古黄芪为试材，采用田间与盆栽试验相结合的方法，以平板稀释法、克隆测序法和DGGE法，研究不同黄芪品种、连作年限（2年、5年和8年连作）和轮作年限（莜麦，5年、10年和15年）黄芪根际土壤微生物多样性的时空变化规律，探讨黄芪皂苷类和黄酮类含量、根腐病发病状况及产量与根际土壤中微生物的相关性，从根际微生物区系特点和土壤酶活性变化角度，揭示黄芪道地性形成的内在机制，为黄芪的规范化种植提供理论依据。

道地药材是被大众传统公认的、在特定生境下形成的、疗效好且质量优的一类中药材，完善与丰富道地药材形成的理论，对中药材生产规划布局及提高药材产品质量有重要的理论意义和应用价值。目前道地药材的研究多围绕环境及土壤理化因子展开，关于根际土壤微生物多样性对药材道地性形成的影响还缺乏足够认识和系统研究。本研究以蒙古黄芪为实验材料，基于扩增子测序技术探究了不同种源蒙古黄芪根际微生物变化特点，连作与轮作对黄芪根际微生物多样性及土壤酶活性的影响，轮作缓解连作障碍的机制。结果如下：（1）比较了种植在赤峰市翁牛特旗来源内蒙古，山西，甘肃等5个种源蒙古黄芪二年生样本，发现不同种源黄芪根际细菌及真菌群落组成基本相似，微生物多样性主要受生长期影响；（2）黄芪连作后根际土壤细菌、真菌多样性降低，随着连作年限的增加导致对黄芪生长有益的土壤红杆菌目减少，与根瘤形成相关的根瘤菌目、伯克氏菌目和黄色单胞菌目、粘球菌目连续增加，与病害相关的假单胞杆菌属、溶杆菌属丰度较大，根际土壤微生态失衡；随着连作年限的增加，土壤脲酶和蔗糖酶活性降低，对其根际土壤健康产生不利影响；（3）轮作显著提高黄芪生物量，降低根腐病发病率；轮作提高了变形菌门、放线菌门、绿弯菌门、假单胞菌门等有益菌相对丰度，同时保留了许多特异性细菌，提高了微生物多样性，其中黄芪-燕麦-黄芪轮作显著提高黄芪根际土壤过氧化氢酶和脲酶活性，提高土壤肥力，是比较适用于消减黄芪连作障碍的轮作方式。（4）比较了不同轮作作物根系分泌物，发现燕麦根系分泌物中存在的一些抑菌物质（邻苯二甲酸和苯甲酸）抑制了土壤病原菌的生长和繁殖，从而达到缓解病情的作用。本项目从根际微生物群落特点和土壤酶活性变化角度，发现合理的轮作可以缓解黄芪连作障碍，提高黄芪外观品质，黄芪根际微生物在黄芪道地性形成中扮演重要角色，本项目研究成果为黄芪的规范化种植提供理论依据，对黄芪优质高产具有重要意义。