Abstract: 【Objective】To study the effect of salt stress on processed tomato seedlings,to clarify the maximum salt concentration for normal growth of processed tomato,and to provide a reference for processed tomato cultivation and production and salt-tolerant breeding.【Methods】The seedlings of processed tomato Riegel 87-5 was used as test materials,and 0（CK）,50,100,150,200 mmol/L NaCl solution was irrigated at the seedling stage,to analyze the morphology,physiological indexes and the change of K⁺ and Na⁺ under different concentrations of NaCl solution of processed tomato.【Results】With the increase of NaCl concentration,the plant height and stem thickness of processed tomato seedlings decreased. Under NaCl stress,SOD activity,POD activity,CAT activity,MDA content,and Pro content in processed tomato leaves increased significantly（P<0.05）.Under different concentrations of NaCl stress,the K⁺ content in each organ was stem>leaf>root;when the NaCl concentration was less than 150 mmol/L,the Na⁺ content in each organ was root>stem>leaf,and when the NaCl concentration was greater than 150 mmol/L,it was the stem>root>leaf.【Conclusion】With the increase of NaCl concentration,the growth of processed tomato seedlings was inhibited,and the content of antioxidant enzyme increased with the increase of NaCl concentration;when the NaCl concentration was greater than 150 mmol/L,the cell membrane was damaged,the ion balance was broken,which affected the selective absorption of ions by the plant,and the plant cannot grow normally.

Key words: Processed tomato, Seedling, Salt stress, Antioxidant enzyme, Potassium ion, Sodium ion