Influence of plant growth regulators on the growth and essential oil content of cultured Lavandula dentata plantlets

Micropropagation of L. dentata L. through shoot-tips (ca. 5 mm) was achieve d successfully. Micropropagated plantlets were cultured without plant regul ators in the culture medium (control) or in media containing 0.1 mg l(-1) o f 6-benzyladenine (BA) and/or indole-3-butyric acid (IBA). These plantlets were examined for their essential oil content and composition in relation t o growth rate and density and secretory or postsecretory stage of glandular hairs at five weeks of culture. The growth rates of these plantlets were n ot always correlated with their essential oil content (0.26%-0.65% v/w). Ho wever, all cultured plantlets showed a positive correlation between oil acc umulation and the percentage of glandular hairs in secretory stage. Quantit ative changes in the major monoterpene components (1,8-cineole, fenchol, bo rneol and camphor) and sesquiterpene content of plantlet oil, were also obs erved in response to the effect of varying growth regulator concentration i n the culture medium. The influence of this effect on HMG-CoA reductase act ivity of cultured plantlets is also discussed.