In this study,taking elm(Ulmus pumila L.) seeds as materials,we combined the use of seed vigor detection technology,confocal laser scanning microscopy,protein S-nitrosylation detection technology and pharmacology of many nitric oxide inhibitors,to investigate the role and the mechanism of nitric oxide during seed ageing.The results showed that:(1)Nitric oxide donor SNP can improve seed vigor after ageing.The scavenger of nitric oxide cPTIO can suppress the seed vigor after ageing,and the suppressions can be recovered by nitric oxide donor SNP.These illustrated that nitric oxide can improve the ability of anti-ageing.(2)The substrates of nitrite reductase and nitric oxide synthase like enzyme can improve seed vigor after ageing.The inhibitors of nitrite reductase and nitric oxide synthase like enzyme can suppress the seed vigor after ageing,and the suppressions can be recovered by nitric oxide donor SNP.These illustrated that nitric oxide can be produced by nitrite reductase pathway and nitric oxide synthase like enzyme pathway.(3)Nitric oxide was first produced in cotyledon,then in radical,shoot apex and hypocotyl.The level of protein S-nitrosylation was in accordance with temporal characteristics of nitric oxide produce.In conclusion,nitric oxide can improve the ability of anti-ageing,and can be produced by nitrite reductase pathway and nitric oxide synthase like enzyme pathway.The level of S-nitrosylation was also related to nitric oxide production.