紫花苜蓿和向日葵对黄顶菊的替代控制机理分析

黄顶菊是2001年新发现的外来入侵杂草,替代控制是控制其蔓延的主要途径之一.为探寻对黄顶菊有替代控制作用的植物,该研究通过室内和大田试验,分析了紫花苜蓿Medicago sativa和向日葵Helianthus annuus对黄顶菊Flaveria bidentis的竞争效应.结果表明:黄顶菊水浸提液对2种植物的种子萌发无抑制作用;而紫花苜蓿水浸提液对黄顶菊的种子萌发具有抑制作用,体积质量分数为0.1g/mL时,黄顶菊种子发芽率降低到32%;紫花苜蓿产生的化感物质主要抑制黄顶菊种子胚根的生长.向日葵水浸提液对黄顶菊种子萌发影响不明显.向日葵与低密度紫花苜蓿和黄顶菊混种,能够使黄顶菊株高、分枝数和生物量受到明显的抑制,并能使每平方米黄顶菊植株数量显著地降低.

Study on Displacement Control of Flaveria bidentis Kuntze with Alfalfa and Sunflower

Flaveria bidentis Kuntze is a new invasive weed discovered in 2001 in China,and displacement control is a main approach to checking its spread.In a study reported in this paper,the effect of competition between F.bidentis and alfalfa or sunflower was investigated in the lab and in the field.The results showed that the germination of alfalfa and sunflower seeds treated with the aqueous extract of F.bidentis was not inhibited,but the germination of F.bidentis seeds was suppressed by the extract of alfalfa.F.bidentis seeds treated with alfalfa extract at 0.1g/mL gave a germination rate of 32% only.Further investigation revealed that the allelopathic substance produced by alfalfa retarded the growth of the radicle of F.bidentis while the extract of sunflower had no such effect.Branch number,plant height,biomass and plant density of F.bidentis were markedly restrained by low density alfalfa and sunflower planted in the field.