Tomato fruit quality as influenced by salinity and nitric oxide

The impact of salinity (measured by adding 100 mM of NaCl to the nutrient solution) and spraying with sodium nitroprusside (10 mu M of SNP, NO source) on fruit quality of tomato (Super Strain B) plants grown under field conditions was studied. Irrigation with salinised nutrient solution alone resulted in a significant suppression in fruit fresh and dry biomass, length, diameter, and volume as well as beta-carotene and lycopene contents. This decrease was accompanied by a significant increase in Na accumulation, total alkaloids, and antioxidants, including total phenolics and flavonoids, and reduced ascorbic acid (ASA) content. Similar to total phenolics and flavonoids, the content of some individual phenolic acids such as protocatechuic, vanillic, chlorogenic, ferulic, and sinapic acids were at their high levels under saline conditions. Spraying the salinised plants with SNP improved tomato fruit quality to some extent in regards to salinity impact. Under the studied salinity level there was an enhancement of health-promoting compounds (phenolic compounds, flavonoids, and alkaloids) synthesis in tomato fruits, with significant changes in other quality parameters.