剑麻叶不同溶剂浸提液对假臭草萌发和生长的影响

以剑麻园常见伴生杂草假臭草为受体植物，白菜和萝卜为参照受体植物，采用生物测定的方法研究剑麻新鲜叶片石油醚、乙酸乙酯、三氯甲烷、蒸馏水4种溶剂浸提液对受体植物种子萌发和生长的影响。结果表明，4种溶剂浸提液对受体植物种子萌发率、根长和茎长生长均有不同程度的影响。500mg／mL蒸馏水浸提液和三氯甲烷浸提液对假臭草种子的萌发和幼苗的根长总体上具有显著的抑制作用，抑制率分别达到29％和50％；500mg／mL蒸馏水浸提液对萝卜种子萌发和根长生长具有显著的抑制作用，抑制率分别达到45．00％和64．22％；500mg／mL乙酸乙酯浸提液对白菜种子萌发和根长生长的抑制作用较强，抑制率分别达到30．49％和56．59％。说明剑麻不同溶剂、不同浓度浸提液对不同的受体植物均存在不同程度的化感作用，这为进一步开展利用剑麻的化感物质抑制杂草的研究提供了理论基础。

Allelopathic Effects of Leaf Extracts from Agave sisalana on Germination and Growth of Praxelis clematidea

Using Praxelis clematidea （Griseb.） R.M. King ＆ H . Rob. （syn. Eupatorium catarium Yeldkamp） ,a weed commonly associated to Agave sisalana plantations, as the receptor plant, and Brassica pekinensis （ Lour. ） and Raphanus sativus L. as reference receptor plants, the effect of the petroleum ether, chloroform, ethyl acetate, distilled water solvent extracts from fresh leaves of A. sisalana on the germination and growth of the receptor plants were studied by a bioassay method. The four extracts had different effects on seed germination rate, root length and shoot length of the receptor plants. Water and chloroform extracts at 500 mg/mL inhibited seed germination and root length of E. catarium by 29% and 50%, respectively. At the same concentration, distilled water extracts inhibited seed germination and root length of R.sat~vus 45% and 64% , respectively. Under the same conditions, chloroform extracts had inhibitory effects of 30% and 57% on seed germination and root length of B. pekinensis. Therefore,the allelopathic effects of A. sisalana foliar extracts are mediated by the solvent used ,the extract concentration and the bioassay recep- tor plant , which provides the foundation for furtherstudies on weed control using the allelopathy of A. sisalana.