Abstract: A full-length cDNA（temporarily name it Ps-NCED1）encoding 9-cis-epoxycarotenoid（NCED）was isolated with the techniques of RT-PCR and RACE from petals of tree peony flower and characterized. Phylogenetic tree analysis revealed that amino acids sequence of Ps-NCED1 shared more than 70% identity with the sequence of NCED from plants such as Vitis vinifera，Solanum tuberosum，Daucus carota and so on. Ps-NCED1 also had the highest amino acids sequence identity with At-NCED3 of CCD（carotenoid cleavage dioxygenase）family in Arabidopsis. Cut flowers during full open stage had the lowest endogenous ABA levels，to the contrary，flowers during primary and senescent stages had higher ABA levels. The relative real-time PCR analysis was used to identify the expression of Ps-NCED1 in different parts of tree peony at blooming stage. The expression in root and stamen presented the highest，while that in leaf and sepal the lowest. The expression of Ps-NCED1 in the petals from ABA treated flowers during vasing increased with cut flowers opening and senescence，coincided with the ABA content increase，resulted in the assumption that it might be the main member in regulation the ABA biosynthesis in tree peony responding to the postharvest stress during opening and senescence process.

Key words: tree peony, ABA, NCED, gene, real-time PCR