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Evolution of floral traits related to pollinator attraction in Vanilla (Orchidaceae)

Grant number: 18/07357-5
Support type:Regular Research Grants
Duration: April 01, 2019 - March 31, 2021
Field of knowledge:Biological Sciences - Ecology
Principal Investigator:Emerson Ricardo Pansarin
Grantee:Emerson Ricardo Pansarin
Home Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The pollination systems displayed by orchid flowers have inspired biologists over the centuries. However, despite the economic importance of the genus Vanilla, little attention has been given to the pollination mechanisms and attraction of pollinators in these plants. However, previous studies reveal the most pollination strategies seem to be related to the attraction of male euglossine bees. The understanding of the pollination processes in Vanilla is important, since the fruit production in this genus is based exclusively on hand pollinations. The data on anatomy, histochemical of floral glands and analyses of floral fragrances are scarce when compared to the diversity of this orchid genus. Furthermore, the floral characters and the fragrance compounds have not, to date, been analyzed in an evolutionary context. The project aims to test the hypothesis of convergent evolution in Vanilla, since the pollination by euglossine bees has been recorded in at least two clades within this genus. Furthermore, the project aims to test the hypothesis of variation in the reward production, compotion of floral fragrances and pattern of floral reflectance, since others pollinator groups have been recorded as pollinators in Vanilla. To test these hypotheses, studies on secretory structures, the cells and tissues involved in the secretion, the floral reflectance patterns, as well as the volatile compounds of at least 30 species of Vanilla will be performed. Additionally, cpDNA and nrDNA regions will be analyzed in order to investigate the phylogeny of this plant group. The flower reflectance will also be studied with a spectrophotometer. The floral fragrances will be analyzed by GC-MS. The flowers of each species also will be investigated on basis on morpho-anatomical characters. Based on the obtained data, the patterns of evolution of floral traits related to the pollinators, pollination mechanisms and floral fragrances in this genus will be analyzed. (AU)