Floral scent compounds and emission patterns of three Styrax species

Styrax is a gorgeous species combined with high medicinal and ornamental values, however, information about its floral scents is limited. This study aimed to reveal the floral scent compounds and the dynamic changes in the flowering process of Styrax japonicas, S. grandiflora and S. calvescens. Static headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was adopted in the present study. The results showed that 24, 22 and 22 volatile compounds were present at three flowering stages, among which linalool, ocimene, alpha-pincnc and gcrmacrcnc D dominated in different species. Terpenes were the main floral scent compounds in all species, whereas there was considerable relative content of ketones in S. japonicus. Among the major terpenes, alpha-pinene, ocimene and myrcene were the common volatiles in these species, while beta-elemene and allo-ocimene were the specific volatiles in S. japonicus and S. calvescens, respectively. The highest content of terpenes occurred at initial flowering stage in three species. The differences in the type and content of principal compounds contributed to the fragrance diversity among these species. A solid foundation for understanding the complexity of volatile emission could be obtained from our findings, meanwhile, effective utilization of abundant terpenes in flowers of Styrax species should be applied.