Insight into micromorphology and phytochemistry of Lavandula angustifolia Mill. from Italy

This work combined a micromorphological and phytochemical study approach on Lavandula angustifolia Mill. cultivated at the Ghirardi Botanic Garden (Toscolano Maderno, BS, Italy). The micromorphological observations on leaves and flowers revealed the occurrence of three trichome morphotypes: peltate, short- and medium-stalked capitate. The histochemical dyes evidenced a huge production of terpenes by peltate and medium-stalked capitates, while short-stalked capitates were responsible for hydrophilic secretions. The phytochemical survey concerned the characterization of volatile organic compounds (VOCs) emitted by leaves and flowers, along with the analysis of the composition of the essential oil (OE) from flowering aerial parts. Oxygenated monoterpenes dominated both the leaf and flower profiles (65.66% vs 45.97%). The main compounds emitted by leaves were 1,8-cineole, p-cymene and borneol; linalool acetate, b-caryophyllene and linalool by flowers. 1,8-Cineole was also the dominant exclusive compound in leaves, while linalool acetate in flowers. The EO was characterized by linalool, linalool acetate, 4-terpineol, lavandulol acetate, and b-caryophyllene. Finally, evaluations about the VOC ecology, the EO biological activity and sensory qualities were proposed based on literature. This set of information was made available to the visitors of the Ghirardi Botanic Garden through the realization of a dedicated labelling, coupling the scientific research to the educational missions in an Open Science context.