Are stem nectaries common in Gentianaceae Juss.?

Valdnéa Casagrande Dalvi, Renata Maria Strozi Alves Meira, Aristéa Alves Azevedo
2017 Acta Botânica Brasílica  
Extrafl oral nectaries (EFNs) are specialized structures that produce and release nectar and are located on leaves, cotyledons and, more seldomly, stems. Peculiar leaf nectaries have been described for thirty-three Neotropical species of Gentianaceae, while stem nectaries have been reported for only nine. Th e aim of this study was to verify the occurrence of stem EFNs within Gentianaceae and investigate the existence of a correlation between their occurrence and the geographical distribution
more » ... ical distribution of species. Samples of internodal regions from fi eld and herbarium specimens were submitted to standard light microscopy techniques. Data regarding the geographical distribution of species were acquired from herbarium specimens and the literature. A total of 37 species were investigated, representing 25 genera distributed among fi ve tribes. Nectaries, composed of modifi ed epidermal cells, were observed in 16 species restricted to the Neotropical tribes Helieae, Saccifolieae, Potalieae and Coutoubeinae; exceptions were Cicendia quadrangularis and Zygostigma australe, which both occur in the Neotropics but do not possess EFNs. Th ese results demonstrate that stem EFNs are common among Neotropical taxa of Gentianaceae, and are typically absent from taxa in temperate regions.
doi:10.1590/0102-33062016abb0404 fatcat:cozuxnrdpvf4xjlfx33eqtft2m