A contribuição da quimica para o estudo de Orchidaceae e seus polinizadores

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The investigation of the Orchidaceae pollination is the aim of this work. At first the floral fragrance of five species were studied: Stanhopea lietzeii, Stanhopea insignis, Polystachya estrellensis, Psilochilus modestus and Epidendrum secundum. The fragrances of these species are mixtures of monoterpenoids, sesquiterpenoids, and aromatic compounds and fatty acids derivatives. These work s results show a significant difference between the floral fragrance composition of flowers pollinated by bees and by butterflies. The second part of this work is focused on floral rewards, in this case, floral oils produced in the elaiophers glands, offered by orchidaceae flowers. Floral oils of six Oncidium species and three species of Gomesa genus were studied. The Oncidium species are: O. pubes, O. truncatum, O. hookeri, O. enderianum, and O. varicosum. The Gomesa species are: G. crispa, G. recurva and Gomesa sp. The composition of these oils presents glyceril esters, phenylpropanoids, terpenoids and fatty acid derivatives. The glyceril esters were found as di and triacilglycerols where the glycerol was esterified by one or two acetic acid residues and one fatty acid residue. The identification of these compounds is suggested by the GC/MS and NMR analysis and by comparing the oils data and three synthetic compounds data. These synthetic compounds were produced by using as starting products the D-manitol, oleic acid and acetic acid. This work presents chemical evidences, which suggest that species pollination is not based on attraction-deception system but based on floral rewards. This is the first study on chemical composition of floral oils of these Orchidaceae species.

ASSUNTO(S)

essencias florestais orquidea

ACESSO AO ARTIGO

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