Photochemical response of parsley (Petroselinum crispum (Mill.) Fuss) grown under red light: The effect on the essential oil composition and yield

The effect of different wavelengths on plants morphological characters has been widely described, but also the chemical composition of the essential oil is influenced by the lighting conditions in which they are grown. In the present study, the effect of both the enrichment (reverse Emerson effect) and the monochromatic lighting treatments with red light has been evaluated on the essential oil compositions of parsley (Petroselinum crispum (Mill.) Fuss). Multivariate statistical analysis was performed on the results, with both the hierarchical cluster and principal component analyses. Whilst the red-enrichment of the light spectrum did not induce major changes in the essential oil composition, the end of the day monochromatic red (660 nm) treatment caused a chemotype switch in the essential oil and relevant differences in the overall composition, with an increment of the relative abundance of oxygenated compounds, coupled with a relevant decrement in the abundance of phenylpropanoids. The extraction yields remained unchanged in all the three tested conditions of light (control, red-enriched and monochromatic red). Different lighting conditions could be used as a tool to modulate the compounds present in the essential oil, but further studies would be advisable to assess the effects on different species and chemical classes of compounds