Produção e atividade antioxidante em brotos de feijão mungo em função de luminosidade e aplicação exógena de elicitores

Abstract

The use of elicitors (natural or synthetic) has been evaluated as a biotechnological strategy that aims to increase the synthesis of secondary plant compounds of commercial interest. The objective of this study will be to verify the effect of the exogenous application of salicylic acid (SA), ascorbic acid (AC), sucrose (SAC) and application of eustress through salinity on the biomass production and the content of antioxidant phenolic compounds in Vigna radiata L. sprouts. The treatments were applied during seed imbibition at concentrations of zero, 45, 90, 135, 180, 225 mg L-1, for salicylic acid (SA); zero; 0.3125; 0.625; 1.25 and 2.5 g L-1, for ascorbic acid (AC); zero; 0.25, 0.5 and 1%, for sucrose solution and zero; 25, 50 and 75 mM, for sodium chloride (NaCl) solution. The effect of elicitors on plant metabolism was evaluated through biometric growth parameters (production of aerial and root biomass) and biochemical parameters (activity of superoxide dismutase, guaiacol peroxidase, total protein, percentage antioxidant activity and by 50% inhibitory concentration of DPPH oxidizing activity, total content of phenols and flavonoids). Elicitors applied at higher doses negatively affected shoot growth, which is not commercially interesting. The best total dry mass (TDM) ratios were observed for the following treatments: AS produced in the light, at dosages ranging from 45 to 225 mg.L-1; AC in the dark for the dosage of 0.3125 g.L-1 and dosages of 0.3125 to 1.25 g.L-1 in the light; SAC produced in the dark, for all dosages tested and dosages of 0.25 and 1%, when produced in the dark, as well as for the dosage of 50 mM saline solution, produced in the dark. AS applied in the light provided the highest TDM.CT-1 ratio. The exogenous application of the elicitors allowed all of them to stimulate antioxidant functions in bean sprouts. In the comparison between the doses, for the antioxidant activity, the treatments that stood out occurred for AC at 2.5 g L-1 produced in the light and in the dark and for SAC dosages of 0.5 to 1% produced in the light.