Abstract:Pollination-induced ethylene production plays an important role in regulating flower development. As gynoecium is one of the more important parts in Phalaenopsis orchid flower, the authors have investigated ethylene production and 1-aminocyclopropane-l-carboxylate (ACC) oxidase gene expression in gynoecium following pollination. Experimental studies revealed that ethylene production and ACC oxidase mRNA accumulation decreased steadily in stigma and style, in contrast, exhibited a crescendo increase in the ovary at 12.24 and 48 h after pollination, indicating a close relationship between ethylene production and ACC oxidase gene expression in the gynoecium. In addition ethylene production was found most in stigma and least in ovary among the three parts after pollination.