Manganese toxicity and stress-induced tolerance responses in Psidium cattleianum and Eugenia involucrata

Manganese (Mn) toxicity limits plant growth and productivity, especially in acidic soils in many parts of the world. Thus, it is necessary to use phyto-remediation species in reforestation programs to restore the ecological conditions of the environment. The study aimed to evaluate morpho-physiological and biochemical parameters in addition to Mn translocation in plant tissues of Psidium cattleianum and Eugenia involucrata under different Mn concentrations to assess the phyto-extraction potential of the species to be cultivated in environments contaminated with Mn. P. cattleianum and E. involucrata were cultivated in five Mn concentrations: 2 (control), 30, 60, 90 and 120 μM. Each sampling unit consisted of a pot with five plants. Morphological parameters of the shoot and root system, photosynthetic parameters, photosynthetic pigments, antioxidant enzyme activity, concentration of hydrogen peroxide and lipid peroxidation, as well as Mn accumulation in tissues, and Mn translocation factor (TF) were evaluated. Excess Mn promoted the activation of the enzymatic antioxidant system in Psidium cattleianum and Eugenia involucrata, reducing its negative effects on plant biomass production. Furthermore, high Mn concentrations in plant shoots of P. cattleianum and E. involucrata are indicative of the species’ tolerance to Mn, demonstrating their phyto-extraction potential in soils contaminated by Mn.