Palyno-taxonomic approach through light and scanning electron microscopy for the identification of herbaceous Asteraceae species from Sikaram Mountain Pak-Afghan border

Due to the diverse and rich taxa, Asteraceae needs to explore from the untouched area. In this study, the pollen study was intended to assess the taxonomic value for Asteraceous taxa growing on the Sikaram Mountain Pak-Afghan border. Both microscopic techniques (LM and SEM) play a significant role in the identification and classification of herbaceous species of Asteraceae for their taxonomic and systematic implication. Pollen was observed and measured for the 15 species of Asteraceae. For investigated taxa 15 pollen characters with size, shape, polar view, pollen type, aperture orientation, and exine sculpturing in the eurypalynous pollen. Consequently, the pollen grains are usually Tricolporate, triangular to circular in polar view, while, the shape of pollen varies from subulate, oblate, and prolate along with prolate to spheroidal whereas, sculpturing also varies from Scabrate to micro reticulate, echino-perforate, Scabrate to echinate, echinate to granulate and echinate were observed. Similarly, among the quantitative data minimum values of polar and equatorial were 15.8 +/- 0.74 mu m in Filago pyramidata and 17.85 +/- 0.39 mu m in Heteropappus altaicus was measured respectively, while; the length of the spine with the least value of 2.45 +/- 0.31 mu m in Hertia intermedia and highest with 7.55 +/- 0.31 mu m was observed in Cirsium wallichii. The Exine thickness is a minimum of 1.70 +/- 0.35 mu m in Launaea nudicaulis and a maximum of 5.65 +/- 3.59 mu m in Cirssium vulgare. In addition, the highest pollen fertility (87%) in Centaurea iberica while the highest pollen sterility (32%) was recorded in Cirsium verutum. Furthermore, clustering via UPGMA, PCA, and PCoA analysis was performed for the separation of closely related taxa. It is concluded from this research work that palynological study has a crucial role in taxonomic, pure, and applied sciences. This study can be further authenticated and improved by a Phylogenetic study based on chloroplast DNA analysis & whole genome sequencing.

Automated summary

In this study, the taxonomic value of Asteraceae pollen from the Sikaram Mountain Pak-Afghan border was assessed. Microscopic techniques were used to observe and measure the pollen of 15 species. The study found that the pollen grains were usually Tricolporate, triangular to circular in polar view, with varying shapes and sculpturing. The research also identified differences in pollen size, spine length, and exine thickness among different species. Cluster analysis was used to classify closely related taxa. The study highlights the importance of palynological research in taxonomy and applied sciences.