Trichomes morphology, structure and essential oils of Pelargonium graveolens L'Hér. (Geraniaceae)

The present paper undertakes the study of the essential oils (EO) composition and trichomes distribution, morphology and anatomy of the aerial organs of Pelargonium graveolens L'Hér. which is an aromatic and medicinal species originating from Sfax (Tunisia). In fact, three morphologically distinct types of trichomes which are non-glandular trichomes, capitates glandular trichomes and peltate ones were observed with scanning electron microscopy (SEM) and light microscopy (LM). Besides, the essential oils (EO) were extracted by hydrodistillation and their compositions were determined by Gas Chromatography-mass spectrometry analysis (GC-MS). While in flowers and leaves β-citronellol was the dominant component of their EOs with 24.21% and 19.2%, respectively, in stems the EO was mainly composed of δ-selinene (14.21%).