Aplicação pré-colheita de citocinina e giberelina e sua influência sobre a qualidade e fisiologia do caju

Abstract

The objective of this study was to evaluate the effect of pre-harvest application of gibberellin (GA3) and the cytokinin benzyladenine (BA) at different concentrations (0, 90, 180, 270, and 360 ppm) on the physical, physicochemical, enzymatic characteristics and the metabolic profile of cashew apple (Anacardium occidentale L.) CCP76, a dwarf early-flowering genotype cultivated in the Northeast region of Brazil. The experiment was conducted at the Experimental Station of Embrapa Tropical Agroindustry in Pacajus, Ceará. Treatments were applied to plants at stage 1 of fruit development (green nut and green cashew apple), and fruits were harvested at commercial maturity (dark orange apples) and then analyzed. The treatments did not result in statistically significant differences in physical characteristics or color parameters compared to the control. GA3 reduced the total sugar content inversely with increasing doses, but did not significantly affect titratable acidity (TA) or the soluble solids/titratable acidity ratio (SS/TA). Both GA3 and BA significantly reduced vitamin C content, affecting both the reduced form (ascorbic acid) and the oxidized form (dehydroascorbic acid). Fruit firmness was not significantly affected by the treatments, although GA3 induced an increase in PME and PG enzyme activity, while BA increased PME and reduced PG activity. Both GA3 and BA increased PAL activity; PPO activity increased with GA3 and decreased with BA, without increasing the total phenolic content. Metabolomic analysis revealed significant changes in the profiles of sugars, organic acids, amino acids, and lipids. In conclusion, even without visible changes in physical attributes, the regulators significantly influenced the physiology and metabolism of the cashew apple, reinforcing the potential of plant growth regulators as a pre-harvest management strategy and highlighting the usefulness of metabolomics in identifying metabolic biomarkers in tropical fruits.