# Headspace Volatiles and Endogenous Extracts of _Prunus mume_ Cultivars with Different Aroma Types
## 3 Discussion
### Biomarkers Which Have Made Great Contribution to the Four Aroma Types  
The floral scent is formed by the interaction of various volatile organic components. In addition, it has been widely accepted that compounds with high OAV contribute more to the aroma of the sample [13; 36]. The compounds with higher content and aroma value could be regarded as characteristic components, while the components with lower content and higher odor threshold had a weaker influence on the floral scent [2; 37]. In addition, the contents of volatile and endogenous biomarkers and aroma characteristics among the four aroma types were different. Among them, (_E_)-cinnamaldehyde has a cinnamon-like aroma, which makes the aroma more gentle and soft [38]. While cinnamyl alcohol had a floral-like aroma, and its content was higher in the strong-scented type, it is suggested that it may make a significant contribution to the formation of the strong-scented type [39]. The content of (_Z_)-2-hexen-1-ol in the fresh-scented type was significantly higher than that in other types. Previous studies have shown that C\({}_{6}\), C\({}_{9}\) aldehydes, and alcohols have fresh and green aromas [40; 41], and these aldol compounds were formed by the gradual oxidation, cleavage, and reduction in precursor fatty acids by lipoxygenase (LOX) [42]. Therefore, it is further speculated that they may contribute greatly to the formation of this aroma type. The content of benzoyl cyanide in sweet-scented was higher than in other types. Previous studies have shown that benzoyl cyanide had a bitter almond aroma, which was mainly produced by enzymatic hydrolysis of amygdala in the fruit [42]. As the most potent contributor, its aroma attributes (fruity odor impressions) may match the sensorial properties of the sweet-scented type. Since methyl salicylate with spicy odor and pentyl acetate with fruity aroma characteristics had higher content in light-scented type [13; 43], it is speculated that they may be related to the formation of light-scented type.  
In this study, the compounds of four aroma types were identified, and their differential components and contents were analyzed, which provided a theoretical basis for breeding and developing the essential oil of _P. mume_. However, the fragrance of flowers is a comprehensive function of all aroma components. The contribution and aroma characteristics of some compounds are still unknown. Therefore, it is necessary to combine sniffing test with sensory evaluation, including gas chromatography-olfactory (GC-O) and aroma extraction dilution analysis (AEDA) so as to further determine the functions of these compounds and detect the aroma active substances of _P. mume_ cultivars and then screen out the key different aroma substances of different aroma types, thus providing a theoretical basis for the breeding of _P. mume_ cultivars with different aroma types. Through the continuous study of the floral scent of _P. mume_, the material pool of floral scent in _P._ species and Rosaceae can be expanded, and it is of great significance for studying the evolution of _P._ species and Rosaceae.