Studies on the Allelopathic Influence of Fresh Shoot Aqueous Extract of Tithonia diversifolia (Hemls) A. Gray on Euphorbia heterophylla L.

Effect of fresh shoot aqueous extract (FSE) of Tithonia diversifolia was studied on the germination of Euphorbia heterophylla in the Laboratory of the Department of Plant Science of Ekiti State University Ado Ekiti. Freshly harvested shoots of Tithonia diversifolia were blended and 5 g, 10 g, 15 g and 20g each of the material was separately soaked in 100ml of distilled water for 24 hours and later filtered to make the FSE. Two millilitres from each filtrate were used to moisten the double laid filter paper in the Petri dishes and 20 seeds sowed in each. Speed of germination and germination percentage including other seedling growth were observed. The results showed that higher FSE concentrations reduced germination speed and also reduced total germination percentage of E. heterophylla. While 5g and 10g stimulated increases in the growth of secondary growth, 15 and 20 g did not. Both radicle and plumule lengths of E. heterophylla were negatively affected by the FSE of T. diversifolia. Seedling survival got reduced as the concentration of the fresh shoot increased. The result from this trial suggests that Tithonia diversifolia possesses some herbicidal properties that could help suppress Euphorbia heterophylla in Agricultural lands.