Mining tailings limit plant establishment due to their low fertility and high heavy metal content. Arbuscular mycorrhizal fungi (AMF) can improve plant adaptation in these environments. This study evaluated the response of Festuca arundinacea, Brachiaria brizantha and Cynodon dactylon inoculated with endogenous and exogenous AMF under a tailing gradient (0, 50 and 100%) under controlled conditions. A 3 × 3 × 3 factorial design with sterilized substrate was used to isolate the effect of the inoculum. After 90 days, biomass, mycorrhizal colonization and sporulation were measured. The exogenous inoculum significantly increased biomass and colonization (>50%), particularly under high stress, while the endogenous inoculum showed a limited response (<40). Sporulation increased under extreme conditions, indicating an adaptive strategy of the AMF. These results demonstrate that mycorrhizal function depends on the type of inoculum and the microbiological context and highlight the potential of Festuca arundinacea with exogenous inoculum for establishing vegetation on mining waste.
Hernández-Acosta et al. (Wed,) studied this question.