Objective To analyze the aroma compounds in flowers of Dendrobium chrysotoxum, in order to clarify the material basis of floral scents formation and provide reference for breeding.

Method The aromatic component categories and their release amounts in flowers of native Den. chrysotoxum in different florescence stages were detected and the diurnal variation of full blooming stage were determined by solid-phase microextraction (SPEM) and gas chromatography coupled with mass spectrometry (GC-MS).

Result The floral scents of 33 volatiles were identified as scent components in Den. chrysotoxum, including 15 terpenes, 7 esters, 6 alcohols, 2 aromatic compounds, 2 ketones and 1 aldehydes. Ester and terpenoids were the dominant components of these scents, composing exceed 80% to all detected compounds. The aromatic component categories and their release amounts at full blossoming stage increased at first and then decreased at different sampling time, and reached the maximum at 2:00 p.m. In different blooming stages, the contents of terpenes, esters, alcohols, aromatic compounds, aldehydes and ketones increase and then decrease, and reached the highest at full opening stage.

Conclusion The aroma compounds and their release amounts are distinctly different at different florescence stages and show a diurnal variation in full blooming of Den. chrysotoxum. Octyl acetate, β-ocimene, α-pinene and benzeneacetaldehydo are the main substances responsible for the floral scent formation in Den. chrysotoxum.