AM真菌在草原生态系统中的功能

AM真菌是土壤生态系统中重要的微生物类群,能与陆地生态系统中80%以上的高等植物建立共生体系。目前,AM真菌在维持草原生态系统稳定性中的功能已经成为生态学研究的热点问题之一。基于此,从植物个体、种群、群落和生态系统等不同层次探究AM真菌在维持植物群落多样性和草原生态系统稳定性中的功能。分析发现在个体水平上,AM真菌对宿主植物具有促生效应、抑制效应或中性效应。在种群水平上,分析AM真菌对不同宿主植物吸收土壤矿质营养的分配和调控策略,围绕构成草原植被的两大组成成分:牧草和有毒植物,论述AM真菌对植物种群增长和衰败的调控机制,并从草原植物群落的物种多样性和稳定性角度,探讨AM真菌与植物群落之间的相关性。在生态系统水平上,围绕AM真菌对草原生态系统的演替和退化草原的修复等展开论述,以期为利用AM真菌开展草原生态系统保护和恢复治理提供理论依据,并对草原菌根生态学领域未来的研究进行展望。

Functions of arbuscular mycorrhizas in grassland ecosystems

Arbuscular mycorrhizal (AM) fungi are important soil microorganisms, which can form symbioses with more than 80% of vascular plants in terrestrial ecosystems. It has been demonstrated that AM fungi could improve the growth of host plants through regulation of their physiological and biochemical characteristics. In light of this, AM fungi could regulate plant intra-and inter-specific competition in natural habitats. Recently, using AM fungi to protect plant biodiversity and maintain plant community stability in grassland ecosystems has generated much interest. Here, the functions of AM fungi are discussed at the autecology, population, community and ecosystem levels in order to discover the relationship between AM fungi and host plants. There are three different responses of individual host plants to AM fungi symbiosis, including positive, negative and neutral effects. At the population and community levels, AM fungi could regulate intra- and inter-specific competition by influencing the transportation of nutrients and water among individuals, such as to regulate herbaceous and poisonous plant populations. AM fungi also could maintain plant community structures and plant diversity in grasslands by regulating the plant competition. At the ecosystem level, AM fungi could promote the process of community succession, and thus could be used in bioremediation of damaged ecosystems. This review aims to provide theories and methods for the protection of grassland ecosystems by integrating the uses of AM fungi.