Effect of Arbuscular Mycorrhizal Fungi on Switchgrass Growth and Mineral Nutrition in Cadmium-Contaminated Soil

The effect of arbuscular mycorrhizal fungi (AMF) and cadmium (Cd) treatment on switchgrass (Panicum virgatum) growth, Cd accumulation, mineral element concentrations and soil Cd bioavailability were investigated in a greenhouse experiment. The results showed that switchgrass biomass increased with AMF inoculation at all Cd levels except the 40 mg/kg Cd treatment. AMF decreased the shoots and roots Cd accumulation for the 10 and 40 mg/kg Cd treatments and limited Cd translocation from root to shoot, but enhanced the phosphorus concentrations for all Cd treatments. Furthermore, the presence of AMF reduced the reducible-extractable and acid-extractable Cd concentrations in the 10 and 40 mg/kg Cd soils, respectively. AMF inoculation significantly increased the shoot Ca, Mg, K, and Na concentrations without Cd addition; it decreased Ca, Mg, and Zn concentrations in the roots and Fe in the shoots with the low Cd addition; it increased K, Mg, and Na in the shoots with the 10 mg/kg Cd addition; and it increased Ca and Mg in the shoots and Na in the roots with the 40 mg/ kg Cd addition. In summary, AMF inoculation decreased Cd absorption and translocation, improved P absorption, and took a different strategy to elements absorption under different Cd levels. The improved biomass and decreased Cd concentrations with AMF assistance increased the potential for switchgrass use as a phytoremediation and bioenergy crop in a contamination site.