1.2.1.64 down hairy roots cultures of Daucus carota turn green under continuous illumination, while the content of the major phenolic compound 4-hydroxybenzoic acid is reduced to half as compared to normal hairy roots cultured in darkness. 4-Hydroxybenzaldehyde dehydrogenase (HBD) activity is suppressed in the green hairy roots 743556 1.2.1.64 up hairy root cultures of Daucus carota respond to methyl jasmonate treatment with enhanced accumulation of 4-hydroxybenzoic acid 723889