Germination of Polgonum Hydropiper L. seeds

Palygonum Hydopiper L. is used for garnishing served with raw fish. Its seeds usually have a deep dormancy, and are difficult to germinate in field culture. Useful practice for their germination was studied. Alternating temperature and light stimulate their germination. Prechilling also breaks their dormancy. With seed agin, seeds become somewhat easily germinable, but the extent varies with seed lots. By dehulling, only the light sensitivity disappeared, and alternating temperaature was ever required for their germination. Therefore, it is presumed that light sensitivity of Polygonum Hydropiper seeds exists in their fruit coat and reaction to alternatin temperature is done in their embryo (and endosperm). With regard to the wave lenght of light, red light stimulated their germination and infra-red light much suppreses it. Presoaking under light stimulated their germination to some extent, but its effect disappeared during dry storage after treatment, which indicated the occurence of secondary doemancy. For the storage of Polygonum Hydropiper seeds, low temperature and open storage was better than room temperature and sealed dry storage.