The anatomy and essential oil composition of the different organs of Pimpinella tragium and P. saxifraga (Apiaceae)

This work was aimed at investigating the anatomy and composition of the es-sential oils from different organs of two Pimpinella species, P. tragium and P. saxifraga, originating from the central part of the Balkan Peninsula. The results of the analysis of the anatomy of the different organs of P. tragium and P. saxi-fraga showed that they were very similar in terms of the structure of the roots, stems and petioles. The roots showed a secondary structure and the stems had a primary structure with closed collateral vascular bundles. The petioles were cordatum, ribbed with an adaxial groove, and sparsely covered with short uni-or bicellular non-glandular trichomes with a pointed top (both species) or with long uniseriate, multicellular, non-glandular trichomes (P. saxifraga). Differ-ences were observed in the anatomy of the leaves and in the indumentum of the fruits. The leaves of P. tragium were isobilateral, while those of P. saxifraga were dorsiventral. The P. tragium fruits were pubescent, covered with numerous, multicellular, uniseriate, straight or curved, gradually acuminate non -glandu-lar trichomes, whereas the fruits of P. saxifraga were glabrous. These differences are of ecological and taxonomic significance. Secretory canals were observed in all the investigated organs of both species. The essential oils, isolated by hydrodistillation from the aerial parts with inflorescences, the roots from the flowering and fruiting period, and the fruits of both species, were analysed by GC-FID/MS. Although P. tragium and P. saxifraga essential oils showed certain differences in qualitative and quantitative patterns, all the oils were character-ised by the presence of pseudoisoeugenol type phenylpropanoid epoxy-pseu-doisoeugenyl-2-methylbutyrate, as well as by that of trinorsesquiterpenes pre-geijerene, geijerene and trinoranastreptene. In addition, azulenes were present in all the root essential oils, whereas in the majority of the oils from the fruits and flowering aerial parts the common compound was the sesquiterpene beta-bis-abolene. The occurrence of phenylpropanoids of pseudoisoeugenol type and geijerenes is important from the chemotaxonomic point of view and confirms them as chemical markers of the Pimpinella species analysed so far.

Automated summary

This study aimed to investigate the anatomy and composition of essential oils from different organs of two Pimpinella species from the central Balkan Peninsula. The results showed similarities in root, stem, and petiole structures, but differences in leaf anatomy and fruit indumentum, with presence of specific chemical compounds in the oils from both species. The occurrence of phenylpropanoids and trinorsesquiterpenes in the oils confirms them as chemical markers for the Pimpinella species analyzed.