Efeito do silício e micorrizas arbusculares na atenuação da toxidez de manganês em mudas de leucena.

Abstract

Manganese mining is of great importance to the world economy, however, it is among the human activities that are most damaging to the environment and constitute an imminent risk to human life. Therefore, strategies have been sought in order to minimize the impacts caused by this activity. One technology considered promising is phytoremediation, which succinctly relies on the use of plants to degrade or remove contaminants from the soil. In this sense, the use of arbuscular mycorrhizal fungi (AMF) in association with legumes provides important nutritional benefits to the development of these plants and also increases their tolerance to excess metals in the soil, besides increasing the absorption of Silicon (Si) by plants. The use of Si is another alternative that can complement this process of soil remediation, since the element also has relation with the improvement of the phytotoxicity of heavy metals. Therefore, the objective of this study was to evaluate the interaction between AMF and silicon doses in the attenuation of manganese toxicity (Mn) in Leucaena leucocephala (Lam.) de Wit seedlings. The plant especie has potential as a phytostabilizer in areas degraded by Mn when associated with AMF. The experiment was conducted in a greenhouse for a period of 90 days and the experimental design was completely randomized, in a factorial arrangement 4x2, considering: i) four doses of Si (0; 100; 200; 400 mg kg-1); ii) two treatments (not inoculated - control; inoculated with C. etunicatum) with four replications. The analyzed variables were dry matter of shoot and root, number of leaves, length of root system, mycorrhizal colonization, number of AMF spores in the soil, concentration of manganese in shoot and root and percentage of toxicity. Mycorrhizal plants showed better development and attenuation of toxicity symptoms due to excess Mn in the soil and interaction with Si maximized this attenuation, however more studies are needed to evaluate the effects of this interaction.