Spectral fluorescence variation of pollen and spores from recent peat-forming plants

Abstract

The fluorescence properties of spores and pollen grains examined under ultraviolet incident light are used to assess the maturity of sedimentary organic matter and may have other applications in relation to recent sediments, in areas such as palaeoenvironmental research. In this study pollen grains and spores from 33 species common in peat ecosystems were mounted on a glass slide in accordance with standard palynologycal procedures for recent plants. The main objective of this work was to assess the variability of fluorescence spectra of pollens and spores within a single species or even within a single sample. A minimum of 10 spectra were recorded from each sample and were averaged to obtain a spectrum characteristic of each sample. Both the average scattering and the scattering in different spectral regions were calculated using the standard deviation (SD) and the coefficient of variation (CV). The effect of the preparation techniques was assessed on some samples of Ericaceae taxa. The results indicated similar spectra for alcohol-washed and distilled water-washed samples, whereas the application of an acetolysis solution caused an increase in intensity and a shift to longer wavelengths. The spectra corresponding to the Sphagnum spores had the lowest intensity of all the families studied and displayed their maxima at the lowest registered wavelengths. They often showed a peak in the red region of the spectra, causing a larger scatter in fluorescence in this region. This peak is probably the result of wax or cytoplasmic material attached to the exospore. A significant number of Ericaceae taxa had two fluorescing pollen populations: a blue one of high intensity andsmaller size a yellow-orange one of low intensity and larger size. This difference could be related to different degrees of maturity of the pollen grains. In the case of pollen grains of herbaceous, tree and bush plants the largest scatter was found in the tails of the spectra towards the blue and red regions. The decreasing trend of fluorescence intensity with the shift of the spectra towards red was not observed in the pollen and spores of fresh plants. A good correlation was found between the spectral maxima ( max ) and the red-green quotient (Q R/G ) regardless of the type of plant.

Optimizing a Simple Natural Dye Production Method for Dye-Sensitized Solar Cells: Examples for Betalain (Bougainvillea and Beetroot Extracts) and Anthocyanin Dyes

“…The spectrum obtained with Solution 2 gives two main peaks at 424 and 456 nm, then absorbance diminishes and slightly increases again for 718 nm up to a scarce 20% of the main peaks. Flavonoids can account for 2-5% of pollen dry weight [2], but the specific compounds depend on geographical area [46], and FT-IR spectroscopy or spectral fluorescence analysis should be required to identify them [47,48]. This would complicate our analysis.…”

Facile isolation and analysis of sporopollenin exine from bee pollen

“…Although the sporopollenin itself also shows some autofluorescence 71 , 72 , the smooth, protruding intine wall could clearly be distinguished (Fig. 1 a).…”

Flow cytometric analysis of pollen and spores: An overview of applications and methodology

“…Natural autofluorescence of sporopollenin in the pollen wall can also be used for taxonomic identification and sorting of environmental pollen samples (e.g., airborne pollen [24]) and fossil pollen from sediments [23,25]. While such autofluorescence is relatively uniform within species, users should be aware that exceptions have been observed [26]. Gating based on fluorescence may be further enhanced in the case of fluorescently-tagged lines (FTLs) [27], membranepermeable DNA stains [9], or the latter combined with SSC variation [28].…”