Three mechanisms of mycorrhizae that may improve stormwater biofilter performance

Stormwater biofilters rely on healthy plant communities to perform essential functions of stormwater management. Mycorrhizae are a class of fungi which may confer benefits to plants growing in green stormwater infrastructure, just as they do in natural ecosystems. Few studies have investigated the roles of mycorrhizae outside natural ecosystems or agricultural systems. This review describes three mechanisms of mycorrhizal symbiosis which could influence plant function in stormwater biofilters. The first mechanism is mycorrhizae acting as an extension of plant roots, providing water and nutrient for plant growth and resistance to stress. Through this mechanism metal removal could also be improved. The second mechanism, mycorrhizal interaction with the rhizosphere, can contribute to soil organic carbon and impact microbial community structures that ultimately affect the N cycle. A third mechanism is discussed in relation to the impact of mycorrhizae on the photosynthetic activity of plants and its subsequent effect on plant growth and resistance to environmental stress. These three mechanisms will be placed into the context of how mycorrhizae could play a crucial role on plant performance and nutrient and metal removal in stormwater biofilters.