Abstract
The study of alleopathic potential of Seriphidium leucotrichum (Krasch. ex Ladyg.) K. Bremer & Humphries ex Y.R. Ling, on seed germination and early seedling growth of four test plant species including Triticum aestivum (wheat), Zea mays (maize), Brassica compestris (mustard) and Pennisetum americanum (millet), was conducted under laboratory conditions. Aqueous extract of the air-dried plants of S. leucotrichum at different concentrations i.e. (25, 50, 75 and 100% of stock solution) inhibited germination of the test species in the order: Brassica compestris> Zea mays> Triticum aestivum> Pennisetum americanum. Root and shoot growth of the test species was also reduced by the extracts in the order: Brassica compestris> Zea mays> Triticum aestivum > Pennisetum americanum. It was observed that the soil application of the aqueous extract had considerable delaying effect on Triticum aestivum growth while shoot spray or root dip treatment had no such effects. Decaying shoot of S. leucotrichum in sandy–loam at 5, 10 and 20g/400g soil caused considerable inhibition of germination and seedling growth of Pennisetum americanum at high concentration (20 g/400g soil). Bioassay of the ether extract of S. leucotrichum exhibited three zones of inhibition at Rf values 0.7-0.8, 0.8-0.9 and 0.9-1.0 while a promoter was detected between Rf value 0.4-0.5. Paper Chromatography was employed for the identification of phenolic constituents and as a result, caffeic acid, p-coumaric acid and gallic acid were identified while one constituent remained unknown. In this connection, the possible role of the phenolic compounds through their allelopathic effect in driving the structure of natural communities is discussed.
