Salinity is one of the important environmental factors that limit plant growth and product. Grapes are classified as salt sensitive plants. This paper attempts to evaluate the salinity effects on membrane lipid peroxidation, antioxidant components and antioxidative enzymes activity in four grape genotypes (Vitis vinifera L., Gharashani, LaaleBidaneh, Sachagh and Shahroodi) that commonly grow in the regions around Urmia Salt Lake. We came to the conclusion that malondialdehyde content and antioxidative enzymes activity increased significantly (P<0.05) in roots and leaves of all these genotypes. Gharashani and LaaleBidaneh genotypes showed higher antioxidative enzymes activity and lower membrane lipid peroxidation. Also, salinity had a significant effect on the accumulation of total phenolics content and phenylalanine ammonia lyase activity in all genotypes. Gharashani genotype showed the highest total phenols and PAL activity. There was a significant positive correlation among antioxidant enzymes activity, total phenolics content and PAL activity in leaves of all genotypes. It seems that Gharashani and LaaleBidaneh genotypes have a better antioxidant system compared with others and show higher efficiency for salinity tolerance.

Salinity tolerance of four grape genotypes [GharaUzum, Hosseini, AghUzum and Keshmeshi] was studied under various salinity levels (25, 50 and 100 mM NaCl). As a result, growth indices were significantly (P<0.05) reduced by salinity, whereas Cl^- and Na⁺ contents in the plant parts were increased. Cl^- accumulation exceeded than that of Na⁺ in all treatments. Among the genotypes studied, GharaUzum and Keshmeshi had the lowest and highest Cl^- concentrations in the leaf lamina, respectively. Photosynthesis and transpiration rate as well as stomatal conductance were greatly reduced by salinity and were shown to be highly correlated with leaf Cl^- content. GharaUzum showed lower reduction in photosynthesis parameters. Soluble sugars, proline and glycine betaine contents increased in the leaf lamina of all the genotypes studied treated with moderate salinity (50 mM). In conclusion, the results showed that GharaUzum and Keshmeshi had the highest and lowest salt stress tolerance among the genotypes studied, respectively.