Silício como mitigador dos efeitos do cádmio sobre o Metabolismo bioquímico de Khaya ivorensis A. Chev

Abstract

Cadmium (Cd) is one of the most toxic heavy metals for plants, animals and has high levels of accumulation in soils. Silicon (Si) is used as a beneficial nutrient, acting as a stress attenuator, regulating detoxification processes. African mahogany (Khaya ivorensis A. Chev), belongs to the Meliaceae family and has noble wood with great potential for commercialization. The objective of the research was to evaluate the effects of Cd on the biochemical metabolism of K. ivorensis A. Chev and the capacity of silicon to mitigate the stress caused by this metal. The experiment took place at the Federal Rural University of Amazon and the experimental design used was in randomized blocks, in a 4x4 factorial scheme with five replications, and the factors constituted by increasing levels of heavy metal (Cd 0, 25, 50 and 75mg L -1), and doses of silicon (Si 0, 100, 150 and 300 mg L-1), totaling 80 experimental units, the data obtained were submitted to statistical analysis, using the Statistica 7.0 software (Statsoft, 2007). The Cd stress interfered in the biochemical concentrations of African mahogany leaves and roots, increasing nitrate, ammonium, proline and glycine betaine. While the reducing sugar, nitrate reductase, glutamine synthetase and amino acids in leaves and roots showed a reduction as the Cd concentrations increased. Si did not promote satisfactory responses in the plant's metabolism, failing to mitigate the stress by Cd even at the lowest dose of the metal (Cd 25 mg L-1).