Especiação química de ferro em alface (lactuca sativa L.) biofortifcada: cultivo por hidpronia

Abstract

Iron enrichment was carried out in hydroponic lettuce cultivars (Lactuca sativa L.) and iron determination through chemical speciation methods. Lettuce seedlings from conventional cultivation were replanted in commercial nutrient solution with additions of Iron at concentrations of 0.03 g/L (Control); 0.042 g/L; 0.06 g/L and without addition of Iron (called White). The methodological approach was completely randomized with 14 treatments of 2 replications, totaling 7 experimental units. The nutrient solution and lettuce growth were monitored over a period of 65 days in terms of pH, conductivity and dissolved oxygen. The study of the results of iron extraction (leaves+roots) was carried out in the laboratory. First, the samples were dried in ovens with ventilation and the sequential methodology was applied with 5 extractors: Extractor A (calcium chloride 1.0 mol/L); Extractor B (0.1 mol/L acetic acid with 5% m/v ammonium acetate [pH=5.0]); Extractor C (0.5 mol/L acetic acid); Extractor D (NaOH pH 12) and Extractor E (HCl 2.0 mol/L). Iron quantification was performed by the spectrophotometric instrumental technique using the ophenanthroline method. The enriched iron yield was low due to operational failures, mainly in the nutrient solution, such as lack of pumping the solution, inadequate concentration of some micro-macro nutrients and inadequate volume dosage in its replacement during cultivation, in addition to the great exposure to solar radiation.