Paper Reviewed
Batista, D.S., de Castro, K.M., Koehler, A.D., Porto, B.N., da Silva, A.R., de Souza, V.C., Teixeira, M.L., das Gracas Cardoso, M., de Oliveira Santos, M., Viccini, L.F and Otoni, W.C. 2017. Elevated CO2 improves growth, modifies anatomy, and modulates essential oil qualitative production and gene expression in Lippia alba (Verbenaceae). Plant Cell, Tissue and Organ Culture 128: 357-368.

Writing as background for their work, Batista et al. (2017) state that "many natural compounds present in plants show biological activity and act as antimicrobial agents," among which, they say, are essential oils that "are used in [plant] pest control and are involved with the development of technologies to reduce the negative effects of oxidants, radicals and migroorganisms." One plant in particular that produces such important oils is Lippia alba, whose extracts, according to Batista et al., have "antiulcerogenic, antimicrobial, anti-inflammatory, anti-helminth, antioxidant, cytostatic and gastroprotective properties."

Against this backdrop, the team of eleven Brazilian researchers set out to examine the impact of elevated CO2 on "in vitro morphogenesis, anatomy and qualitative production of essential oils as well as its effect on expression of genes related to the synthesis of essential oil in three chemotypes." To accomplish their objective, they cultivated in vitro plantlets of Lippia alba in a controlled environment facility under 360 or 1000 ppm CO2 for a period of 45 days, after which they performed "oil extraction and profile analyses, histochemical analysis, stomatal density, growth evaluation and expression analysis." So what did they learn?

Batista et al. say their results "highlight that enrichment with CO2 enhances in vitro performance of Lippia alba, by increasing growth characteristics, photosynthetic pigments, stomatal density and lignin content." What is more, they report that CO2 enrichment was effective in significantly altering the profile of essential oils in two of the three chemotpyes analyzed, leading to improvement in oil production. Consequently, the authors conclude that their findings will help to further enable "the targeted production of essential oils [under CO2 enrichment] with greater economic and industrial interest.