Abstract: In order to investigate the effect of tomato rootstock，scion and their potential interaction on chilling tolerance，the approach grafting between chilling-sensitive tomato cultivar‘060911’（S）and chilling-resistant tomato cultivar‘060112’（R）was proceeded to generate grafted seedlings RS/RS with double rootstocks and scions. By selectively detaching one rootstock or scion from RS/RS，newly formed seedlings of six combinations with different rootstock and scion，i.e.，R/R，R/RS，R/S，S/R，S/RS，S/S were raised in the growth chamber with light intensity of 22 klx and photoperiod of 12 h/12 h. Seedlings were treated with low temperature at 10 ℃ in the day and 3 ℃ at night for 9 days and recovered at 25 ℃ in the day and 15 ℃ at night for 3 days. The level of reactive oxygen species（ROS），and the key enzymes and antioxidants in AsA-GSH cycle in leaves and roots of grafted seedlings were measured after the chilling treatment and recovery. The content of hydrogen peroxide and production rate of superoxide anion in leaves and roots of grafted tomato seedlings were significantly increased under low temperature stress. The ROS level in grafted seedlings with R rootstock or R scion was significantly lower than that with S rootstock or S scion，respectively. The decrease of ROS level between R and S rootstock was more significant than that between R and S scion，indicating that rootstock conferred more chilling resistance than scion. Low temperature stress increased the accumulation of AsA，DHA，GSH and GSSG，and enhanced the activities of APX，MDHAR，DHAR and GR. Moreover，enzyme activities and the content of antioxidants except for DHA and GSSG were highest in grafted seedlings with R rootstock or R scion，lowest in those with S rootstock or scion，and intermediate in those with RS rootstock or scion，indicating that the ability of anti-oxidation in grafted seedlings with R rootstock or R scion under cold stress was significantly higher than that in grafted seedlings with S rootstock or S scion. In addition，the ability of anti-oxidation in leaves of RS-R grafted seedling was significantly higher than that in RS-S grafted seedlings. Statistical analysis showed that probability（P）values of interaction between rootstock and scion were less than 0.01（or 0.05），indicating that rootstock and scion posses significant interaction effects on the chilling tolerance of grafted tomato seedlings.

Key words: tomato, rootstock, grafting, low temperature stress, AsA-GSH cycle