Effect of Allelopathy of Conyza canadensis L. Water Extract on Seedling Growth of Sweet Cabbage and Brassica chinensis L.

The allelopathic potentials of aqueous extracts of Conyza canadensis L.were investigated to determine the role of allelopathic potentials of vegetable.In this study,with C.canadensis L.as Allelochemicals donor plants,sweet cabbage and Brassica chinensis L.seeds as the receptors,respectively,the filter paper method of petri dishes was used to examine how water extract of plant aerial parts affect the root length,seedling height,and fresh weight of sweet cabbage and B.chinensis L..The result showed that water extract of aerial parts of C.canadensis L.had obvious allelopathic effect on seedling growth of sweet cabbage and B.chinensis L.,and different concentrations of aqueous extracts made different effects.The inhibition of aqueous extracts to root growth was observed,which become stronger with the concentration of aqueous extracts going up.The concentrations of 0.25,0.50,1.00 g/mL,compared to the control,root length of sweet cabbage decreased by 69.3%,95.1% and 100.0%,respectively;and these of B.chinensis L.decreased by 69.0%,93.7% and 100.0%,respectively.For seedling height the effect of aqueous extracts of C.canadensis L.beneficial under lower concentration and inhibitory under higher concentration.