西北沙区花棒土壤共生真菌物种多样性演替规律研究

Hedysarum scoparium,which is constructive speices in quicksand environment and endemic species in Asian desert, mainly distribut in desert area of northwest China,and is increasingly paid attention for its differentiation of ecogeographical pattern,growth characteristics and scientific value.The symbiotic relationships between desert plant and soil fungi served as a starting point of this project.Soil and roots samples were collected along with the natural distribution of Hedysarum scoparium for three consecutive years,according to the different ecological sites,host plants and sampling plots.AM and DSE fungi were collected and cultured,and fungal species were classificated and identificated in terms of morphology,micro-morphology,histochemistry,molecular techniques and geographical variation and variation of traits analyzing.The community composition and species diversity of AM and DSE fungi,and interaction with host plants and soil environment. Afterward,the succession dynamics of AM and DSE fungi and formation mechanism of mycorrhizal symbiosis with host plant ecogeographical differentiation were clarified,and the resources of AM and DSE fungi were excavated.In summary,this project is to reveal the symbiotic mechanism of host plant and soil fungi,and ecological strategy adaptable to the extreme desert environments,and provide the basis for mycorrhizal biotechnology for the resource protection and vegetation restoration of Hedysarum scoparium.

花棒（Hedysarum scoparium），又名细枝岩黄耆，隶属于豆科岩黄耆属，是亚洲内陆沙地特有种和流沙环境下的先锋植物和植被建群种，主要分布于我国西北荒漠地区，其特殊的物种地理分化格局、生长特性和科学价值倍受关注。本项目以沙生植物与土壤真菌共生关系作为切入点，通过连续三年沿花棒天然分布带，分不同生态区、样地和宿主植物采集土壤和根系样品，分离培养AM和DSE真菌，通过形态学、微形态学、组织化学和分子方法研究相结合，进行真菌地理变异、性状变异统计和系统分类，比较分析不同样地AM和DSE真菌群落组成、物种多样性及其与宿主植物和土壤因子之间的相互作用，阐明AM和DSE真菌随花棒物种地理分化的演替规律和菌根形成特征；发掘和保育AM和DSE真菌资源，揭示花棒与土壤真菌共生机制及其适应极端环境的生态策略，为菌根生物技术应用和荒漠植被恢复提供依据。

花棒（Hedysarum scoparium）隶属于豆科岩黄耆属，是亚洲内陆沙地特有种和流沙环境下的先锋植物和植被建群种，主要分布于我国西北荒漠地带，是防风固沙和荒山绿化的重要灌木。本项目首次研究了花棒微生物群落结构和功能多样性，AM和DSE真菌物种多样性及其生态地理分布规律。共分离AM真菌9属50种，DSE真菌10属20种，发现自然条件下，部分DSE菌株能够产生休眠孢子。AM真菌Diversispora celata 和 Diversispora trimurales，DSE真菌Embellisia chlamydospora，Hypocrea lacteal，Microascus cirrosus，Cladosporium oxysporum，Preussia aemulans，Curvularia spicifera和Schizothecium inaequale为荒漠生态系统首次报道。花棒根围土壤微生物群落结构以细菌为主，其中细菌＞放线菌＞真菌＞AM 真菌；主要利用的碳源分别为碳水化合物、多聚物、羧酸和氨基酸类。花棒均能与AM和DSE真菌形成良好的共生体，AM真菌孢子表面纹饰、附属结构等微形态特征和分子特征对于AM真菌物种多样性研究有重要参考价值。AM和DSE真菌物种多样性和生态分布具有明显时空异质性，并与宿主植物和环境因子密切相关，AM和DSE真菌存在明显生态位竞争现象，DSE真菌相比AM真菌，在极端干旱荒漠环境中有较高定殖率。共生真菌对极端荒漠环境具有良好的生态适应性，花棒与土壤真菌共生是其适应极端干旱荒漠环境的重要因素。微生物群落结构时空异质性和球囊霉素能够综合反映荒漠土壤质量变化状况，应作为土壤质量和功能评价的新指标。本项研究成果对于揭示花棒与土壤真菌共生关系及其适应极端干旱环境的生态对策有重要意义，也为菌根生物技术在花棒资源保护和荒漠植被恢复中的应用提供了科学依据和种质资源。