Ontogenesis and harvest time are crucial for high quality lavender – Role of the flower development in essential oil properties

Abstract

The goal of the study was to detect quantitative and qualitative changes of the volatile accumulation of lavender flowers during their development. Four Lavandula angustifolia and three Lavandula × intermedia cultivars were studied in a field trial during 2018 and 2019 in Budapest, Hungary. Samples were collected in three flowering phases (bud, full bloom, and end of flowering) in three replicates. Essential oil content was determined by hydrodistillation (Clevenger apparatus) and the composition by GC–MS analyses based on retention indices and MS libraries. The highest essential oil content was detected at the end of flowering phenophase in L. angustifolia cultivars for both years, while for L. × intermedia varieties, it was different in each year of the experiment. The amount of precipitation occurring prior to the sampling may play an important role in this issue.For the majority of the cultivars, the highest linalool percentages are obtained by harvesting at the end of flowering phase. The highest ratio of linalyl acetate was measured in most of the samples at the full bloom phase. The proportions of camphor and borneol showed significant but varying tendencies depending on both variety and year. The values of linalool, trans-β-ocimene, terpinene-4-ol, α-terpineol, and lavandulol percentages increased significantly during flower development, while the proportion of 1,8-cineole, and caryophyllene-oxide decreased in three cultivars. Altogether, the effect of phenophase on the essential oil composition was remarkable, especially in ‘Budakalászi’ (L. angustifolia), and ‘Grappenhall’ (L. × intermedia) cultivars, while ‘Munstead’ (L. angustifolia) exhibited the most stable essential oil pattern.