Abstract: Herbaceous peony cut flowers of‘Banker Hill’and‘Yangfei Chuyu’were used to investigate the effects of ethrel on flower opening and senescence processes. Nine ethylene biosynthesis- and signal transduction-genes，including PlACS，PlACO，PlACO5，PlETR1，PlERS1，PlETR2，PlEIN4， PlCTR1 and PlEIN3 were cloned from the two cultivars. The expression patterns of the nine genes were analyzed by qRT-PCR. The results showed that‘Banker Hill’had longer vase life than‘Yangfei Chuyu’under normal conditions，and both cultivars were sensitive to ethylene. Ethrel treatment inhibited flower opening severely，and resulted in bull flower and even wilting directly in‘Yangfei Chuyu’，while it accelerated the processes of flowering opening and senescence in‘Banker Hill’. Sequence alignments of nine genes showed that they were highly conserved in the two cultivars，and the sequence identity was above 98%. The qRT-PCR results showed that ethrel treatment could increase all the above gene expression level except PlEIN3 in two cultivars，in 12–36 h. In 0–12 h，the nine genes had higher expression level in‘Yangfei Chuyu’than in‘Banker Hill’，and it was deduced that the endogenous ethylene synthesis and signal transduction were more active in‘Yangfei Chuyu’，while in 24–36 h，ethrel treatment promoted the ethylene synthesis- and signal transduction-genes expression in‘Banker Hill’，and the ethylene signal transduction-genes expression levels in‘Banker Hill’were higher than those in‘Yangfei Chuyu’. The delayed ethylene responses could promote flower quality of‘Banker Hill’. Therefore，it was suggested that‘Yangfei Chuyu’is more sensitive to ethylene than‘Banker Hill’. Differences of expression levels of ethylene biosynthesis- and signal transduction-genes may cause different sensitivity type to ethylene of the two cut flowers，and affect flower opening and senescence process.

Key words: herbaceous peony, cut flower, ethrel, ethylene biosynthesis- and signal transduction- gene, gene expression