Study Of Artificial Seeds Of Submerged Macrophyte Potamogeton Crispus L.

Restoration of submerged vegetation is the key step of restoration of aquatic ecosystem in eutrophic lakes.If the seed bank of the water body was strongly destroyed, it is necessary to get plenty of seedlings for restoration of submerged macrophytes because of the difficulty of getting enough seeds.Seedlings of submerged macrophytes are usually harvested from other water bodies,this way may damage the source vegetation and also may encounter insufficient supply of macrophytes.The technique of artificial seeds is a promising method to provide a large number of seedlings in a short time without limitation of season,long distant transportation and harm to the natural macrophyte community.Methods for the preparation of artificial seeds of Potamogeton crispus L.was established to meet the demand of seedlings of submerged macrophytes in aquatic ecological restoration.The node segments of Potamogeton crispus were encapsulated with sodium and calcium to form artificial seeds.In this study the effects of hormone types and concentration,temperature,light intensity,concentration of nitrogen and phosphorus and substrate type on the germination and conversion of artificial seeds of Potamogeton crispus were investigated.Experiments of germination and conversion of the artificial seeds in lake were also conducted.The germination and conversion frequencies of artificial seeds,which embedded in IBA 1.0 mg/L and 6-BA 0.5 mg/L,were 80%and 20%respectively in autoclaved tap water.No significant effect of temperature was found on the germination and conversion in range of 15-25℃.Similarly nitrogen and phosphorus cause no significant change on the germination and conversion.Light intensity affected the germination and conversion significantly.Higher light intensity favored the germination of artificial seeds.The germination and conversion rates of the artificial seeds reached 68%and 36% respectively at light intensity of 40μmol/m~2·s.Substrate types also affected the germination significantly.Sandy soil was better than sandstone and silt to support the germination.The germination rate was 60%on the sandy soil.The germination and conversion frequencies of artificial seeds of P.crispus were 28%and 15%respectively, under water depth of 0.6 m in the Eastlake in Wuhan city.In addition,the development of artificial seeds was investigated in an enclosure in lake Hong,and the germination and conversion rates of the artificial seeds reached 31%and 29%respectively.