Abstract: Coumarin is the main allelochemical produced by Poa pratensis. To screen seed materials suitable for reseeding in the Poa pratensis grassland,we selected Lespedeza davurica 'Jinnong No.1',Bothriochloa ischaemum 'Taihang',Orychophragmus violaceus and 3 varieties of P. pratensis ('Luckystar','Everest',and 'Nuglade') for germination experiments of seeds,which were treated under the imbibition of various concentrations of coumarin (0,20,40,60,80,and 100 μg·mL^-1 for T0,T20,T40,T80,and T100 respectively). The performances of seed germination and seedling growth were measured to calculate the comprehensive allelopathic effects (CE). The results showed that seed germination and seedling growth of L. davurica and B. ischaemum were most significantly promoted at T20 and T40,respectively. With the increase of coumarin concentration,the least inhibition was found for B. ischaemum,followed by L. davurica. In consideration of their symbiosis in the natural grassland,it was concluded that L. davurica 'Jinnong No.1' and B. ischaemum 'Taihang' might be the best choice to be selected for mix sowing with P. pratensis in the grassland reseeding. This study laid the foundation for the subsequent reseeding experiments.

Key words: Coumarin, Poa pratensis, Germination, Allelopathy, Reseeding

摘要： 香豆素是草地早熟禾(Poa pratensis)产生的主要化感物质，为筛选适宜补播草地早熟禾草地的种子材料，本试验采用不同浓度(0，20，40，60，80，100 μg·mL^-1)的香豆素处理'晋农1号’达乌里胡枝子(Lespedeza davurica 'Jinnong No. 1’)、'太行’白羊草(Bothriochloa ischaemum 'Taihang’)、二月兰(Orychophragmus violaceus)和3个品种的草地早熟禾：'幸运星’(Poa pratensis 'Luckystar’)、'珠峰’(Poa pratensis 'Everest’)、'新歌莱德’(Poa pratensis 'Nuglade’)进行发芽试验，测定种子萌发、幼苗生长指标，计算综合化感效应指数。结果表明，达乌里胡枝子、白羊草分别在20 μg·mL^-1和40 μg·mL^-1香豆素处理下，种子萌发与幼苗生长受到化感促进作用最显著；随处理浓度升高，白羊草受化感抑制程度最轻，其次是达乌里胡枝子。结合天然草地中的共生情况，推测'晋农1号’达乌里胡枝子和'太行’白羊草适宜与草地早熟禾组合，在草地补播中发挥重要作用。本研究结果可为后续补播试验奠定基础。

关键词: 香豆素, 草地早熟禾, 萌发, 化感作用, 补播