Culture of Glochidia of Hyriopsis cumingii in Artificial Media and Morphological Variation of Transformed Juvenile

Glochidia of the freshwater pearl mussel Hyriopsis cumingii was cultured at(24±1)℃ in common incubator and completed metamorphosis development in artificial media.The results showed that the survival rate of glochidia decreased to 50.7% after rejection in fresh water.The duration of glochidia development until the juvenile stage was 15 days in artificial media.The proportion undergoing metamorphosis was(7.5±3.9)%,(13.3±12.0)%,(42.1±10.0)% respectively in three different media(Group A,B,C) which had glucose from high ratio to low.There was significant negative relationship between the content of glucose in artificial media and metamorphosis rate of glochidia(r=-0.886).The proportion undergoing metamorphosis was(66.1±3.8)% in Group D(L-15) and significantly higher than in Group C(MEM 199)(p=0.007).The microstructure of juvenile was observed by microscope and scanning electron microscopy.The number of pit and depth on the surface of shell of newly transformed juvenile decreased,the margin of mantle became thicker than glochidia and foot developed fast.Numerous protuberances with different patterns were found on the surface of margin of mantle and foot respectively.There were great variations that took place in exterior morphology and interior organs,and all results indicated that golchidia underwent nonparasitic metamorphosis development successfully in artificial media.