The aim of the study was to assess the effect of varying boron levels in the nutrient solution used for fertigation on the macro- and micronutrient content and antioxidative compound content such as vitamin C, lycopene and polyphenolic compounds as well as the antioxidant activity of tomato fruit (Lycopersicon esculentum Mill., cv. Alboney F1 and Emotion F1). Plants were grown in rockwool using a nutrient solution with the following content of boron (mg·dm-3): Control (0.011), 0.4, 0.8, 1.6 in the form of: Na2B4O7·10H2O (treatments of the designated symbols, respectively, B-I, B-II, B-III, B-IV). Standard nutrient solution for tomato cultivation was used with the following nutrient content (in mg·dm-3): N-NH4 – 2.0, N-NO3 – 230, P – 50, K – 420, Ca – 140, Mg – 60, Cl – 30, S-SO4 – 120, Fe –1.80, Mn – 0.3, Zn – 0.50, Cu – 0.07. The concentration of boron in the medium modifies the mean content of nitrogen, phosphorus, magnesium (significantly the lowest content was determined in the B-IV treatment), and potassium (the lowest content in the B-I and B-IV treatments). In the range of boron concentrations of 0.011 - 1.60 mg B·dm-3, a decrease in the mean iron content and an increase in the content of manganese and zinc in tomato fruits were found. The variety significantly differentiated the content of potassium (B-II and B-III), magnesium (B-II), iron (B-I and B-II), manganese (B-II), copper (B-II), the antioxidant activity and lycopene content in tomato fruit. Increasing concentrations of B in the nutrient solution caused a statistically significant decrease of vitamin C in fruit. The higher content of lycopene in the Alboney F1 variety was reported at all concentrations of boron (94.4 - 102.4 mg kg-1). In the Emotion F1 variety, the lycopene content was demonstrated to be 53.2 – 71.9  mg kg-1 of FW. The experiment showed that colour parameters of tomato fruits did not change significantly in response to higher boron doses. 

24.3.2019