Allelopathy of Trifolium repens L. on Abutilon theophrasti Medic.and Echinochloa crusgalli L.

In order to ascertain the allelopathy activity of Trifolium repens on weeds, the allelopathic effect of aqueous extract from the aerial part and root of T. repens under different concentrations on the germination rate, physiological and biochemical mechanism of germinating seeds of Abutilon theophrasti Medic. and Echinochloa crusgalli L. were studied. Both of the aqueous extract from aerial part and root of T. repens inhibited the germination rate of weed seeds, root activity and respiratory rate, and the activities of superoxide dismutase peroxidase and catalase of germinating seeds; enhanced the activity of peroxi dase and the content of malondialdehyde. The germination rate reduced by 56% when barnyardgrass seed was treated with 0. 1 g/mL aqueous extract from the aerial part, the activities of superoxide dismutase peroxidase and catalase of germinating seeds were reduced by 24. 78% , 48. 69% , the root activity and respiratory rate were reduced by 40. 63% , 36. 28% , the activity of peroxidase and the content of malondialdehyde were enhanced by 32. 30% , 87. 40% at the same time. The allelopathic effect became stronger along with the increase of concentration of aqueous extract, the allelopathy of aqueous extract from the aerial part of T. repens on two weeds is higher than that of the aqueous extract from the root, the allelopathy on E. crusgalli is higher than that on A. theophrasti.