The purpose of this study was to evaluate the effects of arbuscular mycorrhizal fungi (AMF) on pacara earpod tree (Enterolobium contorstisiliquum) growth and phytoprotection in soil containing coal-mining waste. A greenhouse experiment was carried out with three inoculation treatment groups (non-inoculated, inoculated with Rhizophagus clarus, and inoculated with Acaulospora colombiana) in two substrates (0 or 30% tailings). After 90 days the seedlings were collected to quantify growth parameters, quality, mycorrhizal root colonization rate, and leaf content of chlorophylls and carotenoids. Macronutrients were quantified in the shoots; Cu, Zn, and Mn levels were measured in the shoots and roots; and glomalin content was measured in the rhizosphere. Colonization by A. colombiana (40%) promoted phytoprotection and better growth in seedlings planted in partial tailing substrate, due to the lower Cu (1.04 mg kg-1) and Zn (13.4 mg kg-1) levels in shoot dry mass and reduced translocation of these elements to the shoots. A. colombiana increased soil glomalin concentrations (2.98 mg kg-1) and the accumulation of nutrients necessary for synthesizing chlorophylls and carotenoids in the leaves. Colonization by R. clarus (81%) produced no phytoprotective effects.
Keywords: AMFs; Plant protection; degraded areas; heavy metals; pacara earpod tree.