三叶鬼针草对岩溶木本植物任豆和香椿的化感作用

为了探讨三叶鬼针草(Bidens pilosa L.)对岩溶木本植物的化感作用,利用生物检测法研究了三叶鬼针草叶和根水浸液对任豆(Zenia insignis Chun)和香椿(Toona sinensis Roem.)的种子萌发和幼苗生长的影响,及叶水浸液对任豆和香椿幼苗光合作用的影响.结果表明,三叶鬼针草叶片水浸液对香椿的种子萌发和幼苗生长有明显抑制作用,根部水浸液仅在高浓度(0.1g/ml)对香椿的种子萌发和幼苗生长有轻微抑制作用;三叶鬼针草叶片和根部的水浸液在0.1g/ml浓度时对任豆种子萌芽和幼苗生长有轻微抑制作用,其它浓度时均为促进作用.香椿的种子萌芽和幼苗生长对三叶鬼针草浸提液比任豆更敏感;叶片的化感抑制作用强于根部.三叶鬼针草使任豆幼苗的净光合速率下降,使香椿幼苗的净光合速率增强.

Allelopathic Effects of Bidens pilosa L.on Zenia insignis and Toona sinensis in Karst Region

In order to explore the allelopathy of an invasive plant of Bidens pilosa to Kasrt woody plants, we determined in this study the effect of aqueous extracts of leaf and root of B. pilosa on seed germination and seedling growth of Zenia insignis and Toona sinensis, and the effect of aqueous leaf extracts of B. pilosa on photosynthesis of seedlings of Z. insignis and T. sinensis. The result showed that the aqueous leaf extracts of B. pilosa could evidently inhibit seed germination and seedling growth in T. sinensis, and the T. sinensis''s was slightly inhibition from the aqueous root extracts of B. pilosa at 0.1g/ml concentration. Only at 0.1g/ml concentration the aqueous leaf and root extracts of B. pilosa could slightly inhibit the seed germination and seedling growth of Z.insignis, whereas its effect was not significant occasionally at the others concentration or even promoted action to them. The allelopathy of aqueous extract of B. pilosa was stronger inhibition to T. sinensis than Z. insignis on seed germination and seedling growth. The inhibitory effects of B. pilosa leaf extract at same concentration stronger than the root''s. It was the barriers of photosynthesis of Z. insignis''s seedling. Yet it was enhanced of photosynthesis of T. sinensis''s seedling.