Micropropagação e caracterização preliminar de compostos orgânicos voláteis de Lippia martiana Schauer (Verbenaceae) da Serra do Cipó, MG, Brasil

Abstract

Lippia martiana Schauer is an endemic species of Brazil, belonging to the Verbenaceae family, with high aromatic and medicinal potential. Additionally, it occurs in restricted natural populations distributed among rocky outcrops in the campos rupestres of the Serra do Cipó. In this context, the present study aimed to evaluate the response of Lippia martiana cultures to different concentrations of plant growth regulators under in vitro conditions, as well as to preliminarily characterize the profile of volatile organic compounds (VOCs) produced under controlled conditions. For this purpose, in vitro establishment was performed using disinfected seeds germinated in MS medium, followed by in vitro multiplication and rooting experiments using increasing concentrations of benzylaminopurine (BAP), naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA). The evaluated variables included number of shoots, number of internodes, plant height, root formation, root length, and callogenesis. Data were subjected to analysis of variance (ANOVA), and means were compared using the Scott–Knott test at a 5% significance level. The results indicated that in vitro multiplication was enhanced by combinations of BAP and NAA, particularly at 1.0 mg L⁻¹ BAP associated with 0.01 and 0.1 mg L⁻¹ NAA, whereas higher BAP concentrations promoted increased callus formation and reduced rhizogenesis. During rooting, IAA and IBA were more effective in root induction and elongation, while NAA showed a less pronounced effect. Preliminary characterization of volatile organic compounds revealed the predominance of carvacrol (83.43%), thymol methyl ether (7.1%), terpinen-4-ol (2.5%), and α-caryophyllene (2.0%) in in vitro-grown L. martiana. The results demonstrate the potential of in vitro micropropagation as a strategy for the multiplication and conservation of L. martiana, as well as providing a basis for future studies on the production of secondary metabolites under controlled conditions.