Nutrient solutions (NS) containing moderate to high concentrations of salts are frequently supplied to improve the taste of tomato fruits grown in soilless systems. The aim of this study was to determine whether salinity and water stress affect the tomato fruit quality similarly. The research was conducted in Mola di Bari, Italy, during Autumn 2004, and compared the nutrient film technique (NFT) with the trough-bench technique [Subirrigation (SUB)] in terms of tomato (Lycopersicon esculentum Mill. cv. Kabiria) fruit quality. In the NFT, the plants were grown with two electrical conductivity (EC) levels (2–4 and 6–8 dS·m-1) of NS. The highest EC was obtained by increasing all the ions in the NS. In the SUB system, two water tensions (-4 and -8 kPa) of substrate (perlite) were examinated. At harvest, in each cluster (six/plant), fruit dry matter (DM) and total soluble solids (TSS) were determinated. In the fourth and sixth cluster, vitamin C content and titratable acidity were determined. Total yield was not influenced by either soilless system, while the average weight of the fruit was lower in the SUB. The DM and TTS were influenced by soilless system (on average, 6.6 vs 7.3 g/100 g of fresh matter and 5.3 vs. 5.9 °Brix, with NFT and SUB, respectively). Both of the stresses resulted in the increase of DM and TSS, principally in SUB (water stress) in respect to NFT (salinity stress), while vitamin C and titratable acidity were not influenced by soilless system or water/salinity stress (25.2 mg/100 g fresh matter and 0.45 g/100 mL of citric acid juice, respectively). Results of NFT with the highest EC of NS exceeded 9 dS·m-1, without any stress symptoms in the plants, while EC in the SUB system remained unchanged (about 2.5 dS·m-1).
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