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| Author(s): |
Cristina Ribeiro Marinho
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2013-06-24 |
| Examining board members: |
Simone de Pádua Teixeira;
Marília Contin Ventrella;
Élder Antônio Sousa e Paiva;
Leandro Freitas;
André Olmos Simões
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| Advisor: | Simone de Pádua Teixeira |
| Abstract | |
Although the Leguminosae family is rich in species showing wide geographic distribution and a large morphological variation, their representatives have been poorly studied in terms of floral secretory structures. Such structures can be located in different parts of the flower and are associated with attraction of pollinators and/ or defense. Flowers pollinated by animals emit scents that are produced and released by means of scent glands or osmophores, structures that show a great morphological variety. Anatomical studies of these glands are important because besides providing information for the understanding of ecological interactions of plants and their pollinators, they can provide data to assist in the determination of phylogenetic relationships among species. This study aimed (1) to identify the secretory structures present in the flowers of Leguminosae species with nocturnal pollination, (2) to reveal floral anatomical features shared by these species, (3) to determine whether relationships exist between the diurnal and nocturnal pollination and the morphology of osmophores in Leguminosae (4) and to investigate if trichomes can function as osmophores. Flower buds and flowers of 14 zoophilic species of Leguminosae were fixed and processed for analysis in light, scanning electron and transmission electron microscopy. Analysis in CG and HPLC were performed in leaf and floral trichomes in Bauhinia. Flowers pollinated at night have several characteristics consistent with this type of pollination, as anthesis with duration of one night, inconspicuous coloration and strong odor. The aestivation or fusion of the perianth and the presence of cup-shaped hypanthium allows the nectar accumulation in these flowers. The large amount of nectar produced in the chiropterophilous species is related to the robust structure of their nectaries. In the perianth, especially in petals, occur structures responsible for producing the scent in the Leguminosae species with zoophilic pollination. The presence of non-specialized secretory regions in the epidermis and mesophyll of sepals and/ or petals confirms the diffuse release of scent in most species. Typical osmophores, i.e., scent glands with anatomical structure specialized in the emission of fragrances, restricted to certain regions of the flower, were observed in four of the 12 species studied. The studied osmophores always exhibited some type of cell or tissue secreting terpene; but phenolic compounds and proteins were also detected. Other types of secretory structures often associated with defense mechanisms, such as secretory trichomes, idioblasts and cavities were found. Among these are the cavitated trichomes in Bauhinia, which secrete the same classes of compounds in the leaves and flowers and thus have no role in the pollinator attraction but in the plant defense. It is concluded that there is no relationship between the type of osmophore (typical or diffuse) and the habit of pollinator (diurnal or nocturnal). The floral secretory structures found (except nectaries), have biological and/ or taxonomic significance, but they cannot be associated with a particular syndrome. However, the anatomy of nectaries showed correlations among their size, the amount of nectar produced and the type of pollinator demonstrating their great importance in the flower-pollinator relationship (AU) | |
| FAPESP's process: | 09/01057-0 - Floral anatomy of species of Leguminosae with nocturnal pollination emphasizing the osmophores. |
| Grantee: | Cristina Ribeiro Marinho |
| Support Opportunities: | Scholarships in Brazil - Doctorate |