Abstract:

This review systematically summarizes recent advances in the research on the patterns of manifestations，driving factors，and regulatory mechanisms underlying floral volatile substances variation in the family Orchidaceae. Groups such as Cymbidium，Phalaenopsis，and Dendrobium exhibit genus-level specificity differentiation in volatile substances. Terpenoid compounds constitute the characteristic volatile fragrance components of most current orchids，whereas certain “specialized” taxa produce distinctive odors dominated by ketones，sulfur-containing compounds，amines，and other uncommon constituents. Volatile substance variations of Intra-specific and hybrid orchids are reflected not only in the composition and relative abundance，but also in the diversity of emission rhythms，which are highly synchronized with pollinator activity patterns. From the perspective of influencing factors，genetic factors represent the fundamental determinants of volatile substances diversity in orchids. In recent years，a series of key genes involved in the biosynthesis of terpenoids，phenylpropanoids，and other volatile compounds（such as structural genes like TPS） have been obtained，and they are strongly influenced by developmental stages，diurnal changes and trait trade-off. Non-biological factors can also alter the release intensity and component ratio of volatile substances. The metabolism of the main volatile substances is mainly regulated by transcription，and forms a cellular activity pattern of storage-release or active transport. In addition，the adaptive evolutionary relationship among pollinators may be an important ecological driver of scent diversification. The olfactory preferences of different pollinator groups（such as moths，bees，and beetles，etc.） have promoted the evolution of species-specific floral scent signals，thereby contributing to reproductive isolation and species differentiation. However，there are still some deficiencies in current researches. For instance，the functions and genetic patterns of volatile substances in the flower parts of some orchidaceae plants remain unclear，the molecular regulatory networks synthesized by them have not been fully elucidated，and the mechanism of exogenous regulation of flower fragrance is not systematically studied. In the future，by integrating research methods from biology and ecology，multi-omics technology and gene editing technology，the molecular mechanisms of the synthesis and regulation of volatile substances in the flower parts of orchids can be deeply explored，revealing their diverse evolutionary driving forces，and providing theoretical basis and technical support for the targeted breeding of new varieties of aromatic orchids and the development of functional products.

Key words: Orchid plants, floral scent, volatile organic compounds, biosynthetic pathway, regulatory mechanism, pollination interaction