Histology and Histochemistry on the Pearl Sac Formation of Pearl Oyster Pinctada martensii

A nucleus-inserting operation on pearl oyster Pinctada martensii was performed following the common procedure in the pearl culture.The pearl sac of P.martensii was sampled at day 1,3,7,15,20,30 and 60r,espectively,after the operation,and then its histological and histochemistrical changes in the pearl sac formation were observed by the methods of H.E staining and histochemistrical examination.It was found that the epithelial cells of pearl sac originated from the outer epithelial cells of mantle piece inserted in the oysters.At day 1-3,after nucleus-inserting operation the aletocytes in the oysters encircled the mantle piece when water temperature was 27 ℃.At day 7-15 after operation,aletocytes aggregated on the paraffin nucleus.At day 15-20 the outer epithelial cells in mantle tissue proliferated and formed pearl sac.The epithelial cell in the pearl sac and its nuclear were both flat.At day 20-30 after operation,the epithelial cell in the pearl sac transformed from plat to columnar.At day 60 after operation it formed flat epithelial cells of pearl-sac which had steady secretory function.Its nucleus was round or oval.