Silicon application and mycorrhiza inoculation promoted Leucaena leucocephala growth in a soil highly contaminated by manganese

Accepted ABSTRACT: Arbuscular mycorrhizal fungi (AMF) can increase the acquisition of silicon (Si) and, therefore, alleviate the problems caused by metallic toxicity in plants, but this effect remains poorly understood. The objective was to evaluate the influence of Si application on the growth of Leucaena leucocephala inoculated with AMF (Claroideoglomus etunicatum) in a soil contaminated by manganese (Mn). We exposed plants to increasing levels of Si (0, 100, 200 and 400 mg kg-1) in the soil for 90 days. Intermediate levels of Si and AMF inoculation significantly increased shoot and root dry mass, the number of sheets, root system length and mycorrhizal colonization. The abundance of AMF spores decreased linearly with increasing levels of Si applied to the soil, suggesting a low correlation with mycorrhizal colonization. In addition to the higher Mn contents in the shoots and, mainly, in the roots, the combined application of Si and inoculation with AMF significantly reduced foliar toxicity by more than 40%, when compared to the absence of Si and AMF inoculation. Our results demonstrated a synergistic effect of AMF and Si in improving the growth and tolerance of L. leucocephala plants in soil contaminated by Mn. Superscript/Subscript Available更多