Arbuscular Mycorrhizal Fungi in Wetland Habitats and Their Application in Constructed Wetland: A Review

Over the last three decades, the presence and functional roles of arbuscular mycorrhizal (AM) fungi in wetland habitats have received increasing attention. This review summarized the mycorrhizal status in wetlands and the effect of flooding on AM fungal colonization. Plants of 99 families living in 31 different habitats have been found to be associated with AM fungi, even including submerged aquatic plants and several plant species that were thought to be nonmycorrhizal (Cyperaceae, Chenopodiaceae, and Plumbaginaceae). The functions of AM fungi in wetland ecological systems could be concluded as their influences on the composition, succession, and diversity of the wetland plant community, and the growth and nutrition of wetland plants. Affecting the composition, succession, and diversity of the wetland plant community, AM fungi have positive, negative, or neutral effects on the performance of different wetland species under different conditions. The factors that affect the application effect of AM fungi in constructed wetland (CW) include flooding, phosphorus, plant species, aerenchyma, salinity, CW types, operation modes of CW, and wastewater quality. The generalist AM fungi strains can be established spontaneously, rapidly, and extensively in wastewater bioremediation technical installations; therefore, AM fungi can be considered ideal inhabitants of technical installations for the plant-based bioremediation of groundwater contaminated by organic pollutants or other contaminants. In the future, roles of AM fungi and factors that affect the purifying capacity of AM-CW system must be understood to optimize CW ecosystem.