Abstract:Potamogeton malaianus is a dominant submersed aquatic macrophyte that has colonized the lakes across the middle and lower reaches of the Changjiang River.Vegetative reproduction is prevalent in P.malaianus and is highly visible,because of the extraordinary capacity of this plant to spread by fragmentation.Because of this,sexual reproduction has been considered of limited importance and little is known about the seed germination of this species.Laboratory studies were conducted on seeds of P.malaianus to determine the substrate,temperature and light requirements necessary for maximum seed germination.Seed germination was also examined in different duration of cold storage.The results showed that few 3-month-old whole seeds germinated in all treatments,but rose after the seed coats were cracked.Optimum germination occurred in a temperature of 25℃ and water substrate.Photoperiod significantly effected the seed germination.Seed retain viability for a short period in the cold storage condition,the highest germination occurred in 6-month storage seeds.The ecological implications of such behavior are discussed.