Abstract: Allelopathy was determined by studying the effect of a Medicago varia cv.caoyuan No.2 aqueous extract on the germination of selected grass seeds using biological detection.Root,stem and leaf extracts of Medicago varia cv.caoyuan No.2 were used to treat seeds of Medicago varia cv.caoyuan No.2,Agropyron mongolicum Keng,Agropyron cristatum(L.) Gaertn and Onobrychis viciaefolia Scop.The purpose of this experiment is to measure the germination rate,height of seedling,length of root,and the allelopathy of Medicago varia cv.caoyuan No.2 and selected receptor plants by biological detection.Results show that these aqueous extracts have self-toxicity for seeds of Medicago varia cv.caoyuan No.2 and allelopathy with a concentration effect.Different concentrations of aqueous extract form Medicago varia cv.caoyuan No.2 root,stem and leaf have different effects on the germination of seeds,height of seedling,length of root of different receptor plants.The aqueous extract of Medicago varia cv.caoyuan No.2 leaves have less inhibitory effect on Agropyron cristatum(L.) Gaertn and Agropyron mongolicum Keng than Medicago varia cv.caoyuan No.2 and Onobrychis viciaefolia Scop.The aqueous extract of Medicago varia cv.caoyuan No.2 root,stem and leaf have geater promotion on height of seedling and length of root Agropyron mongolicum Keng and Agropyron cristatum(L.) Gaertn than that of Onobrychis viciaefolia Scop and Medicago varia cv.caoyuan No.2.Therefore,Medicago varia cv.caoyuan No.2 overdrilling mixed with either Agropyron mongolicum Keng or Agropyron cristatum(L.) Gaertn grow better than both unicast and overdrilling with Onobrychis viciaefolia Scop.

Key words: Medicago varia, Allelopathy, Aqueous extracts

摘要： 通过研究草原2号杂花苜蓿(Medicago varia cv. caoyuan No.2)浸提液对4种牧草种子萌发的影响,探索利用生物检测法初步确定其与自身及其他3种牧草间化感作用。用草原2号杂花苜蓿根、茎、叶水浸提液处理草原2号杂花苜蓿、蒙古冰草(Agropyron mongolicum Keng)、扁穗冰草(Agropyron cristatum (L.) Gaertn.)和红豆草(Onobrychis viciaefolia Scop.)的种子,测定其发芽率、苗高、根长,利用生物检测法确定草原2号杂花苜蓿对受体植物的化感效应。结果表明:草原2号杂花苜蓿的自毒性及化感作用存在浓度效应,即不同浓度的根、茎、叶浸提液对不同受体植物种子萌发、幼苗高度、根长影响效果不同,其叶浸提液对扁穗冰草和蒙古冰草种子发芽的抑制效应小于草原2号杂花苜蓿和红豆草;其叶、茎、根浸提液对蒙古冰草、扁穗冰草的苗高、根长的促进作用大于红豆草和草原2号杂花苜蓿;根据试验结果,初步认为草原2号杂花苜蓿与蒙古冰草、扁穗冰草混、间播效果要比与红豆草混、间播和单一连播杂花苜蓿效果好。

关键词: 杂花苜蓿, 化感作用, 水浸提液