中文摘要：

以西洋参幼苗为受体,采用玻璃砂培养方法研究不同浓度（25、50、100 mg·L^-1）的人参皂苷粗提液对西洋参早期生长及生理代谢的影响,并用透射电镜观察幼苗根尖在处理过程中亚显微结构的变化.结果发现：（1）在不同浓度人参皂苷粗提液处理下,西洋参幼苗早期生长的各项生理指标均表现出不同程度的低促高抑现象.（2）各处理对西洋参幼根及幼苗的生物量无显著影响,但中高浓度处理对根长的抑制作用明显大于苗高.（3）中高浓度均对根系活力具有显著抑制作用（P〈0.05）;在高浓度下幼苗叶片中超氧阴离子自由基（O2^-·）的产生速率和丙二醛（MDA）含量均显著增加,叶片及幼根中相对电导率也有明显增加,而叶片可溶性蛋白和叶绿素（Chl）合成受到轻微的促进作用,Chl含量随处理时间的延长虽呈逐渐下降趋势,但仍高于对照.（4）高浓度处理的幼苗根尖细胞的核膜膨胀、核仁变形,液泡膜解体,不能完成正常的生命活动.研究表明,不同浓度的人参皂苷粗提液对西洋参早期生长具有化感效应,且对受体地下部分的影响明显大于地上部分.

英文摘要：

Sand culture method was adopted to investigate the allelopathic effects of crude ginsenoside extracts from Panax quinquefolium at different concentration（25,50,100 mg·L^-1）on early growth and its physiological metabolisms,and to examine the submicroscopic structure of root-tip of P.quinquefolium by transmission electron microscopy.The results showed a dose-dependent effect of ginsenosides on early growth in P.quinquefolium.There were no significant effects on biomass of seedlings and roots but root lengths.Ginsenosides extracts significantly decreased the root activities with the increasing concentration.O2^-· production rate and MDA content in seedlings both were markedly promoted（P〈0.05）and the highest was at 100 mg·L^-1 treatment 48 h.However,soluble protein and Chl contents increased slightly after 25～100 mg·L^-1 application,and which decreased with time prolonging,but still higher than that of the control.Otherwise,relative electric conductivity in leaves and roots increased slightly compared with the control as enhanced concentration of ginsenosides.The treated submicrostructure of root-tip cells exhibited deformations of nuclear membrane and nucleolus and dissolution of vacuole membrane,therefore the life cycle of cells was unable to complete.Taken together,these findings indicated that ginsenoside extracts had allelopathy on early growth of P.quinquefolium,while inhibited underground growth more than aboveground growth.