Taxonomic studies on Solanum macrocarpon Linn. and Solanum incanum Linn.

Abstract

The present study investigated the comparative taxonomic properties of S. macrocarpon Linn. and S. incanum Linn. members of Solanaceae in the Niger Delta Tropics, Nigeria. They are used as vegetable and medicine. The plants are erect annual sub-wood, attain up to 120cm in height. The leaves are ovate to lanceolate and glabrous up to 18.5 ±5.0cm in length and 8 ± 3.0cm wide for S. macrocarpon Linn. while that for S. incanum Linn. is glabrous, obovate and cuneate base, acute apex and variegated shiny surface up to 27 ± 6cm in length and 15 ± 4.5cm wide with alternate phyllotaxy. The inflorescence has 4 to 6 flowers for S. macrocarpon Linn. but a panicle of 4 to 5 flowers for S. incanum Linn.. The petals are whitish up to 0.6cm in length and 0.3cm wide with greenish sepals for the former whereas the latter has very large flowers having violet coloured petals measuring 1.3 to 2.0cm in length and 0.3cm wide with long greenish sepals. The berry fruit is greenish when unripe and yellowish when ripe up to 4.5cm in diameter for the formerand darkish green up to 5.5cm in diameter for the latter. The epidermis revealed anisocytic stomata whereas the trichomes aresimple uniseriate and the flowers are axile in placentation. The anatomy of mid-ribs and petioles showed bicollateral vascular systems. There are 3 vascular traces at primary growth phases and node is unilacunar. At secondary growth phases, their mid-ribs and petioles revealed vascular arcs and the stems have rings of open vascular systems. The cytological studies showed a diploid chromosome number of 2n = 24. Alkaloids, saponins, tannins, flavonoids, combined anthraquinones and cardiac glycosides are present in both specieswhile free anthraquinones is absent only in Solanum macrocarpon Linn. and phlobatannin is absent in both species.

Keywords: Morphological, Anatomical, Cytological, Phytochemical, Studies