APLICAÇÃO FOLIAR DE COBRE E SILÍCIO NO ACÚMULO DE COMPOSTOS BIOATIVOS EM FOLHAS E GRÃOS DE SOJA

Abstract

Abstrac t- Soybean (Glycine max L.) is one of the most important agricultural crops in Brazil, standing out for its economic relevance and the high nutritional value of its seeds. In addition to yield, the biochemical composition of soybean has attracted considerable interest due to the presence of bioactive compounds, such as isoflavones and phenolic compounds, which play important antioxidant roles in plant protection. In this context, the present study aimed to evaluate the effect of foliar application of copper and silicon on the accumulation of bioactive compounds in soybean leaves and grains. The experiment was conducted during the 2024/25 growing season, using the cultivar HO Paraguaçu I2X. The experimental design was a randomized complete block design with six treatments and four replications, comprising different combinations of silicon and copper doses: T1 (absolute control), T2 (Si 0.60 g L⁻¹ and Cu 0.0 g ha⁻¹), T3 (Si 0.0 g L⁻¹ and Cu 164 g ha⁻¹), T4 (Si 0.60 g L⁻¹ and Cu 164 g ha⁻¹), T5 (Si 0.0 g L⁻¹ and Cu 328 g ha⁻¹), and T6 (Si 0.60 g L⁻¹ and Cu 328 g ha⁻¹). Potassium silicate and copper chelate were used as sources and applied foliarly at the phenological stages R3, R5.1, and R6. The concentrations of catechin, daidzin, genistein, and genistin were evaluated in soybean leaves and grains. Data were subjected to analysis of variance, Scott-Knott mean comparison test, and canonical discriminant analysis. The results showed that the combined application of copper and silicon promoted greater accumulation of the evaluated bioactive compounds in both leaves and grains, indicating a positive effect of nutrient interaction on the secondary metabolism of soybean plants. It was concluded that foliar application of copper associated with silicon is a promising strategy to improve the biochemical quality of soybean by enhancing the accumulation of compounds with nutritional and functional importance.