The influence of environmental factors on the germination of Acorus calamus seeds

Acorus calamus is an emergent macrophyte with great potential for use in wetland restoration in North America. We studied the germination response of A. calamus seed to different environmental conditions by subjecting them to experimental manipulations of light, temperature, moisture, pH and storage. Seed germination occurred only in full light and it varied significantly (P < 0.0001) across temperatures. Maximum germination occurred in spring (15/25°C) and summer (20/35°C) temperatures when seeds were fully submerged. Germination velocity (Timson's Index) was significantly (P < 0.0001) greater in moist, acidic, late spring temperatures and had significant moisture × temperature (P < 0.0001), temperature × pH (P < 0.0001) and moisture × pH (P < 0.0001) interactions. Seeds germinated more rapidly in moist environments. Acorus calamus can create persistent seed banks germinating when soil turnover exposes them to light. There was no significant difference in seed germination after storage for 24 months. Results indicate that A. calamus seeds can indeed be used for a wide range of wetland restoration projects. Seeding of A. calamus is best conducted at the very onset of projects when there is more light available at the soil surface.