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|Type:||Artigo de periódico|
|Title:||THE PERFUME FLOWERS OF CYPHOMANDRA (SOLANACEAE) - POLLINATION BY EUGLOSSINE BEES, BELLOWS MECHANISM, OSMOPHORES, AND VOLATILES|
|Abstract:||The perfume syndrome and pollination by fragrance-collecting euglossine bees in the neotropic solanaceous genus Cyphomandra was confirmed by field observations. In SE Brazil, C. sciadostylis was visited by Eufriesea violacea, and C. diploconos by Euglossa mandibularis; C. hartwegii was pollinated by Eulaema meriana in Costa Rica. The primary attractant, fragrant droplets that ooze from the dorsally bulged connectives, is mopped up by the males with the forebasitarsi. Thereby, the poricidal thecae are inadvertently pushed causing the dry pollen to dust the bee's sternum. The number and direction of the pollen jets are related to pollinator size and stigma structure. The flowers are homogamous, self-sterile, and last three days. The androecium is optically non-contrasting or has cryptic colour. Flowers of C. sciadostylis and C. diploconos undergo a colour change and an almost three-fold increase in corolla size when scent production and visits cease. The dorsal papillar epidermis of the connective is underlain by a glandular parenchyma typical of osmophores. GC techniques revealed germacrene D as the main component in the mentholic scent of C. sciadostylis, ipsdienol, heneicosane, and tricosane as dominant in the nutmeg-like scent of C. diploconos, and benzyl acetate and benzyl alcohol in the sweet fragrance of C. hartwegii. In all cases, these were accompanied by numerous minor components of heterogeneous chemical nature. - Pollen release by means of a peculiar pneumatic bellows mechanism appears as a necessary and probably ubiquitous feature of Cyphomandra. Even a slight pressure exerted upon the thin, elastic thecal walls blows pollen jets through the pores. Unusual anatomic changes accompany anther maturation. Initially voluminous parenchymatic locular intumescences (placentoids) contract completely during meiosis, then expand once more when the pollen is ripe, pushing the grains against the locular wall, and contract a second time, allowing air to enter the thecae. - Cyphomandra pinetorum was found to be exceptional in exhibiting a pollen flower syndrome, and not cryptical but optically contrasting yellow anthers, as known for Solanum.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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