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Leaf and stem anatomy and essential oil composition of four Brazilian Aldama species (Asteraceae) and their taxonomic significance
- Filartiga, Arinawa Liz, Bombo, Aline Bertolosi, Garcia, Vera Lúcia, Appezzato-da-Glória, Beatriz
- Revista brasileira de botânica 2017 v.40 no.2 pp. 503-516
- Asteraceae, cell walls, essential oils, flame ionization, germacrene, histology, hydrodistillation, leaves, phloem, phylogeny, spectrometers, stems
- Aldama La Llave is one of several Asteraceae genera that pose phylogenetic problems. The close similarity between species, as well as the inconsistencies found in the most recent phylogenetic analysis, shows that new data are needed to help delimit group species. Aldama anchusifolia (DC) E.E.Schill. & Panero, Aldama megapotamica (Malme) Magenta & Pirani, Aldama nudibasilaris (S.F.Blake) E.E.Schill. & Panero and Aldama pilosa (Baker) E.E.Schill. & Panero are difficult to identify because they are very closely related. Therefore, the aim of this study was to detect anatomical and phytochemical characteristics to help elucidate phylogenetic issues raised by Aldama. Aerial vegetative organs were prepared using the standard histological techniques. Essential oils were obtained by hydrodistillation, and their components identified using a gas chromatograph coupled to a mass spectrometer and flame ionization detector. Each species presented a set of unique leaf and stem anatomical features. The front view of the epidermal cell walls in the leaves, the presence of secretory ducts in the phloem and medulla sclerification in the stems proved useful in delimiting these species. The essential oils were characterized by the predominance of sesquiterpenes such as t-caryophyllene, germacrene D and bicyclogermacrene. Some unique constituents in each species were also identified as potential chemical markers.