Abstract:The effect of low temperature on the allelopathy of aqueous extraction from Galinsoga parviflora Cav. was studied by using micronucleus assay in Vicia faba root tip cells. The results showed that the mitotic index of V. faba root tip cells treated with the aqueous extraction decreased and micronucleus and aberration rates increased under normal temperature. However, after G. parviflora was treated at low temperature, the mitotic index of V. faba root tip cells soaking in low concentration of aqueous extraction enhanced and it decreased in high concentration of aqueous extraction, but micronucleus and aberration rates increased significantly. These suggested that low temperature stress could chang the allelopathic effect of G. parviflora.