Abstract: The floral composition and its relative contentin flowers of Cymbidium tracyanum in the diurnal variation of full blooming stage and different flower organs were determined by solid-phase microextraction (SPEM) and gas chromatography coupled with mass spectrometry (GC-MS).In a day at 10∶00,14∶00 and 18∶00,88,87 and 83 compounds were identified respectively in flowers of C. tracyanum;72,66 and 62 compounds were identified respectively in flower petals,labellun and gynandrium;These include aldehydes,alcohols,ketones,esters,terpenes,alkanes,ethers,furans,phenols,and aromatic ten compounds.The floral constituents are mainly α-pipene and p-cresol;the main aroma components of the petals are α-pipene and β-pinene;the main floral components of the lips are p-cresol and α-pipene;the main floral component of the column is p-cresol,hexanal and 1-hexanol.The species of floral components in C. tracyanum gradually decreased during different time periods;the flower constituents of flower organs gradually increased from the column to the petal species,explaining that the main aroma release site is the petal.In different time periods and flower organs,terpenes,alcohols and esters accounted for a large proportion of the amount and relative content,indicating that terpenes,alcohols and esters are the main component of C. tracyanum orchid incense.

Key words: Cymbidium tracyanum L., flower aroma components, SPME, GC-MS technology