REGENERATION OF PLANTS AND PRODUCTION OF VOLATILES FROM CALLUS-CULTURES OF MELISSA-OFFICINALIS L .1. EFFECT OF EXOGENOUS GROWTH-REGULATORS ON ORGANOGENESIS OF TISSUE-CULTURES AND CHARACTERIZATION OF THE ESSENTIAL OIL FROM PLANT REGENERATES

Investigation was undertaken to achieve rapid multiplication and impro vement of Melissa officinalis L. by plant regeneration from callus. Th e explants from leaves and stems excised from intact plants and root s egments from aseptic seedlings were cultured on Murashige and Skoog (1 962) and Abou-Mandour (1977a) media supplemented with KIN, BAP, IBA, I AA, NAA, and 2,4-D individually and in various combinations (at concen trations of 0,3-10 mg.l-1). Best callus induction was noted on MS medi um with 2 mg.l-1 or 1 mg.l-1 IBA. Although leaf and stem explants prov ed to be the best source for compact and nodulated callus, only the ca llus from root segments showed differentiation. Root cultures obtained from root callus with NES treatment were regenerated into intact plan ts with IBS supplemented MS-medium. For Melissa officinalis, no regene ration has been reported in the literature. Under in vitro conditions regenerates are producing an essential oil similar to very young Melis sa plants. This oil consisted of only small amounts of sesquiterpenes (2.6% of total amount) and citronellal (less than 1%). The oil content of the leaves is 0.1% (g/g dry weight), which is within the range of naturally occurring variability.