Do mycorrhizae increase plant growth and pollutant removal in stormwater biofilters?

Abstract

Mycorrhizae can improve plant growth and drought tolerance by enhancing plant uptake of nutrients and water, which are important targets for biofilters, a common stormwater treatment system. This study evaluated the role of mycorrhizal inoculation on plant growth, photosynthetic efficiency and pollutant removal in two Australian plant species grown in stormwater biofilters. During the establishment period and column study, Ficinia nodosa showed over 80% mycorrhizal colonization, leading to a doubling of shoot and root biomass compared to the control, while Carex appressa showed less than 26% mycorrhizal colonization and no effect on shoot and root biomass. Columns planted with mycorrhizal-inoculated F. nodosa had 5% higher removal of total phosphorus and 10% higher removal of total nitrogen (Figure 5), phosphate (Figure 6), and cadmium (Table 3). Mycorrhizal colonization did not appear to affect plant stress during drought as indicated by similar photosynthetic efficiencies within species. Our results indicate that mycorrhizal inoculation can be highly successful in biofilters while increasing plant growth and nutrient removal, opening opportunities to further study the role of mycorrhizae in enhancing plant drought tolerance and pollutant removal in existing biofiltration systems.