EFFECT OF PAR AND UV-B RADIATION ON THE QUALITY AND QUANTITY OF THE ESSENTIAL OIL IN SWEET BASIL (OCIMUM BASILICUM L.)

Sweet basil seedlings (Ocimum basilicum L. cv. bageco) were cultivated in a greenhouse compartment under natural light until the two primary leaves were fully expanded.
Subsequently, some of the seedlings were exposed to 15 mol m^-2 d ¹ photosynthetically active radiation (PAR, 400-700 nm), whereas half of them were additionally treated with 2 kJ m^-2 d^-1 of biologically effective UV-B light (280 320 nm). The control plants remained untreated.
The experiment was conducted over 18 days until the plants had six developed leaves and a plant height of 12-15 cm.
The essential oil was distillated from frozen leaves with SDE (simultaneous steam distillation and solvent extraction) for two hours.
Qualitative and quantitative analyses were conducted with GC-MS. The total amount of essential oil significantly increased with increase of the radiant energy, particularly detected in the case of the most important flavor compounds 1,8 cineole, linalool, and eugenol.
Moreover, the level of the main compound methyleugenol significantly decreased with UV-B radiation.
This result is of special importance because this compound is of toxicological concern to human health due to the structural similarity to known carcinogenic phenylpropans such as estragole

VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition

G.M. Nitz, W.H. Schnitzler

sweet basil, Ocimum basilicum L., methyleugenol, eugenol, UV-B

https://doi.org/10.17660/ActaHortic.2004.659.50