Allelopathic Inhibition on Hibiscus esculentus and Chemical Composition of Aqueous Extract from Cymbopogon citratus Leaves

Allelopathic effect of the aqueous extract from Cymbopogon citratus 1eaves on the germination and seedling growth of Hibiscus esculentus wasstudied in petri dish with laboratory bioassay. The chemical composition of the extract wasdetermined using GC-MS.Depending upon the concentration, the extractexhibited varied effects on the germination of H. esculentus seeds. At the concentration of 5 g·L^-1, the extract stimulated the seed germination. In contrast, at 30 g·L^-1 to 40 g·L^-1 it displayed significant inhibitory effects on the germination, root growth as well asweight of individual seedlings.The seedlings were most sensitive to the extract during growth stage. There were 16 compounds identified by the analysis that represented 82.76% of the total content. Among them, geranial, nerol and geranic acid were the major constituents, which included phenolic acids (8.27%), fatty acids (2.12%) and terpenoids (52.19%)constituting 62.58% of the entirechemical composition in the extract.