3种茜草科药用植物乙醇浸提液对萝卜种子萌发及幼苗生长的化感作用

Allelopathic effects of ethanol extract of three medicinal plants from rubiaceae family on seed germination and seedling growth of Raphanus sativus L.

以3种茜草科药用植物鸡屎藤〔Paederia scandens（Lour.）Merr.〕、剑叶耳草（Hedyotis caudatifolia Merr.et Metcalf）、玉叶金花（Mussaenda pubescens L.）为试材,采用乙醇提取的方法制备不同浓度的乙醇提液,通过测定其对受体萝卜（Raphanus sativus L.）发芽率、根系活力、叶片游离脯氨酸和叶绿素含量的影响,比较化感作用强弱。结果表明：不同供试植物乙醇提液其化感效应不同,且浓度高时,化感作用强;供试植物乙醇提液均显著降低了萝卜发芽率、发芽速率指数,且剑叶耳草在这两个指标的抑制作用显著高于另二者;供试植物乙醇提液均极显著抑制萝卜胚根和胚芽的生长,其中鸡屎藤乙醇提液抑制胚芽的作用最强,玉叶金花提液抑制胚根的作用最强;鸡屎藤比玉叶金花更显著地抑制萝卜幼苗根系活力,然而剑叶耳草却显著地促进;供试植物乙醇提液显著降低萝卜幼苗叶绿素含量,显著提高叶片脯氨酸含量;鸡屎藤乙醇提液使叶绿素含量减少69.47%~87.00%,且叶绿素a/叶绿素b随处理浓度的增加而降低。

The allelopathic effects of ethanol extract of Paederia scandens（Lour.） Merr., Hedyotis caudatifolia Merr. et Metcalf and Mussaenda pubescens L. on Raphanus sativus L. were compared by determining germination, chlorophyll content, free proline content of leaves and root activities of the acceptor. Results showed that different concentration of ethanol extract from donors had certain allelopathic effect on R. sativus, and the allelopathic effects enhanced with the increase of concentration. Ethanol extract from donors significantly reduced germination percentage, germination rate index.And H. caudatifolia in the inhibition of these two indexes was significantly higher than the other two donors. The three donors all significantly inhibited the seedling growth of radish, with the strongest inhibition of germ and radical growth caused by P. scandens and M. pubescens, respectively. P. scandens also caused more significant inhibition of root activity of R. sativus than M. pubescens, while H. caudatifolia remarkably improved it. Ethanol extract from donors significantly increased the free proline content of acceptor＇s leaves, and resulted in 69.47%-87.00% reduction of the chlorophyll content of acceptor, while chlorophyll A / chlorophyll B decreased as the increase of ethanol extract concentration.