入侵植物根系分泌物对入侵地菌根共生体系的重构及调控机理研究

Invasiveness of alien plants and ecosystem invasibility were profoundly affected by the interactions between invasive plants and soil mycorrhizal symbiosis system. This project intends to integrate ecological, molecular biological, chemical, microbiological methods and technologies, to clarify effect of invasive plant root exudates on reconstruction of mycorrhizal symbiosis system and its regulation mechanism , summarized as follows：(1) to conduct quantitative and qualitative analysis of Wedelia trilobata invasion influence on soil mycorrhizal fungi community structure by using 18S rDNA sequence analysis as well as DGGE and RT Q-PCR; (2) to study the influence of exogenous addition root exudates on mycorrhizal fungi symbiotic system, which will be further confirmed by the soil pot experiment after treated by root exudates, and to elucidate the role of root exudates on soil mycorrhizal community function and its feedback; (3) to isolate and identify the active substance of root exudates by chemical analysis and spectral analysis methods, and to clarify the impact of the root exudates on the mycorrhizal fungi and their symbiotic system under the sterile culture system, finally reveal the mechanisms of root exudates reconstruct and regulate the mycorrhizal fungi symbiosis. The project results not only reveal ecological mechanism of successful invasion of exotic plant in the terms of mycorrhizal symbiosis, but also contribute to lay the theoretical foundation for further prevention and control of alien plants invasion.

外来植物入侵力和生态系统可入侵性受到入侵植物与土壤菌根共生体系互作的深刻影响。本项目拟以成功入侵的外来植物和本地近缘种为研究对象，通过生态学、分子生物学、化学、微生物学等方法与技术，从以下几方面研究来阐明入侵植物根系分泌物对入侵地菌根共生体系的重构及调控机理：(1)采用18S rDNA序列分析结合DGGE、RT Q-PCR技术定性和定量分析南美蟛蜞菊入侵对土壤菌根真菌群落结构的影响；(2)通过外源添加收集的根系分泌物研究其对菌根真菌共生体系的影响，进一步通过土壤盆栽实验明确根系分泌物对土壤菌根群落功能的影响及其反馈作用；(3)通过化学分析及波谱解析方法分离鉴定根系分泌物活性物质，再利用无菌培养体系，阐明活性物质对菌根真菌及其共生体系的影响，解析根系分泌物重构和调节菌根真菌共生体系的机理。项目结果不仅可从菌根共生体系方面揭示外来植物成功入侵的生态学机制，还可为外来植物的防控提供新的理论基础。

围绕外来入侵植物根系分泌活性物质及其生态功能，特别是对入侵植物的成功入侵起到的贡献，研究了入侵植物不同组织部位浸提物的化感作用研究；入侵植物根系分泌物土壤反馈实验；入侵植物根系分泌物的收集装置研发；入侵植物系分泌物对土传病原真菌的影响；入侵植物根系分泌物的化感效应评价及其化学成分研究；入侵植物根系分泌物中主效化感物质的化感活性及其机理研究；入侵植物根系分泌物的自毒作用研究。取得了一系列有特色的创新成果，项目研究结果不仅在理论上佐证和丰富成功入侵植物“新武器”假说，也进一步深刻明确了外来植物成功入侵的资源竞争策略及应对病原物、本地植物等的化学生态机制。