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 observa-tions 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 ace-tate 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 educa-tional missions in an Open Science context.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

This study combined micromorphological and phytochemical approaches to investigate Lavandula angustifolia Mill. cultivated at Ghirardi Botanic Garden in Italy. The study identified three morphotypes of trichomes on the leaves and flowers: peltate, short-stalked capitate, and medium-stalked capitate. Histochemical dyes revealed that peltate and medium-stalked capitate trichomes produced abundant terpenes, while short-stalked capitate trichomes secreted hydrophilic substances. The phytochemical analysis focused on the volatile organic compounds (VOCs) emitted by leaves and flowers, as well as the composition of the essential oil (EO) from the flowering aerial parts. The findings provide valuable information for the ecology, biological activity, and sensory qualities of VOCs and EO in Lavandula angustifolia.