Chemical composition of essential oils of peltate glandular trichomes from leaves and flowers of Lepechinia floribunda (Lamiaceae)

Abstract

The knowledge of the chemical composition of different plant organs provides valuable information for clarifying the functionality of secondary metabolites. Essential oils are secondary metabolites produced and stored in secretory structures on leaves, flowers, and steam. Many studies have shown that the chemical composition of the essential oil can differ depending on the plant organ and the secretory structures even if they are at the same organ. Such differences may be the consequence that organs also differ in type and density of glandular structure. Moreover, the same type of glandular structure can change its chemical composition depending on its position within the same organ. However, no study has been evaluating the chemical composition of the essential oil from the same glandular structure in leaves and fertile floral whorls. The aim of this work was to characterize the chemical composition of essential oils of peltate glandular trichomes from anthers and leaves of Lepechinia floribunda. We found a lower richness of chemical compounds and higher relative abundance of monoterpene hydrocarbons on anthers than leaves. Leaves showed an increased relative abundance of oxygenated sesquiterpenes. Such differences probably respond to a high tissue-specificity expression of genes in different plant organs.