Fortification of tomato with Ca and its effects on the fruit quality, calcium status and nutraceutical values of tomato in different NO3:NH4ratios

This study aimed to investigate the interaction between nitrogen source and calcium on tomato. A soilless culture experiment was accordingly carried out using four different ratios of NO3:NH4(N1 = 1:0, N2 = 3:1, N3 = 1:1, N4 = 1:3) and three concentrations of Ca (2, 4, and 8 mmol/l) to grow the tomato fruits. The results showed that the Ca application increased the Ca levels in the fruits, yield, total amino acid, and auxin hormone of the fruits; however, Ca application decreased Pectin Methyl Esteras activity and the ABA hormone. The highest levels of nitrate and ammonium content were observed in the fruits exposed to N1 and N2 treatments, respectively. At the highest level of calcium, the fruits were more spherical, and the quality and yield of the tomato fruits were improved. The nutraceutical values of the tomato fruits, including amino acid content and composition, and the Ca level were increased, while nitrate accumulation was decreased in 8 mmol L-1Ca and NO3: NH4(100/0).