外来入侵植物黄顶菊的化感作用初步研究

为明确黄顶菊对其他植物的化感作用,利用黄顶菊茎叶的不同提取物对几种植物的生长影响进行了测定。结果表明,黄顶菊茎叶水提物对玉米、小麦、棉花、大豆、花生、马唐和反枝苋都表现出了不同程度的抑制作用,其中以对棉花的化感效应最强,在其浓度为0.2 g/mL时,对根长和茎长的化感指数分别为-0.85和-0.88,而该水提物对水稻的生长则表现为促进作用。黄顶菊茎叶的石油醚、氯仿、乙酸乙酯、丙酮和乙醇的提取物,对几种植物的化感效应要高于水提物,其中以丙酮提取物的化感效应最强。利用重结晶法从黄顶菊茎叶的丙酮提取物中得到了一个具有除草活性的物质,该物质的熔点为192.5℃~193.5℃,最大吸收波长为220 nm,初步判断该化合物是一种碱性有机物,该物质在浓度为1000,500,100,50 mg/L时,对马唐,反枝苋生长均有抑制作用。

Preliminary study on allelopathic effect of the invasive species Flaveria bidentis (L.) Kuntze

To identify the allelopathic effects of Flaveria bidentis(L.) Kuntze on other plants,the effects of different extracts from F.bidentis(L.) Kuntze on the growth of several plants were studied by bioassay.Results show that water extracts inhibited the growth of corn,wheat,cotton,soybean,peanut,Digitaria sanguinalis L.and Amaranthus retroflexus L.,especially cotton,with the reactive index to root and stem being-0.85 and-0.88 at the concentration 0.2 g/mL.But the water extracts accelerated the growth of rice.In addition,the reactive index was higher for the extracts of petroleum ether chloroform,ethyl acetate,acetone and alcohole than that of the water extracts,and that of the acetone extracts was the highest.The refined acetone extract has melting point from 192.5℃ to 193.5℃,and maximum absorbing wave length of 220 nm,herbicide activity,and played inhibitory roles on the growth of D.sanguinalis L and A.retroflexus L.at the concentration 1 000,500,100,and 50 mg/L.