Effect of titanium foliar applications on tomato fruits from plants grown under salt stress conditions

Salt stress affects plant metabolism, while beneficial elements such as titanium (Ti) may stimulate adaptive responses to mitigate salt stress. Here we evaluated the main effects of sodium chloride (NaCl 0, 50 and 100 mM) in the nutrient solution, and of titanium foliar spray (Ti 0.75 and 150 mg L-1), as well as the interaction of these study factors, on tomato cv. 'Rio Supremo' performance in greenhouse. Plants were treated with NaCl during 80 d through automated drip irrigation; while eight Ti foliar sprayings were applied with a manual sprayer, at intervals of 10 d each. Yield and quality parameters of fruits were evaluated in the second cluster. NaCl reduced yield parameters, pH value and increased the titratable acidity (TA), electrical conductivity (EC), and total soluble solids (TSS), as well as the TSS/TA ration in the fruits. Ti did not affect yield parameters, though it reduced the pH and increased the TSS/TA ratio of fruits. NaCl and Ti have differential effects on fruit quality as separate factors, while the interaction of both factors revealed that Ti effects dependent on the presence of NaCl and its level in the nutrient solution. In conclusion, Ti did not mitigate the negative effects of saline stress on the evaluated yield parameters, but importantly, with moderate levels of NaCl in the nutrient solution (50 mM), Ti increased EC, TA and TSS of fruits.