Abstract: Taking own-root tomato (Lycopersicon esculentum Mill. ) seedlings not subjected to NaCl stress as control, p lant growth, abscisic acid (ABA) and polyamine ( PAs) contents in leaves of grafted tomato seedlingswere studied under 100 mmol·L ^{- 1} NaCl stress. Results showed that shoot and root biomass production in grafted seedlingswas significantly higher than that in control. ABA content of grafted seedlingswas significantly higher than that of control, increased by 56.60% on the second day of stress. Total polyamine content of grafted seedlingswas significantly higher than that of control, increased by 14.96% on the second day of stress. Putrescine ( Put) content of grafted seedlings was significantly lower than that of control after 2 d of
stress. Spermidine (Spd) content of grafted seedlings was significantly higher than that of control on the second day of stress, but no significant difference was observed during 4 - 8 d of stress, Spd content of grafted seedlings was significantly lower than that of control on the tenth day of stress. Spermine (Spm) content of grafted seedlings was significantly higher than that of control, increased by 102.80% on the tenth day of stress. Put/PAs value of grafted seedlingswas significantly lower than that of control, while ( Spd + Spm) /Put
value of grafted seedlingswas significantly higher than that of control. The above results indicated that biomass production of grafted seedlings was significantly higher than that of control, ABA and polyamine contents of
grafted seedlings were significantly changed under NaCl stress, which showed the characteristics of stronger salt tolerance of grafted seedlings.