Pollen morphology in certain medicinally important species of solanum

Investigations were carried out on the pollen morphology of six medicinally important species of Solanum - S. aculeatissimum Jacq., S. indicum Linn., S. torvum Swartz, S. melongena var. insanum Prain., S. nigrum Linn., and S. trilobatum Linn. Both light microscopic and SEM studies of the acetolysed and the unacetolysed pollen grains were carried out. Various parameters like pollen aperture, ora, amb, exine ornamentation, size and shape of the pollen of the selected species were included in the present study. Pollen grains are 3-zonocolporate and the exine surface is granulate with dimorphic granules,being either lax or dense or else arranged in striate pattern, pollen with lalongate endocolpium in all the species. In all of them, the ora region of the pollen grain is annulate. Two species, S. aculeatissimum and S. torvum, were found to have deciduous operculum. The pattern of distribution of granules on the exine was found to vary with the species. A comparative study of the size of the acetolysed and unacetolysed grains had shown that there was a marginal increase in the polar diameter and equatorial diameter of the pollen grains on acetolysis. The scope of pollen morphology as an index in population screening for fixing genetic resources is high, and important for this medicinal crop.