Allelopathic effects of giant sensitive plant (Mimosa pigra) leaf powder on germination and growth of popping pod and purslane.
The most of invasive alien species possess allelopathic properties for beneficial success in site establishment. Giant sensitive plant (Mimosa pigra L.) is an important invasive species in nature. The objective of this study was to evaluate the allelopathic activity of M. pigra leaf residues on the germination, survival percentage and growth in two weeds, namely popping pod (Ruellia tuberosa L.) and purslane (Portulaca oleracea L.). Experiments were carried out under laboratory (agar medium) and greenhouse (soil medium) conditions with the addition the M. pigra leaf powder at varying concentrations of 1, 2, 3 and 4% (w/w) into the agar and soil medium. Negative and positive effects of M. pigra leaf residues were assessed. The results under two conditions showed the same trend, namely that the M. pigra leaf samples expressed inhibitory effects on the germination, survival percentage and growth of popping pod and exhibited stimulatory effects on purslane for all parameters. The soil experiment showed more prominent effects than the laboratory bioassay, with the dry biomass of popping pod being decreased up to 70.27% whereas the dry biomass of purslane sharply increased up to 1,562.50% and the effects became stronger when the concentration of M. pigra increased. The results indicated that the allelopathic effects of M. pigra were species-specific and concentration-dependent. The M. pigra leaf residues could be considered as a source of biologically active compounds.