NITROGEN FERTILIZATION EFFECTS ON GROWTH, PHENOLIC COMPOUNDS CONTENT, AND ANTIOXIDANT ACTIVITY OF BASIL

Abstract

This study evaluated the effects of six nitrogen concentrations (0, 12.5, 25, 50, 75 and 100 %) on growth and physiological responses of basil (Ocimum basilicum L.) under greenhouse conditions. Nitrogen concentrations were supplied via the Long Aston nutrient solution that contains 160.25 μg N mL^-1 at 100 % N. After 120 d, plant height (H), root length (RL), number of leaves (NL), total dry weight (TDW), leaf area (LA), content of total soluble phenolic compounds (TSPC) and total antioxidant activity (TAOX) in leaves were determined. No significant differences were observed on H, RL, NL, TDW and TSPC as a response to varied N concentrations. Application of 100 % N resulted in lower TSPC (424.8 μg g^-1) than the control (0 % N) with 826.9 μg g^-1. LA and TAOX showed significant differences (α = 0.05); plants with 75 % N had higher LA (538.67 cm²) than the control (296.94 cm²). The greatest TAOX was achieved in control plants (5.9 mM g^-1), whereas the lowest value was obtained with 100 % N (3.1 mM g^-1). N-deficiency did not affect plant growth, but enhanced both TSPC and TAOX. The latter must be taken into account to keep the nutraceutical properties of this plant species.