农业生态系统中的AM真菌多样性

农业生态系统复杂庞大,是由如麦田生态系统、水稻田生态系统、果园生态系统、草地生态系统、保护地生态系统等组成的一个复合生态系统。重点介绍农业生态系统中丛枝菌根(AM)和AM真菌多样性,探讨农业生态系统中调控AM真菌多样性的途径以及今后研究的动向。

Advances in the study of AM fungal diversity in agroecosystems

Arbuscular mycorrhizal(AM) fungi are soil inhabitants in a variety of ecosystems including agroecosystems,forest ecosystems,desert ecosystems,sea island ecosystems etc.They form mutual symbiosis with plant roots and play an important role in increasing sustainable agricultural production and keeping ecological balance.Among the ecosystems,agroecosystems have many forms,and are very large and complicated.They include many subecosystems,such as wheat field ecosystems,rice field ecosystems,orchard ecosystems,grassland ecosystems,covered shed farming ecosystems,etc.Research into mycorrhizas,and particularly AM and AM fungal diversity in agroecosystems,has received more attention in recent years.It has been shown that agroecosystems have rich diversity of AM fungi.There are also large differences in morphological and anatomical structures of mycorrhizas developed in various agroecosystems.The functional roles of AM fungi include bioremediation of soils,induction of disease resistance of plants,increase of nutrient circulation in ecosystems,enhancement of sustainable agricultural production,and maintenance of agroecosystem stability.Both biotic and nonbiotic factors influence biodiversity of AM fungi.It is obvious that host plants are the most important biotic factor which affects AM fungal biodiversity.More and more experiments have proved that plant species diversity determines the species diversity of AM fungi under different modern agroecosystem conditions.There are large differences in AM fungal diversity between traditional and organic agricultural management practices.Fertilization,irrigation and other farming practices are also important strategies in regulating AM fungal diversity.There are four research topics in the present and planned study:(1) to investigate AM fungal diversity in rice field ecosystems,grassland ecosystems,and covered shed farming ecosystems,in order to verify the species and genera composition,dominant group or community,species richness,and other resource status;(2) to study resource ecology of AM fungi in agroecosystems by field surveying and laboratory analysis,to determine the characteristics of key ecological factors that affect incidence,richness,relative aboundance,evenness,and diversity of AM fungi;(3) to set up long-term observation sites in subecological systems and to research the functional diversity of AM fungi,to clarify the important role of AM fungi in increasing agricultural production,and to improve ecological environment and keep ecological balance;and(4) to explore and evaluate pathways of regulating AM fungal diversity,to provide foundations and techniques for the field application of AM fungi.The future research prospects are also discussed in the paper.It was concluded that both differences and similarities of AM diversity,AM fungal species diversity and their functional diversity existed among the various agroecosystems.Carrying out related research work is helpful to protect biotic resources and biodiversity,to maintain ecological balance,to establish a multiple-level and comprehensive management system,and to obtain the most effective,high quality and yield,and sustainable development of agroecosystems.