Sensibilidade do cedro ao estresse por alumínio e manganês

Abstract

In acidic soils, the bioavailability of Al and Mn increases, which enhances the phytotoxic effect of these elements for plants. Knowing the level of adaptive plasticity of tree forest species with timber potential, at concentrations of Al and Mn, is essential to support silvicultural techniques aimed at preserving and/or increasing the productivity of these species. The study aimed to investigate the effect of Al and Mn concentrations on early cedro development. We cultivated 90 days of age plants under the effect of five concentrations of Al (0; 125; 250; 500 and 1000 µmol L-1) and six concentrations of Mn (0.0; 1.5; 3.0; 9 ,0, 50 and 200 µmol L-1) in a completely randomized design with five replications. We observed that increasing Al doses reduced nutrient absorption and accumulation, dry matter production, fluorescence index and chlorophyll index. However, we noticed an increase in the concentration of proline in roots and shoots. The critical level of Al toxicity ranged from 38 and 75 µmol L-1. In turn, increasing Mn doses in the early development stage had a positive effect on nutrient content, dry matter production and root growth in the estimated range of 2.39 to 5.55 µmol L-1 of Mn, with reduction in proline production. Therefore, we conclude that cedro plants are sensitive to Al and require Mn in small concentrations at this stage of development.