Abstract: Aiming to reveal the influencing factors of allelopathy,the commonly used perennial grasses for ecological restoration in alpine grasslands of Qinghai-Tibet Plateau were used as research objects. The effect of soil microorganisms on seed germination and seedling growth were investigated by laboratory bioassay. By calculating the comprehensive effect,microorganisms on allelopathic effects were compared and analyzed. The germination rates of the five alpine forage seeds with the unsterilized soil U100 as the matrix were the highest,and the completely sterilized soil U0 was the lowest. Different proportions of unsterilized soil U75,U50 and U25 showed different differences due to different forage seeds. The seedling heights of Elymus nutans ‘Qinghai’, Elymus sibiricus ‘Tongde’ and Festuca sinensis ‘Qinghai’ increased with the increase of soil microbial content. Under the treatment of U100,the root length of the five cultivated grass seedlings was the highest. The variation trend of seedling dry weight is similar to that of seedling height. The results showed that the soil microorganisms are crucial for root growth during the growth stage of seedlings. Soil microorganisms could promote the germination rate of seeds,but the effects on different species are different.

Key words: Artificial grassland, Germination, Seedling growth, Grassland degeneration, Allelopathic

摘要： 为研究探讨土壤微生物对化感效应的潜在作用，以高寒草地生态修复常用牧草为研究对象，通过室内生物学实验，测定种子发芽率及幼苗的苗高、根长和干重，计算分析化感综合效应。结果显示：以未灭菌土壤U100为基质的5种牧草种子发芽率均为最高，完全灭菌土壤U0的均为最低，不同比例未灭菌土壤U75，U50和U25则因牧草种子的不同而表现出不同差异；幼苗生长方面，‘青海’垂穗披碱草(Elymus nutans ‘Qinghai’)、‘同德’老芒麦(Elymus sibiricus ‘Tongde’)和‘青海’中华羊茅(Festuca sinensis Qinghai)幼苗苗高随灭菌土壤增加而减小；5种牧草幼苗的根长均在U100处理下最长；幼苗干重的变化趋势同苗高相似。未灭菌土壤对5种牧草的影响主要表现在根系生长和干重方面。研究证明在幼苗生长阶段土壤微生物对根系生长至关重要，土壤微生物能缓解化感效应提高种子发芽率，但对不同物种的影响存在差异。

关键词: 人工草地, 种子发芽, 幼苗生长, 草地退化, 化感效应