中文摘要：

采用砂粒为培养地黄苗的基质，利用XAD-4柱循环收集地黄根系分泌物，通过对地黄、莴苣、芝麻、萝卜的生物测定，将有影响的组分进行GC-MS物质鉴定。研究结果显示：根系分泌物的酸性组分和中碱性组分对作物胚根和胚芽伸长都有抑制作用，随添加量的增加抑制加强，其中对萝卜胚根的影响表现为低促高抑。分别将两种组分进行GC—MS物质鉴定，发现在两种组分中都含有长链脂肪酸和阿魏酸等常见的化感物质。

英文摘要：

Sand was used as the substrate of cultivating the seedlings of Rehmannia glutinosa, the exudates from the root system of Rehmannia glutinosa seedlings were cyclically collected by XAD - 4 resin column, then the bioactivity of the exudates to Rehmannia glutinosa, lettuce, sesame and radish was determined, finally the influential fractions in root exudates were identified by GC -MS. The results showed that both the acidic fraction and alkaline fraction in root exudates had restraining effect on the radical and embryo elongation of four crops, and the restraining effect strengthened along with the increase of the added fractions in quantity, the low density of the two fractions promoted radical of radish, while the high density inhibited it. The two fractions were analyzed by gas chromatography - mass spectrometry, the common allelochemicals such as long - chain fatty acids and ferulic acid were both found in two fractions.