# Headspace Volatiles and Endogenous Extracts of _Prunus mume_ Cultivars with Different Aroma Types  
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Correspondence: [EMAIL_ADDRESS] Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China; [EMAIL_ADDRESS] (X.W.); [EMAIL_ADDRESS] (Y.W.); [EMAIL_ADDRESS] (H.Z.); [EMAIL_ADDRESS] (H.Z.); [EMAIL_ADDRESS] (J.X.); [EMAIL_ADDRESS] (Q.F.); [EMAIL_ADDRESS] (M.B.) {x.y.z.  
caused by the changes of endogenous extracts content and the evaporation of headspace volatiles [3]. Therefore, it is necessary to analyze the headspace volatiles and endogenous extracts independently so as to obtain the relative contribution to the final aroma components [3; 10; 11].  
There are three methods to extract the volatile compounds, such as extraction, distillation, and headspace methods [12]. At present, most of the volatile compounds in ornamental flowers are determined by headspace solid-phase microextraction (HS-SPME), including _Malus ionesis_[13], _Chrysanthemum_[14], and _Iris_[2]. HS-SPME can accurately analyze the volatile samples, enrich and separate the aroma components with a low threshold, which is more specific, simple and reliable to living plants. Solvent extraction is used to extract effective components from the raw materials according to their solubility in different solvents. This is suitable to study the endogenous components of the petals, such as _Petunia axillaris_[3], _Jasminum_[9], and _Dianthus_[10]. At present, GC-MS is often used to obtain chromatograms and mass spectra of VOCs [15; 16].  
_Prunus mume_ (mei) is a traditional flower in China that has a long cultivation history and belongs to the \(P\). genus of the Rosaceae family [8; 11; 17]. _P. mume_ is native to the Yangtze River Basin in southwestern China and is also widely planted in northern China. It usually blooms from January to February, and it is a famous traditional ornamental plant in China [17; 18]. Compared to other species of _Prunus_, mei has a unique floral ascent [19]. Previous studies have already focused on the main volatile components, including benzyl acetate and eugenol, and their synthesis-related genes in mei. For instance, [PERSON] et al. [20; 21; 22] mainly concerned the volatile components of different _P. mume_ cultivars and their temporal and spatial patterns. Benzyl acetate and eugenol, the metabolites of the phenylpropanoids/benzenoids metabolism pathway, were found to be the main compounds of the emitted and endogenous floral scent compounds of _P. mume_ and hybrids [11]. Additionally, promoting and interfering with the expression of _PmBEAT34_, _36_ and _37_ could regulate the production of benzyl acetate in the petal protoplasts of _P. mume_[17]. Additionally, [PERSON] et al. found that _PmCEAT1_ contributed to eugenol biosynthesis in _P. mume_[23]. However, little is known about the diversity of the floral scent in the _P. mume_ cultivars with different aroma types and the difference in composition between headspace volatiles and endogenous extracts.  
In this study, the headspace volatiles and endogenous extracts of eight _P. mume_ cultivars with four aroma types were analyzed by headspace solid-phase micro-extraction (HS-SPME) and organic solvent extraction (OSE) combined with gas-chromatography mass-spectrometry (GC-MS), respectively. Then, the variable importance in projection (VIP) values were used to screen the differential compounds among the four aroma types as biomarkers. In addition, further analysis of odor activity value (OAV) screened out several biomarkers that made great contributions to the four aroma types. This study lays a foundation for the classification and breeding of _P. mume_ cultivars in the future.