Foram investigados os efeitos de ácido indol acético (11,42 μmol L -1 ) e benzilaminopurina (8,87 μmol L -1 ) sobre o crescimento e composição do óleo essencial de plantas in vitro de Melissa officinalis. Plantas desenvolvidas em meio de Murashige e Skoog (MS) apresentaram o incremento de 1,4 vezes na proporção de nerol e de 4,1vezes de geraniol, quando comparadas às plantas ex vitro. Tratamentos com 11,42 μmol L -1 de ácido indol acético mais 8,87 μmol L -1 de benzilaminopurina resultaram em aumentos de 1,7 e 2,2 vezes na proporção de nerol e geraniol, respectivamente, em plantas de 60 dias. Estes aumentos podem estar associados à ação dos reguladores de crescimento, por estimularem o desenvolvimento vegetal (na organogênese e alongamento de brotos) e retardarem a oxidação de álcoois em aldeídos.It was investigated the effects of indole-3-acetic acid (11.42 μmol L -1 ), benzylaminopurine (8.87 μmol L -1 ) on essential oil composition and on the growth of Melissa officinalis in vitro plants. In vitro plantlets developed on MS media, showed 1.4 times in the proportion of nerol and 4.1 of geraniol, when compared with ex vitro plants. Treatments with 11.42 μmol L -1 indole-3-acetic acid plus 8.87 μmol L -1 benzylaminopurine led to 1.7 and 2.2 fold in proportion of nerol and geraniol, respectively in 60-day-old whole plants. These increases might be associated with the action of growth regulators wich stimulate plant growth (shoot organogenesis and elongation) and delaying the alcohol oxidation to aldehydes.
Keywords: Melissa officinalis, essential oil composition, VOCs, GC/MS, growth regulators, tissue culture
IntroductionMelissa officinalis Lam. (Lamiaceae) also known as lemon balm, is a perennial herb that presents a lemon flavor. The infusion of its leaves is used in folk medicine due to its sedative and antispasmodic properties. The chemical composition of the essential oil of the M. officinalis leaf (0.02-0.3% dry weight) has been previously studied, being the major compounds citronellal (2-40%) and citral (mixture of neral and geranial: 10-30%), followed by β-caryophyllene, germacrene D, ocimene and citronellol. 1 The growth of sprouts and roots and the composition of the essential leaf oil can be altered by addition of selected phytohormones into the nutrition medium. 2 Culture media supplemented with high concentrations of BA induced Melissa officinalis plants to accumulate more than 10% alloaromadendrene. 3 In order to identify possible factors affecting the oil production and its quality, M. officinalis was cultured in vitro and the effect of growth regulators on the essential oil yield and composition were evaluated by gas chromatography and gas chromatography/mass spectrometry.
Experimental
Plant materialSeeds acquired from ISLAR, batch Nº 8250 were used to obtain the plant material. Erika Von Sohsten Medeiros
Treatment with growth regulatorsNodal segments of in vitro plantlets were cultured in four different media composition: MS0; MS plus 11.42 μmol L -1 Indole-3-acetic acid (IAA); MS plus 8.87 μmol ...