Analysis of flowering characteristics and release pattern of floral aroma components of Rhus chinensis Mill.

Abstract [Objective] This study aims to explore the flowering characteristics and flower fragrance components and their release patterns of Rhus chinensis, so as to provide a basis for further development and utilization of floral fragrance of R. chinensis. [Methods] Scanning electron microscope was used to observe pollen morphology. Headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) techniques were used to analyze the main floral scent components in different flowering stages and daily change pattern. [Results] A total of 92 floral substances (29 terpenes, 19 aldehydes, 15 esters, 14 alcohols, 5 ketones, 4 olefins, 2 aromatic hydrocarbons, and 1 each of phenols, alkanes, acids, and others) were detected in different flowering periods. Its relative content was increased and then decreased, reaching a maximum (3.60 μg/g) at the full-flowering stage, with significant differences among the flowering stages. A total of 84 floral aroma substances were detected during full flowering stage. The release showed a parabolic daily variation trend, which was higher during the day than at night and reached the maximum at 18:00 (4.80 μg/g), and then continued to decrease and reached the lowest at 6:00, with 2.58 μg/g. Terpenes were the main floral substances of R. chinensis, with a relative content of about 70% of the total floral components. [Conclusion] R. chinensis is rich in floral components, with a clear diurnal rhythm. Terpenes are its main floral substances.