Sweet basil (Ocimum basilicum L.) productivity when growing in greenhouses using led lighting

The purpose of research is to study the effect of lighting only with LED panels with different spectral composition of light on the growth and development of green-leaf and red-leaf varieties of basil when grown in the winter-spring period (February-April). The study used two varieties of contrasting basil leaves, Green Basil Anise Flavor and Red Basil Opal. Plants were grown under 16/8-hour light/dark conditions in two modes: control - illumination only with white LEDs; option 1 - simultaneous illumination with white LED light and LED lamps with emission spectra in two maxima (blue spectral region (450 nm): red spectral region (660 nm) = 30 : 70 %). The lamps were placed at a height of 85 cm from the top edge of the cassette, the photon flux density was 180 µmol/m2s. In control and experimental plants, physiological and photosynthetic parameters were measured after 30 and 60 days of illumination. The shoot height, leaf weight, leaf area, chlorophyll content, carotenoids, the amount of flavonoids, phenolcarboxylic acids (chlorogenic and coffee acids) were determined. Illumination with red-blue light in combination with white LED light had a clear advantage in almost all growth and development parameters measured for both varieties of basil. Plants at both stages of accounting for the yield were taller, had a larger mass and larger leaves. Illumination with red-blue light together with white light allowed red-leaved basil plants to outperform control plants by about one and a half times in terms of yield, antioxidant properties and adaptive potential. In long-term basil cultivation, white LEDs initiated a more efficient photoprotective mechanism, especially in green leaf basil plants.