In vitro and in vivo copper-treated Myrtus communis L.: terpene profiles and evidence for potential cultivation on metal-contaminated soils

The intensive application of agro-chemicals, and in particular of copper (Cu)-based compounds, causes increasing pollution of agricultural land, with serious risks for human health. Aromatic plants used for purposes other than food, can be considered for the exploitation and/or remediation of metal-polluted substrates, since contamination of the essential oils by these metals was not significant. Myrtle ( Myrtus communis L.) is a Mediterranean evergreen shrub whose essential oil has many commercial applications. In this work, the effect of an excess of Cu in respect to control conditions was assessed on M. communis growth and foliar terpene composition. Metal accumulation in roots and shoots was also evaluated for the possible use of this species in phytoremediation. The amount of Cu applied in our experiments minimally affected the terpene profiles of in vitro grown plants, whereas no variations were detected in in vivo plants. The presence of the metal in the soil did not significantly impair plant growth, thus allowing its cultivation on polluted substrates. On the other hand, the amount of Cu in the plant was not enough to result in a significant reduction of Cu levels in the soil. Therefore, myrtle plants proved to be good candidates for the re-vegetation of Cu-contaminated lands.