Allelopathic potential of aqueous extracts of <i>Solanum americanum</i> Mill. fruits on radish seeds

Abstract

This study had the objective to test the allelopathic potential of aqueous extracts of nightshade fruits (Solanum americanum Mill.) on radish seed germination and leaflet early growth (Raphanus sativus L.). The extracts were prepared in the concentrations of 2, 4 and 8%, and characterized as to phytochemical profile, pH and osmotic potential. Treatments consisted of four replications of 25 radish seeds distributed in Petri dishes with two sheets of germitest paper and 5 mL of water extract. Germination parameters consisted of the germination percentage (PG), germination speed (VG), germination speed index (IVG) and germination uniformity coefficient (CUG). The initial growth was evaluated by length (root and shoot), mass (fresh, dried and water content) and chlorophyll content (a, b and total). The fruit extracts affected the PG, VG and IVG for germination. The extracts also reduced the root length, fresh mass and chlorophyll a levels. The extracts action is not related to the osmotic potential and pH and the qualitative identification tests reveals the presence of flavonoids, indicating allelopathic activity.