COMPARATIVE STUDY OF OPTICAL SIGNALS FROM FLOWERS RELEVANT IN BIOCOMMUNICATION

IRIEL, A.; LAGORIO, M. G.

La Serena

Congreso; X Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2010

Universidad de Santiago de Chile

The light that emerges from the flowers is an important signal used for biological systems to communicate with pollinator agents. In general, the spectral composition of the emerging light is due to reflected radiation. However, in some cases, phenolic compounds and dyes present in petals may contribute with fluorescence emission.             The aim of this study was to evaluate the relative importance of fluorescence compared to reflectance for biocommunication. Intact petals from Portulaca grandiflora, Lanpranthus productus, Bellis Perennis, Citrus anarantium, Antirrhinium majus  among others were studied in detail.             In a preliminary study we adapted a methodology described in literature for calculating the fluorescence quantum yield in intact petals.1 Following this procedure we were able to estimate quantitatively the fluorescence contribution for the studied species. In addition, reflectance spectra of the flowers were recorded. These results were evaluated in combination with the color vision system of the pollinators, the illumination source and the background contrast.              In all cases, the fluorescence emission that resulted was negligible compared to the light reflected by the petals, so that it was concluded that only reflectance signals should be relevant in biosignal communication with pollinators. In addition, a quantitative estimation of the relative amount of photons absorbed by the eye photoreceptors was achieved. Quantum catches were calculated for humans, for honeybees and for a species of bird.             This research involves a quantitative description of the light emerging from the flowers that could complement behavioural experiments of pollinators.