入侵植物黄顶菊与本地植物的竞争

Competitiveness of invasive plant Flaveria bidentis with native weed plants

温室和田间试验条件下,对黄顶菊与4种本地植物(马唐、牛筋、反枝苋和苘麻)在3种混生比例下的竞争效应进行了研究。温室试验结果表明:黄顶菊与马唐或牛筋混生所占比例低时,其株高受到明显抑制,在混生比例相同或黄顶菊所占比例高时,其株高未受到抑制;与反枝苋或苘麻混生时,黄顶菊的株高受到明显抑制,而反枝苋和苘麻的株高未受到抑制;黄顶菊与这4种本地植物混生,相对产量总和接近1;与马唐混生时,黄顶菊在高比例下的相对产量与1接近,而在其他比例下的相对产量均<1;与牛筋、反枝苋和苘麻混生时,黄顶菊的相对产量均显著<1;与4种本地植物混生,黄顶菊的竞争攻击力系数均<0。田间试验和温室试验结果一致。研究表明,黄顶菊与马唐、牛筋、反枝苋和苘麻利用相同的营养资源,其竞争力比供试的本地植物弱。

Greenhouse and field experiments were conducted to study the competitiveness of invasive plant Flaveria bidentis with native weed plants Digitaria sanguinalis,Eleusine indica,Amaranthus retroflexus,and Abutilon theophrasti.The greenhouse experiment showed that the height growth of F.bidentis was obviously inhibited when the invasive plant was grown at low proportion with D.sanguinalis or E.indica,but not inhibited at equal or high proportion.When F.bidentis was grown with A.retroflexus or A.theophrast,the height growth of the invasive plant was inhibited significantly,but that of the two native weed species was not inhibited.When F.bidentis was grown with the four native weed species,the sum of their relative yields was nearly equal to 1.The relative yield of F.bidentis was nearly to 1 when grown at high proportion with D.sanguinalis,but less than 1 when at equal or low proportion.The relative yield of the invasive weed was significantly less than 1 when it was grown with E.indica or A.retroflexus or A.theophrasti.The competitive aggressivity coefficient of F.bidentis was all less than 0 when the invasive weed was grown with any of the four native species.Field experiment showed the same results as the greenhouse experiment did.The findings from this study suggested that F.bidentis and the native weed species utilized the same nutrient resources,and the invasive species was less competitive than the native species when they grew together.