Analysis Of Aroma Components And Its Emission Pattern In Paeonia Ludlowii

The fragrance of peony is one of its ornamental characters.The release of floral substance will occur with the blooming of flowers,the kinds and content of floral substance vary in different flowering stages and different parts of flower organs.Paeonia ludlowii belongs to Paeonia(Paeoniaceae),which is a native shrub of deciduous flowers in Tibet.It is also a valuable germplasm resource of wild peony,which has high ornamental and medicinal value.HS-SPME and GC-MS were used in this study,the changes and differences of floral aroma components of P.ludlowii in different flowering stages(S1,S2,S3,S4,S5,S6)and different parts of flower organs(whole flower,petals,stamens,pistils,sepals)were determined and analyzed,at the same time,the threshold value of aroma substances was analyzed and the sensory evalution of P.ludlowii was carried out.Draw the following conclusions:(1)A total of 66 aroma compounds were detected in the whole flower of P.ludlowii.The main aroma compounds were esters,ketones,alcohols and aldehydes.With the development of flowers,the release of floral substances reached the peak at S3 and S6.There was no significant difference in floral aroma components among different periods.The aroma components were similar in S3,S4 and S5.(2)61,63,44 and 49 kinds of volatile components were detected in petals,stamens,stamens and sepals,respectively.The major chemical compounds in the petal were alcohols,the major chemical compounds in stamens,pistils and sepals were ketones.The amount of aroma compounds released from petals reached the peak at S3 and S6;the amount of aroma compounds released from stamens and pistils reached the peak at S5;and the amount of aroma compounds released from sepals reached the peak at S2.(3)The main components in the petals were(E)-2-hexenal,linalool,acetophenone,α-methyl-benzenemethanol,ethyl benzoate and β-copaene;the main components in stamens are acetophenone,benzaldehyde,Linalool,β-copaene,α-methyl-benzenemethanol and jasmonone;the main components in pistils are nopinone,2,7-dimethyloxazepine,perillyl alcohol,6,6-dimethyl bicyclo [3.1.1] heptane-2-one and 6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-carboxaldehyde;the main components in the sepals are nopinone,perillylalcohol,benzaldehyde,6,6-dimethylbicyclic[3.1.1]heptane-2-one,6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-carboxaldehyde and(E)-2-hexenal.(4)2,3-dimethoxytoluene,bicyclogermacrene,ethyl benzoate,6,6-dimethyl-bicyclo[3.1.1]heptane-2-methanol are the volatile compounds that distinguish different flowering stages;6,6-dimethyl-bicyclo [3.1.1] hept-2-ene-2-carboxaldehyde,paeonol,benzyl alcohol and 1-(3-hydroxyphenyl)-ethanone are the volatile compounds that distinguish different parts of flower organs.(5)The whole flower of P.ludlowii is similar to the petals and stamen,and the contribution of flower fragrance mainly comes from the petal and stamen.The main release sites of aroma components are petals and stamens.(6)The key volatile compounds of P.ludlowii are ethyl benzoate,benzaldehyde,1-(3-hydroxyphenyl)-ethanone,2,3-dimethoxytoluene,acetoph enone and linalool.Linalool and acetophenone are the characteristic aroma compounds of P.ludlowii,together with other key substances form a complex aroma with fruit flavor.P.ludlowii released its unique floral aroma in S3,and the floral aroma in S6 decreased significantly.The conclusions indicated that the key aroma components and characteristic aroma components of P.ludlowii were determined by analyzing the change of aroma components in different developing stages and parts of flower organs,the key sites of the floral substance release were determined,which can provide the chemical basis for the study of the formation mechanism of floral fragrance and the exploitation of floral aroma gene resources,it provides a theoretical basis for guiding the follow-up research of peony fragrance breeding,resource development and utilization.