【目的】对3种野生牡丹花器官的挥发性成分进行研究与分析,明确关键挥发性成分及释香部位,为指导牡丹花香育种、探索花香遗传规律等后续研究和开发相关产品提供参考。【方法】采用顶空-气相色谱质谱联用(HS-GC-MS)技术对大花黄牡丹(Paeonia ludlowii)、黄牡丹(P. lutea)、杨山牡丹(P. ostii)花器官不同部位(整花、花瓣、雄蕊)的挥发性成分进行测定,并对3种牡丹检测出的挥发性成分进行主成分分析(PCA)和偏最小二乘法判别分析(PLS-DA)。【结果】在3种牡丹花器官中共检测出147种挥发性物质。大花黄牡丹花器官中的化合物主要为酮类、醇类、烯烃类和醛类,整花中的挥发性成分以苯乙酮、6,6-二甲基双环[3.1.1]庚烷-2-甲醛和芳樟醇为主;花瓣中的挥发性成分以β-古巴烯、苯乙酮和芳樟醇为主;雄蕊中的挥发性成分以苯乙酮和芳樟醇为主。黄牡丹花器官中的化合物主要为烯烃、烷烃和醇类,整花和花瓣部位的挥发性物质主要是α-蒎烯、β-古巴烯、芳樟醇;雄蕊部位以辛烷、β-古巴烯和α-蒎烯为主。杨山牡丹花器官中的挥发性物质以烯烃和烷烃类为主,整花部位中的挥发性成分主要为α-蒎烯、罗勒烯、十五烷;花瓣的主要挥发性成分为罗勒烯,相对含量高达81.58%;雄蕊中的挥发性成分以罗勒烯、十五烷为主。依据检出的挥发性成分构建的PCA和PLS-DA模型,可实现将3种牡丹有效分类,并筛选出了15种差异性成分,变量投影重要性(V_VIP)>1(P<0.05)。【结论】3种牡丹之间以及同种牡丹不同部位之间的挥发性化合物种类和相对含量存在较大差异。大花黄牡丹的主要香气成分为苯乙酮和芳樟醇,黄牡丹的主要香气成分为α-蒎烯、 β-古巴烯和芳樟醇,杨山牡丹的主要香气成分为罗勒烯、α-蒎烯、十五烷。3种牡丹雄蕊中烷烃类化合物的相对含量均远高于整花与花瓣,雄蕊可能是烷烃类化合物的重要合成部位。不同挥发性物质构成了3种牡丹各自独特的香气特征,大花黄牡丹和黄牡丹散发出浓烈的花香,杨山牡丹表现为草香和蜡香。

【Objective】This study aimed to investigate and analyze the volatile components of three wild tree peony species and identify the key volatile components and aroma-releasing sites. This was done to provide a reference for future research, such as on the breeding and genetic regulation of the floral fragrance of tree peony, and for the development of related products. 【Method】The volatile components in different parts of flower organs (whole flower, petals and stamens) of Paeonia ludlowii, P. lutea and P. ostii were analyzed using headspace-gas chromatography-mass spectrometry, and based on the identified volatile components, three tree peony species were analyzed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). 【Result】 A total of 147 volatile compounds were detected in the flowers of three species of tree peony. The main volatile components in P. ludlowii were ketones, alcohols, olefins and aldehydes. The main compounds in the whole flower of P. ludlowii were acetophenone, 6,6-dimethyl-bicyclo[3.1.1]heptane-2-carboxaldehyde and linalool, while β-copaene, acetophenone and linalool were the main compounds of petals, and acetophenone and linalool were the main compounds of stamens. The main components of P. lutea were olefins, alkanes and alcohols. α-pinene, β-copaene and linalool were the main compounds of the whole flower and petals in P. lutea, while 1-octane, β-copaene, and α-pinene were the main compounds of stamens. The main components of P. ostii were olefins and alkanes. The main compounds in the whole flower of P. ostii were α-pinene, ocimene and pentadecane; ocimene was the main compound of petals and its relative content was as high as 81.58%; and ocimene and pentadecane were the main compounds of stamens. These three tree peony species were effectively classified by the PCA and PLS-DA models based on their volatile components, and 15 differential components of the three peony species were identified using the PLS-DA model (V_VIP > 1, P < 0.05). 【Conclusion】 There were significant differences among the types and relative contents of compounds among the three tree peony species and among different parts of the same tree peony species. The main aromatic components of P. ludlowii were acetophenone and linalool. The main aroma components of P. lutea were α-pinene, β-copaene and linalool. The main aroma components of P. ostii were ocimene, α-pinene and pentadecane. The relative alkane contents in the stamens of the three tree peony species were much higher than those in whole flowers and petals, suggesting that the stamen may be an important alkane synthesis site. Different volatile components formed the unique aroma characteristics of the three tree peony species, P. ludlowii and P. lutea showed intense floral attributes, whereas P. ostii had herbal and waxy attributes.