Abstract: Comparison of the activities of protective enzymes, contents of osmotic adjustment substances and photosynthetic characteristics was made between grafted and self-root tomato (Lycopersicon esculentum Mill. ) seedlings under NaCl stress. The results showed that activities of superoxide dismutase (SOD) , peroxidase ( POD) , ascorbate2specific peroxidase (APX) and content of ascorbic acid (AsA) in leaves of grafted seedlings were significantly higher than those of self-root seedlings. Malondiadehyde (MDA) content in leaves of grafted seedlings was significantly lower than that of self-root seedlings. The contents of free proline, soluble sugar and soluble protein in the leaves of grafted seedlings were significantly higher than those of self-root seedlings. Photosynthesis was inhibited under NaCl stress, but the performance of the grafted seedlings was superior to that of self-root seedlings. The Na⁺/ K⁺ value in the roots of grafted seedlings was significantly lower than that of self-root seedlings. Base on these results, it could be concluded that the resistance to NaCl stress of grafted tomato seedlings was stronger than that of self-root seedlings.

Key words: Tomato, Grafted, NaCl stress, Antioxidant enzyme, Osmotic adjustment substance, Photosynthetic characteristic