气相色谱-质谱联用分析杜鹃红山茶挥发性成分

采用固相微萃取和气相色谱-质谱联用技术，分析杜鹃红山茶花朵不同花期、不同部位和一天中不同时间段的挥发性成分及其相对含量，并对其变化规律进行研究。结果表明：杜鹃红山茶花蕾期的挥发性成分有8种、始花期20种、盛花期21种、衰落期17种，其中始花期和盛花期为挥发性成分释放的主要时期；花朵开放过程中，醇类化合物的相对含量逐渐升高，烯类、酯类和烷烃类先升高后降低，醛酮类总体呈下降趋势。杜鹃红山茶盛花期花朵的4个部位中，萼片的挥发性成分有20种，花瓣22种、雄蕊21种、雌蕊13种，其中花瓣和雄蕊为挥发性成分释放的主要部位；花瓣、雄蕊、萼片中烷烃类相对含量均最高，分别占挥发性成分总量的49.86%、51.59%和44.66%；雌蕊中醛酮类含量最高，为83.87%。挥发性成分的相对含量在一天中变化明显，8:00时到12:00时是烯类、醇类、酯类和烷烃类化合物释放的高峰期，而醛酮类在14:00时到18:00时的释放量较高。

GC-MS Analysis of Volatile Components in Camellia azalea Flowers

Volatile compounds in Camellia azalea flowers at different stages during flower development,in their different parts and at different hours of a day were analyzed by solid phase micro-extraction and gas chromatography-mass spectrometry(GC-MS).Totally 8,20,21 and 17 volatile compounds were identified in early-stage,full bloom and withering flowers,respectively.Volatile compounds were released mainly during the early flowering and full bloom stages.During flower development,the content of alcohols revealed a gradual increase.Alkenes,esters and alkanes revealed an initial increase and a final decrease,while aldehydes and ketones revealed a decrease trend during the whole process.Totally 20 compounds were identified in sepals,22 in petals,21 in stamens and 13 in pistils.The major parts releasing volatile components were petals and stamens.Alkanes were the most dominant volatile compounds in sepals,stamens and petals,accounting for 49.86%,51.59% and 44.66% of the total volatiles,respectively,while the most dominant volatile compounds in pistils were aldehydes and ketones with a relative content of 83.87%.An obvious intraday variation was observed in the relative contents of volatile compounds in Camellia azalea flowers.The peak hours for releasing alkenes,alcohols,esters and alkanes were 8:00 to 12:00,while higher release levels of aldehydes and ketones were found from 14:00 to 18:00.