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A comparative anatomical and morphological study on the petioles and leaves of 10 neotropical Rondeletia species (representing 10 sections) has been made in order to investigate interspecific variations which may be useful in species identification. All species have bifacial and hypostomatic leaves, contain tannins and crystal sand. The central vascular bundle in the petiole and the midrib are open to the upper side and are collateral. The species differ in presence or absence of non-glandular trichomes, in the structure of the petiole and leaf blade. A combination of these characters may be useful in species identification. The results, however, do not support the classification into 10 sections but provide a comprehensive petiole and leaf anatomical and morphological character-set typical for the genus. [ABSTRACT FROM AUTHOR]

The family Solanaceae includes several melliferous plants, which tend to produce copious amounts of nectar. Floral nectar is a chemically complex aqueous solution, dominated by sugars, but minor components such as amino acids, proteins, flavonoids and alkaloids are present as well. This study aimed at analysing the protein and alkaloid profile of the nectar in seven solanaceous species. Proteins were examined with SDS-PAGE and alkaloids were analyzed with HPLC. The investigation of protein profile revealed significant differences in nectar-protein patterns not only between different plant genera, but also between the three Nicotiana species investigated. SDS-PAGE suggested the presence of several Nectarin proteins with antimicrobial activity in Nicotiana species. The nectar of all tobacco species contained the alkaloid nicotine, N. tabacum having the highest nicotine content. The nectar of Brugmansia suaveolens, Datura stramonium, Hyoscyamus niger and Lycium barbarum contained scopolamine, the highest content of which was measured in B. suaveolens. The alkaloid concentrations in the nectars of most solanaceous species investigated can cause deterrence in honeybees, and the nectar of N. rustica and N. tabacum can be considered toxic for honeybees.