Root system and antioxidant mechanisms of <i>Eugenia uniflora</i> plants promote greater tolerance to aluminum stress

Abstract

Aluminum (Al) toxicity is an issue in many cultivated areas in the world, affecting the productivity of the most diverse crops. Therefore, it is necessary to assess whether excess Al has negative effects on the growth of tree species such as Eugenia uniflora, which has great ecological, economic, food and medicinal potential. Thus, this study aimed to evaluate Al tolerance of E. uniflora seedlings, based on the effects of Al on physiological, biochemical and morphological variables. We used a completely randomized experimental design, consisting of five Al concentrations (0, 15, 30, 45 and 60 ?M) and four replications. At the end of the period of exposure to the treatments, morphological (shoot and root dry weight and root morphology), physiological (chlorophyll a fluorescence) and biochemical (photosynthetic pigment concentration, hydrogen peroxide content (H₂O₂), guaiacol peroxidase (POD) and superoxide dismutase (SOD) activity)) variables were evaluated. The absence of significant differences in shoot and, root dry weight of E. uniflora seedlings, regardless of Al concentrations, suggest that E. uniflora is aluminum tolerant. The maintenance of the content of photosynthetic pigments and the values of Fv/Fm, as well as the low H₂O₂ content in roots also confirm the tolerance of E. uniflora to aluminum.