Substantial UV-B-mediated induction of essential oils in sweet basil (Ocimum basilicum L.)

The effect of supplementary UV-B treatment on the essential oils of glassho use-grown sweet basil (Ocimum basilicum L.) was examined. Two weeks treatme nt with supplementary W-B given in the early morning was found to enhance t he levels of most of the major volatiles, both phenyl-propanoids (eugenol, methyl eugenol) and terpenoids, notably linalool, 1,8-cineole and trans-bet a-ocimene. The phenyl-propanoids were sensitive to UV-B at an earlier devel opmental stage than the terpenoids. Overall, the effect of UV-B was a nearl y fourfold stimulation in the oldest plants examined. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.