中药材

目的：分析北沙参根系分泌的化感物质对北沙参和受体植物种子萌发及幼苗生长的化感效应。方法：采用气相色谱-质谱联用(GC-MS)技术对连作和非连作北沙参根际土壤化学组分的种类及相对含量进行分析，选择连作根际土壤比非连作根际土壤占总量比增幅明显的化合物进行单物质浇灌试验，验证其化感效应。结果：与非连作处理相比，连作北沙参根系分泌物占总量比增幅明显的化合物主要有邻苯二甲酸二丁酯、2,4-二叔丁基苯酚、人参炔醇、甲氧补骨脂素。不同浓度的4种外源化合物对北沙参种子胚的生长及幼苗的生长整体呈现抑制作用；不同浓度的4种外源化合物均抑制受体植物种子萌发，随浓度增加，抑制作用越明显；对受体植物幼苗生长的作用综合表现呈低浓度促进高浓度抑制的剂量效应。结论：北沙参根系分泌物产生的4种化合物具有较强的化感效应，北沙参连作障碍的发生可能与化感物质的积累密切相关。

Objective: To analyze the allelopathic effects of allelopathic substances secreted from the roots of Glehnia littoralis on seed germination and seedling growth of Glehnia littoralis and receptor plants.Methods: Gas chromatography-mass spectrometry(GC-MS) technology was used to analyze the types and relative contents of chemical components in the rhizosphere soil of continuous and non continuous cropping Glehnia littoralis,the compound whose total proportion of rhizosphere soil in continuous cropping was significantly higher than that in non-continuous cropping rhizosphere soil was selected for single substance irrigation test to verify its allelopathic effect.Results: Compared with the non-continuous cropping treatment, the main compounds that increased significantly in the total proportion of root exudates of continuous cropping Glehnia littoralis were dibutyl phthalate, 2,4-di-tert-butylphenol, panaxynol and methoxypsoralen.The growth of seed embryo and seedling was inhibited by four different concentrations of exogenous compounds.The four different concentrations of exogenous compounds inhibited seed germination of the recipient plant, and the inhibitory effect was more obvious with the increase of the concentration.The overall effect on the growth of the recipient plant seedlings showed a dose effect of low concentration promotion and high concentration inhibition.Conclusion: The four compounds produced by the root exudates of Glehnia littoralis have strong allelopathic effects, and the occurrence of continuous cropping disorder of Glehnia littoralis may be closely related to the accumulation of allelopathic substances.