瑞香狼毒（Stellera chamaejasme）根际微生态系统对其种群在天然草地扩张的作用研究

Stellera chamaejasme L. has spread in recent decades and formed into monodominant communities in natural grasslands. It has led to substantial deterioration in ecological environment of grasslands and caused serious problems to environment and local economies. This project focuses on the rhizosphere micro-ecological system of S. chamaejasme, to explore the impact of population expansion on rhizosphere micro-ecological system of S. chamaejasme, we will select study sites according to the population coverage gradient, and comparative analyze the physical and chemical characteristics and enzyme activities of rhizosphere soil, soil microbial communities and the allelochemicals of rhizosphere soil. And on this basis, depending on the theoretical foundation of soil microorganisms feedback mechanism, we will study the feedback of soil microbes to S. chamaejasme, and compare the feedback effects of soil microbes to the main accompanying plants and S. chamaejasme, so as to ascertain the influence of soil microorganisms on the succession of plant communities. Besides, in order to explain interaction of biologic and environmental factors on the growth of S. chamaejasme, we will start from the allelopathic substances, study on the regulation effects of allelopathy during the process of population expansion of S. chamaejasme. The implementation of this project would be not only revealed the roles of rhizosphere micro-ecological system during the spread of S. chamaejasme in the natural grassland, but significant to the reasonably and effectively regulating the rhizosphere micro-ecological system and improving utilization efficiency of nutrients resources, and also provide a theoretical basis for the comprehensive control of this poisonous weed in the natural grasslands.

有毒杂草瑞香狼毒在天然草地扩张并形成单优势群落，导致草地生态环境日益恶化，造成了严重的经济和生态问题。本项目以瑞香狼毒根际微生态系统为研究对象，选取瑞香狼毒种群密度由低到高的梯度样地，对根际土壤理化性质及酶活性、根际微生物群落结构以及化感物质种类和含量进行比较分析，明确瑞香狼毒种群扩张对根际微生态系统的影响；在此基础上，以土壤微生物学反馈机制为理论依据，研究土壤微生物对瑞香狼毒生长和竞争的反馈作用，揭示土壤微生物对植物群落竞争演替的影响；同时从瑞香狼毒化感物质入手，探讨化感作用在瑞香狼毒种群扩张过程中的调节作用，阐明生物和环境因子对瑞香狼毒的交互影响作用。本项目的实施，不仅能揭示瑞香狼毒根际微生态系统对其种群在天然草地扩张中的生态学作用和意义，而且对合理有效地调控根际生态系统，提高养分资源利用效率具有重要意义，也为有毒杂草科学有效的生态控制策略提供理论依据。

毒杂草爆发和植被逆向演替是造成我国天然草地退化的重要因素，毒草化已成为第二大严重危害天然草原的问题。有毒杂草瑞香狼毒（Stellera chamaejasme L.）在天然草地扩张并形成单优势群落，导致草地生态环境日益恶化，造成了严重的经济和生态问题。项目以不同种群密度瑞香狼毒根际微生态系统为研究对象，采用微生物多样性高通量测序技术，明确了瑞香狼毒入侵过程中根际微生物群落结构和变化规律；以根际土壤粗提物结合化感物质原位富集技术，采用高效液相色谱检测法，系统研究了随着瑞香狼毒生长发育及种群密度增加，化感物质种类和含量的时空变化趋势，并结合不同种群密度下瑞香狼毒根际土壤理化性质和酶活性的变化，明确了瑞香狼毒种群扩张对根际微生态系统的影响以及变化规律。基于土壤微生物学反馈机制，采用土壤微生物接种法，以瑞香狼毒的主要伴生牧草为受体植物，探明了土壤微生物对瑞香狼毒生长和竞争的反馈作用，并揭示了土壤微生物对瑞香狼毒种群扩张的作用，及对植物群落竞争演替的影响。采用非靶向代谢组学研究技术，对瑞香狼毒及其伴生牧草根际土壤中的差异产物及代谢途径进行分析，明确了瑞香狼毒入侵对伴生牧草根际代谢物组份的影响。采用添加活性炭吸附化感物质的方法，明确了活性炭对瑞香狼毒及其伴生牧草根际微生态系统的影响；并将单因素分析升级为双因素交互控制实验，探讨化感作用在瑞香狼毒种群扩张过程中的调节作用，综合分析了化感物质对伴生植物及土壤微生物的影响，以及化感物质和土壤微生物对伴生植物的交互影响，从而阐明生物和环境因子对瑞香狼毒种群扩张的双重交互作用。本项目的实施，不仅能揭示瑞香狼毒根际微生态系统对其种群在天然草地扩张中的生态学作用和意义，而且对合理有效地调控根际生态系统，提高养分资源利用效率具有重要意义，也为有毒杂草科学有效的生态控制策略提供理论依据。