PREMISE OF THE STUDY:Fig trees (Moraceae) have remarkable enclosed infl orescences called fi gs or syconia. The fl owers are pollinated by host-specifi c fi g wasps that enter the fi g to lay their eggs. This nursery pollination system is one of the most studied of tropical mutualism interactions, but the source of the volatiles that attract fi g wasps to their specifi c host fi gs has not been confi rmed. The fragrance is the basis of host selection and, therefore, of reproductive isolation among sympatric Ficus species. This study locates and characterizes the glands likely to be responsible for pollinator attraction and also protection from herbivory in the fi gs of nine Ficus species representing all the major lineages within the genus. METHODS:Figs with receptive pistillate fl owers were examined using light and scanning electron microscopy. Tests for histolocalization of substances were employed to detect glandular activity throughout the fi gs. KEY RESULTS:A great diversity of glands is found throughout the fi g, and for the fi rst time, the sites producing fragrances are identifi ed. Scent glands are present on the ostiolar bracts and the outer layers of the fi g receptacle. Laticifers and phenolic-producing idioblasts, epidermis, and trichomes associated with fi g protection occur on the ostiolar bracts, the fi g receptacle, and fl oral tissues. CONCLUSIONS:The volatiles produced by glands on the ostiolar bracts are candidate sources for the long-distance attraction of pollinator fi g wasps. Scent glands on the outer layers of the receptacle may also play a role in chemical perception of the fi gs or may be related to their protection. The high cost to the plants if the fi gs are eaten and the temperature conditions required for nursery pollination are likely the factors that led to the selection of phenolic glands and laticifers during the group's evolution.

Scent glands, or osmophores, are predominantly floral secretory structures that secrete volatile substances during anthesis, and therefore act in interactions with pollinators. The Leguminosae family, despite being the third largest angiosperm family, with a wide geographical distribution and diversity of habits, morphology and pollinators, has been ignored with respect to these glands. Thus, we localised and characterised the sites of fragrance production and release in flowers of legumes, in which scent plays an important role in pollination, and also tested whether there are relationships between the structure of the scent gland and the pollinator habit: diurnal or nocturnal. Flowers in pre-anthesis and anthesis of 12 legume species were collected and analysed using immersion in neutral red, olfactory tests and anatomical studies (light and scanning electron microscopy). The main production site of floral scent is the perianth, especially the petals. The scent glands are distributed in a restricted way in Caesalpinia pulcherrima, Anadenanthera peregrina, Inga edulis and Parkia pendula, constituting mesophilic osmophores, and in a diffuse way in Bauhinia rufa, Hymenaea courbaril, Erythrostemon gilliesii, Poincianella pluviosa, Pterodon pubescens, Platycyamus regnellii, Mucuna urens and Tipuana tipu. The glands are comprised of cells of the epidermis and mesophyll that secrete mainly terpenes, nitrogen compounds and phenols. Relationships between the presence of osmophores and type of anthesis (diurnal and nocturnal) and the pollinator were not found. Our data on scent glands in Leguminosae are original and detail the type of diffuse release, which has been very poorly studied.

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