Fruit quality and partitioning of mineral elements in processing tomato in response to saline nutrients

A sand culture experiment was conducted to study the effect of saline water on the growth and fruit quality of processing tomato (Lycopersicon esculentum Mill.) Seedlings of five tomato cultivars were transplanted in quartz-sand pots in a greenhouse at the Agricultural Experiment Station of Sultan Qaboos University. There were four saline nutrient solutions and a control consisting of half-strength Hoagland solution. Salinity treatments were: 50 mM NaCl + 3 mM K₂SO₄ (EC 6.75), 50 mM NaCl + 1.5 mM orthophosphoric acid (EC = 7.18), 50 mM NaCl + 1.5 mM orthophosphoric acid + 3 mM K₂SO₄ (EC 7.29), and 50 mM NaCL (EC = 5.6). Treatments were applied daily commencing two weeks after transplanting. Data were collected on growth, and fruit yield and quality. Partitioning of mineral elements was determined in the vegetative tissue. The results obtained clearly show that concentrations of total soluble solids were increased in fruits treated with saline nutrients. Dry matter content of fruits exposed to salinity were higher than those from the control plants. Fruit acidity was increased with salinity, possibly due to a lower water content and increased organic acid accumulation. In the saline treatments, sodium (Na) content was decreased when potassium (K) was applied with NaCl but Na was higher in stems followed by root and leaf tissues. The partitioning of K followed a trend opposite to that for Na but with higher content in leaves. A similar situation was observed for calcium (Ca) and magnesium (Mg). Accumulation of phosphorus (P) was the lowest among all the ions. These results indicated that survival under saline conditions was accompanied by high ion accumulation. The study confirmed that saline nutrients are important for improving fruit quality of processing tomatoes.