Effect of Light Quality on the Biomass Yield, Photosystem 2 Fluorescence, and the Total Essential Oil Content of Ocimum basilicum

The effect of artificial light with different spectral compositions (white, WW; white–red, WR; white–blue, WB; and white–red—blue, WRB) on the wet weight, plant height, total leaf surface area, variable fluorescence parameters of photosystem 2 (PS2), and the content of the total fraction of essential oils in 30‑ and 50-day-old Cinnamon Aroma basil plants was studied. Thirty-day-old basil plants adapted to WB light were characterized by the highest chlorophyll content and the highest value of the photochemical quenching coefficient of PS2 fluorescence but by the smallest wet weight and total leaf surface as compared to plants grown in light with a different spectral composition. A longer adaptation (50 days) of the basil to illumination of a different spectral composition at the same intensity led to plant alignment in terms of chlorophyll content and height. A positive correlation was found between changes in the photochemical quenching coefficient of PS2 fluorescence and wet weight in 50-day-old plants. Fifty-day-old plants grown in light with a high proportion of red radiation (WR and WRB) and having generative shoots with buds contained the largest amount of the total fraction of essential oils.