Systematic Importance of Pollen Morphology of Some Plants of (Lamiaceae)

Abstract

Pollen morphology of seven taxa belonging to Lamiaceae and common used as medicinal plants were examined by light (LM) and scanning electron microscopy (SEM). Thymus vulgaris L., Mentha longifolia (L.) Huds. Mentha spicata L., Ocimum basillicium L., Salvia elegans Vahl, Salvia farinacea Benth, and Salvia splendens Sellow ex Roem. and Schult. Pollen morphological characteristics are provided for these taxa. Among the studied taxa, Mentha longifolia has the smallest pollen grains, and Ocimum basillicium possesses the largest ones. The main shape of pollen grains in the most taxa  suboblate, oblate – spheroidal or prolate–spheroidal. However subprolate are recorded for Salvia elegans. The grains are hexacolpate in all taxa, but in S. farinacea octacolpate pollen was found. Three distinct exine sculpturing exist, reticulate–perforate the common type, also reticulate, granulate and bi-reticulate. However, the fine details are characteristic to differentiate between the pollen species. Exine is microreticulate in case of S. elegans and S. farinacea, but reticulate-foveolate in case of S. splendens. As well as, the presence of holes on colpus membrane ornamentation can be used as a taxonomic tool for sectional division between. S. elegans from S. splendens is clearly distinct from the other taxa examined by its characteristic pollen morphology.