甘肃旱区盐渍化土壤种子库特征及DNA图谱构建

Soil seed banks plays a critical role in vegetation restoration and biodiversity maintenance and has become a hot research topic in the study of recovery ecological and conservation ecology in the world, and have made certain theoretical achievement. However, the characteristics of soil seed banks and soil microbial diversity in saline soil of arid regions were not very clear as yet. Therefore, the study takes the saline soil in Arid regions of Gansu Province belong to 5 CST Subgroups 13 genera as objects to analysis the evolution characteristics of soil seed banks and its relationship with environmental factors. To explain the distribution characteristics of soil seed banks in different genera of saline soil and major environmental factors affecting the distribution characteristics of soil seed banks. The method of UltraClean Soil DNA Isolation Kit is optimized and will used to extract genomic DNA from the saline soil of 5 CST Subgroups 13 genera, to construct DNA fingerprinting database of saline soil of CST Subgroups 13 genera using PCR followed by denaturing gradient gel electrophoresis (DGGE) and silver stains, applying the methods of statistics and software to analyze DGGE, to identifying soil microorganisms system using the methods of sequence analysis of 16s rRNA Gene, to disclose the molecular mechanism of the ecology between genera of saline soil and soil biodiversity at molecular level，and provide certain scientific basis for vegetation recovery construction in saline soil in arid and semi-arid regions.

土壤种子库在植被恢复和生物多样性维持等方面起着重要作用,目前已成为国际恢复生态学和保育生态学研究的热点和前沿，并取得了一定的成果，但对旱区盐土种子库的分布特征和土壤微生物的多样性还不清楚。为此，本研究拟以甘肃省旱区盐土5个亚类13个土属的土壤为研究对象，对土壤种子库演化特征以及与环境因子的耦合关系进行研究，阐明不同土属土壤种子库的分布特征，解析影响土壤种子库分布的主要环境因子。同时对不同土属土壤运用UltraClean Soil DNA Isolation Kit提取DNA，并应用聚合酶链反应-变性梯度凝胶电泳(PCR-DGGE)技术对菌种分离，采用银染法构建DNA指纹图谱，应用多元变量的统计学方法对DGGE 图谱用软件分析，16S rRNA 序列分析比对鉴定微生物区系，从分子水平上揭示盐土土属与土壤生物之间的生态学机制，为干旱、半干旱盐渍化地区植被恢复重建提供理论依据和技术支撑。

土壤种子库在植被恢复和生物多样性维持等方面起着重要作用,目前已成为国际恢复生态学和保育生态学研究的热点和前沿，并取得了一定的成果，但对旱区盐土种子库的分布特征和土壤微生物的多样性还不清楚。为此，本研究以甘肃省旱区盐土5个亚类13个土属的土壤为研究对象，对其土壤理化性状、种子库分布特征以及微生物多样性进行了研究，取得了如下主要结果：.(1)探明甘肃旱区5个亚类13个土属盐土的分布区域、盐渍化程度以及土壤盐分、pH、8大离子、有机质、速效氮、磷、钾，微量元素Fe、Mn、Zn、Cu, 脲酶、过氧化氢酶、碱性磷酸酶、硝酸还原酶、脱氢酶、土壤呼吸速率的季节性（4、7、11月）动态变化规律。.(2)对甘肃省5个亚类13个土属盐土植被分布状况进行了调查，主要植被有芦苇、梭梭、沙米、白刺、盐爪爪、冰草、芨芨草、红柳、沙枣、狗尾草、骆驼刺、花花柴、驴尾巴蒿子、白杞等15种植被，隶属于9个科15个属。.(3)甘肃旱区5个亚类13个土属盐土种子库共发现34种植物，隶属于14科31属。其中藜科9种，占植物种类总数的26.47%；菊科和禾本科各5种，分别占14.71%；豆科3种，占8.82%；蓼科和旋花科各2种，分别占5.88%，蒺藜科、紫草科、苋科、茄科、十字花科、唇形科、毛茛科和石竹科各含1个物种，共占22.53%。.(4)对甘肃省5个亚类13个土属盐土的0-5、5-10cm土层细菌、真菌、放线菌进行了季节性动态监测。研究发现细菌数量最多，真菌数量最少，分别占总数的88.12%和0.04%。.(5)采用 Illumina MiSeq/HiSeq 测序平台，对甘肃省5个亚类13个土属盐土的细菌、真菌、古菌微生物多样性进行了测序，构建了DNA文库，从分子水平揭示盐土不同亚类、不同土属之间的遗传多样性，获得甘肃省盐土完整系统的遗传分类情况及亲缘关系资料。