Influence of the Ratio of Red and Green Light in the Lighting Spectrum on Growth Indicators and the Component Composition of Parsley (Petroselinum Crispum (Mill.) Fuss) Essential Oil

Regulation of spectral composition of light makes it possible to influence not only plant morphology, but also the amount and composition of secondary metabolites in aromatic plants. We tested 3 types of light-emitting diode (LED) irradiators with the following spectrum (blue: green: red: far red): B15:G35:R40:FR10, B15:G50:R30:FR5 and B15:G25:R50:FR10 when growing parsley. The highest fresh mass (by 32%) and leaf surface area were obtained in the variants with higher proportion of G in the spectrum (G35 and G50), and also differed by a high content of total chlorophyll. Increasing the proportion of G to 50% reduced the content of nitrates by 47%, but negatively affected the accumulation of essential oils (by 41%). The content of Apiol decreased and 1,3,8-p-Menthatriene which is responsible for parsley aroma, increased. The variant G25 is characterized by an increase in the composition of phenylpropanoids by 4%, and decrease in monoterpenes. It has been established that by adjusting the ratio of R and G light in the irradiation spectrum, it is possible to influence the component composition of parsley essential oil. The best option for oil accumulation and plant growth was 10B:15:G35:R40:FR10, which is similar in proportion to the sunlight spectrum.