Time change rule of contents of essential oil and its main compositions in leaves of different chemical types of Cinnamomum camphora var.linaloolifera

The variation status of essential oil content and relative content of main compositions in essential oil from leaves of different chemical types(including linalool-,cineol-and camphora-type) of Cinnamomum camphora var.linaloolifera Fujita.at different months in a whole year was analyzed,and the change rule of essential oil content and relative content of its main composition linalool in leaves of the excellent linalool-type clones in June to December and at different times in a whole day was also analyzed.The results show that essential oil content and relative content of main compositions in essential oil from leaves of different chemical types have differences among different months in a whole year.In which,there is a similar change regulation in essential oil content,that is,higher in growing season and lower in non-growing season with a higher level in May and from July to September.Change regulation of relative content of main composition in essential oil is complex.Relative content of linalool,which is the main composition in essential oil from leaves of linalool-type,reaches the highest in June,then descends slightly with a little change until December.That of camphora,which is the main composition in essential oil from leaves of camphora-type,reaches the highest in July,then decreases in other months but only with a little difference.That of 1,8-cineol,which is the main composition in essential oil from leaves of cineol-type,reaches the highest in April,then decreases and keeps steadily after June.From June to December,essential oil content in leaves of the excellent linalool-type clones reaches the highest in September,then decreases to the lowest in December,but relative content of linalool in essential oil is the lowest in September and increases to the highest in December.Essential oil content and relative content of linalool in leaves of the excellent linalool-type clones have obvious difference at different times in a whole day.The essential oil content is the lowest in the morning,increases gradually after sunrise,and reaches the highest in 16:00 to 17:00.While relative content of linalool in essential oil is the highest in the morning and decreases slightly but with a little change range in other times.The result of comprehensive analysis indicates that suitable collection month of leaves of C.camphora var.linaloolifera is from August to September,and suitable collection time in a day is from 8:00 to 17:00.