Abstract: The objective of this study was to reveal the effects of white clover (Trifolium repense L.) plant aqueous extracts on the germination, seedling growth and physiological metabolism of dandelion (Taraxacum mongolicum Hand.). The results showed that the aqueous extracts of clover plants had obvious effect on the germination potential and physiological metabolism of dandelion. The aqueous extracts of high concentrations (0.04~0.05 g·mL^-1) inhibited the seed germination, root length, chlorophyll content and respiratory intensity of dandelion, and increased the IAA accumulation of dandelion, whereas the aqueous extracts of lower concentration promoted the root length and respiration of dandelion. Meanwhile, the aqueous extracts of white clover plants changed the cell membrane permeability of dandelion, resulting in the electrolyte leakage of dandelion and increased soluble sugar, soluble protein, proline, malondialdehyde contents of dandelion.

Key words: White clover, Allelopathy, Dandelion, Cell membrane permeability, Osmotic adjustment

摘要： 蒲公英（Taraxacum mongolicum Hand.）是白三叶（Trifolium repense L.）建植中主要的杂草，通过测定白三叶植株水浸液对蒲公英种子发芽特性、幼苗生长和生理指标的影响，明确白三叶浸提液对蒲公英种子和幼苗的化感作用及其机制。结果表明：以酚类为主的白三叶植株水浸液对蒲公英的发芽率、生长指标有显著的影响，高浓度（0.04～0.05 g·mL^-1）下有抑制作用，而且随着浓度的增加抑制作用越为明显，同时在浓度超过0.04 g·mL^-1时，白三叶植株水浸液可造成蒲公英叶绿素含量减少、改变呼吸强度和增加生长素（IAA）在植物体内的积累，胚根长和呼吸强度表现出“低促高抑”的现象。白三叶植株水浸液可改变蒲公英细胞膜透性，造成电解质外渗，同时可溶性糖、可溶性蛋白、脯氨酸、丙二醛等含量随白三叶植株水浸液浓度增高而明显增加。

关键词: 白三叶, 化感作用, 蒲公英, 细胞膜透性, 渗透调节