Study On The Differences And Dynamic Chances Of Floral Fragrance Compounds Of Three Varieties Of Chimonanthus Praecox

In order to better understand the differences and dynamic changes of floral fragrance compounds of Chimonanthus praecox(C.praecox),chromatography-mass spectrometry(HS-SPME-GC-MS)was used to collect and analyze the floral fragrance compounds of three varieties of C.praecox.These results showed that(I)There were significant differences in floral fragrance compounds among different varieties of C.praecox.Terpenes,esters,phenols,alcohols and heterocyclic substances were the main floral fragrance compounds of C.praecox var.concolor,while in C.praecox var.patens were terpenes.α-Ocimene,benzyl acetate,eugenol,benzyl alcohol and indole had the highest relative contents in C.praecox var.concolor,while C.praecox var.patens included β-ocimene,α-ocimene and trans-β-ocimene.(II)In C.praecox var.grandiflorus,the number of floral fragrance compounds during different flowering stages were gradually decreased,while the total compounds released first increased,then decreased.Terpenes were the main floral fragrance compounds,their relative contents showed a high-low-high trend.The difference was that esters was the main flower volatiles in the bud stage,while the flowering stage also included esters and phenols.From the bud stage to the decay stage,the relative content of α-ocimene gradually increased.From the bud stage to the flowering stage,benzyl acetate,eugenol and indole were gradually increased,while benzyl alcohol showed a decreasing trend.(III)The main floral fragrance compounds release regularity of C.praecox var.grandiflorus was significantly during different day-night time.From the nocturnal to diurnal,the types of flower volatiles were smilar,but the number of flower volatiles first increased,then decreased,reached a peak at 12 noon,and totally released was gradually increased,and reached a peak at 12 midnight.The relative content of terpenes was gradually increased,and significant higher in the daytime than at night,while esters and phenols were significant higher at night than in the daytime,with a decreasing trend.During different time rhythm,the relative contents of α-ocimene released first decreased,then increased,while benzyl acetate and eugenol gradually decreased.In addition,the changes in the relative contents of benzyl acetate,cinnamyl alcohol and eugenol were positively correlated with humidity and negatively correlated with temperature,while α-ocimene was negatively correlated with humidity.(IV)In whole life flower stages,the flower volatiles amount and total release of C.praecox var.grandiflorus showed a low-high-low trend,and reached a peak on 21 December.α-Ocimene benzyl acetate,eugenol,benzyl alcohol and indole were the main floral fragrance compounds.With the flowering stages progressed,the relative contents ofα-ocimene released first increased,then decreased,while benzyl acetate and eugenol were increased and decreased,respectively.With respect to other flower stages,the end-flowering stage had the highest relative contents of benzyl acetate,and sharply increase after January 11.The relative contents of benzyl alcohol and indole showed no obviously release regularity.In addition,the relative content changes of benzyl alcohol in whole life flower stages were both positively correlated with temperature and humidity,while benzyl acetate and indole were negatively correlated with temperature,and indole,α-pinene and 3-carene were negatively correlated with humidity.This study provides a theoretical basis for investigating the metabolic pathways and trends of floral compounds of C.praecox,and has some reference value for the development and utilization of the resources among the genus C.praecox.