【研究目的】为了寻找一种能够快速，有效捕获紫茎泽兰活体释放的根系分泌物的方法。【方法】本文分别采用水培提取法和循环水-树脂吸附法提取，比较评估了紫茎泽兰根系分泌物对紫花苜蓿的化感潜势。【结果】水培提取法和循环水-树脂吸附法获得的根系分泌物对苜蓿根长和芽长均有显著的抑制作用。其中，水培提取法获得的根系分泌物对紫花苜蓿发芽率、发芽速率、根长和芽长的化感指数分别为-0.18、-0.31、-0.21和-0.30，而循环水-树脂吸附法获得根系分泌物对紫花苜蓿发芽率、发芽速率、根长和芽长的化感指数分别为-0.28、-0.32、-0.24和-0.53。【结论】两种方法对紫茎泽兰根系分泌物化感潜势评估结果无明显影响，但与循环水-树脂吸附法相比，水培提取法操作简便、快速、且受环境干扰小，故更适合于紫茎泽兰根系分泌物化感潜势评估的研究。

【OBJECTIVE】To find a fast and effective way for the capture root exudates released from by Ageratina adenophora.【METHOD】We collected the root exudates using the water-culture method and the recycled water-resin extraction method, then comparatively assessed the allelopathy of root exudates to Medicago sativa L..【RESULTS】The root exudates from the two extraction methods have significantly inhibited the growth of its root and shoot. Among them, the relative allelopathic impacts of the water-culture method on the germination rate, germination index, root growth and shoot growth reached -0.18, -0.31, -0.21 and -0.30; Response Index (RI) of water-resin extraction method were -0.28, -0.32, -0.24 and -0.53, respectively.【CONCLUSION】The two methods had no obvious difference in the assessment potential allelopathy of A. adenophora’s root exudates. But compared with the recycled water-resin extraction method, water-culture method was simple, rapid and not so easily interferenced by environment, it is more suitable for assess the potential allelopathy of root exudates of A. adenophora.