ABSTRACT Most species of Anacardiaceae have drupes containing secretory structures.. The substances produced by these structures may have importance to industry and folk medicine, and may even cause allergenic effects. This work describes the ontogeny of pericarp of Tapirira guianensis with an emphasis on the secretory structures present at different stages of development. Ovary and fruits in various stages of development were collected, fixed and processed for studies using light and scanning electron microscopy according to conventional techniques. Histochemical tests were employed to identify the major metabolites present in the tissues. The fruit is a drupe formed by exocarp, mesocarp containing secretory ducts and idioblasts, and endocarp with some lignified layers. Fruit growth occurs through the division and elongation of cells. The secretory ducts produce mainly phenols and lipids and are active during all stages of development. The secreted substances protect the fruit against pathogens and predators. In ripe fruits the cells of the mesocarp accumulate starch. This study is the first report of the presence of a secretory endocarp in young fruits of a species of Anacardiaceae. The substances produced by the endocarp in early developmental stages may play an important role in seed dispersal and germination.

Supostas domácias foliares de Anacardium humile (Anacardiaceae) são na realidade nectários extraflorais - Anacardium humile , uma espécie do cerrado brasileiro, está associada a formigas forrageadoras, o que leva à descrição da estrutura presente em suas folhas como domácias. No entanto, as formigas coletam a secreção das folhas, um fenômeno que inspirou este estudo, que visa justamente elucidar esta estrutura. Por esta razão, foi realizada uma análise da distribuição, micromorfologia, anatomia e histoquímica das supostas domácias. Elas estão localizadas nas axilas das nervuras foliares de maior calibre e são compostas por tricomas glandulares. Os tricomas exsudam glicose, portanto, são descritos aqui como nectários extraflorais (NEFs). Os tricomas nectaríferos estão localizados no mesmo nível que as células da epiderme em folhas jovens, enquanto, nas folhas maduras, foram encontradas nas depressões da lâmina foliar. A atividade secretora nos NEFs é limitada a fases juvenis, degenerando em folhas maduras. Carboidratos e substâncias lipofílicas foram detectados na secreção produzida. Pode-se concluir que a presença de formigas forrageando folhas para coleta nos NEFs indica uma interação mutualística, com a planta fornecendo recursos para as formigas em troca de proteção contra herbivoria, uma vez que as mesmas estão presentes em folhas ainda em desenvolvimento.

Presumed domatia are actually extrafloral nectaries on leaves ofAnacardium humile (Anacardiaceae), a species from the Brazilian savannah, is associated with foraging ants, which leads to the description of the structure of its leaves as domatia. However, the ants collect secretions on the leaves, a phenomenon that inspired us to elucidate this structure. To this end, we conducted an analysis of the distribution, micromorphology, anatomy and histochemistry of these supposed domatia. They are located in the axil of thicker leaf veins and are composed of glandular trichomes which exude glucose; they are, therefore, described here as extrafloral nectaries (EFNs). The nectariferous trichomes are located at the same level as the other epidermal cells on young leaves, while in mature leaves they were found in depressions of the leaf blade. The secretory activity of EFNs is limited to juvenile phases, becoming degenerated in mature leaves. Carbohydrates and lipophilic compounds were detected in the produced secretion. It can be concluded that the presence of ants foraging leaves to collect from EFNs indicates a mutualistic interaction, with the plant providing a sugar resource to the ants in return for protection against herbivory since they are present in developing leaves.