Abstract:To understand the relationships in seed germination and judge the aging of Platycladus orientalis,we determined and analyzed the dynamic changes of 1 000-grain weight,germination index,reactive oxygen species (ROS) and malonyldialdehyde (MDA) contents,activities of anti-oxidation enzymes by using the seeds of different ages of P.orientalis collected from Yellow Emperor mausoleum,Songyang Academy,Dai Temple,Jinci Temple,Zhongshan Park and Sleeping Buddha Temple.The results showed that 1 000-grain weight had no significant correlation with the ages of P.orientalis collected from six regions.Germination index and the active of anti-oxidative enzyme of 20-year-old P.orientalis were higher than that of old P.orientalis.However,the content of ROS did not go up with tree age of old P.orientalis.Above all,the seeds of old P.orientalis which taken from different ages and locations had no significant correlation between germination index,ROS (O-·2,H2O2,·OH),MDA contents and activities of anti-oxidation enzymes (SOD,POD,CAT,GR,APX).Compared to the seeds of 20-year-old and 3000-years-old P.orientalis,there were higher germination index and activities of anti-oxidation enzymes and lower contents of ROS and MDA contents.The research discovered that seed vitality of 20-year-old P.orientalis was relatively strong,but there were no clear decline in physiological functions of old P.orientalis seeds in different locations.