Abstract: Xanthium spinosum [WTBZ] is an annual invasive species, and it was originated from South American. It has a wide adaptability to barren soil and saline or alkaline soil as well as flood and drought conditions. Just because of its transmission capability, [WTBX]X.spinosum[WTBZ] devastates the native biodiversity, plant distribution, community formation and intercrop evolution. In this paper, the aqueous extract from the roots, stems and leaves of [WTBX]X.spinosum[WTBZ], at concentrations of 0.012 5, 0.250, 0.050 g·mL-1 and 0.100 g·mL-1, was used as a treatment solution to study its allelopathic effect on seed germination of [WTBX]Triticum aestivum[WTBZ] and [WTBX]Medicago sativa[WTBZ]. The results revealed that the seed germination of [WTBX]T.aestivum[WTBZ] and [WTBX]M.sativa[WTBZ] was significantly inhibited by the aqueous extract at concentration ≥ 0.012 5 g·mL-1. All the aqueous extract of the roots, stems and leaves inhibited seed germination of [WTBX]T.aestivum[WTBZ] and [WTBX]M.sativa[WTBZ], which not only reduced the germination rate of seeds but also prolonged the period of ultimate germination. The allelopathic effect of the aqueous extract was in an order of stem > leaf > root, and the effect was intensified at higher extract concentration. The results are of the theoretical significance and practical value in conducting biological control of exotic species and developing new biological pesticide.

Key words: font-size: 10.5pt, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, Xanthium spinosum')">mso-bidi-language: AR-SA" lang="EN-US">Xanthium spinosum, allelopathic effect, Triticum aestivum, Medicago sativa, seed germination, invasive plant