Pollen Morphology and Taxonomic Significance of Melliferous Flora in the Northern Area of KPK, Pakistan

Abstract This study investigates the palynological diversity and taxonomic significance of melliferous flora, focusing on pollen morphology and pollination features. 24 plant taxa from 11 families were analyzed using light microscopy to document pollen size, shape, exine ornamentation, and apertures. Reticulate, rugulate, granulate, scabrate, striate, echinate, and psilate types exine ornamentations were studied in the present work. Apertures on the pollen surface varied among the studied taxa, showing colpi and pores that included tri-colpate, tri-colporate, bi-colpate, hexa-colporate, octa-colpate, and crypto-colpate types. In the studied taxa, different pollen shapes oblate-spheroidal, sub-oblate, prolate-spheroidal, sub-prolate and prolate were investigated. Quantitatively, pollen grains size ranged from 2.1 to 55.6 µm, with an average polar diameter of 32.4 µm and equatorial diameter of 28.7 µm across the studied taxa. The pollen shape index varied from 0.82 to 1.45, reflecting considerable diversity in pollen morphology. The results shown a diverse range of pollen character, with larger pollen sizes (5–10 µm) primarily supporting insect-pollinated process (entomophily) and smaller sizes (2 µm) evolved to wind pollination (anemophily). Differences in pollen surface patterns and aperture numbers are key features for distinguishing plant species and understanding their pollination adaptations. Nectar production and pollen accessibility were noted key factor in honeybee visitation and pollination efficiency, with higher nectar-producing taxa attracting more pollinators. Hierarchical clustering of studied taxa using pollen attributes presented evolutionary patterns and phylogenetic relationships to enhance understanding of plant pollinator dynamics. The study highlights the vital role of pollen morphology and floral compensations in plant insect interactions, contributing valued understandings into biodiversity conservation and sustainable apiculture.