外来入侵植物刺苍耳各部位的化感作用研究

为了探讨入侵植物刺苍耳各部位(根、茎、叶、果实)的化感作用,以及化感物质在水浸提液和醇浸提液中的富集程度,通过室内生物测定法检测质量浓度为0.05 g/m L的浸提液对金狗尾草、黑麦草、莴苣及小白菜种子萌发及幼苗生长的影响。结果表明:刺苍耳各部位的水浸提液中总体以叶的化感作用最强,其对金狗尾草、黑麦草、莴苣、小白菜发芽率的抑制率分别为36.4%、17.9%、25.8%、18.7%,对根长的抑制率分别达到了62.7%、68.4%、26.8%、34.7%;刺苍耳各部位的醇浸提液中,除了叶对4种植物根长的抑制率较高,分别达到92.5%、89.3%、36.7%、48.4%以外,根和果实也都显示出较强的化感作用,分别对其中3种植物根长产生显著的抑制作用,抑制率分别为21.2%~46.4%(小白菜除外)和48.0%~54.8%(黑麦草除外);总体上,各部位醇浸提液的化感作用强于相应的水浸提液。由此可见,刺苍耳的主效化感物质主要集中在叶中,且在醇浸提液中富集程度更高。

Allelopathy of Each Part of Invasive Plant Xanthium spinosum L.

The allelopathic effect of aqueous and ethanol extracts of different plant parts ( i. e. root,stem, leaf,fruit) of the invasive plant Xanthium spinosum L. was evaluated at 0. 05 g/mL on Setaria glauca,Lo-lium multiflorum,Lactuca sativa and Brassica chinensis. The results showed that among the aqueous ex-tracts,leaf extract exhibited the most potent inhibitory activity,which suppressed the germination rate and root length of S. glauca,L. multiflorum,L. sativa,B. chinensis by 36. 4%,17. 9%,25. 8%,18. 7% and 62. 7%,68. 4%,26. 8%,34. 7%,respectively. The ethanol extract of leaves inhibited root length of S. glauca,L. multiflorum,L. sativa and B. chinensis by 92. 5%,89. 3%,36. 7% and 48. 4%,respectively. Furthermore,root and fruit extracts also showed significant allelopathic activity against three plants,inhibi-ting root growth by 21. 2%—46. 4%( except B. chinensis) and 48. 0%—54. 8%( except L. multiflo-rum) ,respectively. Overall,the inhibitory activity of the ethanol extracts was stronger than the aqueous ex-tracts. This study reveals that the major active allelochemicals are present in the leaf ethanol extract.