No abstract

No abstract

No abstract

Pollen morphology of seven species, belonging to seven Asteraceae genera from the flora of Kaghan Valley was investigated by light and scanning electron microscopy. The species named Achillea millefolium Linn., Chrysanthemum leucanthemum Linn., Gerbera gossypina (Royle) Beauv., Senecio chrysanthemoides DC. Prodr., Sonchus asper Linn., Tagetes erecta Linn. and Xanthium strumarium Linn. were studied which showed considerable variation in pollen shape, size, length and number of spines, colpi and sculpturing in light as well as electron microscopy. The maximum pollen size was found in G. gossypina which was 38.3 µm in polar view and 57.75 in µm equatorial view whereas minimum pollen size in polar view that is, 23.65 µm was found in X. strumarium and 19 µm in equatorial view was found in A. millefolium. Psilate pollen sculpturing was observed in G. gossypina however the other species had spines on their pollen. The psilate sculpturing was considered as an advanced feature when compared to echinate sculpturing of pollen which was regarded as the primitive form. It was concluded that this research work has provided new dimensions towards further investigations in the field of palynology.

Pollen morphology & pollen fertility estimation of three medicinal species belonging to genus Hypericum L. from flora of Kaghan valley, Northern Pakistan was investigated by light and scanning electron microscopy for the first time. The species are Hypericum elodeoides Choisy in, Hypericum oblongifolium Choisy, and Hypericum perforatum L. Pollen morphological characteristics with considerable variation are provided for these taxa. Among the studied taxa, the pollen grains were 3-4 colporate type and the largest pollen size was found in H. oblongifolium in polar view 23.0 µm and in equatorial view was 25.35 µm. The smallest pollen was of H. elodeoides in polar view which was 19.91 µm and in equatorial view was observed 12.53 µm in H. perforatum.The shape of the all pollen grain was circular to semi-angular in polar view, however in equatorial view the shape of the grains was oblate-spheroidal, in H. elodeoides, and H. oblongifolium while prolate in H. perforatum. Exine sculpturing was observed by scanning electron microscopy which showed foveolate sculpturing in H. elodeoides, reticulate in H. oblongifolium and scabrate in H. perforatum. Pollen fertility estimation ranged from 82.66% to 90.90% which shows that flora of selected species is well established.