Effect of amino acids foliar spraying on growth and physiological indices of tomato under salt stress conditions

Water and soil salinity are considered as one of the major problems for agriculture in arid and semi-arid regions of the world which restrict cultivation and as a result, crops yield decrease. There are some solutions for reducing its damages. Among them, using bio-fertilizers and environmentally friendly in the production process can be mentioned. In this regard, a factorial experiment was conducted based on completely randomized design with three replications in 2014. The first factor was salinity in 0, 30 and 60 mM rates, and the second factor was amino acid including arginine, tryptophan and proline. The interactive effects of salinity and amino acids on the number of pancakes, proline content, electrolyte leakage percentage, total chlorophyll content, and their simple effects on stem length, the number of leaves and nodes were significant. With an increase in salinity level, stem length, the number of leaves and nodes decreased. Amino acid consumption increased the number of leaves, but proline showed a more positive effect in the number of nodes and stem length. The negative role of proline salinity and positive role of proline in the number of pancakes and total chlorophyll content and the positive role of salinity in increasing the amount of proline and the percentage of leaf electrolyte leakage were significant. Therefore, under the conditions of salt stress in the fields as well as increased soil salts and irrigation water in the greenhouse, the growth conditions in tomato can be improved by using biofertilizers.