Reducing the salinity impact on soilless culture of tomatoes using supplemental Ca and foliar micronutrients

Salt stress is known as one of the most severe abiotic factors limiting the plant production all over the world. In this study, three additives: (i) supplemental Ca (5 mmol L–1) to nutrient solution, (ii) foliar application of micronutrients (Fe, Mn and Zn at 60, 160 and 110 mg L–1, respectively), and (iii) combination of both of them were evaluated aiming to reduce the negative impact of salt stress on tomato plants cultivated in a soilless culture and improve the internal quality of fruits. The obtained results show that salinity reduced vegetative growth and physiological parameters, fruit yield and its components, and even more lowered fruit market classification of tomatoes. Salinity treatment reduced most of essential macro- and micronutrients in tomato fruit, whilst Na content was increased. Tomato productivity and fruit quality were ameliorated under saline conditions by increasing Ca into nutrient solution and applying a foliar application of micronutrients. A combination of both additives ranked the first to alleviate the adverse effects of salinity on tomatoes, followed by solo supplemental Ca into saline nutrient solution. On the other hand, the internal fruit quality of antioxidant compounds, such as vitamin C, lycopene, α-carotene, β-carotene and lutein as well as acidity, total soluble solid and dry matter percent, were increased under saline conditions.