Abstract: The respiration rate，the ethylene production，the ACC content，and the ACS and ACO activities of the flowers and the petals of Chinese peony‘Taohua Feixue’during the different development stages were analyzed. The results showed that the flower of‘Taohua Feixue’belonged to the like ethylene climacteric type and the respiration climacteric type. The ethylene production of the petals had an obvious climacteric peak，while the ethylene production of the intact flower increased during later stage. It revealed that the respiration rate of the petals and the intact flower was characterized by a typical climacteric peak and the respiration rate of the petals peaked earlier. Compared to the intact flower，the ethylene production and respiration rate of the petals were higher than those of the intact flower. The results indicated that the petals were the major organ of the ethylene production，which was closely associated with the flower opening and senescence. The ACS activity was consistent with the endogenous ethylene production，which suggested that ACS was the important rate-limiting enzyme of the ethylene biosynthesis.

Key words: Chinese peony, development stage, ethylene metabolism, ACS activity