REGENERATION OF PLANTS AND PRODUCTION OF VOLATILES FROM CALLUS-CULTURES OF MELISSA-OFFICINALIS L .3. EFFECT OF EXOGENOUS GROWTH-REGULATORS ON ESSENTIAL OIL COMPOSITION

Regenerates of lemon balm (Melissa officinalis L., Lamiaceae) have bee n established to serve as in-vitro-system to study the effects of sele cted exogenous growth regulators. In this communication we report the efficiency of NAA, BAP, and ABA on morphology and essential oil compos ition. Long term cultivation only leads to changes of minor compounds in relation to total essential oil. Citronellal, citronellol, nerol, a nd geraniol are elevated whereas geranyl acetate is depressed. The ess ential oil of plants growing under the influence of NAA exhibit compar able changes of citronellal, citronellol, and geranyl acetate. Therefo re it refers to plants belonging to an advanced stage of development. Nutrition media supplemented with high concentration of BAP induce pla nts to accumulate more than 10% alloaromadendren. This sesquiterpenehy drocarbon is only a trace compound in control plants and has not been described before for the essential leaf oil of naturally grown Melissa officinalis. Beside a small effect of ABA to the production of some m inor compounds it shows a synergistic effect in combination with BAP. In this case only the BAP-specific changes are expressed at a BAP-conc entration that leads to negligible changes in single application. We c ould demonstrate the induction of an unusual alloaromadendren-type of essential oil obtained from lemon balm.