Analysis Of Volatile Components And Content Of Litchi Flowers In Different Varieties At Different Blooming Stages

Litchi(Litchi chinensis Sonn)belongs to Sapindaceae family,litchi genus,a typical subtropical evergreen fruit species.Litchi flower is very large,in order to reduce theconsumption of flowering tree nutrient,increase the fruit setting rate,litchi production process carried out deblossoming.And cut off the flower spike directly abandoned in the field,so study of litchi flowers and development of more litchi flowers use of the way and the product is necessary.Litchi flowers are small,but the flowers are rich flavor,flower is an important material to attract bees,so it is very important to the growth and development of litchi,however,there are few studies on volatile substances in litchi flower.This study selected 18 litchi varieties as the researc h object,record the flowering and fruit development phenology,take three developmental stages of male and female flowers as test materials,analysis of volatile components and contents by using HS-SPME and GC-MS technology,combined with PCA,heat image clustering analysis method to explore the relationship between floral material and litchi ripening the development of the flowers.The main results were as follows:1.The method of determining the volatile matter of litchi flower wasoptimized,Ultimately determine the balance time of 20 min,extraction time of 30 min,1g litchi flower powder as sample quality,The column temperature keep at 40? for 2min,then raised to 60?at a rate of 5?/min keep at 2 min,last raised to 180? at 2?/min keep at 10 min,as experimental method.2.The samples were extracted by headspace solid phase microextraction and analysed by gas chromatography–mass spectrometry.A total of 56 volatiles were identified,composed of terpenes(17),alkene(6),benzodiazepines(4),heterocycle(4),aldehydes(2),alcohols(2),esters(1),and others(3).The results showed that the terpenes were the main components of the volatile substances in litchi flower.3.By comparing the differences of volatile compounds in different litchi cultivars,the results showed that there were significant differences in compound categories and content of volatile components in different litchi cultivars.In‘Feizixiao',‘Ruanzhizaohong',‘Yingzhizaohong',‘Yulindingxiang',‘Lanzhu'the main floral fragrance is alpha-zingiberen,in ‘Wuyejiu',‘Zhuangtyuanhong',‘Songjiaxiang',‘Xiafanzhi',‘Baili',the main component of floral fragrance is Bicyclo germacrene,in ‘Guilin','Kulin','Shuilin','Jinzhong',the main component of floral fragrance is beta-Bisabolene and 10 s,11s-Himachala-3(12),4-diene,in ‘Nuomici',‘Ziniangxi',Guiwei,‘Dajinzhong',the dominant aroma substances are beta-elemene,caryophyllene,aromadendrene,bicyclo germacrene and beta-Bisabolene.4.The litchi flower volatile matter PCA and thermal clustering analysis and find that a ll varieties of litchi are divided into four categories.The first class: ‘Yingzhizaohong',‘Xiafanzhi'and ‘Wuyejiu';second: ‘Feizixiao',‘Ruanzhizaohong',‘Yulingdingxiang',‘Songjiaxiang',‘Lanzhu'and ‘Zhuangyuanhong';third:‘Nuomici',‘Dajinzhong',‘Ziniangxii'and ‘Guiwei';fourth categories: ‘Guilin',‘Kulin' and ‘Jinzhong' and ‘Shuilin'.5.beta-Ocimene,Ethyl2-(5-methyl-5-vinyltetrahydrofuran-2-yl)propan-2-ylcarbonate,(3R,6S)-2,2,6-Trimethyl-6-vinyltetrahydro-2H-pyran-3-olwillincrease,hexamethyl,Myroxide,Cyclotrisiloxane,yangene,alfalfaring floral volatiles increase with the development of flowers.However,the process of the development of litchi flower in Yilan was decreased gradually caryophyllene were detected in the samples.