P.D. Gaikwad and S.M. Samudra
Abstract
Allelopathy plays a significant role in weed and crop interactions by influencing seed germination and early seedling development through the release of bioactive secondary metabolites. The present study evaluated the allelopathic potential of Acanthospermum hispidum L., a common agricultural weed, using laboratory bioassays. Aqueous extracts prepared from different plant parts, leachates and root-zone soil were assessed for their effects on seed germination, radicle length and shoot or hypocotyl growth of wheat (Triticum aestivum L.) and chickpea (Cicer arietinum L.). The results revealed marked, concentration-dependent and species-specific responses. In chickpea, most treatments, particularly root and whole-plant extracts, caused pronounced inhibition of root and shoot growth, including complete suppression of shoot elongation at several concentrations. Wheat exhibited a more variable response, with inhibitory effects under root and whole-plant treatments, but stimulatory responses under leaf and stem extracts at lower concentrations. Leachate assays confirmed the phytotoxic effects under simulated natural release conditions, with wholeplant leachates producing the strongest inhibition in both crops. Root-zone soil did not affect seed germination; however, it reduced seedling growth in wheat while enhancing radicle and hypocotyl elongation in chickpea. Overall, the study demonstrates that A. hispidum possesses substantial allelopathic potential, with effects strongly dependent on plant part, mode of chemical release and target crop species. These findings highlight the ecological significance of weed-derived allele chemicals and suggest that A. hispidum may influence crop establishment in agroecosystems, warranting consideration in weed management strategies.