Biochemical and morpho-physiological mechanisms of Handroanthus chrysotrichus to chromium excess

Resumo

Pollution with heavy metals (chromium (Cr), in particular) has become a major global issue, and their participation in the soils needs to be addressed. Thus, it is essential using species tolerant to toxic metals in reforestation programs to restore the environment’s ecological conditions. Therefore, the objective was to evaluate tolerance to Cr in H. chrysotrichus seedlings, based on the effects of Cr on physiological, biochemical and morphological variables. H. chrysotrichus seedlings were cultivated at five different Cr concentrations (0, 50, 100, 150 and 200 mg L^-1). Shoot and root morphological variables, photosynthetic variables, photosynthetic pigments, hydrogen peroxide concentration, lipid peroxidation, guaiacol peroxidase (POD) and superoxide dismutase (SOD) enzymes were assessed. The highest Cr concentrations had negative effect on most of the assessed variables. On the other hand, there was not significant difference between treatments concerning shoot height, main root, total length and mean root diameter. SOD and POD were activated in the roots and the highest MDA values were observed at the highest Cr concentrations. Thus, the assessed species tolerated Cr concentrations up to 100 mg L^-1 Cr, which may indicate its tolerance to this metal and its likely use for the phytoremediation of Cr-polluted soils.