Exogenous Salicylic Acid Increases Productivity and Elicits Betalains and other Bioactive Compounds in Red Beetroot

Elicitation in a simple and efficient strategy to increase plant functional metabolites. This work aimed to determine the effect of salicylic acid foliar application on biomass production and the synthesis of bioactive compounds in red beetroot ( Beta vulgaris L.). The experiment was conducted on potted plants under greenhouse conditions. The application of salicylic acid was carried out at concentrations of 0.0, 0.5, 1.0, 1.5 and 2.0 mmol L −1 for three consecutive days in the vegetative phase. Plants treated with 0.5 and 2.0 mmol L −1 salicylic acid showed higher fresh and dry weight values (leaf, root and total), leaf area (total and specific), number of leaves, leaf mass ratio, root diameter and length and productivity. Salicylic acid application of 1.5 mmol L −1 increases chlorophyll, total soluble solids and flavonoids concentrations. The elicitor effect was observed at 1.0 mmol L −1 of salicylic acid, resulting in greater economic value of the biomass in the higher concentrations of polyphenols, anthocyanins, β -carotene, lutein, betacyanin, betaxanthin and total betalains. Additionally, an increase in the root antioxidant activity was obtained at the concentrations of 1.0 and 2.0 mmol L −1 . The elicitation of red beetroot by salicylic acid foliar pulverisation during the vegetative growth is efficient to promote higher productivity of roots and nutritional value.