Abstract: The allelopathic effects of aqueous extracts from the moss species Hygrohypnum ochraceum on seed germination and seedling growth of the weed plant Ipomoea purpurea were examined in the laboratory. With H. ochraceum water extract for treatment liquid, I. purpurea seeds for biological materials, seed germination and seedling growth of I. purpurea had been investigated, and germination rate (GR), germination energy (GE), seedling length (SL), biomass (fresh weight and dry weight) and vigor index (VI), allelopathic effect response index (RI), synthetic effect (SE) were tested. The results showed that the seed germination and seedling growth of I. purpurea was obviously suppressed by water extracts of H. ochraceum. GR, GE, SL and biomass of I. purpurea were significantly reduced with the concentration increasing of H. ochraceum water extracts, and the indices of treatment groups were remarkably lower than that of control group (P<0.05). VI of I. purpurea seedling was significantly inhibited by H. ochraceum water extracts, and there was obvious decreasing trend with concentration increasing of water extracts. By analysising of the sensitivily of I. purpurea to the allelopathic effects of H. ochraceum, the highest SE value was -0.837（±0.038）. Thus, the moss species H. ochraceum could be used for weed plant (including Ipomoea purpurea) controlling.

Key words: allelopathy, seed germination, seedling growth, Ipomoea purpurea, Hygrohypnum ochraceum