Salt tolerance of five grape (Vitis vinifera L.) cultivars, including ‘Asgari’, ‘Crimson Seedless’, ‘Flame Seedless’, ‘Shiraz’ and ‘Sultana’ were evaluated using phytochemical indices under greenhouse conditions. When plants reached the fifteen leaf stage, sodium chloride (NaCl) at four levels including 0, 25, 50 and 100 mM were given to the pots for a ten weeks period. Phytochemical indices allowed us to characterize grape cultivars in response to salinity. The highest ion leakage and lipid peroxidation were observed in ‘Sultana’ and the lowest in ‘Shiraz’ and ‘Crimson Seedless’. At 100 mM NaCl, the maximum leaf relative water content was related to ‘Shiraz’ grape cultivar and the least amount was related to ‘Sultana’ grapevine. Under salinity stress, the amount of photosynthetic pigments decreased in all studied cultivars. The chlorophyll stability was higher in ‘Shiraz’ and ‘Flame Seedless’ cultivars in comparison to other cultivars. Proline and soluble carbohydrates as well as activity of antioxidant enzymes were higher in ‘Shiraz’ and ‘Flame Seedless’ cultivars as compared to other cultivars. At 100 mM NaCl dose, the highest and lowest amount of leaf ABA and polyamines was related to ‘Flame Seedless’ and ‘Sultana’ cultivars respectively. Based on measured indicators the cultivars were ranked as ‘Flame Seedless’, ‘Shiraz’, ‘Crimson Seedless’, ‘Asgari’, and ‘Sultana’ based on their tolerance to saline condition.
