对4 ℃低温层积0～120 d紫椴（Tilia amurensis Rupr.）、辽椴（T. mandshurica Rupr. et Maxim.）和美洲椴（T. americana Linn.）种子的O^-·₂和H₂O₂含量以及SOD、POD和CAT活性变化进行了比较。结果表明：在低温层积过程中，3种植物种子的O^-·₂含量以及辽椴和美洲椴种子的H₂O₂含量总体上高于对照（层积0 d），但紫椴种子的H₂O₂含量低于对照；3种植物种子的抗氧化酶活性呈现不同变化趋势，其中，辽椴种子的SOD和POD活性以及美洲椴种子的POD活性均高于对照。总体来看，低温层积可促进3种植物种子中活性氧的积累，并增强辽椴种子的SOD和POD活性及美洲椴种子的POD活性。

Variations of O^-·₂ and H₂O₂ contents and SOD, POD, and CAT activities in seeds of Tilia amurensis Rupr., T. mandshurica Rupr. et Maxim., and T. americana Linn. during 4 ℃ low temperature stratification for 0-120 d were compared. The results show that during low temperature stratification, O^-·₂ content in seeds of three species and H₂O₂ content in seeds of T. mandshurica and T. americana are generally higher than those of the control (stratification for 0 d), but H₂O₂ content in seeds of T. amurensis is lower than that of the control; antioxidant enzyme activities of three species show different variation tendencies, in which, SOD and POD activities in seeds of T. mandshurica and POD activity in seeds of T. americana are all higher than those of the control. It is suggested that in general, low temperature stratification can promote reactive oxygen species accumulation in seeds of three species, and increase SOD and POD activities in seeds of T. mandshurica and POD activity in seeds of T. americana.