Path analysis of the influence of cadmium on mahogany

Abstract

African mahogany (Khaya grandifoliola) is a tree species that has gained space in the forestry market, presenting utility in a wide range of uses, especially in Brazilian territory, where it is the main substitute for Brazilian mahogany wood. The objective of this work was to perform a path analysis between the response of nutrient solution to cadmium treatment and the other variables and attributes studied: amino acid, nitrate, protein, ammonium, reductase, IDM, cadmium. The experiment was carried out in a greenhouse. At first, seedlings were habituated to be later taken to the treatment, where the applicability was given by cadmium chloride monohydrate (CdCl 2.H₂O) according to the nutrient solution. The experimental design was completely randomized (DIC), mixed in five concentrations (0; 10; 20; 30 and 40 mg L^-1) with seven replications, totaling 35 experimental units. To perform the comparative examination, the data were exposed to the analysis of variance, followed by regression analysis. The path analysis allowed to directly verify that increasing doses of treatment with Cadmium (CAR) reflected in a negative correlation with the amino acid content (AAR) in the roots of mahogany plants. Abiotic stress, which was exposure to a toxic chemical (cadmium), decreased, in this case, the ability of plants to synthesize amino acids. Increasing doses of cadmium treatment (CAL) reflected in negative correlation with the protein content in the leaf (PRL) of mahogany plants. Evidently, the higher the cadmium concentration, the greater the damage to mahogany's metabolic systems. With this study, we showed that excess cadmium in the soil affects the development of seedlings of forest species such as mahogany.