Sprecher
Beschreibung
Accurate pollen identification is fundamental to palaeoecological reconstruction, yet traditional morphology-based approaches often struggle to distinguish closely related taxa. In recent years, spectroscopic techniques such as Fourier-transform infrared (FTIR) and Raman spectroscopy have provided new insights into pollen wall chemistry and improved taxonomic resolution. Fluorescence Lifetime Imaging Microscopy (FLIM) offers an alternative approach by detecting fluorescence lifetime signatures associated with sporopollenin composition.
To evaluate the potential of FLIM in palynology, we investigated pollen from six species of the mangrove genus Sonneratia, an ecologically important taxon with a rich fossil record. Fluorescence lifetime data were obtained from pollen walls and analysed using multivariate statistics. The results demonstrate that FLIM effectively differentiates the six species into four major groups, with the long-lifetime component (τ₃) representing the principal variable responsible for species separation. Hybrid taxa occupy intermediate positions in fluorescence lifetime space, showing broad correspondence with previously proposed phylogenetic relationships. Furthermore, the introduced species Sonneratia apetala exhibits a distinct fluorescence lifetime signature compared with native Chinese species, suggesting differences in pollen wall chemistry related to evolutionary history and ecological adaptation.
Our results indicate that fluorescence lifetime signatures preserve taxonomic, phylogenetic, and ecological information that complements traditional morphology and other spectroscopic methods. By establishing reference datasets from modern taxa, FLIM provides a promising framework for comparing extant and fossil pollen. Future integration of FLIM with FTIR, Raman spectroscopy, and machine-learning approaches may significantly improve species-level pollen identification and enhance palaeoecological reconstructions of mangrove ecosystems and other vegetation types.