Mantle histology, histochemistry and ultrastructure of the pearl oyster Pinctada margaritifera (L.)

Abstract

Thc cdgc and isthmus of the mantlc of Pilletada margaritirera (Mol/usc, Bivalvia) were studied using light and clectron microscopy l'rom a morphological and histochemical point of vicw. Six areas with several subarcas wcre diffcrentiated in the mantle edge. One of thesc areas is similar to epithelium isthmus, Trials to elucidate the nature of the pigment responsible for the black colour of the shcll and pearl indicate a melanin-likc material. Possible funetions of the distinctive cpithelial areas in Pinetada margaritilera mantle are discussed aceording to avaiJable data on the secretion of organie matrix of the shell, protein sc1erotization and deposition of crystals in sorne pearl-forming molluses. Three different the epithelial areas in the outer mantle edge of pjllC1ada margaritiféra are probably involvcd in the scquential processes of deposition of calcite prisms, aragonite fibres and aragonite rhombs.