Effect of Salt Stress on Seed Germination, Plant Growth, Photosynthesis and Ion Accumulation of four Tomato Cultivars

Plant growth and seed germination are severely affected by saline conditions. Local tomato cultivars could be better adapted to salt stress. For this reason, to test that, the effect of four levels of salinity (0, 50, 100 and 150 mM NaCl) on seed germination, plants growth (relative fresh and relative dry weight), K+ and Na+ content and photosynthetic rate of the four local cultivars (Heb, Ram and J1) and one commercial cultivar (Mar) was studied. Significant difference in G50 of Heb cultivar was seen at 50 and 100 mM NaCl when compared with the other four cultivars (p<0.05) and the only one achieved 50% germination at 150 NaCl. Salt stress reduced plant growth of all cultivars, but Ram and Mar cultivars were characterized as the most tolerant and sensitive, respectively. No significant difference was seen in K+/Na+ ratio among four cultivars tested, but Ram showed the maximum value of 5.72 and 35.09 at 50 and 100 mM NaCl, respectively. Ram also showed better photosynthesis rate (5.1, 3.71) at 50 and 100 mM NaCl, respectively, than the other four cultivars.