Micropropagação e análise de compostos terpênicos voláteis em Stachytarpheta odorata P.H.Cardoso & Salimena (Verbenaceae)

Abstract

Verbenaceae occur in a great diversity of terrestrial ecosystems, not only being found in the Antarctic zone. Currently, this family has around 800 members, and this number increases as new species are discovered, as is the case of the recently described Stachytarpheta odorata P.H.Cardoso & Salimena. Although the literature presents many studies on in vitro cultivation of Verbenaceae, there are only two studies with the genus Stachytarpheta. Taking into account that the only known population of S. odorata is established ex situ at the experimental station of the Federal University of Juiz de Fora, where few individuals are cultivated, the creation of a micropropagation protocol for the species, as well as the analysis of Its chemical compounds are of great relevance for conservation and potential uses. Therefore, the objective of the present study was to establish and multiply in vitro cultures of S. odorata, evaluating the effect of different concentrations of growth regulators on multiplication and rooting, ending with the acclimatization of the plants in ex vitro conditions. Furthermore, an analysis of the main volatile terpene compounds was carried out in order to identify the components that give the species a certain odor, an unusual condition for plants of the Stachytarpheta genus. For the in vitro multiplication phase, the medium supplemented with 3 μM BAP and free of ANA proved to be the most prolific, as it provided the greatest number of nodal segments in response to treatments. For rooting, the medium with 0.1 μM NAA was the most suitable, presenting microccutings with a greater number of roots and without the undesirable formation of callus. Survival of plantlets in the ex vitro acclimatization process was approximately 80%. The results obtained contribute to the propagation and demonstrate the advantages and potential of the suggested protocol for the conservation of the species which, despite being recently described, is already in a critical state of conservation. The analysis of volatile terpenoids revealed the presence of Thymol as the majority component, a substance with antibacterial action widely used by the pharmaceutical industry.