Allelopathic effects of Euphorbia thyrsoidea and Oxalis latifolia on germination and seedling growth of Triticum aestivum

Abstract

Allelopathy involves the release of bioactive compounds from plants that may inhibit or stimulate the germination and growth of neighboring species. This study evaluated the allelopathic effects of Euphorbia thyrsoidea Boiss. and Oxalis latifolia Kunth. on wheat (Triticum aestivum L.) germination and early seedling growth. The experiment was arranged in a completely randomized design with three replicates. Fresh shoot and root aqueous extracts of both weed species were prepared at 5%, 10%, and 15% (w/v), while dried plant materials were used as mulch treatments. The treatments included individual shoot and root extracts, combined extracts of both weed species, individual dried mulch, and mixed dried mulch, with distilled water as the control. Wheat seeds were incubated in sterilized petri dishes at 25 °C, and germination percentage, plumule length, radicle length, root number, and leaf area were recorded after 72 h. Most fresh shoot and root extracts reduced germination and seedling growth parameters compared with the control. However, some treatment combinations stimulated specific growth traits. The combined shoot extract increased radicle length to 6.2 cm compared with 5.3 cm in the control and plumule length to 9.0 cm compared with 6.6 cm in the control. Fresh root extract at 5 g enhanced radicle length to 7.6 cm, while the combined root extract increased it to 7.3 cm compared with 6.9 cm in the control. Mixed mulch increased leaf area to 2.1 cm2 compared with 1.5 cm2 in the control and did not reduce germination. These findings indicate that E. thyrsoidea and O. latifolia have plant-part- and treatment-dependent allelopathic effects on wheat.