The Research Of Volatile Organic Compounds Release From Four Osmanthus Fragrans Cultivar Groups And Photosynthetic Characteristics

In this paper,Osmanthus fragrans(Thunb.)Lour.‘Thunbergii',Osmanthus asiaticus Nakai,Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' and Osmanthus fragrans(Thunb.)Lour.‘Sijigui' in natural condition were chosen as research subjects.Dynamic headspace collecting and TDS-GC-MS were adopted,monitoring the Osmanthus fragrans' blooming process from four cultivar groups of Osmanthus fragrans,collecting and testing the leaves of VOCs component which release in diurnal change.At the same time,four cultivar groups of Osmanthus fragrans were studied from four aspects: the leaf pigment content,light response curves,diurnal Variation on chlorophyll fluorescence as well as chlorophyll Photosynthesis.The main results are concluded as follows:1?Results showed that four Osmanthus fragrans varieties were listed in descending order by the release amount: Osmanthus fragrans(Thunb.)Lour.‘Sijigui'(1704.6)> Osmanthus asiaticus Nakai(1675.3)> Osmanthus fragrans(Thunb.)Lour.‘Thunbergii'(1383.5)>Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus'(1062.8).All of four were single-peak-curve,and reached the most release amount in the full bloom stage.Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' released the most kinds of VOCs.More than 63% of VOCs,in the four O.fragrans varieties,was the terpene during the full bloom stage.Besides,we have detected that all of them contained hydrocarbons,aldehydes,alcohols,ketones,esters and aromatic compounds.2?Analyzing the VOCs component and content from four cultivar groups of Osmanthus fragrans' leaves in diurnal change(9:00,12:00,16:00),it was obvious that the VOCs component and content in Osmanthus fragrans' leaves were much less than those in flowers.The content in Osmanthus fragrans' leaves was not only low but the variation was also not obvious.The main species of VOCs in leaves of Osmanthus fragrans was Terpenoids,but the content of Esters was increased greatly.3?The total chlorophyll content from four cultivar groups of Osmanthus fragrans was ranked: Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' > Osmanthus fragrans(Thunb.)Lour.‘Thunbergii' > Osmanthus asiaticus Nakai > Osmanthus fragrans(Thunb.)Lour.‘Sijigui'.Among them,the contents of chlorophyll a,chlorophyll b and chlorophyll were the highest Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' and Osmanthus asiaticus Nakai were significantly different in carotenoid content.However,there was no obviously different chlorophyll a as well as chlorophyll b from four Osmanthus fragrans' leaves.4 ? The light response curve parameters,species ecological factors of four Osmanthus fragrans,indicated that Pn value was different: Osmanthus asiaticus Nakai > Osmanthus fragrans(Thunb.)Lour.‘Sijigui' > Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' >Osmanthus fragrans(Thunb.)Lour.‘Thunbergii'.The Pn value of Osmanthus asiaticus Nakai kept a leading position.With the increase of Pn value,Cond and Tr increased,and WUE increased to a fixed value then decreased,while Ci decreased gradually.In addition,Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' and Osmanthus fragrans(Thunb.)Lour.‘Thunbergii' were also good at using strong light,while Osmanthus fragrans(Thunb.)Lour.‘Sijigui' and Osmanthus asiaticus Nakai are more inclined to the use of week light.5?The diurnal variation parameters,the physiological indicators of of four Osmanthus fragrans,indicated that there was comparatively different in diurnal variation parameters among four cultivar groups of Osmanthus fragrans.Osmanthus fragrans(Thunb.)Lour.‘Aurantiacus' was of strong physiological activity and adaptability.6?The diurnal variation parameters of chlorophyll fluorescence,four cultivar groups of Osmanthus fragrans,showed that the activity of PSII in Osmanthus fragrans(Thunb.)Lour.‘Sijigui' was more stable and tolerant to photoinhibition,and the PIABS index was the highest and the activity was the strongest.And Osmanthus fragrans(Thunb.)Lour.‘Thunbergii' was more sensitive to the temperature and light changes.There was no significant difference in ETO / RC value among four cultivar groups of Osmanthus fragrans,and the ratio change trends of ABS / RC,TRO / RC and DIO / RC were similar.