Volatile components of different periods and different parts of Dendrobium chrysotoxum based on GC-MS

In order to investigate the characteristics and release pattern of volatile components during flowering of Dendrobium chrysotoxum. In this study, solid-phase microextraction(SPME)combined with GC-MS was used to detect the volatile components of D. chrysotoxum in four periods: bud period, first-flowering period, full-flowering period and last-flowering period, and four parts of the labellum, sepals, petals and pistil column in full-flowering period, and on the basis of this analysis, we carried out the analysis of principal components and the pattern of fragrance release. The results were as follows:(1)A total of 29 volatile components were detected in the 4 periods of D. chrysotoxum, consisting of 13 alkenes, 6 alcohols, 2 aldehydes, 2 esters, 2 alkanes, 1 phenol, 1 acid and 1 other; a total of 39 volatile components were detected in the 4 parts of D. chrysotoxum during the full-flowering period, consisting of 15 alkenes, 9 alcohols, 4 alkanes, 3 esters, 3 ketones, 2 aldehydes, 2 others and 1 acid.(2)The volatile components and content in D. chrysotoxum gradually increase and then decrease during the whole process from full-flowering to decaying, and there are up to 22 volatile components in the full-flowering period, mainly alkenes and esters.(3)A total of 7 volatile components, namely, octyl acetate, ocimene,(+)-α-pinene,(-)-β-pinene, laurolene, d-limonene and 1-octanol, were important volatile components in D. chrysotoxum. Among them, octyl acetate and ocimene were the most released in the full-flowering period, which accounted for 31.74% and 24.98% of the total content, and the contents of acetic acid, octyl ester were detected in the three periods of bud, first-flowering and full-flowering, and the content was higher;(+)-α-pinene,(-)-β-pinene, myrcene, d-limonene and 1-octanol were detected only in the first-flowering and full-flowering periods and their contents increased gradually with the opening of the flowers.(4)The types and contents of volatile components released from different parts of D. chrysotoxum also varied. The main odoriferous parts were petals and sepals, with 29 types of volatile components detected in sepals, 20 types of volatile components in petals, with the highest total content of 5 754.26 ng·g-1. In conclusion, this study shows that the volatile components released by different periods and different parts of D. chrysotoxum are different, and the results of this study lay a theoretical foundation for developing industry of daily chemical products of D. chrysotoxum flower.