Isolation of intact pollen exine using anhydrous hydrogen fluoride

We report the use of anhydrous hydrogen fluoride as a new procedure to extract intact exine from a range of species. Pollen samples were incubated in anhydrous HF in pyridine for 5 hours at 40 degrees C. Exines were recovered after several washes in water and ethanol. The quality of the exine obtained by this method has been followed by SEM micrographs and FT-IR spectroscopy. The morphology of the pollen grains as determined by SEM was maintained after hydrogen fluoride treatment. FT-IR spectra revealed that the chemical composition of the exine was not altered by this protocol. A comparison between this new protocol and the standard acetolysis method has been made. The new procedure presents two important advantages: it is short timing consuming and does not produce any chemical derivatization of the samples.