外来入侵植物美洲商陆提取物的化感活性

研究了外来入侵植物美洲商陆(Phytolacca americana)提取物对黄花草木樨(Melilotus officinalis)、大白菜(Brassica pekinensis)、北美车前(Plantago virginica)和马唐(Digitaria sanguinalis)4种植物种子萌发和幼苗生长的影响。结果表明,与对照相比,1 000～4 000、4 000和2 000～4 000μg·mL-1美洲商陆醇提取物分别对大白菜、北美车前和马唐种子萌发率具有显著抑制作用,1 000～4 000μg.mL-1水提取物对马唐种子萌发率也具有显著抑制作用,最大抑制率分别为32.22%、46.56%、32.69%和28.57%。250～500μg·mL-1醇提取物和250～4 000μg·mL-1水提取物对黄花草木樨幼苗根长,250～1 000μg·mL-1醇提取物和250～4 000μg·mL-1水提取物对黄花草木樨幼苗苗高,以及500μg·mL-1水提取物对黄花草木樨幼苗干质量均具有显著促进作用,最大促进率分别为21.32%、37.89%、12.94%、32.07%和18.81%。1 000～4 000μg·mL-1醇提取物和4 000μg·mL-1水提取物对大白菜幼苗根长,2 000～4 000μg·mL-1醇提取物和水提取物对大白菜幼苗苗高,4 000μg·mL-1水提取物对大白菜幼苗干质量具有显著抑制作用,最大抑制率分别为37.00%、20.95%、25.63%、22.30%和13.67%。250～1 000μg·mL-1水提取物对北美车前幼苗根长,250～4 000μg·mL-1水提取物对北美车前苗高具有显著促进作用,而1 000～4 000μg·mL-1醇提取物对北美车前幼苗根长,4 000μg·mL-1醇提取物对北美车前苗高和干质量具有显著抑制作用,最大抑制率分别为58.06%、29.72%和18.36%。500～4 000、1 000～4 000和2 000～4 000μg·mL-1醇提取物分别对马唐幼苗根长、苗高及干质量,4 000μg·mL-1水提取物对马唐幼苗根长具有显著抑制作用,最大抑制率分别为70.31%、44.65%、42.43%和35.50%。由此可见,美洲商陆对大白菜、北美车前和马唐种子萌发和幼苗生长具有较强的化感抑制作用,对入侵植物黄花草木樨具有化感促进作用,这些都直接或间接地增强了美洲商陆的入侵性。

Allelopathic Activity of the Extract From Phytolacca americana—An Invasive Alien Plant

Effects of extracts from Phytolacca americana,an invasive alien plant,on seed germination and seedling growth of Melilotus officinalis,Brassica pekinensis,Plantago virginica,and Digitaria sanguinalis were investigated in laboratory.Results show that ethanolic extract from the plant 1 000-4 000,4 000,and 2 000-4 000 μg·mL-1 in concentration significantly inhibited seed germination of B.pekinensis,P.virginica,and D.sanguinalis,respectively,and water extract 1 000-4 000 μg·mL-1 in concentration also did significantly that of D.sanguinalis with the highest inhibition rates being 32.22%,46.56%,32.69%,and 28.57%,respectively.The ethanolic extract 250-500 μg·mL-1 in concentration and the water extract 250-4 000 μg·mL-1 in concentration increased root length of M.officinalis seedlings and both the ethanolic extract 250-1 000 μg·mL-1 in concentration and water extract 250-4 000 μg·mL-1 in concentration promoted growth of the seedling in height,and the water extract 500 μg·mL-1 in concentration increased significantly dry weight of the seedlings,with the highest promotion rates being 21.32%,37.89%,12.94%,32.07%,and 18.81%,respectively.The ethanolic extract 1 000-4 000 μg·mL-1 in concentration and the water extract 4 000 μg·mL-1 in concentration both inhibited growth of B.pekinensis roots in length;both the ethanolic and water extracts 2 000-4 000 μg·mL-1 in concentration did the plants in height,and the water extract 4 000 μg·mL-1 in concentration did seedling dry weight of the plant,too,with the highest inhibition rates being 37.00%,20.95%,25.63%,22.30%,and 13.67%,respectively.The water extract 250-1 000 μg·mL-1 in concentration significantly promoted seedling root length of P.virginica,and 250-4 000 μg·mL-1 in concentration it did seedling height,too,but the ethanolic extract 1 000-4 000 μg·mL-1 in concentration significantly inhibited growth of its root in length,and 4 000 μg·mL-1 in concentration it did seedling height and dry weight of the seedlings,with the highest inhibition rates being 58.06%,29.72%,and 18.36%,respectively.The ethanolic extract 500-4 000,1 000-4 000 and 2 000-4 000 μg·mL-1 in concentration inhibited the seedlings of D.sanguinalis in root length,height and dry weight,respectively,and the water extract 4 000 μg·mL-1 in concentration did the seedlings in root length,with the highest inhibition rates being 70.31%,44.65%,42.43%,and 35.50%,respectively.Obviously,P.americana has a strong effect of allelopathic inhibition on seed germination and seedling growth of B.pekinensis,P.virginica and D.sanguinalis,but an effect of allelopathic promotion on invasive plant M.officinalis,which directly or indirectly strengthens its invasiveness.